Terahertz waves emission from plasma under action of p-polarized tightly focused laser pulse

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2023-06, Vol.77 (6), Article 109
• Main Author: Frolov, A. A.
• Format: Article
• Language: English
• Subjects: Angle of reflection; Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Emission; Incidence angle; Lasers; Molecular; Optical and Plasma Physics; Physical Chemistry; Physics; Physics and Astronomy; Plasma; Plasma density; Quantum Information Technology; Quantum Physics; Radiation; Regular Article – Plasma Physics; Spectroscopy/Spectrometry; Spintronics; Terahertz frequencies
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/s10053-023-00693-7

The theory of terahertz (THz) waves generation at the incidence of the focused p -polarized laser pulse on the plasma boundary is developed. The angular, spectral, and energy characteristics of the THz signal are studied as the function of the focusing degree and the incidence angle of laser radiation, as well as the plasma density. The frequency dependence of the THz signal energy is considered and it is established that the emission spectrum contains the broad line, and its position for tight focusing of laser radiation is determined by its reciprocal duration. The radiation pattern of the THz pulse is studied and it is shown that the decrease in the size of the laser pulse focal spot leads to the increase in the angle of radiation with respect to the normal to the plasma boundary, and for the tight focusing of the laser pulse, THz waves are emitted almost along the plasma-vacuum interface. It is established that the energy of the THz pulse noticeably increases when the p -polarized laser pulse is incident almost along the normal onto the near-critical plasma at the angle of total reflection, and the transverse size of the laser pulse decreases. It is shown that the emission of high-power THz pulses with the sufficiently high conversion rate occurs at the almost normal incidence of ultrashort tightly focused laser radiation on the boundary of near-critical plasma with rare electron collisions.