STED microscopy based on axially symmetric polarized vortex beams
Zhou Zhehai†, 
, Zhu Lianqing‡,
, Zhu Lianqing‡, Schematic diagram of the STED microscopy using ASPVBs. PHF: pin-hole filter, L: lens, PV: polarization converter, PF: pupil filter, DS: dichroic splitter.
