Novel piezoelectric heterostructure for all-optical infrared light modulation

We present an innovative-design heterostructure based on the exploitation of in-the-barrier piezoelectric field for all-optical light modulation. The novel layout allows an efficient light modulation with low power densities (few tens of W/cm(2) ), easily attainable with standard laser diodes. The modulation mechanism relies upon drastic photocarrier separation by the piezoelectric field in the barrier layers. We present room temperature results showing that an optical "control" power of 70 W/cm(2) creates in the heart of the structure a space-charge field of about 30 kV/cm, inducing large spectral shifts (similar to 100 nm) in the photoluminescence spectra of a CdHgTe quantum well in the 1.5 mu m range.