Physics, etc. use a strong laser to greatly increase the terahertz pulse energy

[ China Instrument Network Instrument Development ] Terahertz (THz) radiation is located between the mid-infrared and microwave radiation. Due to its unique single photon energy and spectral "fingerprint", it has advantages in materials science, biomedical and national defense security. Important application value. However, the lack of large energy terahertz radiation sources is one of the key bottlenecks that limit the development of terahertz science and applications. There are a variety of electronic and optical methods to obtain terahertz radiation, but so far, the publicly reported terahertz pulse energy is less than millijoule.

Comparison of terahertz peak power obtained by different methods

Li Yutong, a researcher at the Institute of Physics of the Chinese Academy of Sciences/Beijing National Center for Condensed Matter Physics, L05 Group, and a research team composed of Zhang Jie and Liao Guoqian from Shanghai Jiaotong University, produced terahertz radiation from strong laser-solid target interactions. The new approach has been explored. In the early stage, laser-accelerated high-energy electrons were used to excite terahertz-pass radiation work [Phys. Rev. Lett. 116, 205003 (2016)], and recently in collaboration with David Ruelow, professor of the Rutherford Laboratory in the UK. In the experiment, the terahertz pulse energy was greatly improved.

The experiment was carried out at the Vulcan laser device at Rutherford Laboratory, and the experimental protocol was proposed by the Chinese. Using picosecond super-laser devices, they first accelerate a large number of high-energy electrons in a solid film target, and then, when electrons escape from the back of the target to a vacuum, excite radiation to excite high-intensity terahertz radiation. Experiments have shown that terahertz pulse energy is as high as 50 mJ, which is the highest terahertz energy obtained in the laboratory to date.

Terahertz has been used in many research and technology fields, such as full-body scanners for airport security. Such a strong terahertz source driven by a high power laser provides an opportunity for people to study the nonlinear dynamics of matter.

Related research results were recently published in the Proceedings of the National Academy of Sciences (PNAS). The research work was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, the Ministry of Science and Technology, and the Newton Fund.

(Original title: Physics, etc. use a strong laser to greatly increase the terahertz pulse energy)