Viewing records 1-5 of 44 found.

Better by half, S. T. Cundiff, Nature Physics, 3 (), 16-17, (2007) PDF available

The ability to distinguish the high-harmonic emission generated by individual half-cycles of a driving laser leads to a simpler approach to characterizing the laser pulse and isolating a single attosecond pulse.

Probing orbital structure of polyatomic molecules by high-order harmonic generation, R. Torres, N. Kajumba, J. G. Underwood, J. S. Robinson, S. Baker, J. W. G. Tisch, R. de Nalda, W. A. Bryan, R. Velotta, C. Altucci, I. C. E. Turcu and J. P. Marangos, Physical Review Letters, 98 (20), , (2007)

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.

Contrast limitation due to pump noise in an optical parametric chirped pulse amplification system, I. N. Ross, G. H. C. New and P. K. Bates, Optics Communications, 273 (2), 510-514, (2007)

The 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. (C) 2007 Elsevier B.V. All rights reserved.

Nanoscopic Coulomb explosion in ultrafast graphite ablation, M. Lenner, A. Kaplan and R. E. Palmer, Applied Physics Letters, 90 (15), , (2007)

The authors report single-shot femtosecond laser ablation experiments on the highly oriented pyrolitic graphite surface. The yield of positively charged carbon clusters has been measured by time-of-flight mass spectrometry. The reconstructed velocity distribution of atomic carbon ions indicates that the observed Coulomb explosion is most pronounced for fluences slightly above the damage threshold. Atomic force microscopy studies of the damage spots indicate nanoscopic removal of intact monolayers. The results imply a significant degree of charge localization on the surface graphite layers. (c) 2007 American Institute of Physics.

Compact spectral shearing interferometer for ultrashort pulse characterization, A. S. Radunsky, I. A. Walmsley, S. P. Gorza and P. Wasylczyk, Optics Letters, 32 (2), 181-183, (2007)

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 feratosecond laser pulses over the 740-900 nm range with a KDP crystal. (c) 2006 Optical Society of America.