Single-cell bacterium identification with a SOI optical microcavity

International audiencePhotonic crystals and microcavities can act as on-chip nano-optical tweezers for identification or manipulation of biological objects. So far, virus and bacteria optical trapping has been achieved, their presence in the vicinity of the optical resonator being deduced from a shift of the resonant wavelength. Here we show that bacteria can not only be trapped but identified as well if the trapping time is long enough. A silicon on insulator microcavity with a properly tuned quality factor allows to achieve enhanced trapping times. By combining spatial and temporal observation of bacteria-cavity interaction, the optical identification of three different kinds of bacteria is demonstrated