Ultra-sensitive label free imaging below the resolution limit

Abstract

Almost all known nanoscopy methods rely upon the contrast created by fluorescent labels attached to the object of interest. This causes limitations on their applicability to in vivo imaging. A new label-free spectral encoding of spatial frequency (SESF) approach to nanoscale probing of three-dimensional structures has been developed. It was demonstrated that spatial frequencies, encoded with optical wavelengths, can be passed though the optical system independently of the resolution of the imaging system. As a result information about small size structures can be detected even using a low resolution imaging system. Different versions of the SESF imaging have been published [1-7], including a novel contrast mechanism for high resolution imaging [1], real time nano-sensitive imaging [2], reconstruction the axial (along depth) spatial frequency profiles for each point with nano-sensitivity to structural changes [3], and the adaptation of the SESF approach to depth resolved imaging [4,5]. Recently the SESF approach has been applied to overcome the diffraction limit and dramatically improve resolution [6,7]. Here we present further development of the SESF approach including correlation mapping SESF imaging. Both results of numerical simulation and preliminary experimental results, including biological samples, will be presented.

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