arXiv subjects

Ilya Sychugov

Publications and source records attributed to Ilya Sychugov.

6 recordsLinked to original sources

arXiv2026

Reciprocity Violation for Mie Scatterers at the Interface and a Scattering Solar Concentrator

It is shown that reciprocity of the optical path can be violated through asymmetric strength coupling via near-field from resonant Mie scatterers to total internal reflection modes in a dielectric slab. Numerical simulations for silicon nanospheres separated by a nanogap from the glass substrate reveal that at least two orders of magnitude rectification ratio can be realized for such an optical diode configuration. Implementation to a solar light harvesting device, a scattering solar concentrator, is discussed, indicating a similar efficiency is achievable as for the state-of-the-art devices based on luminescence.

physics.optics↗

arXiv2026

Edge photocurrent distribution in luminescent solar concentrators: analytical treatment and solar cell arrangement

In luminescent solar concentrators (LSCs), the light flux along the edges is non-uniform, which causes current mismatch between series-connected edge solar cells. Here, the optical path distribution of photons arriving at an edge point was derived analytically for a rectangular LSC and generalized to convex polygons, with reabsorption and scattering included as a geometric series. The model agrees with Monte Carlo simulations and reproduces measured edge cell currents of a $60\times60$ cm$^2$ LSC within 2-3%. In a square LSC, the series mismatch reduces the current by 8-12% for four cells per edge. Rules for edge solar cell arrangement are formulated.

physics.optics↗

arXiv2026

Polarization-resolved haze in transparent wood - towards wooden glass

Transparent wood (TW) composites possess residual haze that limits image clarity despite their high light transmission, yet the physical origin of this scattering has not been established. Here, polarization-resolved measurements reveal a pronounced polarization dependence of scattering by a wood-polymer composite with improved refractive index matching. Polarization- and spectrally-resolved haze as low as 21% (40-45% at 550 nm for unpolarized light) with transmittance of approximately 92% for polarization perpendicular to the fibers was detected. It is found that the low-haze spectrum closely follows an inverse-square relation over the 400-800 nm range, well described by a weak-index-contrast Rayleigh-Gans-Debye (RGD) model invoking subwavelength birefringent heterogeneities within the cell wall. This physical mechanism was previously obscured by haze-limiting strong scattering from debonding gaps or refraction at the lumen-cell wall interface. Scanning electron diffraction independently reveals spatially distinct domains with markedly different cellulose diffraction responses within the infiltrated cell walls. The observed polarization-dependent refractive-index mismatch is attributed to inherent cellulose birefringence. Time-resolved measurements further support nearly scattering-free quasi-ballistic transport of the sampled transmitted light. It is demonstrated that selecting only a preferential polarization markedly improves image visibility through TW without further material modification. These findings connect polarization-dependent haze to the internal structure of transparent wood and identify ways to engineer a refractive-index match in hierarchical anisotropic composites towards glass-like clarity.

physics.optics↗

arXiv2021

Photon Walk in Transparent Wood: Scattering and Absorption in Hierarchically Structured Materials

The optical response of hierarchical materials is convoluted, which hinders their direct study and property control. Transparent wood (TW) is an emerging biocomposite in this category, which adds optical function to the structural properties of wood. Nano- and microscale inhomogeneities in composition, structure and at interfaces strongly affect light transmission and haze. While interface manipulation can tailor TW properties, the realization of optically clear wood requires detailed understanding of light-TW interaction mechanisms. Here we show how material scattering and absorption coefficients can be extracted from a combination of experimental spectroscopic measurements and a photon diffusion model. Contributions from different length scales can thus be deciphered and quantified. It is shown that forward scattering dominates haze in TW, primarily caused by refractive index mismatch between the wood substrate and the polymer phase. Rayleigh scattering from the wood cell wall and absorption from residual lignin have minor effects on transmittance, but the former affects haze. Results provide guidance for material design of transparent hierarchical composites towards desired optical functionality; we demonstrate experimentally how transmittance and haze of TW can be controlled over a broad range.

physics.optics↗

arXiv2020

Tiling large areas with luminescent solar concentrators: geometry effects

Luminescence solar concentrators act as semi-transparent photovoltaic cells and can be applied to large surface areas in modern urban environment. In this paper their optical efficiencies were analytically derived for different unit shapes as simple, integral-free expressions. Perimeter length increase for the same enclosed area requires more photodetectors, yet reduces optical losses per unit. An exact interplay between these two parameters is presented, which can be directly applied to the analysis of tiling for large areas. An explicit expression for the critical size of an LSC unit, above which its inner part becomes inactive, has been obtained. Fabrication of devices larger than specified by this limit should be discouraged from efficiency considerations.

physics.app-ph↗

arXiv2019

Analytical Description of a Luminescent Solar Concentrator Device

An analytical solution for the optical efficiency of a luminescent solar concentrator is presented. Due to a large number of input parameters and their complex effect on the device efficiency numerical simulations have been previously used for this purpose. The formulas, provided here, derived using a probabilistic approach, significantly reduce the complexity of the problem. The equations were validated by simulations and the obtained explicit expressions provide a clear common ground for the theoretical description of such devices. Implementation by a computer algebra program yields instant results for any set of input parameters. It allows a higher level of analysis, where an inverse task of finding parameters for a given efficiency can be readily solved.

physics.optics↗