Observation of the local field distribution in photonic crystal microcavity by SNOM technique

Abstract

The spatial distribution of the local optical field at the cleavage of photonic crystal smicrocavity has been obtained by the scanning near-field optical microscope (SNOM). The localization of optical radiation at microcavity resonant wavelength in the vicinity of the λ/2 spacer layer is demonstrated. Samples of photonic crystal microcavity are prepared from silicon wafer by electrochemical etching technique. The wavelength of the microcavity mode is optimized for resonance with wavelengths of lasers. The image of the spatial distribution of optical field at the cleaved edge of the facing vertically microcavity is observed. Sample is pumped through external single-mode fiber perpendicularly to the microcavity. SNOM operates in the collection mode with the apertureless tip. We observe the localization of the resonant optical field in microcavity but we do not reveal such localization of the radiation at the non-resonant wavelength.