Measurements of thermooptic characteristics of magnetoactive glasses

Abstract

Summary form only given. Due to the recent increase in the average power of laser systems, the investigations of radiation depolarization caused by the photoelastic effect in Faraday isolators are becoming more important. In earlier work it was predicted that exactly this effect limits the isolation ratio in high average power laser systems, and the figure of merit /spl mu/ characterizing the magnetoactive medium in this regard was determined (the higher /spl mu/, the greater the isolation ratio and, consequently, the better the medium): /spl mu/=Vk/Q/spl alpha/ where V, /spl kappa/, /spl alpha/ are the Verde constant, the thermal conductivity, and the absorption coefficient, respectively, Q is the thermooptic constant characterizing the photoelastic effect. We measured the ratio Q/K for different magnetoactive glasses using an original technique and confirmed experimentally that exactly the photoelastic effect limits the isolation ratio in Faraday isolators at high average powers.