In the current report, we present a dual-mode approach for assessment of twisted light localization in turbid tissue-like scattering media. A unified open-access Monte Carlo (MC) model based on the tracking of transformations of electric filed vector is working in synergy with 3D geometrical exploration techniques for efficient identification of nonlinear structures produced by twisted light and subsequent tracking of their evolutions in turbid media. We report detection of the light’s twist for up to 6 ODs with <98% confidence intervals/threshold. Results are presented in comparison with exact theoretical solutions and experimental data obtained during laboratory studies. The models are accelerated by parallel programming on graphics cards and offer a responsive online interface.
In the current report, we present the international efforts to create a unified open-access Monte Carlo (MC) based computational method and a set tools for simulation of Total Angular Momentum (TAM) of light propagating and localizing in turbid tissue-like scattering media. We specifically focus on performing the simulations with a variety of combinations of spin and orbital angular momentum and the subsequent analyses of the spin-orbit interactions. We present an open-access application and a media model which considers both spatial and volumetric variations in the media optical properties. The online application has been accelerated by parallel computations on graphics cards and is being extensively used in the ongoing studies of light's angular momentum propagation in turbid media (e.g. phantoms and cancerous lesions). Rigorous validation against data obtained during experimental studies is presented.
In the current report, we present further developments of a unified open-access Monte Carlo (MC) based computational tool for simulation of twisted light propagation in turbid tissue-like scattering medium. We introduce an online browser-based application and a media model which considers both spatial and volumetric variations such surface roughness and subsurface scattering optical properties. The online application has been integrated with the parallel simulation framework developed in-house and is being extensively used in the ongoing studies of twisted light propagation in turbid media (e.g. phantoms and cancerous lesions). Rigorous validation against data obtained during experimental studies is presented.
With a primary aim to proof the concept of using complex vector laser light for tissue diagnosis we explore the propagation of cylindrical vector beam (CVB) and Laguerre-Gaussian (LG) beams in turbid tissue-like scattering medium. To observe preservation of the orbital angular momentum, and to assess optical memory and helicity flip the interference of CVB is considered, along with the interference of LG beams and with linearly and/or circularly polarized Gaussian beams. The study include a further development of a unified Monte Carlo (MC)-based computational model for the needs of biophotonics. The model utilizes voxelized representation of the media and considers spatial/volumetric variations in both structural e.g. surface roughness and optical properties. Computer modelling is accelerated by parallel computing on Graphics Processing Units (GPUs) using OpenCL (Open Computing Language). The results of simulation are compared with the experimental results. The preservation of the orbital angular momentum, optical memory and helicity flip are presented and discussed.
In turbid tissue-like scattering medium the conventional polarized light, scattered multiple number of times, is depolarized, and the depolarization rate depends strongly on the size and shape of scattering particles, as well as on the number of scattering events. In fact, the structure of light can be more complicated when the polarization of light across the laser beam can be radially or azimuthally polarized and carry orbital angular momentum. When these vector light beams, known as cylindrical vector beam (CVB) and Laguerre-Gaussian (LG) beams, propagates in turbid tissue-like scattering medium, either anisotropic or inhomogeneous, the spin or angular momentum are changed that leads to spin-orbit interaction. Such a spin-orbit interaction leads to the mutual influence of the polarization and the trajectory of the light propagation. We investigate the applicability of using CVB and LG beams for optical biopsy. In current presentation propagation of CVB and LG beams in anisotropic turbid tissue-like scattering media is considered in comparison to conventional Gaussian beams. We demonstrate that by applying CVB and LG beams the sensitivity of the conventional polarimetry-based approach is increased at least twice in comparison with the experiments utilizing ‘simple’ Gaussian polarized light. The results of the study suggest that there is a high potential in application of vector light beams in tissue diagnosis.
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