Abstract-Hyperspectral data denoising for terahertz pulse time-domain holography

Maksim Kulya, Nikolay V. Petrov, Anton Tsypkin, Karen Egiazarian, and Vladimir Katkovnik

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-13-18456

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 oriented on work in temporal and spectral domains. Experimental data demonstrate the improvement in the quality of the resultant time-domain images as well as phase images and object’s relief. The simulation results are proved by comparison with the experimental ones.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Hyperspectral terahertz pulse time-domain holography: noise filtering

Maksim Kulya, Nikolay Petrov, Karen Egiazarian, and Vladimir Katkovnik

https://www.osapublishing.org/abstract.cfm?uri=DH-2019-Th4B.4

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 oriented on work in temporal and spectral domains. Experimental data demonstrates essential improvement in the quality of the resulting phase imaging.

© 2019 The Author(s)

Abstract-Spatio-temporal and spatiospectral metrology of terahertz broadband uniformly topologically charged vortex beams

Maksim Kulya, Varvara Semenova, Andrei Gorodetsky, Victor G. Bespalov, and Nikolay V. Petrov

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-58-5-A90

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 holography. Accurate metrological study of pulsed single-period THz field propagation allowed us to reveal the spatio-temporal and spatiospectral couplings in broadband uniformly topologically charged vortex beams. Here, we reveal dynamics of such beam propagation in a free space as well as in the experiment with edge diffraction with 50% blocking of the beam focal waist. In this study, we compare the dynamics of freely propagating and edge-diffracted THz vortex. Despite the fact that in the amplitude representation one can observe the emergence of strong asymmetry, analysis of the spectral trajectory of the singular point at some distance from the obstacle and the visualization of phase distribution for individual spectral components testify to the conservation of transverse energy circulation. Similar to the edge diffraction of monochromatic optical vortices, it can be interpreted as self-reconstruction of vortex properties. The given term has not previously been used for the case of pulsed broadband THz beams, to the best of our knowledge.

© 2018 Optical Society of America