Nonlinear quantum interferometry in terahertz spectroscopy

Malkova, Ekaterina I.; Kovalev, Sergey; Кузнецов, К. А.; Китаева, Г. Х.

doi:10.1051/epjconf/201819506020

Cited by 5 publications

(1 citation statement)

References 6 publications

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“…They used a single-crystal interferometer in Young's configuration to measure the absorption of a periodically poled lithium niobate (PPLN) crystal in the terahertz frequency range. A different setup with a Mach-Zehnder geometry was used to measure the linear properties of a 4% magnesium oxide (MgO)-doped lithium niobate (LiNbO 3 ) crystal (7). To that end, two 5% MgO-doped LiNbO 3 crystals were placed right around the investigated object.…”

Section: Introductionmentioning

confidence: 99%

Terahertz quantum sensing

et al. 2020

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Quantum sensing is highly attractive for accessing spectral regions in which the detection of photons is technically challenging: sample information is gained in the spectral region of interest and transferred via biphoton correlations into another spectral range, for which highly sensitive detectors are available. This is especially beneficial for terahertz radiation, where no semiconductor detectors are available and coherent detection schemes or cryogenically cooled bolometers have to be employed. Here, we report on the first demonstration of quantum sensing in the terahertz frequency range in which the terahertz photons interact with a sample in free space and information about the sample thickness is obtained by the detection of visible photons. As a first demonstration, we show layer thickness measurements with terahertz photons based on biphoton interference. As non-destructive layer thickness measurements are of high industrial relevance, our experiments might be seen as a first step towards industrial quantum sensing applications.

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Section: Introductionmentioning

confidence: 99%

Terahertz quantum sensing

et al. 2020

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Quantum Sensing with Extreme Light

et al. 2022

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Optical nonlinear conversion processes are ubiquitously applied to scientific as well as industrial tasks. In particular, nonlinear processes are employed to generate radiation in many frequency ranges. In plenty of these nonlinear processes, the generation of paired photons occurs -the so-called signal and idler photons. Although this type of generation has undergone a tremendous development over the last decades, either the generated signal or the idler radiation has been used experimentally. In contrast, novel quantum-based measurement principles enable the usage of both partners of the generated photon pairs based on their correlation. These measurement approaches have an enormous potential for future applications, as they allow to transfer information from one spectral range to another. In particular, spectral ranges where photon generation and detection is particularly challenging can benefit from this principle. Above all, these include the extreme frequency ranges, such as on the low-frequency side the mid to far infrared or even the terahertz spectral range, but also on the high-frequency side the ultraviolet or X-ray spectral range. In this review article, theoretical and experimental developments based on correlated biphotons are described specifically for the extreme spectral regions.

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Study of SPDC spectra to reveal temperature dependences for optical-terahertz biphotons

Novikova

Кузнецов

Leontyev

et al. 2020

Applied Physics Letters

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Frequency-angular distributions of optical signals generated via spontaneous parametric downconversion with the Stokes idler frequency shifts 0.2–5 THz are studied simultaneously with the same distributions in the anti-Stokes range while the nonlinear Mg:LiNbO3 crystal is cooled from 300 K to 4.2 K. The temperature dependencies of the angular distributions at fixed idler frequencies are analyzed using a theoretical Klyshko–Kirchhoff approach with account of thermal field fluctuations and inherent crystal absorption at terahertz frequencies. Although all the measurements are performed in the optical range, we demonstrate how such analysis enables to predict the temperature behavior of the total number of spontaneous parametric downconversion-generated idler photons in the terahertz range, the temperature variation of the optical-terahertz biphoton function, and to study the contributions of classical thermal and pure quantum field fluctuations to parameters of biphotons. It is shown that the temperature-induced growth of the numbers of signal and idler photons and their non-normalized correlation function is provided by overwhelming increase in classical fluctuations, while the pure quantum contributions to these parameters are not so sensitive to the crystal temperature.

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Nonlinear quantum interferometry in terahertz spectroscopy

Cited by 5 publications

References 6 publications

Terahertz quantum sensing

Terahertz quantum sensing

Quantum Sensing with Extreme Light

Study of SPDC spectra to reveal temperature dependences for optical-terahertz biphotons

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