Photobleaching imprinting microscopy: seeing clearer and deeper.

We present a generic sub-diffraction-limited imaging method - photobleaching imprinting microscopy (PIM) - for biological fluorescence imaging. A lateral resolution of 110 nm was measured, more than a twofold improvement over the optical diffraction limit. Unlike other super-resolution imaging techniques, PIM does not require complicated illumination modules or specific fluorescent dyes. PIM is expected to facilitate the conversion of super-resolution imaging into a routine lab tool, making it accessible to a much broader biological research community. Moreover, we show that PIM can increase the image contrast of biological tissue, effectively extending the fundamental depth limit of multi-photon fluorescence microscopy.