publications
An extended list is available on Google Scholar.
Journal & conference papers
2026
- Bridging classical and quantum approaches for quantitative sensing of turbid media with polarization-entangled photonsLaser & Photonics Reviews, Jan 2026
Polarimetry with quantum light promises improved measurements for various scenarios. However, fundamental understanding of quantum photonic state transport in complex, real media and tools to interpret the state after interaction with the sample are still lacking. Here, we theoretically and experimentally explore the evolution of polarization-entangled states in a turbid medium on example of tissue phantoms. By elaborating mathematical relationship between Wolf’s coherency matrix and density matrix, we introduce a versatile framework describing the transfer of entangled photons in turbid environments with polarization tracking and resulting quantum state representation with the density operator. Experimentally, we reveal a robust trend in the state evolution depending on the reduced scattering coefficient of the medium. Our theoretical predictions correlate with experimental findings, while the model extends the study by photonic states with different degrees of entanglement. The presented results pave the way for quantitative quantum photonic sensing enabling applications ranging from biomedical diagnostics to remote sensing.
ArXiv version (with earlier variant of the text): https://doi.org/10.48550/arXiv.2411.06134.@article{BesagaLopushenko2026, title = {Bridging classical and quantum approaches for quantitative sensing of turbid media with polarization-entangled photons}, author = {Besaga, Vira R. and Lopushenko, Ivan V. and Sieryi, Oleksii and Bykov, Alexander and Setzpfandt, Frank and Meglinski, Igor}, year = {2026}, month = jan, pages = {e01172}, doi = {10.1002/lpor.202501172}, journal = {Laser & Photonics Reviews} }
2025
- Quantum State Density Matrix Modeling: Exploring the Scattering of Polarization-entangled Photon PairsIn Progress In Electromagnetics Research Symposium - Abu Dhabi , May 2025
We explore novel methods of optical characterization with polarization-entangled photons. In particular, we study scattering-based light-matter interaction of the polarization-entangled photonic states on the example of propagation of the Bell state through a tissue-like medium and describe it with a technique rooted in the iterative solution to the Bethe-Salpeter equation. We investigate the relationship between Wolf’s coherency matrix of the polarized light in the classical interpretation and the density matrix of the photonic quantum state. Based on their connection, we introduce a novel Monte Carlo model which generalizes the well-acknowledged statistical description of light transfer through a scattering medium and expand it to the description of polarization-entangled photons, allowing us to follow the evolution of amplitude probability coefficients along photon trajectories. We demonstrate the capabilities of the developed method to predict the medium-affected photonic state in the form of a density matrix independent of the entanglement level of the probing state and validate the model by experimental studies on the example of tissue-mimicking phantoms exhibiting different scattering properties via realization of quantum state tomography. The presented findings are expected to significantly enrich the fields of optical classical and quantum metrology and foster the development of quantum-enhanced optical technologies.
2024
- Exploring the evolution of circular polarized light backscattered from turbid tissue-like disperse medium utilizing generalized Monte Carlo modeling approach with a combined use of Jones and Stokes–Mueller formalismsJournal of Biomedical Optics, May 2024
Significance
Phase retardation of circularly polarized light (CPL), backscattered by biological tissue, is used extensively for quantitative evaluation of cervical intraepithelial neoplasia, presence of senile Alzheimer’s plaques, and characterization of biotissues with optical anisotropy. The Stokes polarimetry and Mueller matrix approaches demonstrate high potential in definitive non-invasive cancer diagnosis and tissue characterization. The ultimate understanding of CPL interaction with tissues is essential for advancing medical diagnostics, optical imaging, therapeutic applications, and the development of optical instruments and devices.
Aim
We investigate propagation of CPL within turbid tissue-like scattering medium utilizing a combination of Jones and Stokes–Mueller formalisms in a Monte Carlo (MC) modeling approach. We explore the fundamentals of CPL memory effect and depolarization formation.
Approach
The generalized MC computational approach developed for polarization tracking within turbid tissue-like scattering medium is based on the iterative solution of the Bethe–Salpeter equation. The approach handles helicity response of CPL scattered in turbid medium and provides explicit expressions for assessment of its polarization state.
Results
Evolution of CPL backscattered by tissue-like medium at different conditions of observation in terms of source–detector configuration is assessed quantitatively. The depolarization of light is presented in terms of the coherence matrix and Stokes–Mueller formalism. The obtained results reveal the origins of the helicity flip of CPL depending on the source–detector configuration and the properties of the medium and are in a good agreement with the experiment.
