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Title: Effect of temporal pulse shape on optical damage

Abstract

The conditions under which optical materials are susceptible to laser-induced damage is a topic which has been the subject of considerable study. Laser parameters such as wavelength and temporal pulse duration have been studied extensively. Until this work the effect of temporal pulse shape has not been considered. The authors present here data from a simple single-parameter model and a supporting experiment which predicts that a flat-in-time pulse will produce damage at approximately 80% of the fluence of a Gaussian pulse of the same duration.

Authors:
; ;  [1]
  1. Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
20971780
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 90; Journal Issue: 4; Other Information: DOI: 10.1063/1.2431705; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DAMAGE; LASERS; PULSE SHAPERS; PULSES; WAVELENGTHS

Citation Formats

Carr, C. W., Trenholme, J. B., and Spaeth, M. L. Effect of temporal pulse shape on optical damage. United States: N. p., 2007. Web. doi:10.1063/1.2431705.
Carr, C. W., Trenholme, J. B., & Spaeth, M. L. Effect of temporal pulse shape on optical damage. United States. doi:10.1063/1.2431705.
Carr, C. W., Trenholme, J. B., and Spaeth, M. L. Mon . "Effect of temporal pulse shape on optical damage". United States. doi:10.1063/1.2431705.
@article{osti_20971780,
title = {Effect of temporal pulse shape on optical damage},
author = {Carr, C. W. and Trenholme, J. B. and Spaeth, M. L.},
abstractNote = {The conditions under which optical materials are susceptible to laser-induced damage is a topic which has been the subject of considerable study. Laser parameters such as wavelength and temporal pulse duration have been studied extensively. Until this work the effect of temporal pulse shape has not been considered. The authors present here data from a simple single-parameter model and a supporting experiment which predicts that a flat-in-time pulse will produce damage at approximately 80% of the fluence of a Gaussian pulse of the same duration.},
doi = {10.1063/1.2431705},
journal = {Applied Physics Letters},
number = 4,
volume = 90,
place = {United States},
year = {Mon Jan 22 00:00:00 EST 2007},
month = {Mon Jan 22 00:00:00 EST 2007}
}
  • The conditions under which optical materials are susceptible to laser-induced damage is a topic which has been the subject of considerable study. Laser parameters such as wavelength and temporal pulse duration have been studied extensively. Until this work the effect of temporal pulse shape has not been considered. We present here data from a simple single-parameter model and a supporting experiment which predicts that a Flat-In-Time-pulse will produce damage at approximately 80% of the fluence of a Gaussian pulse of the same FWHM duration.
  • We report the results of numerical studies of the impact of asymmetric femtosecond pulses focused in the bulk of the material on the femtosecond modification of fused silica. It is shown that such pulses lead to localisation of absorption in the process of femtosecond modification and to a decrease in the threshold energy of modification. It is found that the optimal asymmetry parameters for reaching the maximum plasma density in the focusing region depend on the pulse energy: at an initial energy of about 100 nJ, it is preferable to use pulses with positive TOD; however, when the energy ismore » increased, it is preferable to use pulses with negative TOD. This is explained by differences in the dynamics of the processes of absorption of energy of a pulse propagating in the material. (optical fibres, lasers and amplifiers. properties and applications)« less
  • We investigate the effects of the input laser beam's temporal pulse shape on a forward degenerate four-wave mixing (FDFWM) signal, assuming two-level saturable absorbers. Under conditions in which the coherence time is far shorter than the pulse-duration, we can calculate the signal easily in the time and frequency domains. From this result it is shown that, when the pulse duration is longer than ten times the population relaxation time, the calculated signal intensity is almost the same as that obtained by assuming a steady state throughout duration of the laser pulse. With this assumption, we obtain the signal by summingmore » all the steady-state signals at each time-domain grid point during the pulse. The calculation is performed with three input beam temporal pulse shapes: square, Gaussian, and typical Q-switched pulses. After reaching a maximum, the signal intensity decreases. The rates of the signal increase and decrease depend strongly on the temporal shape of the input beam. For the same average power, the square-pulse input saturates the absorber faster than the other pulses. These results indicate that the weak part of the pulse input plays an important role in generating the signal, yielding differences in saturation behavior of the signal intensity and the spectral line shape. We compare the calculations with experiments by fitting the saturation curve of the FDFWM signal of argon atoms in a radio frequency inductively coupled plasma. Also, the spectral line shape of the DFWM signal is fitted with the calculation by use of published experimental data. {copyright} 2001 Optical Society of America« less