Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses

Abstract Modern sources of THz radiation generate high-intensity pulses allowing to observe nonlinear effects in this spectral range. To describe many nonlinear effects theoretically, it is necessary to know the nonlinear refractive index coefficient of optical materials. The work studies the applic...

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Autores principales:	Maksim Melnik, Irina Vorontsova, Sergey Putilin, Anton Tcypkin, Sergei Kozlov
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2019
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/99b93776c2434cb58a2587797d8d2104
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spelling	oai:doaj.org-article:99b93776c2434cb58a2587797d8d21042021-12-02T15:07:53ZMethodical inaccuracy of the Z-scan method for few-cycle terahertz pulses10.1038/s41598-019-45735-62045-2322https://doaj.org/article/99b93776c2434cb58a2587797d8d21042019-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-019-45735-6https://doaj.org/toc/2045-2322Abstract Modern sources of THz radiation generate high-intensity pulses allowing to observe nonlinear effects in this spectral range. To describe many nonlinear effects theoretically, it is necessary to know the nonlinear refractive index coefficient of optical materials. The work studies the applicability of the Z-scan method to determine the nonlinear refractive index coefficient in the THz frequency range for few-cycle pulses. We have discussed the correctness of the known Z-scan method for calculating the nonlinear refractive index coefficient for broadband THz radiation regarding number of cycles pulses have. We have demonstrated that the error in determining the nonlinear refractive index coefficient is always greater than 70% for true single-cycle pulses. With the increase in the number of oscillations to the measurement error shows strong dependence on the sample thickness and can vary from 2% to 90% regarding the parameters chosen. The fact that such radiation dispersion length is commensurate with the nonlinear length or even less than the latter results in the discrepancy mentioned. It is demonstrated that the decrease in the sample thickness leads to the reduction of the nonlinear refractive index coefficient determination error, and this error is <2% when the ratio between the sample thickness and the pulse longitudinal spatial size is ≤1. This can relate to the fact that the nonlinear effects in such a thin sample occur faster than the dispersion ones.Maksim MelnikIrina VorontsovaSergey PutilinAnton TcypkinSergei KozlovNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 9, Iss 1, Pp 1-8 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Maksim Melnik Irina Vorontsova Sergey Putilin Anton Tcypkin Sergei Kozlov Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses
description	Abstract Modern sources of THz radiation generate high-intensity pulses allowing to observe nonlinear effects in this spectral range. To describe many nonlinear effects theoretically, it is necessary to know the nonlinear refractive index coefficient of optical materials. The work studies the applicability of the Z-scan method to determine the nonlinear refractive index coefficient in the THz frequency range for few-cycle pulses. We have discussed the correctness of the known Z-scan method for calculating the nonlinear refractive index coefficient for broadband THz radiation regarding number of cycles pulses have. We have demonstrated that the error in determining the nonlinear refractive index coefficient is always greater than 70% for true single-cycle pulses. With the increase in the number of oscillations to the measurement error shows strong dependence on the sample thickness and can vary from 2% to 90% regarding the parameters chosen. The fact that such radiation dispersion length is commensurate with the nonlinear length or even less than the latter results in the discrepancy mentioned. It is demonstrated that the decrease in the sample thickness leads to the reduction of the nonlinear refractive index coefficient determination error, and this error is <2% when the ratio between the sample thickness and the pulse longitudinal spatial size is ≤1. This can relate to the fact that the nonlinear effects in such a thin sample occur faster than the dispersion ones.
format	article
author	Maksim Melnik Irina Vorontsova Sergey Putilin Anton Tcypkin Sergei Kozlov
author_facet	Maksim Melnik Irina Vorontsova Sergey Putilin Anton Tcypkin Sergei Kozlov
author_sort	Maksim Melnik
title	Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses
title_short	Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses
title_full	Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses
title_fullStr	Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses
title_full_unstemmed	Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses
title_sort	methodical inaccuracy of the z-scan method for few-cycle terahertz pulses
publisher	Nature Portfolio
publishDate	2019
url	https://doaj.org/article/99b93776c2434cb58a2587797d8d2104
work_keys_str_mv	AT maksimmelnik methodicalinaccuracyofthezscanmethodforfewcycleterahertzpulses AT irinavorontsova methodicalinaccuracyofthezscanmethodforfewcycleterahertzpulses AT sergeyputilin methodicalinaccuracyofthezscanmethodforfewcycleterahertzpulses AT antontcypkin methodicalinaccuracyofthezscanmethodforfewcycleterahertzpulses AT sergeikozlov methodicalinaccuracyofthezscanmethodforfewcycleterahertzpulses
_version_	1718388333589037056

Methodical inaccuracy of the Z-scan method for few-cycle terahertz pulses

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