Spectroscopic properties and laser operation of RE~(3+)-ion doped garnet materials

摘要

There has been considerable interest in the trivalent rare earth-ion-doped ceramic laser materials because of its numerous advantages over melt growth methods, including faster production times, solid solution allowing the fabrication of multi-phase transition materials, highly homogeneous materials and the ability to engineer profiles and structures before sintering. Much progress has been made in improving the optical quality from ceramics, as well as exploring new materials. Successfully developed concentrated Nd:YAG ceramics was opened the way for drastic heat reduction by directly upper laser level pumping. In this present, after the spectroscopic investigation of rare-earth doped garnet materials includes ceramics, we report about the heat generation properties with the radiative quantum efficiency. Lately developed RE~(3+)-ion-doped disordered laser ceramic materials, Y_3Sc_xAl_(5-x)O_(12), which are a solid solution of YAG and Y_3Sc_2Al_3O_(12)(YSAG), have been interested in because of its compositional tuning of parameter x. The disordered Y_3ScAl_4O_(12) (YAG/YSAG) ceramics exhibit relatively low minimum pump intensity (I_(min)) and broad emission bandwidth. The value of I_(min) in the Yb:Y_3ScAl_4O_(12) ceramics was found to be 2/3 compared with the Yb:YAG single crystal under 970nm zero-line pumping. Efficient laser oscillation of 72% slope efficiency was obtained for input power. Next, we have demonstrated passively mode-locked Yb:Y_3ScAl_4O_(12) disordered ceramic laser by using a semiconductor saturable-absorber mirror. Pulses as short as 280 fs having an average power of 62 mW at 1035.8 nm was obtained. As a conclusion, the possibility of tailored fluorescence spectral profile in layer-by-layer type ceramic composite will be discussed.