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    AuthorTitleYearJournal/ProceedingsReftypeDOI/URL
    Frank, F., Arrell, C., Witting, T., Okell, W.A., McKenna, J., Robinson, J.S., Haworth, C.A., Austin, D., Teng, H., Walmsley, I.A., Marangos, J.P. & Tisch, J.W.G. Invited Review Article: Technology for Attosecond Science 2012 Review of Scientific Instruments
    Vol. 83(7), pp. 071101-071101-23 
    article DOI URL 
    Abstract: We describe a complete technological system at Imperial College London for Attosecond Science studies. The system comprises a few-cycle, carrier envelope phase stabilized laser source which delivers sub 4 fs pulses to a vibration-isolated attosecond vacuum beamline. The beamline is used for the generation of isolated attosecond pulses in the extreme ultraviolet (XUV) at kilohertz repetition rates through laser-driven high harmonic generation in gas targets. The beamline incorporates: interferometers for producing pulse sequences for pump-probe studies; the facility to spectrally and spatially filter the harmonic radiation; an in-line spatially resolving XUV spectrometer; and a photoelectron spectroscopy chamber in which attosecond streaking is used to characterize the attosecond pulses. We discuss the technology and techniques behind the development of our complete system and summarize its performance. This versatile apparatus has enabled a number of new experimental investigations which we briefly describe.
    BibTeX:
    @article{frank_invited_2012,
      author = {Frank, F. and Arrell, C. and Witting, T. and Okell, W. A. and McKenna, J. and Robinson, J. S. and Haworth, C. A. and Austin, D. and Teng, H. and Walmsley, I. A. and Marangos, J. P. and Tisch, J. W. G.},
      title = {Invited Review Article: Technology for Attosecond Science},
      journal = {Review of Scientific Instruments},
      year = {2012},
      volume = {83},
      number = {7},
      pages = {071101--071101-23},
      url = {http://rsi.aip.org/resource/1/rsinak/v83/i7/p071101_s1},
      doi = {http://dx.doi.org/10.1063/1.4731658}
    }
    
    Ganeev, R.A., Witting, T., Hutchison, C., Frank, F., Redkin, P.V., Okell, W.A., Lei, D.Y., Roschuk, T., Maier, S.A., Marangos, J.P. & Tisch, J.W.G. Enhanced high-order-harmonic generation in a carbon ablation plume 2012 Physical Review A
    Vol. 85(1), pp. 015807 
    article DOI URL 
    Abstract: We report on the observation of enhanced high harmonics from a carbon plasma using sub-5-fs laser pulses. The efficiency of harmonic generation in the range of 14–25 eV was up to five times higher in the case of a plasma medium (graphite ablation) compared with gas (argon) under similar experimental conditions. The harmonic enhancement can be attributed to the presence of carbon nanoparticles in the ablation plumes.
    BibTeX:
    @article{ganeev_enhanced_2012,
      author = {Ganeev, R. A. and Witting, T. and Hutchison, C. and Frank, F. and Redkin, P. V. and Okell, W. A. and Lei, D. Y. and Roschuk, T. and Maier, S. A. and Marangos, J. P. and Tisch, J. W. G.},
      title = {Enhanced high-order-harmonic generation in a carbon ablation plume},
      journal = {Physical Review A},
      year = {2012},
      volume = {85},
      number = {1},
      pages = {015807},
      url = {http://link.aps.org/doi/10.1103/PhysRevA.85.015807},
      doi = {http://dx.doi.org/10.1103/PhysRevA.85.015807}
    }
    
    Ganeev, R.A., Hutchison, C., Za�r, A., Witting, T., Frank, F., Okell, W.A., Tisch, J.W.G. & Marangos, J.P. Enhancement of high harmonics from plasmas using two-color pump and chirp variation of 1 kHz Ti:sapphire laser pulses 2012 Optics Express
    Vol. 20(1), pp. 90-100 
    article DOI URL 
    Abstract: We have investigated resonance effects in high-order harmonic generation (HHG) within laser-produced plasmas. We demonstrate a significantly improved harmonic yield by using two-color pump-induced enhancement and a 1 kHz pulse repetition rate. Together with an increased HHG output, the even harmonics in the cutoff region were enhanced with respect to odd harmonics. We report the observation of a resonance-induced growth in intensity of 20th harmonic in silver plasma (2×), 26th harmonic in vanadium plasma (4×), and 28th harmonic in chromium plasma (5×).
    BibTeX:
    @article{ganeev_enhancement_2012,
      author = {Ganeev, R. A. and Hutchison, C. and Za�r, A. and Witting, T. and Frank, F. and Okell, W. A. and Tisch, J. W. G. and Marangos, J. P.},
      title = {Enhancement of high harmonics from plasmas using two-color pump and chirp variation of 1 kHz Ti:sapphire laser pulses},
      journal = {Optics Express},
      year = {2012},
      volume = {20},
      number = {1},
      pages = {90--100},
      url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-20-1-90},
      doi = {http://dx.doi.org/10.1364/OE.20.000090}
    }
    
    Ganeev, R.A., Hutchison, C., Witting, T., Frank, F., Okell, W.A., Zaïr, A., Weber, S., Redkin, P.V., Lei, D.Y., Roschuk, T., Maier, S.A., López-Quintás, I., Martín, M., Castillejo, M., Tisch, J.W.G. & Marangos, J.P. High-order harmonic generation in graphite plasma plumes using ultrashort laser pulses: a systematic analysis of harmonic radiation and plasma conditions 2012 Journal of Physics B: Atomic, Molecular and Optical Physics
    Vol. 45(16), pp. 165402 
    article DOI URL 
    BibTeX:
    @article{ganeev_high-order_2012,
      author = {Ganeev, R A and Hutchison, C and Witting, T and Frank, F and Okell, W A and Zaïr, A and Weber, S and Redkin, P V and Lei, D Y and Roschuk, T and Maier, S A and López-Quintás, I and Martín, M and Castillejo, M and Tisch, J W G and Marangos, J P},
      title = {High-order harmonic generation in graphite plasma plumes using ultrashort laser pulses: a systematic analysis of harmonic radiation and plasma conditions},
      journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
      year = {2012},
      volume = {45},
      number = {16},
      pages = {165402},
      url = {http://iopscience.iop.org/0953-4075/45/16/165402},
      doi = {http://dx.doi.org/10.1088/0953-4075/45/16/165402}
    }
    
    Hutchison, C., Ganeev, R.A., Witting, T., Frank, F., Okell, W.A., Tisch, J.W.G. & Marangos, J.P. Stable generation of high-order harmonics of femtosecond laser radiation from laser produced plasma plumes at 1 kHz pulse repetition rate 2012 Optics Letters
    Vol. 37(11), pp. 2064-2066 
    article DOI URL 
    Abstract: We present a method for the creation of stable weakly ionized plasmas from laser ablation of solid targets using a 1 kHz pulse repetition rate laser, which can be used for stable high-order harmonic generation from plasma plumes. The plasma plumes were generated from cylindrical rotating targets. Without target rotation the intensity of harmonics in the 40–80 nm range drops by more than one order of magnitude during less than 103 shots, while, with rotation of the target at typically 30 revolutions per minute, stable emission of high-order harmonics from aluminum plasma plumes with variation of less than 10% was maintained for textgreater106 laser shots.
    BibTeX:
    @article{hutchison_stable_2012,
      author = {Hutchison, Christopher and Ganeev, Rashid A. and Witting, Tobias and Frank, Felix and Okell, William A. and Tisch, John W. G. and Marangos, Jon P.},
      title = {Stable generation of high-order harmonics of femtosecond laser radiation from laser produced plasma plumes at 1 kHz pulse repetition rate},
      journal = {Optics Letters},
      year = {2012},
      volume = {37},
      number = {11},
      pages = {2064--2066},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-37-11-2064},
      doi = {http://dx.doi.org/10.1364/OL.37.002064}
    }
    
    Witting, T., Frank, F., Okell, W.A., Arrell, C.A., Marangos, J.P. & Tisch, J.W.G. Sub-4-fs laser pulse characterization by spatially resolved spectral shearing interferometry and attosecond streaking 2012 Journal of Physics B: Atomic, Molecular and Optical Physics
    Vol. 45(7), pp. 074014 
    article DOI URL 
    BibTeX:
    @article{witting_sub-4-fs_2012,
      author = {Witting, T and Frank, F and Okell, W A and Arrell, C A and Marangos, J P and Tisch, J W G},
      title = {Sub-4-fs laser pulse characterization by spatially resolved spectral shearing interferometry and attosecond streaking},
      journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
      year = {2012},
      volume = {45},
      number = {7},
      pages = {074014},
      url = {http://iopscience.iop.org/0953-4075/45/7/074014},
      doi = {http://dx.doi.org/10.1088/0953-4075/45/7/074014}
    }
    
    Altucci, C., Tisch, J.W.G.. & Velotta, R. Single attosecond light pulses from multi-cycle laser sources 2011 Journal of Modern Optics
    Vol. 58, pp. 1585-1610 
    article DOI URL 
    BibTeX:
    @article{altucci_single_2011,
      author = {Altucci, C. and Tisch, J.W.G. and Velotta, R.},
      title = {Single attosecond light pulses from multi-cycle laser sources},
      journal = {Journal of Modern Optics},
      year = {2011},
      volume = {58},
      pages = {1585--1610},
      url = {http://www.tandfonline.com/doi/abs/10.1080/09500340.2011.611913},
      doi = {http://dx.doi.org/10.1080/09500340.2011.611913}
    }
    
