Conversion of CO2 and CO laser radiations in a ZnGeP2 crystal to the 2.3–3.1 μ spectral range

An experimental investigation was made of cascade generation of the fourth harmonic of CO₂ laser radiation and of the second harmonic of CO laser radiation in single crystals of zinc germanium diphosphide. The radiation was converted to the spectral range 2.3–3.1 μ. The overall efficiency of conversion of CO₂ laser radiation to the fourth harmonic was ~0.1 %, but it should be possible to increase it to 20%. The efficiency of conversion of CO laser radiation to the second harmonic was (2.5–10)×10^–3%.