Parametric Frequency Converters Based on New Nonlinear Crystals

Results of investigations into the physical properties of a number of new nonlinear crystals are presented. The parameters of frequency converters manufactured on their basis are compared, and second-harmonic generation of CO2 lasers first excited by frequency conversion in LiInSe2, AgGa1– xInxSe2, AgxGaxGexS2(1 + x), and Hg1–xCdxGa2S4 crystals is investigated. The superiority of HgGa2S4, Hg1–xCdxGa2S4, and AgGa1–xInxSe2 over the well-known crystals has been demonstrated for frequency conversion both within the middle-IR range and from the visible range to the middle-IR range. Advantages of LiInSe2 and AgGa1–xInxSe2 crystals are demonstrated for the direct frequency conversion of femtosecond laser radiation to the middle-IR range compared to the cascade frequency conversion and direct frequency conversion in LiInS2 crystals.