Conclusions
By integrating Jones and Stokes–Mueller formalisms, the combined MC approach allows for a more complete representation of polarization effects in complex optical systems. The developed model is suitable to imitate propagation of the light beams of different shape and profile, including Gaussian, Bessel, Hermite–Gaussian, and Laguerre–Gaussian beams, within tissue-like medium. Diverse configuration of the experimental conditions, coherent properties of light, and peculiarities of polarization can be also taken into account.@article{Lopushenko2024, author = {Lopushenko, Ivan and Sieryi, Oleksii and Bykov, Alexander and Meglinski, Igor}, journal = {Journal of Biomedical Optics}, title = {Exploring the evolution of circular polarized light backscattered from turbid tissue-like disperse medium utilizing generalized Monte Carlo modeling approach with a combined use of Jones and Stokes–Mueller formalisms}, year = {2024}, issn = {1083-3668}, month = may, number = {05}, volume = {29}, doi = {10.1117/1.jbo.29.5.052913}, publisher = {SPIE-Intl Soc Optical Eng}, }
2023
- Depolarization composition of backscattered circularly polarized lightIvan Lopushenko , Alexander Bykov , and Igor MeglinskiPhysical Review A, Oct 2023
We consider the origin of unpolarized light resulting from the backscattering of circularly polarized light by a turbid tissue-like medium. We reveal the dynamics of the backscattered fraction of unpolarized light, disclosing its decomposition into two fully polarized components characterized by opposite helicities. Concurrently, their superposition, driven by multiple scattering within the medium, leads to the appearance of a fraction of linear polarization. We emphasize that the in-depth binding of light circular polarization memory when the helicity flips occurs within the scattering medium, meaning the conservation of spin angular momentum. We anticipate that the results obtained hold significant implications for future studies, particularly in the field of tissue polarimetry and light vortices.
@article{Lopushenko2023, author = {Lopushenko, Ivan and Bykov, Alexander and Meglinski, Igor}, journal = {Physical Review A}, title = {Depolarization composition of backscattered circularly polarized light}, year = {2023}, issn = {2469-9934}, month = oct, number = {4}, pages = {l041502}, volume = {108}, doi = {10.1103/physreva.108.l041502}, publisher = {American Physical Society (APS)}, } -
Computer algebra solution to Mie scattering problem for the stratified sphere with nonlocal plasmonic layersIvan LopushenkoIn 20th Electromagnetic and Light Scattering Conference , May 2023Plasmonic particles with scale less than 10 nm are known to exhibit unique scattering properties related to the nonlocal spatial dispersion effects. These are not accounted for in the majority of electromagnetic solvers that are conventionally used to simulate scattering by nanostructures. Several nonlocal-corrected Maxwell-based models were recently proposed in attempt to interpret dispersive phenomena in terms of classic constitutive equations and boundary conditions (BC). Among these models Generalized Nonlocal Optical Response (GNOR) theory with hard wall BC and an approach based on mesoscopic BC are being actively studied. For the specific cases they both provide results close to experimental measurements.
Each of the Maxwell-based approaches (traditional Mie theory, GNOR, or mesoscopic) implies its own scattering problem statement involving possibly modified Maxwell equations, BC, and radiation conditions. For spherical particles these problems have analytic solutions. However, corresponding analytic expressions usually must be coded independently because expansion coefficients have to be obtained from scratch for each problem. For a sphere with present nonlocal layers, it is a straightforward but practically cumbersome task due to the lengthy expansions and presence of highly oscillating longitudinal fields.
In this work, outlined problems are solved with a universal computer algebra algorithm (symMie) implemented in the MATLAB/Octave symbolic package framework. The algorithm allows user to construct a set of BC (which could be either classic Mie, GNOR hard wall or mesoscopic) for a stratified sphere optionally involving nonlocal layers. The code comes with symbolically pre-defined full basis set of SVWFs (spherical vector wave functions, including longitudinal ones) and field expansions. Moreover, it is not limited to them, enabling one to flexibly adjust functional basis for the specific problem. Eventually, constructed BC set forms a system of linear equations with unknown Mie expansion coefficients, which can be solved either fully symbolically or with variable precision arithmetic allowing to constrain rounding errors. This approach proves useful when it is necessary to obtain an analytic solution to a scattering problem with spherical geometry given the lack of resources for an implementation of problem-specific code.
