Comparison of currently available high-peak-power THz sources. The data are referenced from previously reported typical results of THz sources based on conventional accelerators (black squares), optical rectification from crystals (blue circles) like lithium niobate (LN) and organic crystals, and gas/solid-density plasmas (green triangles). The red star represents the data presented in this paper. Magenta curves represent different energy ranges for half-cycle THz pulses. [Image from Institute of Physics]

Electromagnetic waves between infrared and microwaves are called as Terahertz (THz) radiation. It is a big challenge to generate intense THz radiation, which is significantly important for THz sciences and applications in many interdisciplinary fields. Although THz sources have been generated with electronic and optical techniques in recent decades, the THz pulse energy reported is lower than a millijoule. Results recently published in PNAS show that strong terahertz bursts with tens millijoules of energy, a world record for laboratory sources, can be obtained using high-power lasers.

Prof. Li Yutong’s groups from the Institute of Physics of the Chinese Academy of Sciences, Prof. Zhang Jie’s group from Shanghai Jiaotong University, in collaboration with Prof. David Neely from the Central Laser Facility of STFC Rutherford Appleton Laboratory, Prof. Paul McKenna from the University of Strathclyde, and UK scientists from the University of York have studied THz radiation from intense laser-metal foil interactions. The Vulcan laser at the Central Laser Facility has achieved the record for the highest energy in a single pulse of terahertz radiation achieved in a laboratory.

The generation of such a strong THz source is mainly due to coherent transition radiation when an energetic electron bunch crosses the rear surface of the thin foil. The high-charge electron bunch is accelerated by the high intensity laser pulses in the mm-sized solid metal foil.

Terahertz are already used in tech in many fields. For example, the full body scanners for airport security checks. The powerful THz source driven by high power lasers provides opportunities to look at nonlinear dynamics in matter.

This study, entitled "Multi-millijoule coherent terahertz bursts from picosecond laser-irradiated metal foils" , was published in PNAS.

The study was supported by the National Science Foundation, the Ministry of Science and Technology of China, the Chinese Academy of Sciences, the National Postdoctoral Program for Innovative Talents, and the Newton and Engineering and Physical Sciences Research Council of the UK.

For more information, please contact:

Prof. Li Yutong

Email: ytli@iphy.ac.cn

Source: Institute of Physics