Use of GSGG:Cr:Nd crystals with photochromic centers as active elements in solid lasers

Gadolinium scandium gallium garnet crystals doped with Cr and Nd (GSGG:Cr:Nd) were investigated at low pump energies. The absorption by phototropic centers was optimized and a self-Q-switched laser was constructed. The efficiency of the laser was 1%, the pulse repetition frequency was 25 Hz, and the pump energy was 6 J/pulse. The energy of the output pulses was 65 mJ and their duration was 20 nsec. The gain of GSGG:Cr:Nd crystals with phototropic centers was determined, efficient lasing due to the ⁴F_3/2→⁴I_13/2(λ= 1.32μ) was achieved, and it was concluded that distributed phototropic losses in GSGG:Cr:Nd crystals can suppress parasitic stimulated transitions.