Effect of zero-order gratings on photonic localization of anisotropic periodic structures

Photonic localization in a periodic anisotropic structure with a defect of zero-order gratings has been investigated using the finite element method. The grating structure possesses a period that is small compared with the wavelength of light. The form-birefringence effect, caused by grating high spatial frequency, is introduced into the periodic structures by modifying the grating parameters, such as groove depth, filling factor, and refractive index of the intermixing material. This defect results in a peak in transmission for circularly polarized light with the same handedness as the chiral structure. The artificial dielectrics play a fundamental role in confining and manipulating light to affect the position, power transmittance and phase retardation of the defect mode. By changing the intermixing material of the grating into a different medium, the linearity of the sweep in defect wavelength depends on refractive index of the medium. The integrated optical device should be useful for application of (bio-)chemical sensors or optical refractometers.