    Austin, D.R., Witting, T., Arrell, C.A., Frank, F., Wyatt, A.S., Marangos, J.P., Tisch, J. W.G.. & Walmsley, I.A. Lateral shearing interferometry of high-harmonic wavefronts 2011 Optics Letters
    Vol. 36(10), pp. 1746-1748 
    article DOI URL 
    Abstract: We present a technique for frequency-resolved wavefront characterization of high harmonics based on lateral shearing interferometry. Tilted replicas of the driving laser pulse are produced by a Mach–Zehnder interferometer, producing separate focii in the target. The interference of the resulting harmonics on a flat-field extreme ultraviolet spectrometer yields the spatial phase derivative. A comprehensive set of spatial profiles, resolved by harmonic order, validate the technique and reveal the interplay of single-atom and macroscopic effects.
    BibTeX:
    @article{austin_lateral_2011,
      author = {Austin, Dane R. and Witting, Tobias and Arrell, Christopher A. and Frank, Felix and Wyatt, Adam S. and Marangos, Jon P. and Tisch, John W.G. and Walmsley, Ian A.},
      title = {Lateral shearing interferometry of high-harmonic wavefronts},
      journal = {Optics Letters},
      year = {2011},
      volume = {36},
      number = {10},
      pages = {1746--1748},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-36-10-1746},
      doi = {http://dx.doi.org/10.1364/OL.36.001746}
    }
    
    Baker, S., Walmsley, I.A., Tisch, J.W.G. & Marangos, J.P. Femtosecond to attosecond light pulses from a molecular modulator 2011 Nat Photon
    Vol. 5(11), pp. 664-671 
    article DOI URL 
    BibTeX:
    @article{baker_femtosecond_2011,
      author = {Baker, S. and Walmsley, I. A. and Tisch, J. W. G. and Marangos, J. P.},
      title = {Femtosecond to attosecond light pulses from a molecular modulator},
      journal = {Nat Photon},
      year = {2011},
      volume = {5},
      number = {11},
      pages = {664--671},
      url = {http://dx.doi.org/10.1038/nphoton.2011.256},
      doi = {http://dx.doi.org/10.1038/nphoton.2011.256}
    }
    
    Skopalová, E., Lei, D.Y., Witting, T., Arrell, C., Frank, F., Sonnefraud, Y., Maier, S.A., Tisch, J.W.G. & Marangos, J.P. Numerical simulation of attosecond nanoplasmonic streaking 2011 New Journal of Physics
    Vol. 13(8), pp. 083003 
    article DOI URL 
    BibTeX:
    @article{skopalova_numerical_2011,
      author = {Skopalová, E and Lei, D Y and Witting, T and Arrell, C and Frank, F and Sonnefraud, Y and Maier, S A and Tisch, J W G and Marangos, J P},
      title = {Numerical simulation of attosecond nanoplasmonic streaking},
      journal = {New Journal of Physics},
      year = {2011},
      volume = {13},
      number = {8},
      pages = {083003},
      url = {http://iopscience.iop.org/1367-2630/13/8/083003},
      doi = {http://dx.doi.org/10.1088/1367-2630/13/8/083003}
    }
    
    Springate, E. & Tisch, J. W.G.. High harmonic generation as a seed source for free electron lasers 2011 Journal of Modern Optics, pp. 1-11  article DOI URL 
    BibTeX:
    @article{springate_high_2011,
      author = {Springate, Emma and Tisch, John W.G.},
      title = {High harmonic generation as a seed source for free electron lasers},
      journal = {Journal of Modern Optics},
      year = {2011},
      pages = {1--11},
      url = {http://www.tandfonline.com/doi/abs/10.1080/09500340.2011.591505},
      doi = {http://dx.doi.org/10.1080/09500340.2011.591505}
    }
    
    Witting, T., Frank, F., Arrell, C.A., Okell, W.A., Marangos, J.P. & Tisch, J.W.G. Characterization of high-intensity sub-4-fs laser pulses using spatially encoded spectral shearing interferometry 2011 Optics Letters
    Vol. 36(9), pp. 1680-1682 
    article URL 
    Abstract: We report on the full amplitude and phase characterization of high-intensity few-cycle laser pulses generated in a single-stage hollow core fiber system with subsequent compression by ultrabroadband chirped mirrors. We use a spatially-encoded arrangement (SEA) spectral phase interferometry for direct electric field reconstruction (SPIDER) with spectral filters for ancilla generation to characterize the sub-4 fs pulses with spatial resolution.
    BibTeX:
    @article{witting_characterization_2011,
      author = {Witting, Tobias and Frank, Felix and Arrell, Christopher A. and Okell, William A. and Marangos, Jonathan P. and Tisch, John W. G.},
      title = {Characterization of high-intensity sub-4-fs laser pulses using spatially encoded spectral shearing interferometry},
      journal = {Optics Letters},
      year = {2011},
      volume = {36},
      number = {9},
      pages = {1680--1682},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-36-9-1680}
    }
    
    Bustard, P.J., Sussman, B.J. & Walmsley, I.A. Amplification of Impulsively Excited Molecular Rotational Coherence 2010 Phys. Rev. Lett.
    Vol. 104(19), pp. 193902– 
    article URL 
    Abstract: We propose a scheme for preparation of high-coherence molecular dynamics which are phase stable with respect to ultrashort pulses. We experimentally demonstrate an example of this scheme using a phase-independent, nanosecond-duration, pump pulse to prepare a rotational coherence in molecular hydrogen. This rotational coherence is made phase stable with respect to a separate source of ultrashort pulses by seeding. The coherence is used to generate spectral broadening of femtosecond probe radiation by molecular phase modulation.
    BibTeX:
    @article{bustard_amplification_2010,
      author = {Bustard, Philip J and Sussman, Benjamin J and Walmsley, Ian A},
      title = {Amplification of Impulsively Excited Molecular Rotational Coherence},
      journal = {Phys. Rev. Lett.},
      year = {2010},
      volume = {104},
      number = {19},
      pages = {193902–},
      url = {http://link.aps.org/doi/10.1103/PhysRevLett.104.193902}
    }
    
    Chipperfield, L.E., Robinson, J.S., Tisch, J.W.G. & Marangos, J.P. Ideal Waveform to Generate the Maximum Possible Electron Recollision Energy for Any Given Oscillation Period 2009 Physical Review Letters
    Vol. 102(6), pp. 063003 
    article DOI  
    Abstract: We present the perfect waveform which, during a strong field interaction, generates the maximum possible electron recollision energy for any given oscillation period, over 3 times as high as that for a pure sinusoidal wave. This ideal waveform has the form of a linear ramp with a dc offset. A genetic algorithm was employed to find an optimized practically achievable waveform composed of a longer wavelength field, to provide the offset, in addition to higher frequency components. This second waveform is found to be capable of generating electron recollision energies as high as those for the perfect waveform while retaining the high recollision amplitudes of a pure sinusoidal wave. Calculations of high harmonic generation demonstrate this enhancement, by increasing the cutoff energy by a factor of 2.5 while maintaining the harmonic yield, providing an enhanced tool for attosecond science.
    BibTeX:
    @article{chipperfield_ideal_2009,
      author = {Chipperfield, L. E and Robinson, J. S and Tisch, J. W. G and Marangos, J. P},
      title = {Ideal Waveform to Generate the Maximum Possible Electron Recollision Energy for Any Given Oscillation Period},
      journal = {Physical Review Letters},
      year = {2009},
      volume = {102},
      number = {6},
      pages = {063003},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.102.063003}
    }
    
    Mercer, I., El-Taha, Y., Kajumba, N., Marangos, J., Tisch, J., Gabrielsen, M., Cogdell, R., Springate, E. & Turcu, E. Instantaneous Mapping of Coherently Coupled Electronic Transitions and Energy Transfers in a Photosynthetic Complex Using Angle-Resolved Coherent Optical Wave-Mixing 2009 Physical Review Letters
    Vol. 102(5), pp. 057402 
    article DOI URL 
    BibTeX:
    @article{mercer_instantaneous_2009,
      author = {Mercer, Ian and El-Taha, Yasin and Kajumba, Nathaniel and Marangos, Jonathan and Tisch, John and Gabrielsen, Mads and Cogdell, Richard and Springate, Emma and Turcu, Edmund},
      title = {Instantaneous Mapping of Coherently Coupled Electronic Transitions and Energy Transfers in a Photosynthetic Complex Using Angle-Resolved Coherent Optical Wave-Mixing},
      journal = {Physical Review Letters},
      year = {2009},
      volume = {102},
      number = {5},
      pages = {057402},
      url = {http://prl.aps.org/abstract/PRL/v102/i5/e057402},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.102.057402}
    }
    
    Anderson, M.E., Witting, T. & Walmsley, I.A. Gold-SPIDER: spectral phase interferometry for direct electric field reconstruction utilizing sum-frequency generation from a gold surface 2008 Journal of the Optical Society of America B
    Vol. 25(6), pp. A13-A16 
    article DOI URL 
    Abstract: We report on a version of spectral phase interferometry for direct electric field reconstruction (SPIDER) that uses no nonlinear crystals, instead relying on the harmonic signal from a gold mirror. Surface harmonic generation holds the promise of being able to upconvert extremely broad bandwidths over a large tuning range, thus providing access to both extremely short pulses and wavelengths outside of traditional methods. In this proof of principle demonstration, SPIDER traces for chirped and transform-limited 55 fs pulses are presented.
    BibTeX:
    @article{anderson_gold-spider:_2008,
      author = {Anderson, Matthew E. and Witting, Tobias and Walmsley, Ian A.},
      title = {Gold-SPIDER: spectral phase interferometry for direct electric field reconstruction utilizing sum-frequency generation from a gold surface},
      journal = {Journal of the Optical Society of America B},
      year = {2008},
      volume = {25},
      number = {6},
      pages = {A13--A16},
      url = {http://josab.osa.org/abstract.cfm?URI=josab-25-6-A13},
      doi = {http://dx.doi.org/10.1364/JOSAB.25.000A13}
    }
    
