SEDL / STP / STP954-EB / STP23108S

Automated Pulsed Testing Using a Scatter-Probe Damage Monitor

Franck, JB
Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

Seitel, SC
Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

Hodgkin, VA
Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

Faith, WN
Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

Porteus, JO
Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

Pages: 6    Published: Jan 1986

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Abstract

This paper describes automated pulsed testing of infrared mirrors based on scatter-probe detection of laser damage. Advantages of our approach are (1) ability to monitor minute changes in surface condition without an observer, (2) rapid sampling of a large matrix of test fluences and test positions on the mirror, (3) automatic selection of test fluences, (4) automatic control of laser intensity drift, and (5) compatibility with a vacuum test environment.

Automated determination of damage frequencies and relative damage onsets will be described for single-layer-coated and uncoated metal and semiconductor mirrors. Tests were performed at 2.7 and 10.6 μm with 1/e² focal spot diameters of 150 and 240 μm, respectively, using a nominal 100-ns pulse length in all cases. Results obtained with the scatter probe will be compared with those obtained from Nomarski postdamage analysis.