Abstract

We investigate self-focusing and self-defocusing of a transversely excited atmosphere CO₂ laser pulse (1.3 MW) in the medium of CF₃Br molecules. Self-focusing of the 9R(30) line and self-defocusing of the 9R(26) and 9R(28) lines are observed. Nonlinear absorption cross sections (σ) are first measured for various fluences of the laser beam to permit us to obtain an accurate expression for the nonlinear absorption coefficient α. The beam-narrowing effect of the nonlinear absorption (α) modifies the far-field spatial profile of the beam. Finally, from the distorted profile we derive the nonlinear refractive-index coefficient n₂ with an improved accuracy. The nonlinear refractive-index coefficients for the three lines are −7.9 ± 0.6 × 10⁻¹³ cm²/(W Torr) for 9R(26), −3.7 ± 0.5 × 10⁻¹³ cm²/(W Torr) for 9R(28), and 4.9 ± 0.4 × 10⁻¹² cm²/(W Torr) for 9R(30).

© 1993 Optical Society of America

Self-focusing and self-defocusing of a transversely excited atmosphere CO₂ laser pulse in a CH₃F medium

Gee Ho Kim, Sang Soo Lee, and Cha Hwan Oh
J. Opt. Soc. Am. B 8(8) 1747-1749 (1991)

Simultaneous nonlinear absorption and index effects in the propagation of intense tea CO₂ laser pulses through CDF₃

P. Galarneau, Z. Y. Niu, F. Yergeau, S. L. Chin, D. K. Evans, and Robert D. McAlpine
Appl. Opt. 24(17) 2804-2808 (1985)

Measurement of refractive indices and thermal refractive index coefficients of the Ti:Mg:LiNbO₃ crystal

Z. D. Zeng, H. Y. Shen, C. H. Huang, W. X. Lin, R. R. Zeng, Y. P. Zhou, G. F. Yu, and J. K. We
J. Opt. Soc. Am. B 10(3) 551-553 (1993)

Temperature dependence of water vapor absorption coefficients for CO₂ differential absorption lidars

Avishai Ben-David
Appl. Opt. 32(36) 7479-7483 (1993)

Optical nonlinearities of tea studied by Z-scan and four-wave mixing techniques

Y. M. Cheung and S. K. Gayen
J. Opt. Soc. Am. B 11(4) 636-643 (1994)