    Anderson, M.E., Monmayrant, A., Gorza, S., Wasylczyk, P. & Walmsley, I.A. SPIDER: A decade of measuring ultrashort pulses 2008 Laser Physics Letters
    Vol. 5(4), pp. 259-266 
    article DOI URL 
    Abstract: It was ten years ago in Rochester, New York that the first SPIDER was built. This simple acronym belies the subtleties of its inner workings; Spectral Phase Interferometry for Direct Electric-field Reconstruction (the “f? in field conveniently missed the cut) is a device that measures ultrashort pulses, utilizing spectral shearing interferometry and directly recovering the spectral phase. The very first SPIDER apparatus occupied nearly half an optical table, used a scanning monochromator, and had no computerized inversion routine. In the intervening decade, SPIDER has grown up. It has found a strong foothold in ultrafast laboratories throughout the world. Multiple groups have found useful new applications with this vital measurement tool, while others have contributed to the improvement of SPIDER itself, reaching to ever shorter pulses, new wavelength regimes, and making devices more sensitive, robust, smaller and faster. It also adapts to a field of research that changes rapidly. It was first designed to track and quantify the remaining spectral phase in a pulse to perfect its compression. In ten years, with the advent of pulse shapers, the real benefits of field diagnostics are becoming apparent. We have shifted away from the race towards the shortest IR pulse to a wide use of complex shaped pulses in almost every spectral range from far IR to XUV. But the quest of the shortest pulse is not over and new compression techniques utilize really broad spectra that are highly structured. All these applications provide new challenges for characterization techniques. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    BibTeX:
    @article{anderson_spider:_2008,
      author = {Anderson, M. E and Monmayrant, A. and Gorza, S. and Wasylczyk, P. and Walmsley, I. A},
      title = {SPIDER: A decade of measuring ultrashort pulses},
      journal = {Laser Physics Letters},
      year = {2008},
      volume = {5},
      number = {4},
      pages = {259--266},
      url = {http://onlinelibrary.wiley.com/doi/10.1002/lapl.200710129/abstract},
      doi = {http://dx.doi.org/10.1002/lapl.200710129}
    }
    
    Baker, S., Robinson, J.S., Lein, M., Chirila, C.C., Torres, R., Bandulet, H.C., Comtois, D., Kieffer, J.C., Villeneuve, D.M., Tisch, J.W.G. & Marangos, J.P. Dynamic two-center interference in high-order harmonic generation from molecules with attosecond nuclear motion 2008 Physical Review Letters
    Vol. 101(5) 
    article DOI  
    Abstract: We report a new dynamic two-center interference effect in high-harmonic generation from H-2, in which the attosecond nuclear motion of H-2⊕ initiated at ionization causes interference to be observed at lower harmonic orders than would be the case for static nuclei. To enable this measurement we utilize a recently developed technique for probing the attosecond nuclear dynamics of small molecules. The experimental results are reproduced by a theoretical analysis based upon the strong-field approximation which incorporates the temporally dependent two-center interference term.
    BibTeX:
    @article{baker_dynamic_2008,
      author = {Baker, S. and Robinson, J. S and Lein, M. and Chirila, C. C and Torres, R. and Bandulet, H. C and Comtois, D. and Kieffer, J. C and Villeneuve, D. M and Tisch, J. W. G and Marangos, J. P},
      title = {Dynamic two-center interference in high-order harmonic generation from molecules with attosecond nuclear motion},
      journal = {Physical Review Letters},
      year = {2008},
      volume = {101},
      number = {5},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.101.053901}
    }
    
    Boutu, W., Haessler, S., Merdji, H., Breger, P., Waters, G., Stankiewicz, M., Frasinski, L.J., Taieb, R., Caillat, J., Maquet, A., Monchicourt, P., Carre, B. & Salieres, P. Coherent control of attosecond emission from aligned molecules 2008 Nat Phys
    Vol. 4(7), pp. 545-549 
    article DOI URL 
    BibTeX:
    @article{boutu_coherent_2008,
      author = {Boutu, W. and Haessler, S. and Merdji, H. and Breger, P. and Waters, G. and Stankiewicz, M. and Frasinski, L. J. and Taieb, R. and Caillat, J. and Maquet, A. and Monchicourt, P. and Carre, B. and Salieres, P.},
      title = {Coherent control of attosecond emission from aligned molecules},
      journal = {Nat Phys},
      year = {2008},
      volume = {4},
      number = {7},
      pages = {545--549},
      url = {http://dx.doi.org/10.1038/nphys964},
      doi = {http://dx.doi.org/10.1038/nphys964}
    }
    
    El-Taha, Y.C., Springate, E., Carley, R., Rajgara, F., Darios, D., Froud, C., Bonora, S., Symes, D., Tisch, J.W.G., Smith, R.A., Mathur, D. & Marangos, J.P. Electron emission from atomic clusters irradiated with few cycle laser pulses 2008 2008 Conference On Lasers and Electro-optics & Quantum Electronics and Laser Science Conference, Vols 1-9, pp. 2507–2508  inproceedings  
    Abstract: We present the first study of atomic clusters irradiated by ultra-short pulses. A weak prepulse has been shown to allow energetic coupling with the clusters enhancing the electron yield. (C) 2008 Optical Society of America
    BibTeX:
    @inproceedings{el-taha_electron_2008,
      author = {El-Taha, Y. C and Springate, E. and Carley, R. and Rajgara, F. and Darios, D. and Froud, C. and Bonora, S. and Symes, D. and Tisch, J. W. G and Smith, R. A and Mathur, D. and Marangos, J. P},
      title = {Electron emission from atomic clusters irradiated with few cycle laser pulses},
      booktitle = {2008 Conference On Lasers and Electro-optics & Quantum Electronics and Laser Science Conference, Vols 1-9},
      year = {2008},
      pages = {2507–2508}
    }
    
    Kajumba, N., Torres, R., Underwood, J.G., Robinson, J.S., Baker, S., Tisch, J.W.G., Nalda, R. d., Bryan, W.A., Velotta, R., Altucci, C., Procino, I., Turcu, I.C.E. & Marangos, J.P. Measurement of electronic structure from high harmonic generation in non-adiabatically aligned polyatomic molecules 2008 New Journal of Physics
    Vol. 10(2), pp. 025008 
    article DOI URL 
    BibTeX:
    @article{kajumba_measurement_2008,
      author = {Kajumba, N and Torres, R and Underwood, Jonathan G and Robinson, J S and Baker, S and Tisch, J W G and Nalda, R de and Bryan, W A and Velotta, R and Altucci, C and Procino, I and Turcu, I C E and Marangos, J P},
      title = {Measurement of electronic structure from high harmonic generation in non-adiabatically aligned polyatomic molecules},
      journal = {New Journal of Physics},
      year = {2008},
      volume = {10},
      number = {2},
      pages = {025008},
      url = {http://iopscience.iop.org/1367-2630/10/2/025008/},
      doi = {http://dx.doi.org/10.1088/1367-2630/10/2/025008}
    }
    
    Marangos, J.P., Baker, S., Kajumba, N., Robinson, J.S., Tisch, J.W.G. & Torres, R. Dynamic imaging of molecules using high order harmonic generation 2008 Physical Chemistry Chemical Physics
    Vol. 10(1), pp. 35 
    article DOI URL 
    BibTeX:
    @article{marangos_dynamic_2008,
      author = {Marangos, Jon P. and Baker, Sarah and Kajumba, Nathaniel and Robinson, Joseph S. and Tisch, John W. G. and Torres, Ricardo},
      title = {Dynamic imaging of molecules using high order harmonic generation},
      journal = {Physical Chemistry Chemical Physics},
      year = {2008},
      volume = {10},
      number = {1},
      pages = {35},
      url = {http://pubs.rsc.org/en/Content/ArticleLanding/2008/CP/b714126m},
      doi = {http://dx.doi.org/10.1039/b714126m}
    }
    
    Baker, S., Robinson, J.S., Haworth, C.A., Chirila, C.C., Lein, M., Tisch, J.W.G. & Marangos, J.P. Probing fast nuclear wavepackets in light molecules: monitoring structural rearrangement on an attosecond timescale 2007 Journal of Modern Optics
    Vol. 54, pp. 1011–1017 
    article DOI  
    Abstract: A new technique for probing the structural rearrangements of molecules following ionization has recently been demonstrated. Whilst straightforward to implement, this technique offers remarkable time resolution, allowing intramolecular nuclear dynamics to be followed with a precision of 100 as. Here we discuss this technique, termed PACER (probing attosecond dynamics by chirp encoded recollision), examine the processes that a. ect the measurement, and compare the technique to alternative methods for probing vibrational wavepackets in light molecules.
    BibTeX:
    @article{baker_probing_2007,
      author = {Baker, S. and Robinson, J. S and Haworth, C. A and Chirila, C. C and Lein, M. and Tisch, J. W. G and Marangos, J. P},
      title = {Probing fast nuclear wavepackets in light molecules: monitoring structural rearrangement on an attosecond timescale},
      journal = {Journal of Modern Optics},
      year = {2007},
      volume = {54},
      pages = {1011–1017},
      doi = {http://dx.doi.org/10.1080/09500340601022516}
    }
    
