High-sensitive symmetric Fano optical cavity sensor for refractive index detection based on photonic crystal structure

We have designed a high-sensitivity and high-quality factor (Q) photonic crystal (PhC) Fano sensor. By engineering of Fano cavity within a typical Fano structure, the light modes penetrated into the low index medium of the Fano cavity and the sensitivity as well as Q is increased. The transmission spectra of the presented sensor are numerically simulated using FDTD and the theoretical model of the structure is investigated. A sensitivity and Q of 528 nm/RIU and 3 X 10
⁴
have been demonstrated, respectively. To the best of our knowledge, this is the first device with figure of merit (FOM) of 1820 that shows high sensitivity and ultra-high Q simultaneously, while using Fano resonance in output.