Phase-matching and femtosecond difference-frequency generation in the quaternary semiconductor AgGaGe5Se12.
We present data on the linear (transmission, index of refraction) and nonlinear (second-order susceptibility) optical properties of the quaternary semiconductor AgGaGe5Se12 with orthorhombic symmetry--a solid solution in the AgxGaxGe1-xSe2 system with x = 0.17. The nonlinear coefficients are estimated from phase-matched second-harmonic generation near 3 microm. After numerical analysis of the phase-matching configurations for three-wave nonlinear interactions, the first experimental results on difference-frequency mixing, producing tunable (4-7.5-microm) femtosecond pulses at a 1-kHz repetition rate, are described. The pulses of only five optical cycles (FWHM = 84 fs) are generated near 5 microm with energy of 0.5 microJ. Because of its higher damage threshold, larger birefringence and bandgap, and greater variety of phase-matching schemes, AgGaGe5Se12 could become an alternative to AgGaS2 and AgGaSe2, more widely used in high-power and specific applications.
Petrov
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Max Born Institute for Nonlinear Optics and Ultrafast Spectroscopy, 2A Max Born Strasse, D-12489 Berlin, Germany. petrov@mbi-berlin.de
Noack
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Badikov
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Shevyrdyaeva
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Panyutin
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Chizhikov
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