title: Highly efficient terahertz radiation from a thin foil irradiated by a high-contrast laser pulse.
abstract: Radially polarized intense terahertz (THz) radiation behind a thin foil irradiated by ultrahigh-contrast ultrashort relativistic laser pulse is recorded by a single-shot THz time-domain spectroscopy system. As the thickness of the target is reduced from 30 to 2 µm, the duration of the THz emission increases from 5 to over 20 ps and the radiation energy increases dramatically, reaching ∼10.5mJ per pulse, corresponding to a laser-to-THz radiation energy conversion efficiency of 1.7%. The efficient THz emission can be attributed to reflection (deceleration and acceleration) of the laser-driven hot electrons by the target-rear sheath electric field. The experimental results are consistent with that of a simple model as well as particle-in-cell simulation.
authors.affiliation: Photon Pioneers Center, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Z
authors.initials: Z
authors.lastname: Jin
authors.affiliation: College of Science, National University of Defense Technology, Changsha 410073, People's Republic of China.|Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
authors.forename: H B
authors.initials: HB
authors.lastname: Zhuo
authors.affiliation: Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakazawa
authors.affiliation: Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: J H
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Wakamatsu
authors.affiliation: Department of Advanced Interdisciplinary Sciences, Center for Optical Research & Education, and Optical Technology Innovation Center, Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi, 321-8585, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yugami
authors.affiliation: Photon Pioneers Center, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hosokai
authors.affiliation: College of Science, National University of Defense Technology, Changsha 410073, People's Republic of China.
authors.forename: D B
authors.initials: DB
authors.lastname: Zou
authors.affiliation: Institute for Fusion Theory and Simulation and Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China and Institute of Theoretical Physics I, Ruhr University, D-44780 Bochum, Germany.
authors.forename: M Y
authors.initials: MY
authors.lastname: Yu
authors.affiliation: Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.|SUPA, Department of Physics, University of Strathclyde, Glasgow G0 4NG, United Kingdom.|Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
authors.forename: Z M
authors.initials: ZM
authors.lastname: Sheng
authors.affiliation: Photon Pioneers Center, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.|Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.|Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kodama