The Photon Scanning Tunneling Microscope (PSTM)is the photon analogue of the electron Scanning Tunneling Microscope (STM). lt uses the evanescent field due to the total internal reflection of a light beam in a Total Internal Reflection (TIR) prism. The sample, mounted on the base of the prism, modulates the evanescent field. A sharpened optical fiber probes this field, and the collected light is processed to generate an image of the topography and the chemical composition of the surface. We give, in this paper, a description of the microscope and discuss the influence of several parameters such as-polarization of light, angle of incidence, shape of the end of the fiber-on the resolution. Images of various samples-glass samples, teflon spheresare presented.
A novel technique, photon scanning microscopy, is shown to probe directly the evanescent field outside a planar and a channel waveguide. The decay lengths for these evanescent fields were measured and correspond well to the decay lengths of the evanescent fields calculated for each structure. Two-dimensional scanning at constant intensity or constant height reveals lateral variations in these fields due to topographic changes, index of refraction inhomogeneities, or modal variations within the waveguide.
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