Polarization-dependent detection of cylinder nanoparticles with mode splitting in a high-Q whispering-gallery microresonator

Using the single-scatterer-induced coupling mechanism of a pair of counterpropagating high-Q whispering-gallery modes (WGMs), we investigate the highly sensitive detection of single nonspherical nanoparticles. The nonspherical particle may produce distinct frequency splitting and additional damping for TE and TM WGMs. This polarization-dependent effect allows for studying the orientation of single biomolecule, molecule-molecule interaction on the microcavity surface, and possibly distinguishing different inner configurations of similar biomolecules. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3520138]