Wavelength-dependent elasto-optic tensor elements from acoustic Bragg diffraction

Abstract

We report measurements of the elasto-optic constants p11 and p21 as a function of wavelength, for a variety of commercial glasses. The measurements were made using an apparatus based on the Dixon–Cohen design, in which the intensity of light diffracted from an acoustic pulse train is used to extract the elasto-optic tensor, using also data on the index of refraction and speed of sound. A variety of glass compositions were studied, and characterized compositionally using electron microprobe analysis; mechanically using speed of sound measurements; optically, via wavelength-dependent index of refraction; and structurally, using Raman and NMR spectroscopies. The final elasto-optic data were fit using the Wemple–DiDomenico model, and the results interpreted in terms of the effective band gap and deformation potentials, which were found to be sensitive to the different chemical bonds found in the glasses.