Abstract

High-energy laser systems include an optical train and a gas medium that must be capable of transporting and directing the beam. The optical train is termed a laser beam tube. Because of the finite absorption of laser energy, the thermal effects of the beam tube make the beam diffuse and cause degradation of the laser beam’s quality. We study systematically a beam tube consisting of a laser window made from white bijou (i.e., ${\mathrm{Al}}_2{\mathrm{O}}_3$) or fused silica and a tube of nonflowing nitrogen or helium gas. The results show that the thermal effects of the window and the gas on the beam neutralize each other; in particular, in some cases they compensate for each other completely, such that the beam tube has no effect on the beam quality in spite of the fact that separately each has a severe effect. We explain how to acquire the specific cases.

© 2004 Optical Society of America

Three-dimensional calculation of high-power, annularly distributed, laser-beam-induced thermal effects on reflectors and windows

Weiping Wang, Fuli Tan, Baida Lü, and Cangli Liu
Appl. Opt. 44(34) 7442-7450 (2005)

Determination of absorption coefficient based on laser beam thermal blooming in gas-filled tube

B. Hafizi, J. Peñano, R. Fischer, G. DiComo, and A. Ting
Appl. Opt. 53(22) 5016-5023 (2014)

Effects of a gas medium on ultrafast laser beam delivery and materials processing

Ju Sun and Jon P. Longtin
J. Opt. Soc. Am. B 21(5) 1081-1088 (2004)

Influence of thermal deformations of the output windows of high-power laser systems on beam characteristics

Yufeng Peng, Zhaoxia Sheng, Hu Zhang, and Xiaowei Fan
Appl. Opt. 43(35) 6465-6472 (2004)

Similarity of laser window thermal effects

Jianzhu An, Youkuan Li, and Xiangwan Du
Appl. Opt. 47(2) 263-268 (2008)