High sensitive optofluidic sensor array based on ring-shaped holes photonic crystal H0-cavity

Abstract

The main objective of this work is to investigate a high sensitive optofluidic photonic crystal sensor. The proposed structure consists of ring-shaped holes H0-cavity coupled with two waveguides. We demonstrated that the use of the ring-shaped holes configuration provides an excellent optical confinement within the cavity region, which enhances the sensor performances. Furthermore, to overcome the single purpose capacity of the sensor, a multichannel optofluidic sensor has been implemented in a branch array structure. Each detection unit was designed for different cavity spacing and different resonant wavelength. Results obtained using finite-difference time-domain (FDTD) simulations, indicate that the response of each sensor unit shifts independently in terms of refractive index variations. Accordingly, a sensitivity of 450nm/RIU and a crosstalk lower than −43.78dB have been achieved, while maintaining a quality factor as high as 5.74×104. These features make the designed structure a promising platform for performing monolithic integration and high multiplexed label-free detection.