Significant photoinduced refractive index change observed in porous silicon Fabry-Perot resonators

It is shown that a porous silicon Fabry-Perot resonator device exhibits a s ignificant nonlinear optical transmission behavior at wavelengths in the ne ar-infrared region. The input-output (transmission-incident power) response curve shows superlinear or sublinear behavior dependent on excitation wave lengths around the resonant position. These characteristics are interpreted as a result of nonlinear refractive index change, including by enhanced op tical power in the Fabry-Perot cavity configuration and carrier accumulatio n in silicon nanocrystallites. The result leads to further progress of nano crystalline silicon into functional photonic device applications. (C) 2000 American Institute of Physics. [S0003-6951(00)03815-8].