High resolution photon scanning tunneling microscope

Abstract

A photon scanning tunneling microscope with a lateral resolution of a few nanometers is successfully constructed. This is achieved by using a total internal reflection arrangement in combination with an uncoated optical fiber probe. A shear force technique for the tip-to-sample distance regulation is also employed. Chemically etched optical fiber probes have resonance frequency at , with a Q factor of more than 100. The intensity of the evanescent field picked up by a fiber tip is traced as a function of tip-to-sample separation. The intensity decay is exponential, therefore a typical example of an evanescent wave. An optical image of dispersed latex spheres is displayed. The image is in good correlation to the simultaneously obtained topographic image. In the optical image, each sphere is displayed as the dim area. Optical images obtained by Ar laser and Xe lamp are displayed. For Xe lamp the lateral resolution is comparable with the result for Ar laser.