DEVELOPMENT OF AN OPTICAL-SCANNING TUNNELING MICROSCOPE

A photon scanning tunneling microscope (PSTM) with longitudinal resolution in the subnanometer range is described. It operates by monitoring the reflected rather than transmitted tight intensity. The most remarkable differences, as compared to other PSTMs are its possibility to scan over opaque samples and to allow an easier interpretation of the images since one can use, with good approximation, the plane wave theory. This instrument is extremely sensitive to the specimen profile and the measurements show that a variation in profile height of one nanometer gives a variation in the signal amplitude that is twice the long-term reproducibility. Lateral resolution, however, is the same as in classical optical microscopes.