New progress has been made in controlling the terahertz radiation waveform driven by the strong light field of the Institute of Optomechanics, Chinese Academy of Sciences
Papers published by Xu Zhizhan and Li Ruxin of the State Key Laboratory of Strong Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences in the international academic journal "Physics Review Letter" published on June 22 2012)], for the first time, proposed and verified a new method of generating periodic controlled terahertz radiation by using a very short pulse strong field laser of periodic magnitude, which is the precise control of the space-time of the terahertz radiation source and its coherent control in remote sensing and quantum systems Important applications in other fields provide new ideas.
The strong field ultrafast laser-driven air plasma can generate and detect terahertz waves at a long distance, overcoming the absorption of terahertz spectrum by water molecules in the air, and has important application prospects in remote terahertz spectroscopy and imaging detection; and The waveform-controllable terahertz radiation is expected to be used in the research of phase-sensitive terahertz sensing and quantum coherent control, and is developing into the frontier research direction of terahertz science and strong field laser physics.
In recent years, the research group of the Shanghai Institute of Optoelectronics has independently developed and established a carrier envelope phase (CEP) stable infrared band period order very short pulse laser system (center wavelength 1.8um; pulse width 1.5 photoperiod, ~ 9fs) and physical experiments Platform, and successfully applied to the generation and application of terahertz radiation based on air filament plasma. This study found for the first time that the terahertz radiation waveform can be controlled by changing the length of the optical fiber plasma and the CEP driving the laser pulse. In particular, the evolution of the terahertz radiation waveform generated in the optical fiber plasma with the transmission position and even A polarity reversal has occurred.
In the studies reported so far on the laser-driven air-filament plasma to generate terahertz radiation, the fundamental frequency and the double frequency light field are usually used to generate an asymmetric combined light field to obtain enhanced terahertz radiation. In this study, the terahertz radiation is enhanced by the asymmetry of the ultra-fast laser pulse light field with periodic magnitude. The numerical simulation using the photocurrent model and including the transmission effect is in good agreement with the experimental results. In addition, this study also proposes the concept of a modified Gouy phase shift of a periodic light field in a dispersive medium, explains its physical nature, and reveals for the first time the causes of various phase changes in the filament plasma .
Reviewers of Physical Review Letters highly praised the work: "This is an important and timely research paper. The carrier-envelope phase (CEP) stable periodic order laser field produces terahertz radiation until recently. Probably, but its physical mechanism is still unclear .... The paper will undoubtedly take a decisive step in this direction. "" ... I think the paper will lead to terahertz radiation and laser filament formation for lasers with stable carrier envelope phases. There is a better understanding of the complex dynamics in the world, and it will surely arouse a high degree of interest in a wide range of terahertz scientific academia and academia in the field of laser filamentation and plasma physics. "
The research was supported by the National Natural Science Foundation of China and the 973 Program.
New progress has been made in controlling the terahertz radiation waveform driven by the strong light field of the Institute of Optomechanics, Chinese Academy of Sciences
Eye Brushes,Eyebrow Brush,Eyeshadow Blender Brush,Makeup Brush Eyeshadow
DONGGUAN YACAI COSMETICS CO.,LTD. , https://www.yacaicosmetic.com