    Gorza, S.-P., Radunsky, A.S., Wasylczyk, P. & Walmsley, I.A. Tailoring the phase-matching function for ultrashort pulse characterization by spectral shearing interferometry 2007 Journal of the Optical Society of America B
    Vol. 24(9), pp. 2064-2074 
    article DOI URL 
    Abstract: Sum-frequency generation using spectrally asymmetric type II phase matching enables significant simplifications in spectral shearing interferometry as applied for ultrashort optical pulse measurements. We present analytical and numerical models of broadband sum-frequency wave mixing essential to understand the underlying effects. We discuss spectral and temporal limits of the method together with various aspects of experimental implementation: optimization of the retrieval algorithm, calibration procedures, and extension to different spectral regions of particular interest with other crystals.
    BibTeX:
    @article{gorza_tailoring_2007,
      author = {Gorza, S.-P. and Radunsky, A. S. and Wasylczyk, P. and Walmsley, I. A.},
      title = {Tailoring the phase-matching function for ultrashort pulse characterization by spectral shearing interferometry},
      journal = {Journal of the Optical Society of America B},
      year = {2007},
      volume = {24},
      number = {9},
      pages = {2064--2074},
      url = {http://josab.osa.org/abstract.cfm?URI=josab-24-9-2064},
      doi = {http://dx.doi.org/10.1364/JOSAB.24.002064}
    }
    
    Haworth, C.A., Chipperfield, L.E., Robinson, J.S., Knight, P.L., Marangos, J.P. & Tisch, J.W.G. Half-cycle cutoffs in harmonic spectra and robust carrier-envelope phase retrieval 2007 Nat Phys
    Vol. 3(1), pp. 52-57 
    article DOI URL 
    BibTeX:
    @article{haworth_half-cycle_2007,
      author = {Haworth, C. A. and Chipperfield, L. E. and Robinson, J. S. and Knight, P. L. and Marangos, J. P. and Tisch, J. W. G.},
      title = {Half-cycle cutoffs in harmonic spectra and robust carrier-envelope phase retrieval},
      journal = {Nat Phys},
      year = {2007},
      volume = {3},
      number = {1},
      pages = {52--57},
      url = {http://dx.doi.org/10.1038/nphys463},
      doi = {http://dx.doi.org/10.1038/nphys463}
    }
    
    Kaplan, A., Lenner, M. & Palmer, R.E. Emission of ions and charged clusters due to impulsive Coulomb explosion in ultrafast laser ablation of graphite 2007 Physical Review B
    Vol. 76(7), pp. 073401 
    article DOI URL 
    Abstract: The dynamics of ultrafast laser ablation of graphite have been investigated by femtosecond time resolved autocorrelation measurements at 800 nm. The results indicate that multiply charged atomic ions and ionized carbon clusters are repelled by a transient electric field developed on the surface during the laser pulse, the process known as impulsive Coulomb explosion. From time resolved measurements, we estimate that the decay time constant of the surface field is 125±10 fs.
    BibTeX:
    @article{kaplan_emission_2007,
      author = {Kaplan, A. and Lenner, M. and Palmer, R. E.},
      title = {Emission of ions and charged clusters due to impulsive Coulomb explosion in ultrafast laser ablation of graphite},
      journal = {Physical Review B},
      year = {2007},
      volume = {76},
      number = {7},
      pages = {073401},
      url = {http://link.aps.org/doi/10.1103/PhysRevB.76.073401},
      doi = {http://dx.doi.org/10.1103/PhysRevB.76.073401}
    }
    
    Lenner, M., Kaplan, A. & Palmer, R.E. Nanoscopic Coulomb explosion in ultrafast graphite ablation 2007 Applied Physics Letters
    Vol. 90(15), pp. 153119 
    article DOI URL 
    BibTeX:
    @article{lenner_nanoscopic_2007,
      author = {Lenner, M. and Kaplan, A. and Palmer, R. E.},
      title = {Nanoscopic Coulomb explosion in ultrafast graphite ablation},
      journal = {Applied Physics Letters},
      year = {2007},
      volume = {90},
      number = {15},
      pages = {153119},
      url = {http://link.aip.org/link/APPLAB/v90/i15/p153119/s1&Agg=doi},
      doi = {http://dx.doi.org/10.1063/1.2721392}
    }
    
    Levesque, J., Zeidler, D., Marangos, J.P., Corkum, P.B. & Villeneuve, D.M. High Harmonic Generation and the Role of Atomic Orbital Wave Functions 2007 Physical Review Letters
    Vol. 98(18), pp. 183903 
    article DOI URL 
    Abstract: High harmonic spectra were recorded from different rare-gas atoms under identical experimental conditions. It is shown that although each atom’s spectrum is different, the differences are due almost entirely to the orbital influence in the recombination step. The amplitude of the continuum electron wave packet versus kinetic energy is derived from these data and is shown to be largely independent of the atom, in agreement with models of tunnel ionization. We compare the measurements with calculations in both the length gauge and the velocity gauge and show that the two gauges imply a different de Broglie wavelength.
    BibTeX:
    @article{levesque_high_2007,
      author = {Levesque, J. and Zeidler, D. and Marangos, J. P. and Corkum, P. B. and Villeneuve, D. M.},
      title = {High Harmonic Generation and the Role of Atomic Orbital Wave Functions},
      journal = {Physical Review Letters},
      year = {2007},
      volume = {98},
      number = {18},
      pages = {183903},
      url = {http://link.aps.org/doi/10.1103/PhysRevLett.98.183903},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.98.183903}
    }
    
    Radunsky, A.S., Walmsley, I.A., Gorza, S.-P. & Wasylczyk, P. Compact spectral shearing interferometer for ultrashort pulse characterization 2007 Optics Letters
    Vol. 32(2), pp. 181-183 
    article DOI URL 
    Abstract: A simple, compact, and robust implementation of spectral shearing interferometry using a single nonlinear crystal for both ancilla generation and upconversion is demonstrated. The device is capable of accurate characterization of femtosecond laser pulses over the 740-900 nm range with a KDP crystal.
    BibTeX:
    @article{radunsky_compact_2007,
      author = {Radunsky, Aleksander S. and Walmsley, Ian A. and Gorza, Simon-Pierre and Wasylczyk, Piotr},
      title = {Compact spectral shearing interferometer for ultrashort pulse characterization},
      journal = {Optics Letters},
      year = {2007},
      volume = {32},
      number = {2},
      pages = {181--183},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-32-2-181},
      doi = {http://dx.doi.org/10.1364/OL.32.000181}
    }
    
    Ross, I.N.., New, G.H.C.. & Bates, P.K.. Contrast limitation due to pump noise in an optical parametric chirped pulse amplification system 2007 Optics Communications
    Vol. 273(2), pp. 510-514 
    article DOI URL 
    Abstract: textlessptextgreatertextlessbr/textgreaterThe contrast ratio of the recompressed output pulses in an optical parametric chirped pulse amplification system can be limited by temporal noise on the pump pulse. We present a simple analysis which can be used to estimate both the contrast ratio of this background noise and the duration of its pedestal. The estimated values compare well quantitatively with values derived using a more accurate computer simulation code.textless/ptextgreater
    BibTeX:
    @article{ross_contrast_2007,
      author = {Ross, I.N. and New, G.H.C. and Bates, P.K.},
      title = {Contrast limitation due to pump noise in an optical parametric chirped pulse amplification system},
      journal = {Optics Communications},
      year = {2007},
      volume = {273},
      number = {2},
      pages = {510--514},
      url = {http://www.sciencedirect.com/science/article/pii/S0030401807001034},
      doi = {16/j.optcom.2007.01.033}
    }
    
    Torres, R., Kajumba, N., Underwood, J.G., Robinson, J.S., Baker, S., Tisch, J.W.G., de Nalda, R., Bryan, W.A., Velotta, R., Altucci, C., Turcu, I.C.E. & Marangos, J.P. Probing Orbital Structure of Polyatomic Molecules by High-Order Harmonic Generation 2007 Physical Review Letters
    Vol. 98(20), pp. 203007 
    article DOI URL 
    Abstract: The effects of electronic structure and symmetry are observed in laser driven high-order harmonic generation for laser aligned conjugated polyatomic molecular systems. The dependence of the harmonic yield on the angle between the molecular axis and the polarization of the driving laser field is seen to contain the fingerprint of the highest occupied molecular orbitals in acetylene and allene, a good quantitative agreement with calculations employing the strong field approximation was found. These measurements support the extension of the recently proposed molecular orbital imaging techniques beyond simple diatomic molecules to larger molecular systems.
    BibTeX:
    @article{torres_probing_2007,
      author = {Torres, R. and Kajumba, N. and Underwood, Jonathan G. and Robinson, J. S. and Baker, S. and Tisch, J. W. G. and de Nalda, R. and Bryan, W. A. and Velotta, R. and Altucci, C. and Turcu, I. C. E. and Marangos, J. P.},
      title = {Probing Orbital Structure of Polyatomic Molecules by High-Order Harmonic Generation},
      journal = {Physical Review Letters},
      year = {2007},
      volume = {98},
      number = {20},
      pages = {203007},
      url = {http://link.aps.org/doi/10.1103/PhysRevLett.98.203007},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.98.203007}
    }
    
