Nanophotonics Sensor Based on Microcantilever for Chemical Analysis

Abstract—A Si-based cantilever sensor with photonic crystal (PC) resonator as readout for chemical sensing and analysis has been developed. The resonant wavelength shift of PC resonator is resulted from PC deformation induced by cantilever bending, in which this optical readout scheme facilitates cantilever deflec-tion measurements in liquid. Through numerical simulation, we demonstrate that the detection capability of this micromechanical sensor operated in water is better than that of sensor operated in air. The minimum detectable Z-displacement and strain of Si/SiO2 cantilever sensor are derived as 0.6 µm and 0.0098 % in water and 0.812 µm and 0.0144 % in air, respectively. This novel microme-chanical sensor shows its promising future in applications such as detection of proteins and DNA in solution. Index Terms—MEMS, microcantilever, nanomechanical sensor, NEMS, photonic crystal resonator. I