High-Q resonance near zero wave vector in photonic crystal slab for label-free sensing

摘要

We report here experimental result of refractive index (RI) sensing using the singly degenerate high quality (Q) factor mode in photonic crystal slab (PCS) with the incident beam close to normal incidence. Q = 3.2×10~4 was measured with high extinction ratio (ER > 10 dB) for the PCS in air. Q = 1.8��10~4 and spectral sensitivity (S) of 94.5 nm/RIU were measured in liquid for the PCS. A detection limit {DL) of 10~(-5) RIU has been achieved with our device. The high-g for the singly degenerate mode close to normal incidence with relatively high S is very promising to achieve a lower DL for RI sensing.