    Wyatt, A.S., Witting, T., Monmayrant, A., Walmsley, I.A., Haworth, C., Robinson, J.S., Tisch, J.W.G. & Marangos, J.P. Characterizing Spatio-Temporal Coupling of Extreme Ultraviolet Ultrashort Pulses from High Harmonic Generation 2007 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies, pp. CTuW2  inproceedings URL 
    Abstract: We demonstrate a tool for performing measurements of space-time coupling of ultrashort, extreme ultraviolet pulses from high harmonic generation which can be used to study propagation and phasematching effects during the generation process.
    BibTeX:
    @inproceedings{wyatt_characterizing_2007,
      author = {Wyatt, Adam S. and Witting, Tobias and Monmayrant, Antoine and Walmsley, Ian A. and Haworth, Charles and Robinson, Joseph S. and Tisch, John W G. and Marangos, Jonathon P.},
      title = {Characterizing Spatio-Temporal Coupling of Extreme Ultraviolet Ultrashort Pulses from High Harmonic Generation},
      booktitle = {Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies},
      publisher = {Optical Society of America},
      year = {2007},
      pages = {CTuW2},
      url = {http://www.opticsinfobase.org/abstract.cfm?URI=CLEO-2007-CTuW2}
    }
    
    Baker, S., Robinson, J.S., Haworth, C.A., Teng, H., Smith, R.A., Chirila, C.C., Lein, M., Tisch, J.W.G. & Marangos, J.P. Probing proton dynamics in molecules on an attosecond time scale 2006 Science
    Vol. 312(5772), pp. 424–427 
    article DOI  
    Abstract: We demonstrate a technique that uses high-order harmonic generation in molecules to probe nuclear dynamics and structural rearrangement on a subfemtosecond time scale. The chirped nature of the electron wavepacket produced by laser ionization in a strong field gives rise to a similar chirp in the photons emitted upon electron-ion recombination. Use of this chirp in the emitted light allows information about nuclear dynamics to be gained With 100-attosecond temporal resolution, from excitation by an 8-femtosecond pulse, in a single laser shot. Measurements on molecular hydrogen and deuterium agreed well With calculations of ultrafast nuclear dynamics in the H-2⊕ molecule, confirming the validity of the method. We then measured harmonic spectra from CH4 and CD4 to demonstrate a few femtosecond time scale for the onset of proton rearrangement in methane upon ionization.
    BibTeX:
    @article{baker_probing_2006,
      author = {Baker, S. and Robinson, J. S and Haworth, C. A and Teng, H. and Smith, R. A and Chirila, C. C and Lein, M. and Tisch, J. W. G and Marangos, J. P},
      title = {Probing proton dynamics in molecules on an attosecond time scale},
      journal = {Science},
      year = {2006},
      volume = {312},
      number = {5772},
      pages = {424–427},
      doi = {http://dx.doi.org/10.1126/science.1123904}
    }
    
    Chipperfield, L.E.., Knight, P.L.., Tisch, J.W.G.. & Marangos, J.P.. Tracking individual electron trajectories in a high harmonic spectrum 2006 Optics Communications
    Vol. 264(2), pp. 494-501 
    article DOI URL 
    Abstract: The harmonic spectrum generated by a few-cycle laser pulse propagating through a gas jet is calculated. Two complementary atomic response models are used, one based on the time-dependent Schrödinger equation and the other on quantum orbits in which only a single pair of electron trajectories are taken into account. The role played by individual electron trajectories in determining particular features of the spectrum are considered and phase-matching maps are used to help understand their structure. A method based on this connection is proposed for diagnosing the carrier-envelope phase and the pulse duration of the incident laser field.
    BibTeX:
    @article{chipperfield_tracking_2006,
      author = {Chipperfield, L.E. and Knight, P.L. and Tisch, J.W.G. and Marangos, J.P.},
      title = {Tracking individual electron trajectories in a high harmonic spectrum},
      journal = {Optics Communications},
      year = {2006},
      volume = {264},
      number = {2},
      pages = {494--501},
      url = {http://www.sciencedirect.com/science/article/B6TVF-4K66BPY-Y/2/eaca1f8cd4fa0c4d29913955ad5b834c},
      doi = {http://dx.doi.org/10.1016/j.optcom.2006.03.078}
    }
    
    Kaplan, A., Sajwani, A., Li, Z.Y., Palmer, R.E. & Wilcoxon, J.P. Efficient vacuum ultraviolet light frequency downconversion by thin films of CdSe quantum dots 2006 Applied Physics Letters
    Vol. 88(17), pp. 171105 
    article DOI URL 
    BibTeX:
    @article{kaplan_efficient_2006,
      author = {Kaplan, A. and Sajwani, A. and Li, Z. Y. and Palmer, R. E. and Wilcoxon, J. P.},
      title = {Efficient vacuum ultraviolet light frequency downconversion by thin films of CdSe quantum dots},
      journal = {Applied Physics Letters},
      year = {2006},
      volume = {88},
      number = {17},
      pages = {171105},
      url = {http://link.aip.org/link/APPLAB/v88/i17/p171105/s1&Agg=doi},
      doi = {http://dx.doi.org/10.1063/1.2195697}
    }
    
    Robinson, J.S.., Haworth, C.A.., Teng, H., Smith, R.A.., Marangos, J.P.. & Tisch, J.W.G.. The generation of intense, transform-limited laser pulses with tunable duration from 6 to 30 fs in a differentially pumped hollow fibre 2006 Applied Physics B: Lasers and Optics
    Vol. 85(4), pp. 525-529 
    article DOI URL 
    Abstract: Abstract We have investigated experimentally the energy transmission and spectral broadening of 30-fs, 700-μJ laser pulses in a neon-filled, 250-μm inner diameter hollow fibre. We implement a differentially pumped fibre, where a vacuum is maintained at the fibre entrance, and compare this to a statically filled fibre. We obtain significantly higher transmission and increased spectral broadening in the differentially pumped case due to a reduction of ionisation defocusing at the fibre entrance. This arrangement provides a method for the generation of near-transform- limited pulses with smoothly varying pulse duration whilst maintaining constant pulse energy, by simple adjustment of the gas pressure. Compression of ∼450-μJ pulses from the differentially pumped fibre to a duration of 6.5 fs has been achieved for pulses with spectra spanning 650–900 nm, by use of negatively dispersive chirped mirrors.
    BibTeX:
    @article{robinson_generation_2006,
      author = {Robinson, J.S. and Haworth, C.A. and Teng, H. and Smith, R.A. and Marangos, J.P. and Tisch, J.W.G.},
      title = {The generation of intense, transform-limited laser pulses with tunable duration from 6 to 30 fs in a differentially pumped hollow fibre},
      journal = {Applied Physics B: Lasers and Optics},
      year = {2006},
      volume = {85},
      number = {4},
      pages = {525--529},
      url = {http://dx.doi.org/10.1007/s00340-006-2390-z},
      doi = {http://dx.doi.org/10.1007/s00340-006-2390-z}
    }
    
    Stibenz, G., Ropers, C., Lienau, C., Warmuth, C., Wyatt, A.S.., Walmsley, I.A.. & Steinmeyer, G. Advanced methods for the characterization of few-cycle light pulses: a comparison 2006 Applied Physics B
    Vol. 83(4), pp. 511-519 
    article DOI URL 
    BibTeX:
    @article{stibenz_advanced_2006,
      author = {Stibenz, G. and Ropers, C. and Lienau, Ch. and Warmuth, Ch. and Wyatt, A.S. and Walmsley, I.A. and Steinmeyer, G.},
      title = {Advanced methods for the characterization of few-cycle light pulses: a comparison},
      journal = {Applied Physics B},
      year = {2006},
      volume = {83},
      number = {4},
      pages = {511--519},
      url = {http://www.springerlink.com/content/jt3w42h43un67154/},
      doi = {http://dx.doi.org/10.1007/s00340-006-2190-5}
    }
    
    Wabnitz, H., Mairesse, Y., Frasinski, L.J., Stankiewicz, M., Boutu, W., Breger, P., Johnsson, P., Merdji, H., Monchicourt, P., Salières, P., Varjú, K., Vitteau, M. & Carré, B. Generation of attosecond pulses in molecular nitrogen 2006 The European Physical Journal D
    Vol. 40(2), pp. 305-311 
    article DOI URL 
    BibTeX:
    @article{wabnitz_generation_2006,
      author = {Wabnitz, H. and Mairesse, Y. and Frasinski, L. J. and Stankiewicz, M. and Boutu, W. and Breger, P. and Johnsson, P. and Merdji, H. and Monchicourt, P. and Salières, P. and Varjú, K. and Vitteau, M. and Carré, B.},
      title = {Generation of attosecond pulses in molecular nitrogen},
      journal = {The European Physical Journal D},
      year = {2006},
      volume = {40},
      number = {2},
      pages = {305--311},
      url = {http://www.springerlink.com/content/k744p234v560311j/},
      doi = {http://dx.doi.org/10.1140/epjd/e2006-00148-5}
    }
    
    Wyatt, A.S., Walmsley, I.A., Stibenz, G. & Steinmeyer, G. Sub-10 fs pulse characterization using spatially encoded arrangement for spectral phase interferometry for direct electric field reconstruction 2006 Optics Letters
    Vol. 31(12), pp. 1914-1916 
    article DOI URL 
    Abstract: We demonstrate an extremely accurate method for measuring ultrabroadband, sub-10 fs pulses even if they exhibit a highly modulated spectrum, space-time coupling, or both. The method uses a spatially encoded arrangement for spectral phase interferometry for direct electric field reconstruction, which allows a zero additional phase measurement to be performed with a relatively low signal-to-noise ratio in real time and single shot.
    BibTeX:
    @article{wyatt_sub-10_2006,
      author = {Wyatt, Adam S. and Walmsley, Ian A. and Stibenz, Gero and Steinmeyer, G�nter},
      title = {Sub-10 fs pulse characterization using spatially encoded arrangement for spectral phase interferometry for direct electric field reconstruction},
      journal = {Optics Letters},
      year = {2006},
      volume = {31},
      number = {12},
      pages = {1914--1916},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-31-12-1914},
      doi = {http://dx.doi.org/10.1364/OL.31.001914}
    }
    
