Similar Role of Transient Kerr Effect and Two-Photon Absorption in a Nonlinear Photonic Crystal Nanocavity

The impacts of transient Kerr effect (TKE) on the characteristics of a nonlinear photonic crystal (PC) nanocavity are theoretically and numerically investigated. It is found that the features of TKE are very similar to those of two-photon absorption (TPA), but the mechanisms for them are essentially different. The relative magnitude of TKE to TPA is calculated, and the result indicates that the contribution of TKE should also be considered in actual designs of PC devices with Kerr nonlinearity. The theory presented in this paper will be helpful for the precise designs of nonlinear PC devices.