Maksim Kulya

Maksim Kulya
ITMO University | SPbNRU ITMO · Department of Photonics and Optical Information Technology

Candidate of Sciences

About

39
Publications
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396
Citations

Publications

Publications (39)
Article
The nonlinear response of liquids in the terahertz regime has recently attracted significant interest, even though very few measurements have been reported. Here, we report on our measurements based on a z-scan technique of the nonlinear refractive-index coefficient n2 at terahertz frequencies for several liquids with noncentrosymmetric molecules,...
Article
We investigated the peculiarities of the terahertz pulse time-domain holography principle in the case of raster scanning with the balance detection system. The noise in this system represents a Skellam distribution model, which differentiates it from systems based on a photoconductive antenna. We analyzed this Skellam model and provided both numeri...
Article
Here, we present a comprehensive study of the reconstruction quality in terahertz (THz) pulse time-domain holography. We look into single wavelength reconstructions, as well as broadband recovery enabled by the ultrabroadband nature of radiation and coherent detection enabled by electro-optic or photoconductive sensing. We demonstrate the transvers...
Article
Full-text available
In this paper, we consider a Huygens filter for a specified frequency lying within a broad spectrum of a pulsed THz radiation which represents simplest two-zone plate. The condition of the infinite plane wave and the Gaussian beam are separately used as the initial source has been discussed. A property method of terahertz spectral filter has been e...
Article
We investigated data denoising in hyperspectral terahertz pulse time-domain holography. Using the block-matching algorithms adapted for spatio-temporal and spatio-spectral volumetric data we studied and optimized parameters of these algorithms to improve phase image reconstruction quality. We propose a sequential application of the two algorithms o...
Article
Full-text available
A comprehensive characterization of the diffraction properties of terahertz (THz) pulsed broadband vortex beams consisting of several electromagnetic field oscillations requires state-of-the-art techniques for studying the evolution of a wavefront as it propagates. For this purpose, we have applied the capabilities offered by THz pulse time domain...
Article
Full-text available
Abstract In this paper, we present a novel numerical approach for increasing the resolution of retrieved images of objects after their diffraction patterns are recorded via terahertz pulse time-domain holography (THz PTDH). THz PTDH allows for spectrally resolved imaging with high spatial resolution and does not require the fine alignment of comple...
Conference Paper
Using the block-matching denoising algorithms adapted to spatio-temporal and spatio-spectral volumetric data, we studied and optimized the parameters of these algorithms to improve the phase/amplitude image reconstruction in hyperspectral terahertz pulse time-domain holography. We propose a sequential application of two different algorithms oriente...
Conference Paper
In this paper, basic principles of broadband femtosecond pulse propagation through an amplitude and phase object are presented. A novel approach of stepwise progressive propagation through the object is introduced and discussed. A comparative analysis of “progressively” and “simultaneously” propagated femtosecond pulses is presented. The algorithm...
Conference Paper
Using the THz-PTDH method we have created the theoretical model and experimental set up for phase imaging of breast tissue sample and designed the image reconstruction procedure suitable for a cancer diagnostics.
Article
Full-text available
In this paper we demonstrate the method of widefield amplitude-phase object images reconstruction from the spatially-limited broadband terahertz wavefield spectral components distributions in the Fresnel diffraction zone, based on the wave propagation equations iterative solution algorithm. Using of this method allows one to overpass the spatial re...
Article
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A modification of the Z-scan technique for measuring nonlinear refractive index n2 in the terahertz spectral region is proposed. Measurements are made at a broadband terahertz radiation intensity of 0.8 × 10⁹ W cm⁻². Coefficient n2 = 2.5 × 10⁻¹¹ cm² W⁻¹ is estimated for semiconductor crystalline ZnSe.
Article
Full-text available
The optical clearing method has been widely used for different spectral ranges where it provides tissue transparency. In this work, we observed the enhanced penetration of the terahertz waves inside biological samples (skin, kidney, and cornea) treated with glycerol solutions inducing changes of optical and dielectric properties. It was supported b...
Article
Full-text available
Terahertz pulse time-domain holography is the ultimate technique allowing the evaluating a propagation of pulse broadband terahertz wavefronts and analyze their spatial, temporal and spectral evolution. We have numerically analyzed pulsed broadband terahertz Gauss-Bessel beam's both spatio-temporal and spatio-spectral evolution in the non-paraxial...
Conference Paper
In given talk we consider the possibilities of terahertz pulse time-domain holography for the spatio-temporal and spatio-spectral analysis of arbitrary broadband beams basing on the spatio-temporal field distribution measured in one transversal plane.
Article
Optical characteristics of polymerization products under variable degrees of neutralization of acrylic acid (AA) and cross-linking agent and at a fixed content of redox components have been studied by IR spectroscopy of frustrated total internal reflection and THz spectroscopy. The results of the analysis show that absorption of IR radiation and di...
Article
Full-text available
We propose a mathematical model for holographic relief reconstruction of phase objects based on the analysis of diffraction patterns of pulsed terahertz radiation, recorded in a dispersive medium. Numerical simulation shows the influence of the dispersion medium on the process of phase and relief reconstruction: disregard of the dispersion due to t...
Article
Full-text available
We present measurements of optical characteristics of sodium polyacrylate in the terahertz frequency range and discuss how material dispersion affects object visualisation in terahertz imaging. We demonstrate how important is to take into account the material dispersion for phase and relief reconstruction of the investigated object.
Article
Full-text available
The unique properties of narrowband and broadband terahertz Bessel beams have led to a number of their applications in different fields, for example, for the depth of focusing and resolution enhancement in terahertz imaging. However, broadband terahertz Bessel beams can probably be also used for the diffraction minimization in the short-range broad...
Article
Full-text available
Orbital angular momentum (OAM) represents new informational degree of freedom for data encoding and multiplexing in fiber and free-space communications. OAM-carrying beams (also called vortex beams) were successfully used to increase the capacity of optical, millimetre-wave and radio frequency communication systems. However, the investigation of th...
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We present the study on spatial distribution of the maximum of terahertz field amplitude in time domain when generated by a femtosecond filament. It is shown that as a result of the propagation of the terahertz field forms a spherical wave front, on the edge of which the maximum of amplitude has a temporary delay in contrary to its central part.
Article
Full-text available
Terahertz pulse time-domain holography (THz PTDH) is the powerful technique for high-resolution amplitude and phase THz imaging that allows mapping spectroscopic information across the imaged object. In this paper, we consider most sought after applications of phase imaging provided by this technique and experimentally demonstrate the ability of th...
Conference Paper
Full-text available
In this paper, we discuss the features of numerical simulation of propagation of the two-dimensional pulsed broadband terahertz (THz) fields. A set of separate spectral components used to describe diffraction of broadband THz pulses. To eliminate sampling theorem restriction in the numerical simulation of diffraction process for the complete spectr...
Article
Full-text available
We numerically investigated the influence of wavelength of terahertz radiation and size of scanning pinhole on the quality of reconstructed image by terahertz pulse time domain holography method. The improvement of the quality is achieved mainly by reducing the wavelength of the radiation, pinhole size and pinhole step (value of the pinhole displac...