SHG in doped GaSe:In crystals

Optical transmission range and phase matching (PM) conditions for second harmonic generation (SHG) of Er3+:YSGG and CO2 laser in indium doped GaSe:In(0.1, 1.23, 2.32 mass%) are studied in comparison with these in pure and sulfur doped GaSe:S(0.09, 0.5, 2.2, 3 mass%) crystals. No changes in transparency curve are found in GaSe crystals up to 2.32 mass% indium content, but as small change as 0.18 in PM angle for 2.79 mu m Er3+:YSGG laser SHG and similar to 0.06 for 9.58 mu m CO2 laser emission line SHG are detected. PM properties of the crystals are evaluated as a function of temperature over the range from -165 to 230 C. The value of d theta/dT, the change in PM angle with variation of temperature, is found to be very small for GaSe: In crystals. While for SHG of Er3+: YSGG laser, d theta/dT = 22 ''/1 degrees C only, it is as small as -4.9 ''/1 degrees C for that of CO2 laser radiation. Linear variation of PM angle with temperature increasing is an indicator of absence of crystals structure transformation within temperature range from -165 to 230 degrees C. Thus, application of GaSe: In solid solutions in high average power nonlinear optical systems seems to be prospective. (c) 2008 Optical Society of America.