Interscale mixing microscopy: far-field imaging beyond the diffraction limit

Abstract

We present an analytical description and an experimental realization of interscale mixing microscopy, a diffractionbased imaging technique that is capable of detecting wavelength/10 objects in far-field measurements with both coherent and incoherent broadband light. This method aims at recovering the spatial spectrum of light diffracted by a subwavelength object based on far-field measurements of the interference created by the object and a finite diffraction grating. A single measurement, analyzing the multiple diffraction orders, is often sufficient to determine the parameters of the object. The presented formalism opens the door for spectroscopy of nanoscale objects in the far-field.

Machine Learning-based Diffractive Imaging with Subwavelength Resolution

“…5, illustrating the robustness of the developed classifier that has been trained exclusively on theory-generated data that is capable of detecting each object (with smallest available to us dimension of 185 nm) with 532nm laser light. Note that while coherent laser light has been used in this work, our previous analysis [26] has indicated that gratings-assisted imaging works with incandescent white-light illumination. Similar to the theoretical studies reported above, not all the objects are classified with the same accuracy.…”

Quantum Limited Source Localization and Pair Superresolution under Finite Emission Bandwidth

“…The remaining integral in expression (13) over the radial distance variable, u, over the range (0, 1) can now be carried out by substituting (14) into that expression, with the result…”

“…More recently, the use of coherent detection techniques [14,15] have promised to enable true super-resolution of closely spaced point sources via quantum-correlated, optical centroid measuring states [16][17][18] and wavefront projections [19][20][21][22][23][24][25][26][27]. These latter papers, led principally by the work of Tsang and collaborators [19], have provided the most fundamental, quantum mechanical estimation-theoretic limits of superresolution possible by any method and their realization in the context of pointsource imaging.…”

Far-field intensity signature of sub-wavelength microscopic objects

“…This approach resembles object recovery in deconvolution microscopy [19]. It is also similar to the interscale mixing microscopy (IMM) [39,8], although we do not share the opinion [8] that a binary grating nonoverlapping with the object could introduce mixing of the evanescent spectrum of the object into the far-field pattern. In fact this concept is not upheld in [7].…”

“…Superresolving optical microscopy becomes increasingly important in medical and biological applications, in nanotechnology, material science etc. Recent advances in computational imaging [1,2] and deep learning [3] reopen the question of how much resolution can be enhanced by data completition methods [4,5,6,7,8]. While scanning near-field optical * rafalk@fuw.edu.pl microscopy [9] as well as techniques based on fluorescence microscopy [10] allow to reach a deeply sub-wavelength resolution down to the order of several nanometers, the resolution of classical optical imaging is restricted by the Abbe diffraction limit.…”