title: Powerful terahertz emission from laser wakefields in inhomogeneous magnetized plasmas.
abstract: Powerful coherent terahertz (THz) pulses with a broad spectrum (0.1-3 THz) can be produced from a laser-driven wakefield through linear mode conversion in inhomogeneous magnetized plasmas with the maximum plasma density of 10(17) cm(-3). This occurs when a laser pulse, with an optimized duration about 300 fs, is incident either normally or obliquely to the density gradient of inhomogeneous magnetized plasmas. The external dc magnetic field has a magnitude of a few tesla. By changing the strength and direction of the magnetic field, one can enhance or suppress the THz emission. The maximum energy conversion efficiency in the magnetized plasmas can be double that in the unmagnetized plasmas. Such wakefield emission can be a powerful THz source at the MW level and capable of affording field strength of a few MV/cm, suitable for THz nonlinear physics. Because these THz emissions are always with a positive chirp, with a proper dispersion compression, single-cycle THz pulses can be generated with higher peak powers and field strengths.
authors.affiliation: Beijing National Laboratory for Condensed Matters, Institute of Physics, Chinese Academy of Science, Beijing 100080, China.
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Wu
authors.forename: Zheng-Ming
authors.initials: ZM
authors.lastname: Sheng
authors.forename: Quan-Li
authors.initials: QL
authors.lastname: Dong
authors.forename: Han
authors.initials: H
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang