Nonresonant four wave mixing in photorefractive CdTe crystals using a picosecond parametric generator

Kestutis Jarašiunas (1) , Vytautas Gudelis (1) , Philippe Delaye (2) , Gérald Roosen (2)

1 Material Science and Applied Research Institut (Vilnius)
2 Laboratoire Charles Fabry de l'Institut d'Optique / Manolia

We demonstrate that a parametrically pumped picosecond laser has enough coherence and energy to write transient phase gratings at nonresonant interaction, thus allowing a study of time-resolved carrier transport in CdTe crystals to be made. Autocorrelation trace of light diffraction efficiency on transient grating allowed us to measure a coherence length of the parametric generator. Carrier diffusion, recombination, and drift in light-created internal space-charge ~SC! electric fields have been studied in vanadium or germanium doped semi-insulating CdTe crystals by nonresonant four-wave mixing technique at 940 nm wavelength. It was found that modification of the deep level charge state in CdTe:V by As codoping has changed the sign of majority carriers, responsible for the creation of SC field. Dynamics of free carrier grating decay in CdTe:Ge revealed an electron-governed very fast initial grating decay which develops with time into the double-exponential hole-governed grating decay. Time-resolved transient grating technique described in this article provides a powerful tool for investigation of the role of deep traps in photorefractive semiconductors and optimization of their photoelectric properties in a required temporal and spectral range

Domains: Optics [physics.optics]

Kestutis Jarašiunas, Vytautas Gudelis, Philippe Delaye, Gérald Roosen. Nonresonant four wave mixing in photorefractive CdTe crystals using a picosecond parametric generator. Review of Scientific Instruments, 1998, 69 (11), pp.3776-3779. ⟨10.1063/1.1149178⟩. ⟨hal-00673495⟩