We have created microscopic Fabry–Perot optical resonator cavities between the flattened end of a tunneling microscope tip and a semitransparent metal film. Power is transferred to cavity modes from a laser beam by means of surface-plasmon–polariton generation and subsequent radiative decay. We compare the dependence of the axial emission from these modes on cavity length and on the angle of incidence with the predictions of a stratified-medium model. The mode structure has a finesse that approaches the theoretical limit. At high incident power, second-harmonic radiation produced by weakly localized surface-plasmon–polaritons is also coupled into the cavity and detected in axial emission.
© 2000 Optical Society of America
(140.4780) Lasers and laser optics : Optical resonators
(190.2620) Nonlinear optics : Harmonic generation and mixing
(240.4350) Optics at surfaces : Nonlinear optics at surfaces
(240.6680) Optics at surfaces : Surface plasmons
Klaus M. Engenhardt and Stephen Gregory, "Surface-plasmon–polariton excitation of optical microcavities and second-harmonic emission," J. Opt. Soc. Am. B 17, 593-599 (2000)