Spectral Approach in the Analysis of Pulsed Terahertz Radiation

Ezerskaya, A. A.; Иванов, Д. В.; Kozlov, S. A.; Kivshar, Yuri S.

doi:10.1007/s10762-012-9907-9

Cited by 24 publications

(5 citation statements)

References 25 publications

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“…2 ), we consider that during the propagation in the crystal, as well as at its output the THz pulse is a single-cycle one and only in the far zone, due to diffraction, it acquires a half-wave 29 . This effect, which is practically not observed for pulses with a large number of oscillations, is clearly pronounced for a single-cycle pulse, which becomes one and a half cycle in the far diffraction zone 30 .…”

Section: Methodsmentioning

confidence: 89%

Radiation shift from triple to quadruple frequency caused by the interaction of terahertz pulses with a nonlinear Kerr medium

Artser

Melnik

Ismagilov

et al. 2022

Sci Rep

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High-intensity optical radiation propagation in a transparent dielectric medium causes the phenomena of pulse self-action and radiation generation at triple frequencies due to the cubic nonlinearity of the medium. However, quadratic nonlinear effects usually outshine the cubic ones in anisotropic nonlinear crystals. In this work, we demonstrate that for certain experimental parameters the nonlinear effect of the third order can be stronger than the second order one in the MgO:$$\hbox {LiNbO}_3$$ LiNbO 3 crystal for terahertz frequency range. We experimentally and theoretically show that this effect can lead to the significant modification of the classical phenomenon of radiation generation at triple frequencies in the case when the pulse represents only one complete oscillation of the optical field. The experiment demonstrated that the phenomenon of generation of radiation at triple frequencies with respect to the frequency of the maximum spectral density in a nonlinear medium of the pulse disappears, and it is replaced by the generation of radiation at quadruple frequencies. The analysis confirms that this effect is based on the asymmetry and large width of the initial spectrum of such extremely short pulses in terms of the number of oscillations.

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Section: Methodsmentioning

confidence: 89%

Radiation shift from triple to quadruple frequency caused by the interaction of terahertz pulses with a nonlinear Kerr medium

Artser

Melnik

Ismagilov

et al. 2022

Sci Rep

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show abstract

“…Comparatively, the absorption values of powder pieces are obviously smaller than those of corresponding cloth, which might be attributed to the elimination of the diffraction effect. 30,32 Additionally, the refractive indexes of different tablets demonstrate bigger value and variation than those of the original cloth (Supplementary Figure S4). The reason may be that these fiber powder tablets are more compact compared with cloth, making the proportion of air lower and the air show the lowest refractive index.…”

Section: Resultsmentioning

confidence: 99%

Study on terahertz spectrum variation of inner package with different wrapped objects

Wang

Yan

Liang³

et al. 2023

Journal of Industrial Textiles

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Terahertz (THz) nondestructive testing has emerged as a promising tool for public security check due to its superior detection accuracy and sensitivity for hidden objects under clothing. However, it is unknown if material composition and textile structure of clothing will influence the THz spectrum of the hidden objects. In this paper, the THz time domain spectroscopy (THz-TDS) was used to detect several natural and artificial fabrics containing pure amino acids with characteristic absorption peaks between 0.2 and 1.6 THz. The results show that the absorption peaks of AAs of various cloth materials have different degrees of decrease and redshift. In addition, the absorption peaks of the THz spectrum disappear when the textile structure is destroyed. Moreover, the simulation results also verify that the textile structure has an obvious effect on the THz field distribution. In this sense, it is necessary to analyze the material composition and textile structure when detecting hidden objects under clothing using the THz signal.

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“…However, writing the boundary condition in the form of a single-cycle pulse (2), we consider that during the propagation in the crystal, as well as at its output the THz pulse is a single-cycle one and only in the far zone, due to diffraction, it acquires a half-wave 29 . This effect, which is practically not observed for pulses with a large number of oscillations, is clearly pronounced for a single-cycle pulse, which becomes one and a half cycle in the far diffraction zone 30 .…”

Section: Analytical Modelmentioning

confidence: 89%

Radiation shift from triple to quadruple frequency caused by the interaction of terahertz pulses with a nonlinear Kerr medium

Artser

Melnik

Ismagilov

et al. 2022

Preprint

View full text Add to dashboard Cite

High-intensity optical radiation propagation in a transparent dielectric medium causes the phenomena of self-action of the pulse and the generation of radiation at triple frequencies due to the cubic nonlinearity of the medium. However, usually the quadratic nonlinear effects outshine the cubic ones in the anisotropic nonlinear crystals. In this work, we demonstrate that for certain experimental parameters the nonlinear effect of the third order can be stronger than one of the second order in MgO:LiNbO3 crystal for terahertz frequency range. We experimentally and theoretically show that it can lead to the significant modification of the classical phenomenon of radiation generation at triple frequencies in the case when the pulse represents only one complete oscillation of the optical field. In the experiment it was shown that the phenomenon of generation of radiation at triple frequencies with respect to the frequency of the maximum spectral density in a nonlinear medium of the pulse disappears, and it is replaced by the generation of radiation at quadruple frequencies. The analysis demonstrates that this effect is based on the asymmetry of the initial spectrum of such extremely short pulses in terms of the number of oscillations.

show abstract

Spectral Approach in the Analysis of Pulsed Terahertz Radiation

Cited by 24 publications

References 25 publications

Radiation shift from triple to quadruple frequency caused by the interaction of terahertz pulses with a nonlinear Kerr medium

Radiation shift from triple to quadruple frequency caused by the interaction of terahertz pulses with a nonlinear Kerr medium

Study on terahertz spectrum variation of inner package with different wrapped objects

Radiation shift from triple to quadruple frequency caused by the interaction of terahertz pulses with a nonlinear Kerr medium

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