Nonlinearity-modulated single molecule trapping and Raman scattering analysis

Single molecule detection and analysis play important roles in many current biomedical researches. The deep-nanoscale hotspots, being excited confined a plasmonic nanocavity, make it possible to simultaneously enhance the nonlinear light-matter interactions molecular Raman scattering for label-free detections. Here, we theoretically show that nanocavity formed tip-enhanced (TERS) system can also achieve valid optical trapping as well TERS signal single molecule. In addition, responses of metallic tip substrate film change their intrinsic physical properties, leading modulation force signal. results demonstrate new degree freedom brought by nonlinearity effectively modulating level. This proposed platform shows great potential various fields research need high-precision surface imaging.