Transformation of the frequencies of nontraditional (4.3 and 10.4 μ) CO2 laser radiation bands in ZnGeP2

Frequency conversion of nontraditional CO₂ laser radiation bands was performed for the first time. The second harmonic of the 4.3μ (10⁰1–10⁰0) band was generated and this was summed with the second sequence band at 10.4μ (00⁰2-10⁰1). The phase matching angles were 55°50' and 54°20', respectively. The spectral and angular phase-matching bandwidths were investigated. The efficiency of doubling of the P(26) line in the 4.3μ band by conversion in a ZnGeP single crystal exceeded 10%.