Radiation robustness of laser ceramics and single crystal for microchip laser remote analysis

レーザー遠隔分析用マイクロチップレーザーのためのレーザーセラミックスと単結晶の耐放射線性

田村 浩司; 中西 隆造; 大場 弘則  ; 平等 拓範*; 若井田 育夫  

Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Taira, Takunori*; Wakaida, Ikuo

Laser pulse energy and pulse build-up time were measured during gamma irradiation at a dose rate of 150 Gy/h to evaluate the radiation-induced effects and robustnesson a laser remote inspection system using ceramics and single crystal microchip laser. Results showed a time-dependent decrease in pulse energy and increase in pulse build-up time during irradiation. Both effects were larger for ceramics than for single crystal due to the amount of generated optical loss. The behaviors of pulse energy and build-up time with the increase in optical loss in the gain medium were simulated using rate equation calculations. The radiation effect on build-up time was larger than that on pulse energy for both specimens. Therefore, build-up time measurement is highly sensitive and effective for the evaluation of radiation effect generated in laser medium, especially for radiation robust specimens or at low radiation dose rate.