SEDL / STP / STP759-EB / STP36997S

1.3 μm Laser Rate Calorimetry and Photoacoustic Studies of the Surface and Bulk Optical Absorption in CaF² Single Crystal Samples

Fernelius, NC
University of Dayton Research Institute, Dayton, Ohio

Dempsey, DV
University of Dayton Research Institute, Dayton, Ohio

O'Quinn, DB
University of Dayton Research Institute, Dayton, Ohio

Pages: 17    Published: Oct 1981

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Abstract

There are a variety of techniques for measuring the surface-to-bulk optical absorption ratio most of which require specially prepared samples. In most works only one technique was employed on a given sample. In this work we tried three different techniques to measure the surface-to-bulk optical absorption ratio, r, at 1.3 μm on a group of similar CaF² single crystal samples. Laser rate calorimetry results on a series of samples of varying thickness gave r = β^S/β^B = 0.14 cm where β^S is the surface absorption and β^B is the bulk optical absorption in cm⁻¹. A second slope was not seen on the long bar samples which implies that r is less than 0.3 cm. Analysis of photoacoustic chopping frequency variation studies using the Bennett-Forman theory gave r = 0.07 cm about half the multithickness result. Considering the experimental uncertainties all three technique yielded consistent results.