Nanoscale Low Crosstalk Photonic Crystal Integrated Sensor Array

We theoretically investigate a flexible design of building nanoscale photonic crystal (PhC) integrated sensor array with low crosstalk. The proposed device consists of array of side-coupled PhC resonant cavities with high Q-factors over 2 ×10³. The extinction ratio of well-defined single resonance exceeds 30 dB. Each resonant cavity has different resonant wavelengths and independently shifts its resonance in response to the refractive index variations. With three-dimensional finite-difference time-domain (3D-FDTD) method, simulation results demonstrate that the proposed sensor array is desirable to perform monolithically integrated sensing and multiplexed detection. Particularly, the design method here makes it possible to effectively enhance sensor array integration density and simultaneously restrain crosstalk between each other adjacent sensors. The refractive index sensitivity of 100 nm/RIU and the crosstalk lower than -4 dB are observed, respectively. Both the specific result and the general idea are promising in future optical multiplexed sensing and nanophotonic integration.