This dissertation describes the force regulated near-field scanning optical microscope (NSOM) and two important adaptations: one for imaging polarization contrast with a linear response, and the other for interference imaging. An introduction to near- field optics is first presented, followed by a description of the background to this work that includes the relevant references to the literature and previous results. A simple theoretical description of the NSOM in terms of scalar fields is then presented, followed by an exposition of an early but relevant rigorous vectorial interpretation of the experiment. The basic force regulated NSOM is presented: its parts, operation, and construction is described and discussed, and its imaging capabilities are shown and discussed with results from different samples. In particular, the ability of the system to simultaneously image topographical and optical characteristics of the samples is described, and the importance of separating the optical and topographical information for the correct operation of the microscope is stressed. An adaptation to the basic NSOM that permits imaging sample-dependent polarization variations with sub-wavelength resolution and with a linear sensitivity is then discussed and analyzed. Results are shown for several samples that include metal on quartz, magneto-optic media, and polymers. Lastly, an interferometric arrangement of the NSOM is presented that allows imaging of phase variations, as well as polarization variations, with a significant signal enhancement achieved with the use of a pseudo-heterodyning technique.
Library of Congress Subject Headings
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Toledo-Crow, Ricardo, "Imaging modes in force regulated near-field scanning optical microscopy: Amplitude, polarization, and interference contrast" (1995). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus