Abstract

A modified photothermal deformation technique is used to measure the absorptance behaviors of optical multilayered dielectric coatings for a high-power laser system. The surface thermal-lensing modification uses an enlarged probe beam to facilitate alignment of the laser beam and data acquisition. The coatings, both reflective and transmissive types, are made by a physical vapor-deposition process. Coating absorptances are observed to depend on the laser’s exposure time and power density. Time-dependent absorptance defect models are proposed. Also, micrometer-sized sites of high absorptance and an area with physical damage can be found during the spatial scans. It is proposed that absorptance values reported for coatings in high-repetition-rate or cw-laser systems include time- and power-dependent behaviors in addition to other relevant irradiation parameters.

© 2000 Optical Society of America

High-average-power dye laser at Lawrence Livermore National Laboratory

Isaac L. Bass, Regina E. Bonanno, Richard P. Hackel, and Peter R. Hammond
Appl. Opt. 31(33) 6993-7006 (1992)

Combined laser calorimetry and photothermal technique for absorption measurement of optical coatings

Bincheng Li, Holger Blaschke, and Detlev Ristau
Appl. Opt. 45(23) 5827-5831 (2006)

Enhanced surface thermal lensing for absorption evaluation and defect identification of optical films

Shu-hong Li, Hong-bo He, Yong-guang Shan, Da-wei Li, Yuan-an Zhao, and Zheng-xiu Fan
Appl. Opt. 49(13) 2417-2421 (2010)

Photothermal detuning for absorption measurement of optical coatings

Honggang Hao and Bincheng Li
Appl. Opt. 47(2) 188-194 (2008)

Liquid surface coating for optical components used in high power laser applications

A. R. Chraplyvy
Appl. Opt. 16(9) 2491-2494 (1977)