This thesis addresses the problem of contrast in scanning optical microscopy by resorting to differential imaging. The use of a unique, two-wavelength laser as the coherent source in a scanning format is investigated. In particular, it is shown that the TEM10 mode of this laser provides a novel method for performing simultaneous conventional and differential microscopy. Results are presented on the use of the laser for performing differential imaging. In addition, the technique is extended to encompass a second, tunable, laser. Rather than performing electronic differentiation, the TEMi0 mode of this, second, laser provides an in-situ, optical differential microscope. Two different optical configurations are implemented, one system relies on electronic differentiation, while the second differentiates optically. These techniques could have special applications in general microscopy, and precision metrology.
Library of Congress Subject Headings
Microscopy; Gaussian beams; Optical scanners
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Iravani, Mehdi Vaez
Chrusch, Peter, "Conventional and differential scanning optical microscopy using higher-order Gaussian-Hermite beam patterns" (1990). Thesis. Rochester Institute of Technology. Accessed from
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