Application of corpuscular and wave Monte-Carlo methods in optics of dispersive media

The hybrid model for analyzing distortions of a laser beam passed through a moderately scattering medium with the number of scattering events up to 10 is developed and investigated. The model implemented the Monte Carlo technique to simulate the beam propagation through a scattering layer, a ray-tracing technique to propagate the scattered beam to the measurements plane, and the Shack–Hartmann technique to calculate the scattered laser beam distortions. The results obtained from the developed model were confirmed during the laboratory experiment. Both the numerical model and laboratory experiment showed that with an increase of the concentration value of scattering particles in the range from 105 to 106 mm−3, the amplitude of distortions of laser beam propagated through the layer of the scattering medium increases exponentially.

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“…In general, there are two Monte Carlo techniques: corpuscular and wave [50]. Both methods have their advantages and disadvantages.…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

“…Choosing each method is a matter of opinion, since both show similar results [50]. We have chosen the "Corpuscular Monte Carlo" technique for our simulation.…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

A Hybrid Model for Analysis of Laser Beam Distortions Using Monte Carlo and Shack–Hartmann Techniques: Numerical Study and Experimental Results

et al. 2023

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“…The use of the MC approach for modeling light wave propagation within biological tissues enables the imitation of the complexity of the randomly structured composition of biological tissues while also considering the partial coherence of the probing laser beam [41][42][43][44][45][46][47][48]. Various limitations of this approach become apparent when the super-sharp focusing occurs, notably with the numerical aperture close to or less than one [40,48,49].…”

Section: Introductionmentioning

confidence: 99%

Non-Paraxial Effects in the Laser Beams Sharply Focused to Skin Revealed by Unidirectional Helmholtz Equation Approximation

2023

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Laser beams converging at significant focusing angles have diverse applications, including quartz-enhanced photoacoustic spectroscopy, high spatial resolution imaging, and profilometry. Due to the limited applicability of the paraxial approximation, which is valid solely for smooth focusing scenarios, numerical modeling becomes necessary to achieve optimal parameter optimization for imaging diagnostic systems that utilize converged laser beams. We introduce a novel methodology for the modeling of laser beams sharply focused on the turbid tissue-like scattering medium by employing the unidirectional Helmholtz equation approximation. The suggested modeling approach takes into account the intricate structure of biological tissues, showcasing its ability to effectively simulate a wide variety of random multi-layered media resembling tissue. By applying this methodology to the Gaussian-shaped laser beam with a parabolic wavefront, the prediction reveals the presence of two hotspots near the focus area. The close-to-maximal intensity hotspot area has a longitudinal size of about 3–5 μm and a transversal size of about 1–2 μm. These values are suitable for estimating spatial resolution in tissue imaging when employing sharply focused laser beams. The simulation also predicts a close-to-maximal intensity hotspot area with approximately 1 μm transversal and longitudinal sizes located just behind the focus distance for Bessel-shaped laser beams with a parabolic wavefront. The results of the simulation suggest that optical imaging methods utilizing laser beams with a wavefront produced by an axicon lens would exhibit a limited spatial resolution. The wavelength employed in the modeling studies to evaluate the sizes of the focus spot is selected within a range typical for optical coherence tomography, offering insights into the limitation of spatial resolution. The key advantage of the unidirectional Helmholtz equation approximation approach over the paraxial approximation lies in its capability to simulate the propagation of a laser beam with a non-parabolic wavefront.

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“…By analogy with the conventional MC, this approach is known as the wave MC. 35 To imitate OCT signal formation by MC, it is necessary to calculate the propagation of the backward wave reflected from the boundaries of structural inhomogeneities localized within the medium. The combination of the wave MC method and the wave equation in the quasioptics approximation potentially makes it possible to simulate with reasonable computing resource requirements of the wave beams with a complex amplitude-phase profile and to take into account diffraction.…”

Section: Introductionmentioning

confidence: 99%

Imitation of optical coherence tomography images by wave Monte Carlo-based approach implemented with the Leontovich–Fock equation

et al. 2020

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We present a computational modeling approach for imitation of the time-domain optical coherence tomography (OCT) images of biotissues. The developed modeling technique is based on the implementation of the Leontovich-Fock equation into the wave Monte Carlo (MC) method. We discuss the benefits of the developed computational model in comparison to the conventional MC method based on the modeling of OCT images of a nevus. The developed model takes into account diffraction on bulk-absorbing microstructures and allows consideration of the influence of the amplitude-phase profile of the wave beam on the quality of the OCT images. The selection of optical parameters of modeling medium, used for simulation of optical radiation propagation in biotissues, is based on the results obtained experimentally by OCT. The developed computational model can be used for imitation of the light waves propagation both in time-domain and spectral-domain OCT approaches.

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Application of corpuscular and wave Monte-Carlo methods in optics of dispersive media

Cited by 21 publications

References 4 publications

A Hybrid Model for Analysis of Laser Beam Distortions Using Monte Carlo and Shack–Hartmann Techniques: Numerical Study and Experimental Results

A Hybrid Model for Analysis of Laser Beam Distortions Using Monte Carlo and Shack–Hartmann Techniques: Numerical Study and Experimental Results

Non-Paraxial Effects in the Laser Beams Sharply Focused to Skin Revealed by Unidirectional Helmholtz Equation Approximation

Imitation of optical coherence tomography images by wave Monte Carlo-based approach implemented with the Leontovich–Fock equation

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