Nonlinear response of a silicon waveguide enhanced by a metal grating

We theoretically demonstrate that nonlinear optical response in a thin silicon waveguide within a wide wavelength regime can be enhanced by a metal grating. Numerical simulation indicates that the enhancement factor of the four-wave mixing signal varies with the position. The largest enhancement factor of the four-wave mixing is more than 10(4) at a certain position in the IR spectrum with proper geometric parameters. More importantly, the wavelength of four-wave mixing with the same enhancement factor can be controlled dynamically within a wide wavelength regime.