arXiv subjects

Evangelos Marakis

Publications and source records attributed to Evangelos Marakis.

3 recordsLinked to original sources

arXiv2025

Anisotropy enables advanced light sheet microscopy with opaque lenses

Advances in fluorescence microscopy have reached a plateau in improving depth-to-resolution ratios for imaging scattering tissues, highlighting an urgent need for innovative techniques. We introduce Wavelens, a groundbreaking opaque lens that combines dynamic wavefront shaping with a passive, angularly anisotropic photonic scattering plate-designed to scatter light predominantly in one direction. This compact, robust optoelectronic device, comparable in size to a conventional microscope lens, delivers superior light sheet formation capabilities. Using Wavelens, we achieved high-resolution LSFM imaging of diverse biological specimens, including 3D tumor spheroids and the intricate neural architecture of Caenorhabditis elegans in vivo. Notably, Wavelens maintains consistent light sheet properties even in dense, scattering-prone samples, overcoming a long-standing limitation of traditional microscopy. This innovative approach has the potential to revolutionize optical imaging, offering unprecedented clarity and resilience, even within dense, scattering-prone biological samples.

physics.optics↗

arXiv2024

Mirror Symmetry in three-dimensional Multiple-Scattering Media

We investigate the effect of a mirror-symmetry plane in multiple-scattering media under plane-wave illumination along the symmetry plane. Designed and fabricated samples' optical transport properties are compared quantitatively with three-dimensional modeling. Strong polarization-dependent deviations of the bulk speckle-averaged intensity distribution at the symmetry plane are observed, showing either up to a factor two enhancement or complete suppression of the ensemble-averaged intensities. We derive analytical expressions for the ensemble-averaged intensity profiles near the symmetry plane. Apart from their interest in fundamental light propagation studies, applications of mirror-symmetric scattering media are envisioned in anti-counterfeiting.

physics.optics↗

arXiv2019

Uniform line fillings

Deterministic fabrication of random metamaterials requires filling of a space with randomly oriented and randomly positioned chords with an on-average homogenous density and orientation, which is a nontrivial task. We describe a method to generate fillings with such chords, lines that run from edge to edge of the space, in any dimension. We prove that the method leads to random but on-average homogeneous and rotationally invariant fillings of circles, balls and arbitrary-dimensional hyperballs from which other shapes such as rectangles and cuboids can be cut. We briefly sketch the historic context of Bertrand's paradox and Jaynes' solution by the principle of maximum ignorance. We analyse the statistical properties of the produced fillings, mapping out the density profile and the line-length distribution and comparing them to analytic expressions. We study the characteristic dimensions of the space in between the chords by determining the largest enclosed circles and balls in this pore space, finding a lognormal distribution of the pore sizes. We apply the algorithm to the direct-laser-writing fabrication design of optical multiple-scattering samples as three-dimensional cubes of random but homogeneously positioned and oriented chords.

cond-mat.soft↗