Parametric conversion of infrared radiation in a GaSe crystal

Radiations emitted by CO and CO₂ lasers were converted parametrically in a nonlinear GaSe crystal by mixing the radiation of one of these lasers with the radiation emitted by a YAG:Nd³⁺ laser. The phasematching angles were determined for the eo–e and oo–e interactions. The emission spectrum of a CO₂ laser was recorded photographically at the sum frequency. A comparison was made of GaSe with other nonlinear crystals suitable for infrared range.