Effects of primary aberrations on the fluorescence depletion patterns of STED microscopy.

Effects of primary aberrations including spherical aberration, coma and astigmatism on the three fluorescence depletion patterns mainly used in stimulated emission of depletion (STED) microscopy are investigated by using vectorial integral. The three depletion patterns are created by inserting a vortex phase plate, a central half-wavelength plate or a semi-circular half-wavelength mask within Gaussian beam respectively. Attention is given to the modification of the shape, peak intensity, the central intensity of the dark hole and the hole size of these depletion patterns in the presence of primary aberrations.