Nanophotonic lab-on-a-chip Raman sensors: A sensitivity comparison with confocal Raman microscope

We compare the performance of the nano-photonic waveguide based evanescent Raman sensors and a typical the confocal microscope. For 1 cm long strip silicon nitride waveguides, we theoretically expect more than 500 times higher signal compared to the confocal microscopic systems. The results of our preliminary measurements indicate at least 50 times higher signal. For slotted waveguides, the preliminary measurement result yields about 300 times higher signal compared to confocal microscope while the theoretical figure is more than 2000.