In this paper, we report the excitation of whispering gallery modes (WGM) using a focused evanescent field. A focused evanescent field generated by total internal reflection at the cover glass-air interface was used to induce two-photon absorption in fluorescent polymer microcavities. By using a focused evanescent field it was possible to effectively couple light into the whispering gallery modes by the efficient overlap between the excitation volume and the cavity modes. The recorded whispering gallery mode spectra using an evanescent wave showed up to 38% enhancement in the spectral characteristics.
In this paper, we report on near field optical tweezers using focused evanescent illumination. The intensity pattern of the focused evanescent field has been characterized using a SNOM. The near field trapping efficiency has been experimentally and theoretically investigated using both TEM<sub>00</sub> and TEM<sub>01</sub> beams. The trapping efficiency was found to be polarization dependent and also changed for the two modes of illumination used. By incorporating the near field and far field optical tweezers one could construct an optical micromanipulation setup with great flexibility and accuracy, which would find applications in optical nanometry. By coupling the techniques like morphology dependent resonance (MDR), one could employ near field tweezers for near field sensing and for characterization of microfluidic channels.