    Altucci, C., Velotta, R., Marangos, J.P., Heesel, E., Springate, E., Pascolini, M., Poletto, L., Villoresi, P., Vozzi, C., Sansone, G., Anscombe, M., Caumes, J.-P., Stagira, S. & Nisoli, M. Dependence upon the molecular and atomic ground state of higher-order harmonic generation in the few-optical-cycle regime 2005 Physical Review A
    Vol. 71(1), pp. 013409 
    article DOI URL 
    Abstract: High-order harmonic generation from molecules (O2, N2, H2, and CO2) and atoms (Xe, Ar, and Kr) has been studied in the few optical cycle domain. Two laser peak intensities; 2×1014 and 6×1014 W cm−2, were compared. At the lower intensity spectra were approximately the same for molecules and atoms with the same ionization potential, at higher laser intensity the cutoff of O2 and CO2 extends far beyond the cutoff of Xe and Kr, respectively, in contrast with N2 and H2 which exhibit cutoffs very close to that of Ar. This behavior is well explained by adopting an atomlike approximation for the molecule response in the high-field regime and employing the Lewenstein’s model, properly modified in order to account for the nonlinear dipole moment of a randomly oriented molecule ensemble.
    BibTeX:
    @article{altucci_dependence_2005,
      author = {Altucci, C. and Velotta, R. and Marangos, J. P. and Heesel, E. and Springate, E. and Pascolini, M. and Poletto, L. and Villoresi, P. and Vozzi, C. and Sansone, G. and Anscombe, M. and Caumes, J-P. and Stagira, S. and Nisoli, M.},
      title = {Dependence upon the molecular and atomic ground state of higher-order harmonic generation in the few-optical-cycle regime},
      journal = {Physical Review A},
      year = {2005},
      volume = {71},
      number = {1},
      pages = {013409},
      url = {http://link.aps.org/doi/10.1103/PhysRevA.71.013409},
      doi = {http://dx.doi.org/10.1103/PhysRevA.71.013409}
    }
    
    Carley, R.E., Heesel, E. & Fielding, H.H. Femtosecond lasers in gas phase chemistry 2005 Chemical Society Reviews
    Vol. 34(11), pp. 949 
    article DOI URL 
    BibTeX:
    @article{carley_femtosecond_2005,
      author = {Carley, R. E. and Heesel, E. and Fielding, H. H.},
      title = {Femtosecond lasers in gas phase chemistry},
      journal = {Chemical Society Reviews},
      year = {2005},
      volume = {34},
      number = {11},
      pages = {949},
      url = {http://pubs.rsc.org/en/Content/ArticleLanding/2005/CS/b509463a},
      doi = {http://dx.doi.org/10.1039/b509463a}
    }
    
    Chipperfield, L.E., Gaier, L.N., Knight, P.L., Marangos, J.P. & Tisch, J.W.G. Conditions for the reliable production of attosecond pulses using ultra-short laser-generated high harmonics 2005 Journal of Modern Optics
    Vol. 52(2-3), pp. 243-260 
    article DOI  
    Abstract: We outline a simple approach for determining plateau positions in harmonic spectra that demonstrates very clearly the requirement for carrier-envelope phase and intensity stabilization in the IR laser pulse for reliable attosecond pulse production. Neglecting the phase and intensity characteristics of the laser pulse will lead to large variations in the duration and number of sub-fs pulses produced via high harmonics cut-off windowing.
    BibTeX:
    @article{chipperfield_conditions_2005,
      author = {Chipperfield, L. E. and Gaier, L. N. and Knight, P. L. and Marangos, J. P. and Tisch, J. W. G.},
      title = {Conditions for the reliable production of attosecond pulses using ultra-short laser-generated high harmonics},
      journal = {Journal of Modern Optics},
      year = {2005},
      volume = {52},
      number = {2-3},
      pages = {243--260},
      doi = {http://dx.doi.org/10.1080/0950034042000275379}
    }
    
    Cormier, E., Walmsley, I.A., Kosik, E.M., Wyatt, A.S., Corner, L. & DiMauro, L.F. Self-Referencing, Spectrally, or Spatially Encoded Spectral Interferometry for the Complete Characterization of Attosecond Electromagnetic Pulses 2005 Physical Review Letters
    Vol. 94(3), pp. 033905 
    article DOI URL 
    Abstract: We propose a method for the complete characterization of attosecond duration electromagnetic pulses produced by high harmonic generation in an atomic gas. Our method is based on self-referencing spectral interferometry of two spectrally sheared extreme ultraviolet pulses, which is achieved by pumping the harmonic source with two sheared optical driving pulses. The resulting interferogram contains sufficient information to completely reconstruct the temporal behavior of the electric field. We demonstrate that such a method is feasible, and outline two possible experimental configurations.
    BibTeX:
    @article{cormier_self-referencing_2005,
      author = {Cormier, Eric and Walmsley, Ian A. and Kosik, Ellen M. and Wyatt, Adam S. and Corner, Laura and DiMauro, Louis F.},
      title = {Self-Referencing, Spectrally, or Spatially Encoded Spectral Interferometry for the Complete Characterization of Attosecond Electromagnetic Pulses},
      journal = {Physical Review Letters},
      year = {2005},
      volume = {94},
      number = {3},
      pages = {033905},
      url = {http://link.aps.org/doi/10.1103/PhysRevLett.94.033905},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.94.033905}
    }
    
    Gundry, S., Anscombe, M.P., Abdulla, A.M., Hogan, S.D., Sali, E., Tisch, J.W.G. & Marangos, J.P. Off-resonant preparation of a vibrational coherence for enhanced stimulated Raman scattering 2005 Physical Review A
    Vol. 72(3) 
    article DOI  
    Abstract: We present a detailed experimental investigation into the off-resonant preparation of a vibrational coherence for multiorder Raman generation. In particular, the importance of the balance between the conflicting requirements for generating a strong coherence and for adiabatic evolution of the system are examined. For the parameters accessible in our experiment, we find that the strongest frequency modulation occurs under conditions for which there is some nonadiabatic behavior, and the coherence is less than the peak value obtainable. We investigate the modulation of a narrowband probe pulse, and an ultrashort probe pulse, in the coherently prepared medium, and demonstrate efficient modulation of both probe pulses resulting in the generation of 360 THz bandwidth fields. This system therefore has an application in the field of subfemtosecond pulse generation.
    BibTeX:
    @article{gundry_off-resonant_2005,
      author = {Gundry, S. and Anscombe, M. P and Abdulla, A. M and Hogan, S. D and Sali, E. and Tisch, J. W. G and Marangos, J. P},
      title = {Off-resonant preparation of a vibrational coherence for enhanced stimulated Raman scattering},
      journal = {Physical Review A},
      year = {2005},
      volume = {72},
      number = {3},
      doi = {http://dx.doi.org/10.1103/PhysRevA.72.033824}
    }
    
    Gundry, S., Anscombe, M.P., Abdulla, A.M., Sali, E., Tisch, J.W.G., Kinsler, P., New, G.H.C. & Marangos, J.P. Ultrashort-pulse modulation in adiabatically preparedRaman media 2005 Optics Letters
    Vol. 30(2), pp. 180-182 
    article DOI URL 
    Abstract: We demonstrate the efficient modulation of an ∼100-femtosecond pulse in a Raman medium coherently prepared by nanosecond pulses. Raman sidebands of the ultrashort pulse spanning 360 THz are generated with an efficiency of textgreater5 We show that the mechanism permitting the sidebands to be generated is the preparation of a significant vibrational coherence in the medium that is robust to disturbance by an intense short pulse. If the observed sidebands were phase compensated, they would form a short train of approximately ten 3-fs pulses. Focusing would permit the realization of a peak intensity of textgreater10textasciicircum13 W cmtextasciicircum-2.
    BibTeX:
    @article{gundry_ultrashort-pulse_2005,
      author = {Gundry, Sarah and Anscombe, Marcel P. and Abdulla, Abubaker M. and Sali, Emiliano and Tisch, John W. G. and Kinsler, Paul and New, Geoffrey H. C. and Marangos, Jon P.},
      title = {Ultrashort-pulse modulation in adiabatically preparedRaman media},
      journal = {Optics Letters},
      year = {2005},
      volume = {30},
      number = {2},
      pages = {180--182},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-30-2-180},
      doi = {http://dx.doi.org/10.1364/OL.30.000180}
    }
    
    Kosik, E.M., Radunsky, A.S., Walmsley, I.A. & Dorrer, C. Interferometric technique for measuring broadband ultrashort pulsesat the sampling limit 2005 Optics Letters
    Vol. 30(3), pp. 326-328 
    article DOI URL 
    Abstract: We present a new technique for measuring ultrashort optical pulses by use of spectral phase interferometry for direct electric-field reconstruction that is suitable for large bandwidth pulses. The method does not require generation of a replica of the pulse to be measured and encodes the spectral phase information in a spatial interference pattern. A major advantage of this method is that the spectral sampling saturates the Whittaker-Shannon bound. Moreover, the technique allows for the characterization of some types of space-time coupling. An experimental demonstration of the technique is presented.
    BibTeX:
    @article{kosik_interferometric_2005,
      author = {Kosik, Ellen M. and Radunsky, Aleksander S. and Walmsley, Ian A. and Dorrer, Christophe},
      title = {Interferometric technique for measuring broadband ultrashort pulsesat the sampling limit},
      journal = {Optics Letters},
      year = {2005},
      volume = {30},
      number = {3},
      pages = {326--328},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-30-3-326},
      doi = {http://dx.doi.org/10.1364/OL.30.000326}
    }
    
