Near-field optical microscopy with a phase-conjugating mirror

To increase the contrast in near-field optical imaging of small objects, we suggest using a phase-conjugating mirror (PCM) as substrate. The expected contrast enhancement is related to the evanescent coupling of scattered light to the PCM. Preliminary experimental results on near-field optical imaging of complicated structures of latex spheres on the PCM surface ale presented. The PCM is established by degenerate four-wave mixing in a Fe:LiNbO3 0.04 wt% photorefractive crystal. Temporal evolution of the near-field optical images is investigated for both external and internal modes of illumination of the surface structures. Possibilities and limitations of the proposed technique are discussed on the basis of the results obtained. (C) 1998 Elsevier Science B.V.