Free-running emerald laser pumped by 660-nm laser diode （LD） was reported. Free-running output power of 24 mW has been obtained with overall efficiency of 1.4% and slope efficiency of 11.9% when the LD incident power was 2.56 W. The laser threshold value of emerald crystal was estimated to be 0.7 W. OCIS codes： 140.3580, 140.3070.
The principal refractive indices and the thermal refractive index coefficients for Be3Al2Si6O18 crystal doped with 1.01wt% Cr2O3 have been accurately measured by the auto-collimation method at wavelengths of 0.488, 0.53975, 1.064, 1.0795 and 1.3414 μm, and temperatures of 308.2, 328.6, 359.1 and 395.4 K respectively. Based on the measured results of principal indices of 0.488, 0.6328, 1.0795 and 1.3414μm, the Sellmeier’s equations and the thermal refractive index coefficients have been obtained, and the result has been proven to be accurate by error analysis.
CHEN Zhenqiang1,2 ,ZHANG Ge1,SHEN Hongyuan1,HUANG Chenghui1 & LIU Wen1 1.Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China
