Optical microscopy is an indispensable tool for researchers, allowing them to closely investigate different organisms, revealing new features and phenomena in biomedical research. Although very useful, conventional imaging techniques that rely only on ballistic, unaffected photons to form images inside inhomogeneous media, like biological tissue, are eventually limited up to the diffusion regime of optical propagation where scattering becomes dominant and no ballistic light can be detected.
Adaptive optics and nonlinear optimization methods that rely on so called guide stars have been employed to overcome this problem and image deeper inside biological tissue. These techniques attempt to recover the optimal wavefront that will enhance the image quality or that will render a focus spot inside the scattering biological tissue. In order to achieve that, they have to iterate through each correction mode (e.g. each pixel on a wavefront shaper) thus trading off measurement time with wavefront resolution. Here we present a new turbidity suppression approach, termed Focus Scanning Holographic Aberration Probing (F-SHARP or F♯) that allows us to directly measure the amplitude and phase of the scattered light distribution at the focal plane (scattered E-field PSF). Knowledge of the E-field enables rapid correction of both aberration and scattering with a high resolution. We demonstrate the power of F-SHARP by correcting for aberration and scattering and imaging neuronal structures through the larval zebrafish and mouse brain and through thinned mouse skull in vivo.
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