Isotropic three-dimensional super-resolution imaging with a self-bending point spread function

Airy beams maintain their intensity profiles over a large propagation distance without substantial diffraction and exhibit lateral bending during propagation(1-5). This unique property has been exploited for the micromanipulation of particles(6), the generation of plasma channels(7) and the guidance of plasmonic waves(8), but has not been explored for high-resolution optical microscopy. Here, we introduce a self-bending point spread function (SB-PSF) based on Airy beams for three-dimensional super-resolution fluorescence imaging. We designed a side-lobe-free SB-PSF and implemented a two-channel detection scheme to enable unambiguous three-dimensional localization of fluorescent molecules. The lack of diffraction and the propagation-dependent lateral bending make the SB-PSF well suited for precise three-dimensional localization of molecules over a large imaging depth. Using this method, we obtained super-resolution imaging with isotropic three-dimensional localization precision of 10-15 nm over a 3 mu m imaging depth from similar to 2,000 photons per localization.