Absorptance behavior of optical coatings for high-average-power laser applications
- Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States)
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. (c) 2000 Optical Society of America.
- OSTI ID:
- 20215991
- Journal Information:
- Applied Optics, Vol. 39, Issue 4; Other Information: PBD: 1 Feb 2000; ISSN 0003-6935
- Country of Publication:
- United States
- Language:
- English
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