Method for the improvement of lateral resolution in stimulated emission depletion microscopy using a pupil filter

Abstract

We present a simple method to improve the lateral resolution of stimulated emission depletion microscopy. In stimulated emission depletion microscopy, a saturated zero-centred spot is usually used to achieve a high lateral resolution. Using a half-coated phase plate, a zero-centred spot was made with a narrow and steep gap at the centre. Numerical and experimental results show that by simply inserting a central obstacle as a pupil filter, it is possible to reduce the central gap of the zero-centred spot. Thus we can get a higher lateral resolution, although this sacrifices light efficiency.