Degenerate four-wave mixing due to intervalance band transition in p-type mercury cadmium telluride

Degenerate four-wave mixing in p-type HgCdTe has been observed with CO2 lasers. A room temperature, third order nonlinear susceptibility χ(3) of 8×10−6 esu has been measured. This is the largest χ(3) with picosecond relaxation time reported. The observed nonlinearity is interpreted in terms of the effective mass change induced by the transition from the heavy to light hole band. This process is shown to be stronger than the nonlinearity caused by the saturation of the intervalence band absorption.