Slowdown of light signals and registration of phase modulation in semiconductor crystals of CdTe at room temperature in infrared

Abstract

We have developed model that describe transformation of time modulated optical signals by the double optical and electrical interferometer: beam coupling and holographic current in the semiconductor crystals. We consider non-local response, when dominant mechanism of the space charge formation is diffusion or drift in a high external electric field.Both phase and amplitude modulation is considered (linear ramp phase modulation, sinusoidal modulation, step-like modulation). For the sinusoidal amplitude modulation slow-down of optical signal is described. Experimental results on CdTe crystal with IR CW laser (P=100mW, wavelength 1064 nm)are in agreement with theoretical predictions.Effective group velocity was slow-downed to 555 cm/s for the modulated signal with period of 8ms.