학술논문

Absorption Calorimetry and Laser Induced Damage Threshold Measurements of AR-Coated ZnSe and Metal Mirrors at 10.6 μm
Document Type
stp-paper
Source
Laser-Induced Damage in Optical Materials: 1990, Jan 1991, Vol. 1991, No. 1141, pp. 113-126.
Subject
CO2-laser
laser induced damage
single-shot
multiple-shot
laser calorimetry
photothermal deflection spectroscopy
ar-coating
metal mirror
video image processing
SURFACES AND MIRRORS
Language
English
Abstract
Absorption and pulsed laser induced damage of antireflective coatings on ZnSe and high reflecting metal mirrors were studied. As deposition materials for the AR-coatings germanium, zinc sulfide, zinc selenide, cadmium selenide and different fluorides were selected. For protecting and enhancing of metal mirrors zinc sulfide and zinc selenide were used in conjunction with ThF4 as low index material. The films were deposited by thermal evaporation.
Absorption measurements were performed with the aid of a laser calorimeter and a cw CO2-laser. Single-shot and multiple-shot (prf, 3 Hz) damage thresholds were measured by a computer controlled test facility using 100 ns pulses from a TEA CO2-laser. The gaussian beam was focussed down to a diameter of 1.4 mm on the sample surface. A scatter measurement system and an on-line video microscope were applied for damage detection. Damage morphology was investigated by Nomarski- and scanning electron microscopy.