STED microscopy based on axially symmetric polarized vortex beams
Zhou Zhehai†, 
, Zhu Lianqing‡,
, Zhu Lianqing‡, The sub-diffraction resolutions using three different ASPVBs when the ratio of the intracavity intensity to the saturation intensity changes from 1 to 100, where NA = 0.95.
