Effects of coherence and vector properties of the light on the resolution limit in stimulated emission depletion fluorescence microscopy.
Stimulated emission depletion (STED) fluorescence microscopy is a diffraction-unlimited microscopy. We report a method of analyzing the intensity distribution in the focal region. The method takes both the coherence and the vector properties of the light into account. By using the Gaussian Schell model to describe the cross-spectral density function of the incident beam, we show that the coherence that exists between the electric field at any two points is one of the factors that limit further increase of the spatial resolution in STED fluorescence microscopy.
Department of Optical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei,Nanjing, Jiangsu 210094, China. gaowangrong@yahoo.com
Wanrong
W
Gao