Dynamic conjugate F-SHARP microscopy

Abstract

Optical microscopy is an indispensable tool in biomedical sciences, but its reach in deep tissues is limited due to aberrations and scattering. This problem can be overcome by wavefront-shaping techniques, albeit at limited fields of view (FOVs). Inspired by astronomical imaging, conjugate wavefront shaping can lead to an increased field of view in microscopy, but this correction is limited to a set depth and cannot be dynamically adapted. Here, we present a conjugate wavefront-shaping scheme based on focus scanning holographic aberration probing (F-SHARP). We combine it with a compact implementation that can be readily adapted to a variety of commercial and home-built two-photon microscopes. We demonstrate the power of the method by imaging with high resolution over extended FOV (>80 µm) deeper than 400 μm inside a mouse brain through a thinned skull.

Microscopy: sharp, deep, wide images with F-SHARP

A new microscopic approach helps obtain sharp images, with a wide field of view, in deep tissues. Focus scanning holographic aberration probing (F-SHARP) was developed by Benjamin Judkewitz of Charité–Universitätsmedizin Berlin and colleagues in Germany. This microscopic scheme can be readily adapted to a variety of two-photon microscopes. The team used their method for imaging neurons in live mice brains through a thinned skull, providing images with a field of view of wider than 80 µm and to a depth of more than 400 µm. F-SHARP uses wavefront shaping and a spatial light modulator to correct the aberrations and scattering that occur when light from a microscope interacts with an inhomogeneous scattering layer, such as a skull when viewing underlying brain tissue. The corrections undo the scattering to focus the image of the underlying tissue.