Simulation of single transparent molecule interaction with an optical microcavity

Finite- element simulations of nanoscale molecule interaction with the evanescent radiation field of an optical resonant microcavity are conducted to characterize the detection of single transparent molecules using the microcavity as an extremely sensitive micro/ nano- sensor. The model sensor is an integrated device consisting of a dielectric microdisk and a waveguide that can be nanofabricated on Si- based dielectric thin film. When the microdisk is operated at a whispering- gallery mode, a strong evanescent field arises, surrounding the periphery of the cavity. Foreign target molecules such as proteins present in the near- field will interact with the electromagnetic resonant field and induce changes to the resonance. Such induced changes are investigated in this report and their significance in the detection of single molecules for nanotechnology development is discussed.