Theoretical study on biosensing characteristics of heterostructure photonic crystal ring resonator

In this paper, we investigate the biosensing characteristics of two-dimensional heterostructure photonic crystals (PCs) ring resonator theoretically by using the finite difference time domain (FDTD). The coupling air holes and inner air holes of ring resonator are treated as coupled sensing area and internal sensing area. When both of the sensing areas are filled with the same biological samples solution, the resonant peak wavelength shift of the ring resonance is different. Both the resonant peak center wavelength and peak intensity are related to the positions of sensing holes. With the same refractive index change of the biological sample, the sensing sensitivity of the coupling sensing area is much higher than that of the inner sensing area. Meanwhile, through the analysis of resonant peak wavelength shift, the refractive index change of the sample filled in the sensor area can be derived, which can be monitored real-time.