All-optical micromechanical chemical sensors

The authors describe experimental results from micromechanical resonators coated with a chemoselective polymer that detect chemical vapors from volatile organic compounds using all-optical interrogation. The shift in the resonant frequency of the gold microbeam is read out using photothermal actuation and microcavity interferometry. Response times of less than 5s are achieved for vapor concentrations as low as 60ppm using optical powers of a few megawatts.