High-Sensitive Double-Hole Defect Refractive Index Sensor Based on 2-D Photonic Crystal

In this paper, we simulate a refractive index sensor based on the 2-D photonic crystal using finite difference time domain methods. The sensor which is called double-hole defect sensor, consists of two waveguides and two-point defect microcavities when the lattice constant is $a=440~{\rm nm}$ . In the optimum structure, the sensitivity of the sensor is $s=500~{\rm nm/ RIU}$ (refractive index unit), whereas the refractive index resolution is very small and $\Delta n=0.0001$ (i.e., resonance wavelength shifts up by 0.05 nm).