Abstract-Radially polarized terahertz radiation in laser-induced linear plasma wake

• Suyun Zhou
• Yanfang Li

• http://www.sciencedirect.com/science/article/pii/S0030402616000073

The radially polarized terahertz radiation from laser-induced oscillating current is investigated by employing a two-dimensions plasma wakefield analytical model. It is shown that in linear plasma wake the currents have a periodical change along laser axis, and the current directions in potential well and potential barrier are opposite. The radial currents vanish at laser axis, which is different from longitudinal current, thus leading to a angle deviation of peak radiated power of radially polarized THz wave from laser axis. The deviation is more significant in thick plasma layer. The dependance of peak radiated power and total power of THz emission on thickness of plasma layer and laser intensity is discussed.

Abstract-Tunable Circularly Polarized Terahertz Radiation from Magnetized Gas Plasma

W.-M. Wang, P. Gibbon, Z.-M. Sheng, and Y.-T. Li

Phys. Rev. Lett. 114, 253901 – Published 23 June 2015

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.253901

It is shown, by simulation and theory, that circularly or elliptically polarized terahertz radiation can be generated when a static magnetic (B) field is imposed on a gas target along the propagation direction of a two-color laser driver. The radiation frequency is determined by ω2p+ω2c/4−−−−−−−−√+ωc/2, where ωp is the plasma frequency and ωc is the electron cyclotron frequency. With the increase of the B field, the radiation changes from a single-cycle broadband waveform to a continuous narrow-band emission. In high-B-field cases, the radiation strength is proportional to ω2p/ωc. The B field provides a tunability in the radiation frequency, spectrum width, and field strength.

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