Abstract

In the present work we have discovered a new type of the four-photon parametric interaction, taking place in highly excited CdS_xSe_1−x crystals in the vicinity of excitonic resonance due to nonlinear change of the refractive index dispersion by two-photon excitation at 4,2 K. The two-photon excitation of mixed CdS_xSe_1−x (x = 0.5) crystals has been performed by neodymium laser radiation with an intensity of 90 MW/cm² propagating along the optical axis. Simultaneously with a usually observed recombination emission of an electron-hole plasma, ω_r (563 nm), an additional radiation at several frequencies ω₁, ω₂, ω₃ was registered in the same spectral range (540-580 nm).

© 1994 IEEE