Whispering gallery modes excited by two-photon absorption induced by an evanescent field

摘要

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.