It is presented that the thermally induced transmitted wavefront aberration of a high-reflectivity sampling mirror was detected on line using a Shack-Hartmann wavefront sensor (SHWS) in the beam quality measurement of an intense laser. As a result of heat absorption in the sampling mirror with active aperture of 120 mm, thermally induced wavefront aberration emerged when the mirror was exposed to high laser intensity of several kilowatts per centimeter square. Time-dependent wavefront aberration curves were acquired, and the transmitted wavefronts were reconstructed based on Zernike mode reconstruction theory. The experimental results indicate that the magnitude of the dynamic transmitted wavefront aberration increases gradually with the growing heat deposit during laser irradiation. The maximum of wavefront aberration observed after irradiation for 5 seconds reaches 0.11 μm of root-mean-square value. After further analysis, the experimental results of dynamic aberration can be applied in modifications for the measurement results of intense laser beam quality or tests for the thermal stability of optics used in the intense laser systems.

Date Published: 4 May 2015
PDF: 6 pages
Proc. SPIE 9543, Third International Symposium on Laser Interaction with Matter, 954325 (4 May 2015); doi: 10.1117/12.2180750

Published in SPIE Proceedings Vol. 9543:
Third International Symposium on Laser Interaction with Matter
Yury M. Andreev; Zunqi Lin III; Xiaowu Ni; Xisheng Ye, Editor(s)