Passive Q-switching in Nd:YAG/Cr4+:YAG monolithic microchip laser

Abstract Composite laser devices of passively Q-switched Nd:YAG were prepared by optical contacting between Nd:YAG and Cr,Ca:YAG crystal wafers followed by prolonged heating at elevated temperatures. Heating of the composite devices under reducing and/or oxidizing environments allowed to control the Cr4+ ion concentration in the Cr,Ca:YAG, thus affecting its absorption saturation behavior. Optical absorption saturation measurements on partially reduced Cr,Ca:YAG crystal were performed. Residual absorption of the saturable absorber at 1064 run results from the Cr4+ ion excited-state absorption. Laser damage threshold at the gain/absorber interface of the composite device, 14.7 J/cm2, is higher than at the entrance face. The device thus obtained was end-pumped by a fiber-optic-coupled diode laser, and exhibited short (∼5 ns), high repetition-rate pulsing.

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