Reuss Matthias, Engelhardt Johann, Hell Stefan W
German Cancer Research Center (DKFZ), Optical Nanoscopy Division, Heidelberg, Germany.
Opt Express. 2010 Jan 18;18(2):1049-58. doi: 10.1364/OE.18.001049.
Stimulated emission depletion (STED) microscopy usually employs a scanning excitation beam that is superimposed by a donut-shaped STED beam for keeping the fluorophores at the periphery of the excitation spot dark. Here, we introduce a simple birefringent device that produces a donut-shaped focal spot with suitable polarization for STED, while leaving the excitation spot virtually intact. The device instantly converts a scanning (confocal) microscope with a co-aligned STED beam into a full-blown STED microscope. The donut can be adapted to reveal, through the resulting fluorescence image, the orientation of fluorophores in the sample, thus directly providing subdiffraction resolution images of molecular orientation.
受激辐射损耗（STED）显微镜通常采用扫描激发光束，该光束由环形STED光束叠加，以使激发光斑周边的荧光团保持暗态。在此，我们介绍一种简单的双折射装置，它能产生具有适合STED的偏振的环形焦斑，同时几乎不影响激发光斑。该装置能立即将配备共轴STED光束的扫描（共聚焦）显微镜转变为功能完备的STED显微镜。通过所得荧光图像，环形光斑可用于揭示样品中荧光团的取向，从而直接提供分子取向的亚衍射分辨率图像。