2022
- Screening of Alzheimer’s Disease With Multiwavelength Stokes Polarimetry in a Mouse ModelIEEE Transactions on Medical Imaging, Apr 2022
The minimum histological criterion for the diagnostics of Alzheimer’s disease (AD) in tissue is the presence of senile plaques and neurofibrillary tangles in specific brain locations. The routine procedure of morphological analysis implies time-consuming and laborious steps including sectioning and staining of formalin-fixed paraffin-embedded (FFPE) tissue. We developed a multispectral Stokes polarimetric imaging approach that allows characterization of FFPE brain tissue samples to discern the stages of AD progression without sectioning and staining the tissue. The Stokes polarimetry approach is highly sensitive to structural alterations of brain tissue, particularly to the changes in light scattering and birefringence. We present the results of the label-free non-destructive screening of FFPE mouse brain tissue and show several polarization metrics that demonstrate statistically significant differences for tissues at different stages of AD.
@article{Borovkova2022, author = {Borovkova, Mariia and Sieryi, Oleksii and Lopushenko, Ivan and Kartashkina, Natalia and Pahnke, Jens and Bykov, Alexander and Meglinski, Igor}, journal = {IEEE Transactions on Medical Imaging}, title = {Screening of Alzheimer’s Disease With Multiwavelength Stokes Polarimetry in a Mouse Model}, year = {2022}, issn = {1558-254X}, month = apr, number = {4}, pages = {977--982}, volume = {41}, doi = {10.1109/tmi.2021.3129700}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, }
2021
- CMLTP Best talkSimulation of elliptically polarized light propagation in turbid tissue-like scattering media with Monte Carlo methodIn II International Advanced Study Conference "Condensed Matter and Low Temperature Physics" , Jun 2021
Current study is devoted to the implementation of MC approach allowing simulation of the full set of Stokes parameters with account for such factors as phase shifts occurring due to light internal reflections inside the tissue and helicity flips occurring along the photon packet trajectory, which can significantly influence the resulting state of the light depolarization. The model is validated experimentally utilizing tissue-like phantoms with known optical properties, and we furtherly intend to apply it in order to study tissue samples influenced by various diseases, including cancer and Alzheimer.
2020
- LJM Invited paperDiscrete Sources Method to Solve Nonlocal Scattering Problems in Plasmonic ApplicationsI. V. Lopushenko , and A. G. SveshnikovLobachevskii Journal of Mathematics, Jul 2020
We present a comprehensive up-to-date review of one of the most recently developed numerical schemes based on the Discrete Sources Method. The aim of these developments is to implement and justify new efficient mathematical models allowing to accurately simulate response of small plasmonic nanoparticles with scale less than 10 nm to the different types of incident fields. Spatial dispersion effects of the material that are non-negligible at the given scales are incorporated into the numerical technique via Generalized Nonlocal Optical Response approach. Electron energy loss and plane wave scattering problems are considered, with the latter additionally featuring account for the presense of the substrate in the medium. Validity of the obtained results is ensured via a posteriori residual estimation, via comparison of computed scattering properties to the other available simulation techniques, and via comparison to the experimental electron energy loss measurements available in reference literature.
Paper invited for publication in the special issue "Mathematical Models and Methods in Wave Theory" by the doctoral dissertation opponent A. S. Il’inskii and editor N. B. Pleshchinskii.@article{Lopushenko2020, award = {Invited paper}, author = {Lopushenko, I. V. and Sveshnikov, A. G.}, journal = {Lobachevskii Journal of Mathematics}, title = {Discrete Sources Method to Solve Nonlocal Scattering Problems in Plasmonic Applications}, year = {2020}, issn = {1818-9962}, month = jul, number = {7}, pages = {1337--1353}, volume = {41}, doi = {10.1134/s1995080220070240}, publisher = {Pleiades Publishing Ltd}, }
2019
- G-RISC award Best projectEffect of Spatial Dispersion on Plasmon Resonance in Silver NanoparticlesI. V. Lopushenko , T. Wriedt , and I. N. ZavestovskayaBulletin of the Lebedev Physics Institute, Dec 2019
Using the modified Discrete Sources Method, the problem of calculating plasmon spectra of the characteristic energy loss of electrons during the interaction with silver nanoparticles from 2 to 8 nm in size is solved. The calculated spectra are compared with the experimental data confirming the significant spatial dispersion effect. The importance of the consideration of this factor when analyzing the properties of plasmonic nanoparticles for applications in biosensorics and biomedicine is discussed.
