title: Investigation of optical nonlinearities in an ultra-high-Q Si nanocavity in a two-dimensional photonic crystal slab.
abstract: We investigated the characteristics of an ultra-high-Q photonic nanocavity (Q = ~230,000 and modal volume = ~1.2 cubic wavelengths) at various input light powers. The cavity characteristics were red-shifted as the input power increased. This nonlinearity could be explained by coupled-mode theory, taking into account two-photon absorption, the associated free-carrier absorption, consequent free-carrier absorption, plasma effect, thermo-optic effect, and a Kerr effect. Nonlinear cavity characteristics were observed at an extremely low input light power of 10 muW. We confirmed that these low-power nonlinear optical effects could be attributed to the ultra-high Q factor of the nanocavity.
authors.forename: Toshitsugu
authors.initials: T
authors.lastname: Uesugi
authors.forename: Bong-Shik
authors.initials: BS
authors.lastname: Song
authors.forename: Takashi
authors.initials: T
authors.lastname: Asano
authors.forename: Susumu
authors.initials: S
authors.lastname: Noda