Abstract

Among the crystals used in laser development, the cubic ones are often considered because of their simplicity and their optical isotropy, leading to several advantages for thermal management and growing properties. However, in high power lasers, it is important to consider the thermally-induced birefringence and anisotropy sources. In this work we report on measurements of the thermal lenses anisotropy and thermal depolarization of Yb:CaF₂ crystals, with different cut-orientations at [110] and [111], and at cryogenic temperature [1,2]. A dedicated experimental setup is used to allow the investigation of the dependency of these thermal properties versus the polarization direction of a probe beam (Fig. 1). The main issue in this setup concerns the signal to noise ratio, due to the strong difference between the very-high pump power and the small depolarization losses. The specificity of the setup and the post-processing will be presented.

© 2017 IEEE