Stress and Piezoelectric Tuning of Silicon’s Optical Properties

In optics, stress modi„es the material’s optical properties through the photoelastic e›ect: a process in which the refractive index varies with the applied stress. More interestingly, acoustic waves, which result in refractive index gratings in the material, lead to an important class of photonic devices called acoustooptic devices, which have been used as optical modulators, beam deÁectors, frequency shifters, and optical couplers [3].