Klar T A, Hell S W
Opt Lett. 1999 Jul 15;24(14):954-6. doi: 10.1364/ol.24.000954.
We overcame the resolution limit of scanning far-field fluorescence microscopy by disabling the fluorescence from the outer part of the focal spot. Whereas a near-UV pulse generates a diffraction-limited distribution of excited molecules, a spatially offset pulse quenches the excited molecules from the outer part of the focus through stimulated emission. This results in a subdiffraction-sized effective point-spread function. For a 1.4 aperture and a 388-nm excitation wavelength spatial resolution is increased from 150 +/- 8 nm to 106 +/- 8 nm with a single offset beam. Superior lateral resolution is demonstrated by separation of adjacent Pyridine 2 nanocrystals that are otherwise indiscernible.
我们通过抑制焦斑外部的荧光，克服了扫描远场荧光显微镜的分辨率限制。近紫外脉冲会产生受激发分子的衍射极限分布，而空间偏移脉冲则通过受激发射淬灭焦点外部的受激发分子。这导致了一个亚衍射尺寸的有效点扩散函数。对于1.4的孔径和388纳米的激发波长，使用单个偏移光束时，空间分辨率从150±8纳米提高到了106±8纳米。相邻的吡啶2纳米晶体原本无法分辨，但通过这种方法实现了分离，证明了卓越的横向分辨率。
