Optical nonlinearities in amorphous silicon-carbon alloys

Picosecond excite/probe and degenerate four-wave mixing experiments in hydrogenated amorphous silicon-carbon alloys have been used to determine absorptive and refractive cross-sections of the photoinduced carriers. A maximum steady-state nonlinear refractive index n₂ of ~ 10^-5 cm²/W was derived from the results for excitation energy (2.33 eV) close to the optical bandgap (E_opt = 2.25 eV). Amorphous all-dielectric interference filters have been designed for 514 nm Ar and 633 nm HeNe laser emissions, using silicon-carbon alloys as the spacer material and multilayers of a-SiC:H and a-SiN:H for the reflecting stacks. We report the first demonstration of optical bistability in these devices. © 1989.