ANALYSIS OF PHOTON-SCANNING TUNNELING MICROSCOPE IMAGES OF INHOMOGENEOUS SAMPLES - DETERMINATION OF THE LOCAL REFRACTIVE-INDEX OF CHANNEL WAVE-GUIDES

Channel waveguides are imaged by a photon-scanning tunneling microscop e (PSTM). The polarization of the light and its orientation with respe ct to the guide axis are shown to be very important parameters in the analysis of the images of such samples. We simulated image formation f or the plane of incidence parallel to the axis of the guide. Our theor etical results are qualitatively in agreement with our measurements. T hese results show the ability of the PSTM to give information about th e local refractive-index variations of a sample.