Compact side-coupled Silicon Nitride Photonic Crystal Nanobeam Cavity for refractive index sensing

In this work, we present a compact high-Q factor S 3 N 4 -based Photonic Crystal Nanobeam Cavity (PhCNC) that achieves calculated Q-factors above 10 ⁶ (experimental 10 ⁴ ) in case over a wide range of upper-cladding refractive index values (1 to 1.45), angle sidewalls (0°, 5° and 7°) and stick widths. In addition, a high sensitivity (~175nm/RIU) for liquids is demonstrated.