SEDL / STP / STP689-EB / STP39120S

Optical Techniques for the Determination of Pulsed Laser Damage in Thin Films

Walker, TW
Air Force Weapons Laboratory, Kirtland AFB, NM

Guenther, AH
Air Force Weapons Laboratory, Kirtland AFB, NM

Nielsen, PE
Air Force Weapons Laboratory, Kirtland AFB, NM

Pages: 9    Published: Jan 1979

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Abstract

Two techniques, to determine the occurrence of pulsed laser induced damage in thin film dielectric coatings, were compared and evaluated against normally employed methods. One of the new techniques utilized near back scattered radiation from the damaging pulse and proved to be as sensitive as the best existing optical probe method while being experimentally facile. The second new method recorded a time delayed probe pulse which was reflected from the thin film damage site. This method appears to be more sensitive to a local index of refraction change in the thin film rather than increased reflectance/scattering from the damage site. Preliminary test results show that most of the morphological damage occurs after the damaging pulse has passed.