Anisotropy of thermo-optic properties of beryllium hexaaluminate crystal doped with chromium ions

We determined the thermo-optic coefficients of Cr3+-doped beryllium hexaaluminate crystal (Cr3+ : BeAl6O10) for light polarizations E vertical bar vertical bar N-p, N-m, and N-g, and present the thermo-optic dispersion formulas for the principal thermo-optic coefficients of Cr3+ : BeAl6O10. We also measured the linear thermal expansion coefficients for this crystal in the directions of optical indicatrix axes N-p, N-m, and N-g. Finally, we modeled the thermo-optic dispersion data in accordance with theory, taking into account contributions both from the change of the electronic bandgap with temperature and fromthe volumetric thermal expansion coefficient. (C) 2022 Optica Publishing Group