Comparison between 355 and 1064-nm damage of high-grade dielectric mirror coatings

Autor: Mark R. Kozlowski, Christopher J. Stolz, Norbert Kaiser, Edward L. Pierce, Axel Bodemann
Rok vydání: 1996
Předmět:
Zdroj: 27th Annual Boulder Damage Symposium: Laser-Induced Damage in Optical Materials: 1995.
ISSN: 0277-786X
Popis: Advanced reactive e-beam evaporation process was used to deposit HfO2/SiO2 HR coatings for 355 nm high power laser applications. Atomic force microscopy studies and Nomarski microscopy have shown that the defect density of these coatings is extremely low exhibiting nearly no nodular defects known for an increased susceptibility to laser damage in the IR spectral region. Standard damage testing (conditioned and unconditioned) was conducted at LLNL at 355 nm (3 ns) for normal (0 degree(s)) and nonnormal-incident designs (45 degree(s)). Damage thresholds between 5 J/cm2 and 8 J/cm2 were obtained. No significant conditioning effect could be demonstrated. The same evaporation technique was used to manufacture normal incident HfO2/SiO2 HR coatings for 1064 nm wavelength from 2 different types of evaporant grade HfO2 as well as from a Hf metal source. Damage test results, as well as defect concentrations and conditioning effect, were compared to the 355 nm samples. Moreover, care was taken on the detection of the origin of damage at fluences near the damage thresholds.
Databáze: OpenAIRE