    Lein, M., De Nalda, R., Heesel, E., Hay, N., Springate, E., Velotta, R., Castillejo, M., Knight, P.L. & Marangos, J.P. Signatures of molecular structure in the strong-field response of aligned molecules 2005 Journal of Modern Optics
    Vol. 52(2-3), pp. 465-478 
    article DOI  
    Abstract: The strong-field response of molecules exhibits interference effects due to the geometric and electronic structure of the molecules and provides a basis for ultrafast imaging of molecular structure. This is demonstrated for high-order harmonic generation and high-order above-threshold ionization in aligned molecules by numerical solution of the time-dependent Schrödinger equation. Experimental and theoretical results for high-order harmonic generation with aligned CO 2 molecules show that the harmonics exhibit an orientation dependence that is explained by the valence orbital symmetry. A detailed discussion of phase-matching effects due to the presence of different molecular orientations in an ensemble of imperfectly aligned molecules is presented.
    BibTeX:
    @article{lein_signatures_2005,
      author = {Lein, M. and De Nalda, R. and Heesel, E. and Hay, N. and Springate, E. and Velotta, R. and Castillejo, M. and Knight, P. L. and Marangos, J. P.},
      title = {Signatures of molecular structure in the strong-field response of aligned molecules},
      journal = {Journal of Modern Optics},
      year = {2005},
      volume = {52},
      number = {2-3},
      pages = {465--478},
      doi = {http://dx.doi.org/10.1080/09500340410001731039}
    }
    
    Marangos, J.P. Ultrafast science Molecular structure in an instant 2005 Nature
    Vol. 435(7041), pp. 435 
    article DOI URL 
    BibTeX:
    @article{marangos_ultrafast_2005,
      author = {Marangos, Jonathan P.},
      title = {Ultrafast science Molecular structure in an instant},
      journal = {Nature},
      year = {2005},
      volume = {435},
      number = {7041},
      pages = {435},
      url = {http://dx.doi.org/10.1038/435435a},
      doi = {http://dx.doi.org/10.1038/435435a}
    }
    
    Moore, A.S., Mendham, K.J., Symes, D.R., Robinson, J.S., Springate, E., Mason, M.B., Smith, R.A., Tisch, J.W.G. & Marangos, J.P. Control parameters for ion heating and X-ray emission from laser induced cluster explosion 2005 Applied Physics B-lasers and Optics
    Vol. 80(1), pp. 101–107 
    article DOI  
    Abstract: The highest energies of the ions obtained from the explosion of an atomic cluster in an intense femtosecond laser field can vary greatly depending on the cluster size, atomic species and the peak intensity, duration and shape of the laser pulse. By careful choice of these parameters the ion energies, electron energies or X-ray emission can be optimised. A relationship is described that allows for rapid determination of the optimum experimental parameters. We present experimental data of keV X-ray emission from Argon clusters, which investigate intensity and pulse duration effects. In addition we present the first results from closed-loop optimal control, pulse-shaping experiments that optimise X-ray emission and show a significant enhancement in the X-ray yield.
    BibTeX:
    @article{moore_control_2005,
      author = {Moore, A. S and Mendham, K. J and Symes, D. R and Robinson, J. S and Springate, E. and Mason, M. B and Smith, R. A and Tisch, J. W. G and Marangos, J. P},
      title = {Control parameters for ion heating and X-ray emission from laser induced cluster explosion},
      journal = {Applied Physics B-lasers and Optics},
      year = {2005},
      volume = {80},
      number = {1},
      pages = {101–107},
      doi = {http://dx.doi.org/10.1007/s00340-004-1672-6}
    }
    
    Sali, E., Kinsler, P., New, G.H.C., Mendham, K.J., Halfmann, T., Tisch, J.W.G. & Marangos, J.P. Behavior of high-order stimulated Raman scattering in a highly transient regime 2005 Physical Review A
    Vol. 72(1) 
    article DOI  
    Abstract: We have investigated the behavior of high-order stimulated Raman scattering in a highly-transient regime. We demonstrate efficient collinear generation of vibrational sidebands in molecular hydrogen and methane using two-color pumping with pulses of duration tau similar to 100 fs tuned to a vibrational Raman transition. A Raman spectrum with a large bandwidth was observed, ranging from the IR to the UV. Under some conditions strong pump depletion was observed and up to five anti-Stokes sidebands were observed to have energies exceeding 10% of the transmitted pump pulse energies. A numerical simulation reproduces qualitatively and quantitatively the experimental results and allows us to explain key experimental features. The simulation also confirms that the molecular coherence in the medium is substantially increased by the two-color pumping and allows us to deduce values for the degree of material excitation. The use of this technique looks promising for efficient subfemtosecond pulse generation.
    BibTeX:
    @article{sali_behavior_2005,
      author = {Sali, E. and Kinsler, P. and New, G. H. C and Mendham, K. J and Halfmann, T. and Tisch, J. W. G and Marangos, J. P},
      title = {Behavior of high-order stimulated Raman scattering in a highly transient regime},
      journal = {Physical Review A},
      year = {2005},
      volume = {72},
      number = {1},
      doi = {http://dx.doi.org/10.1103/PhysRevA.72.013813}
    }
    
    Torres, R., de Nalda, R. & Marangos, J.P. Dynamics of laser-induced molecular alignment in the impulsive and adiabatic regimes: A direct comparison 2005 Physical Review A
    Vol. 72(2), pp. 023420 
    article DOI URL 
    Abstract: Quantum-mechanical calculations are performed of the dynamic alignment of linear molecules induced by a strong nonresonant laser field. Within this framework we have treated in a unified fashion the alignment with laser pulses of varying duration from the short pulse impulsive limit (τpulse⪡Trot) to the long pulse adiabatic limit (τpulsetextgreaterTrot). The temporal behavior of the alignment in both these limits, and in the intermediate pulse duration regime, have been analyzed. For the impulsive limit the dependence of the degree of maximum alignment upon the laser pulse duration was examined and the intensity-dependent optimum pulse duration explained. A comparison between the degree of alignment under the same conditions of pulse intensity and rotational temperature was performed between the impulsive and adiabatic cases. The adiabatic case was found to always provide a better degree of alignment for a given intensity which we show is due to the zero relative phasing between the component states of the superposition that form the pendular states. We have explicitly calculated the angular distribution of an ensemble of linear molecules as it evolves through a rotational revival; a rich structure is found that may be useful in guiding future experiments that utilize the field free alignment in a revival.
    BibTeX:
    @article{torres_dynamics_2005,
      author = {Torres, R. and de Nalda, R. and Marangos, J. P.},
      title = {Dynamics of laser-induced molecular alignment in the impulsive and adiabatic regimes: A direct comparison},
      journal = {Physical Review A},
      year = {2005},
      volume = {72},
      number = {2},
      pages = {023420},
      url = {http://link.aps.org/doi/10.1103/PhysRevA.72.023420},
      doi = {http://dx.doi.org/10.1103/PhysRevA.72.023420}
    }
    
    Vozzi, C., Calegari, F., Benedetti, E., Caumes, J.P., Sansonse, G., Stagira, S., Nisoli, M., Torres, R., Heesel, E., Kajumba, N., Marangos, J.P., Altucci, C. & Velotta, R. Controlling Two-Center Interference in Molecular High Harmonic Generation 2005 Phys. Rev. Letters
    Vol. 95(15), pp. 153902 
    article  
    Abstract: We experimentally investigate the process of intromolecular quantum interference in high-order harmonic generation in impulsively aligned CO2 molecules. The recombination interference effect is clearly seen through the order dependence of the harmonic yield in an aligned sample. The experimental results can be well modeled assuming that the effective de Broglie wavelength of the returninc elctron wave is not significantly altered by the Coulomb filed of the molecular ion. We demsontrate that such interference effects can be effectively controlled by changing the ellipticity of the driving laser fiels.
    BibTeX:
    @article{vozzi_controlling_2005,
      author = {Vozzi, C. and Calegari, F. and Benedetti, E. and Caumes, J. -P and Sansonse, G. and Stagira, S. and Nisoli, M. and Torres, R. and Heesel, E. and Kajumba, N. and Marangos, J. P and Altucci, C. and Velotta, R.},
      title = {Controlling Two-Center Interference in Molecular High Harmonic Generation},
      journal = {Phys. Rev. Letters},
      year = {2005},
      volume = {95},
      number = {15},
      pages = {153902}
    }
    
    Yin, J. Excited states of surfaces and nanostructures in the VUV (Invited Paper) 2005 Proceedings of SPIE, pp. 188-193  inproceedings DOI URL 
    BibTeX:
    @inproceedings{yin_excited_2005,
      author = {Yin, Jin},
      title = {Excited states of surfaces and nanostructures in the VUV (Invited Paper)},
      booktitle = {Proceedings of SPIE},
      year = {2005},
      pages = {188--193},
      url = {http://link.aip.org/link/?PSI/5725/188/1&Agg=doi},
      doi = {http://dx.doi.org/10.1117/12.592487}
    }
    