@article{Lopushenko2019, award = {Best project}, author = {Lopushenko, I. V. and Wriedt, T. and Zavestovskaya, I. N.}, journal = {Bulletin of the Lebedev Physics Institute}, title = {Effect of Spatial Dispersion on Plasmon Resonance in Silver Nanoparticles}, year = {2019}, issn = {1934-838X}, month = dec, number = {12}, pages = {400--404}, volume = {46}, doi = {10.3103/s106833561912008x}, publisher = {Allerton Press}, } - An Analysis of the Quantum Effect of Nonlocality in Plasmonics Using the Discrete Sources MethodYu. A. Eremin , and I. V. LopushenkoMoscow University Physics Bulletin, Nov 2019
We consider the mathematical problem of electromagnetic wave scattering by a plasmonic dimer composed of noble metal nanoparticles with sizes less than tens of nanometers. To develop mathematical models, the efficient discrete sources method is used, which makes it possible to take all peculiar features of such systems into account, including the shapes of particles and the effects of spatial dispersion, which are also known as nonlocal effects. It is shown that in the case of external fields that are independent of the azimuthal harmonics, it is possible to approximate the problem solution using the system of vertical dipoles on the axis of symmetry of the particle. Based on the hybrid scheme of the discrete sources method, the problem of excitation of a dimer by the field of a point charge in uniform straight motion in a homogeneous space is first solved.
@article{Eremin2019, author = {Eremin, Yu. A. and Lopushenko, I. V.}, journal = {Moscow University Physics Bulletin}, title = {An Analysis of the Quantum Effect of Nonlocality in Plasmonics Using the Discrete Sources Method}, year = {2019}, issn = {1934-8460}, month = nov, number = {6}, pages = {570--576}, volume = {74}, doi = {10.3103/s0027134919060134}, publisher = {Allerton Press}, }
2016
- A Hybrid Scheme of the Discrete Sources Method for Analyzing Boundary Value Problems of Nano-OpticsYu. A. Eremin , and I. V. LopushenkoMoscow University Computational Mathematics and Cybernetics, Jan 2016
The problem of the diffraction of a plane linearly polarized wave on a nanodimensional elongated particle located on a permeable substrate is considered. A hybrid scheme of the discrete sources method with allowance for particle geometry is used to construct the solution. The proposed scheme is substantiated mathematically with certain constraints on particle thickness. Numerical results illustrating the capabilities of the method are presented.
@article{Eremin2016, title = {A Hybrid Scheme of the Discrete Sources Method for Analyzing Boundary Value Problems of Nano-Optics}, author = {Eremin, Yu. A. and Lopushenko, I. V.}, journal = {Moscow University Computational Mathematics and Cybernetics}, year = {2016}, issn = {1934-8428}, month = jan, number = {1}, pages = {1--9}, volume = {40}, doi = {10.3103/s0278641915040032}, publisher = {Allerton Press}, }
PhD thesis
2019
- Development and implementation of new mathematical models in nanooptics and plasmonics based on the Discrete Sources MethodIvan LopushenkoLomonosov Moscow State University , Dec 2019
This work aims to implement and justify new efficient mathematical models which would allow to accurately simulate response of 1–10 nm scaled plasmonic nanoparticles to the different types of incident fields. Spatial dispersion effects of the material that are non-negligible at the given scales are incorporated into the numerical technique via Generalized Nonlocal Optical Response approach. Electron energy loss and plane wave scattering problems are considered, with the latter additionally featuring account for the presense of the substrate in the medium. Validity of the obtained results is ensured via a posteriori residual estimation, via comparison of computed scattering properties to the other available simulation techniques, and via comparison to the experimental electron energy loss measurements available in reference literature.
Main results of the thesis are summarized in English in LJM publication. - Разработка и реализация новых математических моделей нанооптики и плазмоники на основе метода дискретных источниковИван Владимирович ЛопушенкоМГУ имени М.В. Ломоносова , Dec 2019
Целью данной работы является разработка новых математических моделей, позволяющих точно предсказывать отклик миниатюрных плазменных наносистем с характеристическим размером от 1 до 10 нанометров при их возбуждении различными видами внешних источников, а также компьютерная реализация данных моделей в форме высокопроизводительного, функционального и гибкого программного обеспечения. Достоверность полученных результатов обеспечивается с помощью перекрестного сравнения с доступными аналитическими решениями для простейших плазмонных систем, сравнения с численными результатами, полученными другими авторами в рамках иных подходов, с помощью апостериорной оценки точности вычислений, и с помощью сравнения результатов с имеющимися в литературе экспериментальными данными.