Photonic crystal nanoslot nanolaser for super-sensitivity bio-sensing

High-performance and low-cost sensors are critical devices for high-throughput analyses of bio-samples in medical diagnoses and life sciences. This report demonstrates GaInAsP photonic crystal nanolaser sensor, which detects the adsorption of bio-molecules from the lasing wavelength shift. It is a promising device, which balances a high sensitivity, high resolution, small size, easy integration, simple setup and low cost. In particular with a nanoslot structure, it achieves a super-sensitivity in protein sensing whose detection limit is 3-5 orders of magnitude lower than that of standard surface-plasmon-resonance sensors, e.g. ~ 100 fM order for BSA and <; 1 aM for streptavidin. Our investigations suggest a candidate mechanism that the nanoslot acts as a protein condenser powered by the optical gradient force, which arises from the strong localization of laser mode in the nanoslot.