Resolution issues in scanning optical microscopies

Several issues concerning lateral spatial resolution in scanning optical microscopes, SOM's, are addressed. After identifying what is meant by resolution in an SOM, the role of probe tip morphology is discussed. Consideration of the physical mechanism of signal transduction is made, and fundamental differences between near field SOM's and evanescent field SOM's are underscored. Therole of dithering of the probe tip in improving resolution is demonstrated and discussed.