Experimental Estimate of the Nonlinear Refractive Index of Crystalline ZnSe in the Terahertz Spectral Range

Tcypkin, Anton; Putilin, S. É.; Kulya, Maksim S.; Melnik, Maksim; Drozdov, A. A.; Bespalov, V. G.; Zhang, X.-C.; Boyd, Robert W.; Козлов, С. А.

doi:10.3103/s1062873818120237

Cited by 9 publications

(6 citation statements)

References 8 publications

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“…The following values are used in these formulas: absorption coefficient α = 0.85 cm −1 , sample length L = 0.3 mm, central frequency of the radiation ν 0 = 1 THz ( λ 0 = 0.3 mm), beam waist radius w 0 = 1.4 mm, aperture radius r a = 1.5 mm, radius of the THz beam w a = 12.5 mm, intensity of the THz beam in caustic I 0 = 3 ⋅ 10 8 W/cm 2 , nonlinear refractive index coefficient n 2 = 4 ⋅ 10 −11 cm 2 /W. This value of n 2 was obtained in experiment previously 31 .…”

Section: Methodssupporting

confidence: 69%

“…These mechanisms are well-described with nonlinear refractive index coefficient n 2 as a material characteristic. These findings have now been confirmed experimentally 31,39,40 . Thus, the use of the Z-scan method is justified allowing to calculate the Kerr nonlinearity in the THz frequency range.…”

Section: Methodssupporting

confidence: 65%

“…They represent the dependence of the transmission through the closed aperture T on the sample position z for the following parameters: central wavelength of the THz radiation λ = 0.3 mm, period of oscillation T 0 = 1 ps, peak intensity in the caustic (a) I 0 = 3.1 ⋅ 10 8 W/cm 2 , and (b) I 0 = 8.3 ⋅ 10 8 W/cm 2 , duration τ 0 = 0.3, 1, 10 T 0 , thickness of the ZnSe L = 0.3 mm. The value of the nonlinear refractive index coefficient n 2 = 4 ⋅ 10 −11 cm 2 /W 31 . As seen, the obtained curves in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Used for monochromatic radiation, the technique can also be applied to femtosecond radiation, which radiation spectrum is quite wide 30 . Recently, the first works on preliminary experiments estimating n 2 coefficient using the Z-scan technique in THz spectral range clearly showed the presence of a significant nonlinear effect 31,32 . However, the application of the Z-scan method raises several questions since the spectrum of pulsed THz sources is even wider than femtosecond one 33 and its electric field can have few cycles only 34,35 .…”

Section: Introductionmentioning

confidence: 99%

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

Melnik

Vorontsova

Putilin

et al. 2019

Sci Rep

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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.

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Section: Methodssupporting

confidence: 69%

Section: Methodssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Melnik

Vorontsova

Putilin

et al. 2019

Sci Rep

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show abstract

“…Originally, it was predicted theoretically [20] that nonlinear refractive index coefficient for various materials in the THz frequency range exceeds the ones in both visible and NIR ranges by several orders of magnitude. Then this fact was proven experimentally by the Z-scan method [21,22]. However, in these works only indirect estimations of n 2 were made.…”

Section: Introductionmentioning

confidence: 99%

High Kerr nonlinearity of water in THz spectral range

Tcypkin¹,

Melnik²,

Zhukova³

et al. 2019

Opt. Express

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The values of the nonlinear refractive index coefficient for various materials in the terahertz frequency range exceed the ones in both visible and NIR ranges by several orders of magnitude. We report the direct measurement of the nonlinear refractive index coefficient of liquid water by using the Z-scan method with broadband pulsed THz beam. Our experimental result shows that nonlinear refractive index coefficient in water is positive and can be as large as 3.5×10 −10 cm 2 /W in the THz frequency range, which exceeds the ones for the visible and NIR ranges by 6 orders of magnitude.

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Optical properties of Fe- and Nd-doped ZnSe crystals measured by pump-probe spectroscopy

Zhukova

Nabilkova

Putilin

et al. 2019

J. Phys.: Conf. Ser.

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We present the excited-state dynamics and optical properties of Fe- and Nd-diffusion doped zinc selenide polycrystals with different concentration measured by pump-probe spectroscopy in the visible and NIR range (400-1000 nm). The introduction of dopants allows one to control the optical properties of samples, which then can be used to create effective optoelectronic components for wide spectral ranges.

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Experimental Estimate of the Nonlinear Refractive Index of Crystalline ZnSe in the Terahertz Spectral Range

Cited by 9 publications

References 8 publications

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

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

High Kerr nonlinearity of water in THz spectral range

Optical properties of Fe- and Nd-doped ZnSe crystals measured by pump-probe spectroscopy

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