Hybrid External Cavity Laser based on a novel Si₃N₄ 1D Photonic Crystal cavity for label-free on-chip sensing applications

In this work we show the employment of a novel design photonic crystal (PhC) cavity in hybrid external cavity laser (HECL) configuration for refractive index sensing applications, with high sensitivity (145nm/RIU) and low detection limit (~10-5 RIU). The HECL RI sensor configuration exhibits a 16x improvement in the detection limit compared to the stand-alone photonic crystal cavity. In addition, the sensor is characterized by its compactness, high-power output, simplicity in fabrication, compatibility to integration process, and multi-sensing capability.