Polarized spectral characteristics and 1.5-1.6 m laser operation of Er:Yb: CaSrAl₂SiO₇ crystal

An Er:Yb:CaSrAl2SiO7 single crystal was grown by the Czochralski method, and its polarized spectral properties were investigated at room temperature. The peak absorption cross-sections of the crystal at 978 nm are 3.30 x 10(-20 )and 1.42 x 10(-20) cm(2) for sigma and pi polarizations, respectively. The peak emission cross-sections at 1536 nm are 0.87 x 10(-20) and 0.95 x 10(-20) cm(2) for sigma and pi polarizations, respectively. The fluorescence lifetime of the 4I13/2 multiplet of Er3+ is 8.66 ms, and energy transfer efficiency from Yb3+ to Er3+ in the crystal is 70%. Pumped by a 975 nm diode laser, a continuous-wave laser with a slope efficiency of 5.5% and a maximum output power of 70 mW was achieved in the Er:Yb:CaSrAl2SiO7 crystal.