Optical tuning of a tellurium cavity - Optical modulation and bistability in the infrared region at room temperature

A new intrinsic device is reported which consists of a plane-parallel semiconductor slab acting as a Fabry-Perot interferometer tunable by means of free carriers created by a multiphoton absorption process. An optical-optical modulator of this type designed for the infrared region wavelengths of (4-11 microns) has been fabricated using semiconducting tellurium. The operation of the device is described in terms of a simple theory using a plane-wave approximation and the Drude-Zehner model. Useful applications of the device are laser pulse shortening and fast switching in the infrared region. At optimum 5.3-micron intensities, switch-on times of 100 ps, limited by the build-up time of the 1.35-mm Fabry-Perot interferometer used should be possible.