One Dimensional SiN/Air Defect Multilayer based Nonlinear Optical Sensor

Nonlinear multilayer structure with a defect layer can be used in optical sensing by exploiting third order Kerr nonlinearity. In the present work, photonic crystal of multilayer structure as $(\mathrm{AB})3^{3}\mathrm{D})(\mathrm{BA})^{3}$ is considered to study the effect of intensity of light on transmission properties. SiN medium is used as higher refractive index as well as the defect layer with different thickness. As a defect layer it produces a defect mode inside photonic band gap region of transmission spectra. SiN material is used as Kerr nonlinear material whose refractive index depends upon intensity of light, therefore this defect mode is shifted due to the changes in refractive index of SiN induced by intensity. Theoretical simulation is obtained by transfer matrix method. Proposed structure can be used as optical sensor to detect the intensity of light in units of TW/cm2.