Terahertz radiation with high power and high efficiency in a magnetized plasma

Abstract

We propose a scheme for the generation of terahertz (THz) radiation in a plasma by beating of two flat-topped laser beams when a static magnetic field is applied to the plasma with a parallel or perpendicular direction. We show that the presence of a static magnetic field can enhance drastically the power and efficiency of THz radiation. The power and efficiency enhancement of the perpendicular magnetic field is greater than that of parallel one. Furthermore, the perpendicular magnetic field produces THz radiation with a square shaped field profile which has many applications in industries especially in optical communication. Optimizing the laser beams and magnetized plasma parameters and considering the interaction (mutual effect) between laser beams, THz radiation, and plasma, the THz radiation efficiency up to 8.3% can be obtained. A comparison between the THz radiation generated by flat-topped and super Gaussian laser beams shows that, at the same conditions, the THz radiation generated by flat-topped beam lasers has some advantages such as about two times wider flat-topped region and more than two times higher efficiency.

Intense terahertz radiation: generation and application

“…By applying a direct current (DC) bias voltage along the direction of the electric field of incident beam, enhanced THz pulses have been measured and the peak field enhanced 32 times of that without external electric field [60]. The efficiency can also be enhanced when a static magnetic field is applied to the plasma parallel or perpendicular to the electric field [61]. Inserting a second harmonic generation crystal before the focal point, the THz radiation generated can be enhanced 40 times [62] and this method is referred to as the two-color filamentation approach.…”

Excitation of terahertz surface magnetoplasmons by nonlinear mixing of laser and its second harmonic on a rippled surface of n type semiconductor

“…These waves have a potential applications in medical imaging [1], material diagnostics [2], explosive detection [3], and spectroscopy [4]. The THz radiation can be produced using a several methods such as optical rectification with crystals [6? ], photoconductive antenna [7,8] and semiconductors [9], plasma-based techniques, and air or gas plasma interaction with lasers [10], relativistic free electron laser interaction with ripple density plasma [11], interaction of high intensity short pulse with nonlinear dielectrics materials and plasma [12][13][14]. Wang et al [15] investigated excitation of THz emission by two-color femtosecond laser-induced filaments in the air in the presence of an external dc field.…”

Terahertz Radiation from a Plasma Cylinder with External Radial Electric and Axial Magnetic Fields

“…THz radiation can also be produced in intense laser interaction with matter [3,5,[6][7][8][9][10][11][12][13][14]. T-rays can also be produced by the oscillating electrons in laser-induced wakefields [15][16][17], Smith-Purcell effect of the electron beams in laser-matter interactions [18], two-color laser gas-plasma interaction [19,20], transition-Cherenkov effect from laser filaments [21], laser-driven wire-guided helical undulators [22], and linear and nonlinear mode conversion [23], as well as laser interaction with strongly magnetized plasmas [24][25][26][27]. However, most such sources of T-rays are rather complex and inconvenient to realize in practice.…”