    Clatterbuck, T.O., Lyngå, C., Paul, P.M., DiMauro, L.F., Gaarde, M.B., Schafer, K.J., Agostini, P., Kulander, K.C. & Walmsley, I. Yield and temporal characterization of high-order harmonics from intense midinfrared excitation of a cesium vapor 2004 Physical Review A
    Vol. 69(3), pp. 033807 
    article DOI URL 
    Abstract: Cesium vapor interacting with a tightly focused, intense midinfrared (3.4 μm) source produces high harmonic radiation in the visible∕UV spectral range. The measured yields of harmonic orders 9–17 are found to yield good quantitative agreement with numerical simulations that include both the single-atom and the macroscopic response. The 5th–9th harmonic orders are generated with sufficient pulse energies (∼100 pJ) for direct temporal measurements using an autocorrelation method and when correlated with bandwidth measurements are found not to be transform limited. A blueshift connected to a strong time-dependent ionization appears to be the cause of this spectral broadening.
    BibTeX:
    @article{clatterbuck_yield_2004,
      author = {Clatterbuck, T. O. and Lyngå, C. and Paul, P. M. and DiMauro, L. F. and Gaarde, M. B. and Schafer, K. J. and Agostini, P. and Kulander, K. C. and Walmsley, I.},
      title = {Yield and temporal characterization of high-order harmonics from intense midinfrared excitation of a cesium vapor},
      journal = {Physical Review A},
      year = {2004},
      volume = {69},
      number = {3},
      pages = {033807},
      url = {http://link.aps.org/doi/10.1103/PhysRevA.69.033807},
      doi = {http://dx.doi.org/10.1103/PhysRevA.69.033807}
    }
    
    Corso, P.P., Daniele, R., Fiordilino, E., Marangos, J.P., Morales, F. & Velotta, R. Electron and nuclear dynamics of a molecular ion in an intense laser field 2004 Physical Review A
    Vol. 70(5), pp. 053410 
    article DOI URL 
    Abstract: The dynamics of a two-dimensional H2+ molecule interacting with a strong laser pulse beyond the usual approximation of fixed nuclei is presented. The motion of the nuclei is studied by using the classical Newton laws while the electron is described with a full quantal treatment. The axis of the molecule, initially not aligned to the laser field, performs a long-period pendular motion around the laser polarization axis. Vibrational degrees of freedom are seen to be excited. The radiation emitted by the oscillating charges presents variations that are synchronous to the pendular motion. The possibility of monitoring the motion of the molecule through the emitted radiation is discussed.
    BibTeX:
    @article{corso_electron_2004,
      author = {Corso, P. P. and Daniele, R. and Fiordilino, E. and Marangos, J. P. and Morales, F. and Velotta, R.},
      title = {Electron and nuclear dynamics of a molecular ion in an intense laser field},
      journal = {Physical Review A},
      year = {2004},
      volume = {70},
      number = {5},
      pages = {053410},
      url = {http://link.aps.org/doi/10.1103/PhysRevA.70.053410},
      doi = {http://dx.doi.org/10.1103/PhysRevA.70.053410}
    }
    
    Mairesse, Y., de Bohan, A., Frasinski, L.J., Merdji, H., Dinu, L.C., Monchicourt, P., Breger, P., Kovaccaronev, M., Auguste, T., Carré, B., Muller, H.G., Agostini, P. & Salières, P. Optimization of Attosecond Pulse Generation 2004 Physical Review Letters
    Vol. 93(16), pp. 163901 
    article DOI URL 
    Abstract: The generation of attosecond pulses by superposition of high harmonics relies on their synchronization in the emission. Our experiments in the low-order, plateau, and cutoff regions of the spectrum reveal different regimes in the electron dynamics determining the synchronization quality. The shortest pulses are obtained by combining a spectral filtering of harmonics from the end of the plateau and the cutoff, and a far-field spatial filtering that selects a single electron quantum path contribution to the emission. This method applies to isolated pulses as well as pulse trains.
    BibTeX:
    @article{mairesse_optimization_2004,
      author = {Mairesse, Y. and de Bohan, A. and Frasinski, L. J. and Merdji, H. and Dinu, L. C. and Monchicourt, P. and Breger, P. and Kovaccaronev, M. and Auguste, T. and Carré, B. and Muller, H. G. and Agostini, P. and Salières, P.},
      title = {Optimization of Attosecond Pulse Generation},
      journal = {Physical Review Letters},
      year = {2004},
      volume = {93},
      number = {16},
      pages = {163901},
      url = {http://link.aps.org/doi/10.1103/PhysRevLett.93.163901},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.93.163901}
    }
    
    Nalda, R. d., Heesel, E., Lein, M., Hay, N., Velotta, R., Springate, E., Castillejo, M. & Marangos, J.P. Role of orbital symmetry in high-order harmonic generation from aligned molecules 2004 Physical Review A
    Vol. 69(3), pp. 031804 
    article DOI URL 
    Abstract: High-order harmonic generation has been explored theoretically and experimentally in CO2, a linear molecule characterized by doubly antisymmetric highest-occupied molecular orbitals. For the first time to our knowledge, the high-harmonic yield is studied as a function of the angle between the molecular axis and the polarization direction. A minimum yield is found at 0° for all harmonics, which constitutes evidence for destructively interfering terms in the ionization probability amplitude playing an important role in strong-field phenomena in molecules. The maximum yield is always found at intermediate angles, but the detailed behavior is harmonic specific. Numerical simulations reproduce the main features observed in the experiment.
    BibTeX:
    @article{nalda_role_2004,
      author = {Nalda, R. de and Heesel, E. and Lein, M. and Hay, N. and Velotta, R. and Springate, E. and Castillejo, M. and Marangos, J. P.},
      title = {Role of orbital symmetry in high-order harmonic generation from aligned molecules},
      journal = {Physical Review A},
      year = {2004},
      volume = {69},
      number = {3},
      pages = {031804},
      url = {http://link.aps.org/doi/10.1103/PhysRevA.69.031804},
      doi = {http://dx.doi.org/10.1103/PhysRevA.69.031804}
    }
    
    Sali, E., Mendham, K.J., Tisch, J.W.G., Halfmann, T. & Marangos, J.P. High-order stimulated Raman scattering in a highly transient regime driven by a pair of ultrashort pulses 2004 Optics Letters
    Vol. 29(5), pp. 495-497 
    article DOI URL 
    Abstract: We demonstrate efficient generation of high-order anti-Stokes Raman sidebands in a highly transient regime, using a pair of textasciitilde100-fs laser pulses tuned to Raman resonance with vibrational transitions in methane or hydrogen. The use of this technique looks promising for efficient subfemtosecond pulse generation.
    BibTeX:
    @article{sali_high-order_2004,
      author = {Sali, Emiliano and Mendham, Kirstie J. and Tisch, John W. G. and Halfmann, Thomas and Marangos, Jon P.},
      title = {High-order stimulated Raman scattering in a highly transient regime driven by a pair of ultrashort pulses},
      journal = {Optics Letters},
      year = {2004},
      volume = {29},
      number = {5},
      pages = {495--497},
      url = {http://ol.osa.org/abstract.cfm?URI=ol-29-5-495},
      doi = {http://dx.doi.org/10.1364/OL.29.000495}
    }
    
    Aseyev, S.A., Ni, Y., Frasinski, L.J., Muller, H.G. & Vrakking, M.J.J. Attosecond Angle-Resolved Photoelectron Spectroscopy 2003 Physical Review Letters
    Vol. 91(22), pp. 223902 
    article DOI URL 
    Abstract: We report experiments on the characterization of a train of attosecond pulses obtained by high-harmonic generation, using mixed-color (XUV+IR) atomic two-photon ionization and electron detection on a velocity map imaging detector. We demonstrate that the relative phase of the harmonics is encoded both in the photoelectron yield and the angular distribution as a function of XUV-IR time delay, thus making the technique suitable for the detection of single attosecond pulses. The timing of the attosecond pulse with respect to the field oscillation of the driving laser critically depends on the target gas used to generate the harmonics.
    BibTeX:
    @article{aseyev_attosecond_2003,
      author = {Aseyev, S. A. and Ni, Y. and Frasinski, L. J. and Muller, H. G. and Vrakking, M. J. J.},
      title = {Attosecond Angle-Resolved Photoelectron Spectroscopy},
      journal = {Physical Review Letters},
      year = {2003},
      volume = {91},
      number = {22},
      pages = {223902},
      url = {http://link.aps.org/doi/10.1103/PhysRevLett.91.223902},
      doi = {http://dx.doi.org/10.1103/PhysRevLett.91.223902}
    }
    
    Mairesse, Y., de Bohan, A., Frasinski, L.J., Merdji, H., Dinu, L.C., Monchicourt, P., Breger, P., Kovacev, M., Taieb, R., Carre, B., Muller, H.G., Agostini, P. & Salieres, P. Attosecond synchronization of high-harmonic soft x-rays 2003 Science
    Vol. 302(5650), pp. 1540–1543 
    article DOI URL 
    Abstract: Subfemtosecond light pulses can be obtained by superposing several high harmonics of an intense laser pulse. Provided that the harmonics are emitted simultaneously, increasing their number should result in shorter pulses. However, we found that the high harmonics were not synchronized on an attosecond time scale, thus setting a lower limit to the achievable x-ray pulse duration. We showed that the synchronization could be improved considerably by controlling the underlying ultrafast electron dynamics, to provide pulses of 130 attoseconds in duration. We discuss the possibility of achieving even shorter pulses, which would allow us to trackfast electron processes in matter.
    BibTeX:
    @article{mairesse_attosecond_2003,
      author = {Mairesse, Y. and de Bohan, A. and Frasinski, L. J and Merdji, H. and Dinu, L. C and Monchicourt, P. and Breger, P. and Kovacev, M. and Taieb, R. and Carre, B. and Muller, H. G and Agostini, P. and Salieres, P.},
      title = {Attosecond synchronization of high-harmonic soft x-rays},
      journal = {Science},
      year = {2003},
      volume = {302},
      number = {5650},
      pages = {1540–1543},
      url = {http://www.sciencemag.org/content/302/5650/1540.abstract},
      doi = {http://dx.doi.org/10.1126/science.1090277}
    }
    

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