Special Issue “Terahertz (THz) Science in Advanced Materials, Devices and Systems”

We have introduced, for the first time, a protocol for Continuous-Variable Measurement-Device-Independent Quantum Key Distribution (CV-MDI-QKD) in the terahertz (THz) frequency band. We have conducted a secret key rate analysis against collective attacks. The proposed THz CV-MDI-QKD is immune to all detector attacks, significantly enhancing the security assurance of practical THz CVQKD implementations. Furthermore, we investigated the impact of finite key length (the finite-size effect) and finite reconciliation efficiency on the performance of practical THz CV-MDI-QKD systems. Our findings reveal that by employing a large number of keys or signals and optimizing the modulation variance, the detrimental effects arising from the finite-size effect and suboptimal reconciliation efficiency can be notably mitigated. These insights play a crucial role in advancing the feasibility of THz CVQKD technology towards practical applications.

Section: Introductionmentioning

confidence: 99%

Continuous-Variable Measurement-Device-Independent Quantum Key Distribution in the Terahertz Band

Liu,

Yang,

Yang

et al. 2024

“…A comprehensive review of the application of THz radiation in various fields of science and technology is given in [23,24].…”

Section: Introductionmentioning

confidence: 99%

Cascaded Stimulated Polariton Scattering in a Single-Pass KTP Crystal under Picosecond Pumping

Vereshchagin,

Morozov

et al. 2023

Cascaded stimulated polariton scattering (SPS) under powerful picosecond pumping of 532 nm wavelength was investigated in a single pass of a KTP (KTiOPO4) crystal. Under ordinary polarization of the pump wave (relatively XOZ-plane) parametric scattering in the KTP crystal was observed. By rotation of the pump wave polarization (from ordinary to extraordinary), this scattering gradually transforms into polariton scattering. Polariton signal components (spots) with gaps between them were registered at external angles of ~2° between the neighboring spots. Five polariton signal components were detected above the pump beam, with a frequency difference between neighboring cascaded components of ~188 cm−1 (5.64 THz). The wavelength of each next component increased regularly with the angle between this component and the pump wave, so this regular sequence of polariton signal components can be regarded as a cascaded SPS.

“…Electromagnetic radiation in the frequency range from 0.3 THz (or 0.1 THz) to 10 THz (or even up to 30 THz) is usually considered as a separate type of radiation ("THz radiation"), mostly due to the specific features of its interaction with matter and to its fairly weak degree of development compared to neighboring spectral ranges [1,2]. Since THz radiation is non-ionizing, it has a great potential for use in biophotonics and medicine [3], as well as in security systems [4].…”

Section: Introductionmentioning

confidence: 99%

An Improvement of the Cherenkov THz Generation Scheme Using Convex Silicon Prism-Lens Adapters

Kitaeva,

Safronenkov,

Starkova

2023

The terahertz (THz) generation efficiency in the Cherenkov optical rectification scheme can be improved significantly if the silicon adaptor, mounted at the lateral surface of a nonlinear crystal, has a convex output surface with proper geometry. We demonstrate and compare with the results of direct experiments a method for theoretically modeling the angular distributions of the spectral power of THz radiation in the case of different Si adaptors, constructed by mounting plano-spherical lenses on a conventional flat Si prism. The applied method of theoretical modeling shows its usefulness in choosing the best Si adapter geometry.