Glass-ceramics with gamma-Ga2O3:Co2+ nanocrystals: saturable absorber for 1.5-1.7 mu m Er lasers

摘要

Transparent glass-ceramics containing gamma-Ga2O3:Co2+ nanosized (7-12 nm) crystals are synthesized in a lithium gallium silicate system. Their spectroscopic and nonlinear properties are studied. The absorption band related to the (4)A(2g)(F-4) -> T-4(1g)(F-4) transition of Co2+ ions in tetrahedral sites for these glass-ceramics is red-shifted up to similar to 1.8 mu m. The absorption saturation fluence is determined to be similar to 0.8 J cm(-2). The developed glass-ceramics are used for passive Q-switching of diode-pumped Er, Yb:glass laser delivering 1.75 mJ 25 ns-long pulses at 1540 nm.