Operational Characteristics of GaSe Crystals for Mid-IR and Far-IR Applications
AbstractGaSe has a number of attractive properties for nonlinear optical applications including large birefringence for ease in phase matching. Its biggest drawback is its mechanical properties. GaSe has a strong tendency to cleave along the <100> plane which has made it difficult to grow and fabricate. We have developed a method to modify GaSe by structurally strengthening the material by doping. We have synthesized large boules of GaSe reacted mixtures and grown centimeter size single crystals by the Bridgman technique. Depending on the dopant and crystal quality, SHG measurements indicate a deff, of 51 to 76 pm/V. SHG power levels were theoretically calculated and appear to be in good agreement with the experimental data. The measured performance of crystals for the fourth harmonic generation and laser damage threshold are also reported in this paper. The damage threshold was greater than 2.8 J/cm2 and 85 KW/cm2 at the surface of the crystal.