Propagation of broadband THz pulses: effects of dispersion, diffraction and time-varying nonlinear refraction

Rasekh, Payman; Saliminabi, Mohammad; Yıldırım, Murat; Boyd, Robert W.; Ménard, Jean‐Michel; Dolgaleva, Ksenia

doi:10.1364/oe.381150

Cited by 11 publications

(5 citation statements)

References 29 publications

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“…For example, many materials during the propagation of broadband THz radiation modify the spectrum due to absorption at individual frequencies [8]. In addition, THz pulses in that frequency range are strongly subject to dispersion spreading [9].…”

Section: Introductionmentioning

confidence: 99%

Spatial chirping of a THz pulse during generation in InAs crystal

Nabilkova

Oparin²,

Shumigay³

et al. 2022

Infrared, Millimeter-Wave, and Terahertz Technologies IX

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It is known that such features of pulsed THz radiation as a small number of periods and an ultra-wide spectrum modify the appearance of linear effects like absorption, dispersion, and diffraction. In this work, we study the influence of the spatial localization of a THz pulse during its generation. It is shown that this leads to a spatial chirp of the pulse. Based on the results obtained, recommendations are formulated for working with such pulses, which make it possible to guarantee that spectral information will not be lost during the propagation of such pulses.

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Section: Introductionmentioning

confidence: 99%

Spatial chirping of a THz pulse during generation in InAs crystal

Nabilkova

Oparin²,

Shumigay³

et al. 2022

Infrared, Millimeter-Wave, and Terahertz Technologies IX

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“…With recent developments in coherent THz radiation sources, phase-locked THz pulses with higher intensities are becoming routinely accessible . As a consequence, THz science has been engaged in studying the nonlinear response of different materials in the THz region of the spectrum; examples include nonlinear response of free electrons to single-cycle THz pulses, THz-induced carrier multiplication via impact ionization, − and THz saturable absorption and high-harmonic generation by hot electrons. − Moreover, it has been shown that the Kerr-type nonlinearity of dense materials such as solids ,− and liquids , is typically larger than their Kerr-type nonlinear response in the optical domain. However, unlike solids and liquids, gaseous materials such as water vapor can have sharp resonances in the THz range, and the Kerr-type nonlinear response of these transitions has not been studied to date.…”

mentioning

confidence: 99%

Terahertz Nonlinear Spectroscopy of Water Vapor

et al. 2021

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The water molecule has millions of rotational transitions in the infrared and terahertz region, and the resulting absorption features dominate the transmission spectrum of atmospheric terahertz measurements, even for propagation distances as short as tens of centimeters. Remarkably, we observe that the absorption at the position of these resonances increases with the THz intensity. We explain this observation by stepwise multiphoton transitions in water molecules. The estimated value of the effective third-order susceptibility is extremely large: χ (3) = (0.4 + 6i) × 10 2 m 2 /V 2 . We note for comparison that the value of χ (3) for fused silica at optical frequencies is on the order of 10 −22 m 2 / V 2 . Furthermore, our results provide new insight into the various transitions of the water molecule and their nonlinear response to electromagnetic radiation, paving the way to more accurate THz spectroscopy, imaging, and sensing systems, thereby facilitating future emerging THz technologies.

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“…The angular frequency and wavenumber of the nonlinear polarization wave are and K , respectively. To start, we develop our calculations focusing on the OR case, which is of great importance in the generation of THz radiation [19] from an infrared pump pulse [15,18,20] interacting with a nonlinear crystal, for example, in the geometry shown in Fig. 1.…”

mentioning

confidence: 99%

Selection rules for the orbital angular momentum of optically produced THz radiation

et al. 2021

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In this work, we theoretically study the transduction of orbital angular momentum (OAM) l for infrared pump lasers into the THz domain. In the case of optical rectification, the transduction of OAM occurs only through a spin–orbit interaction, with the selection rule on the OAM l = 0 valid for any kind of polarization of the pump, which means that there is no transfer of OAM along the propagation axis. In difference frequency generation, the selection rule for the difference Δ l between the OAM of the pump fields with linear or circular polarization is l = Δ l , whereas l ranges from Δ l − 2 to Δ l + 2 in cases of both radial and azimuthal polarization. Moreover, for THz generation in the latter case, the high diffraction obtained with tightly focused pumps yields l tending to Δ l ± 2 , while l tends to zero in the opposite case of large pump beams.

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Propagation of broadband THz pulses: effects of dispersion, diffraction and time-varying nonlinear refraction

Cited by 11 publications

References 29 publications

Spatial chirping of a THz pulse during generation in InAs crystal

Spatial chirping of a THz pulse during generation in InAs crystal

Terahertz Nonlinear Spectroscopy of Water Vapor

Selection rules for the orbital angular momentum of optically produced THz radiation

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