As the frontier of ultrafast science, attosecond physics has quickly become a hot topic in the conference. Attosecond pulse has many application prospects because of its high photon energy, wide spectrum and weak intensity. Experts and scholars attending the meeting conducted in-depth discussions on this key issue. Academician Yang Guozhen pointed out: "At present, attosecond pulse and free electron laser are in the X-ray band. After years of development, free electron lasers have formed many application methods, and attosecond lasers can learn from these methods. "
Professor Zeng Zhinan from Shanghai Institute of Optics and Mechanics, Chinese Academy of Sciences, Professor Liu Yunquan from Peking University and Professor Ding Dajun from Jilin University discussed how to overcome the difficulties in the application research of attosecond physics from multiple dimensions and angles, and put forward various possible directions that can bypass the current difficulties and achieve new breakthroughs.
Development of attosecond laser
The concept of attosecond laser may be strange to ordinary people. If we go back to 1960, the concept of laser is as difficult as describing colors for the blind. Nowadays, lasers have been widely used in various fields. For example, we can buy a few laser pens, and all children know what a laser is. Most people's impression of laser is mainly limited to color, but in fact the color of laser is determined by its frequency or wavelength.
There is a simple conversion relationship between laser frequency and wavelength, and their product is equal to the speed of light. In addition, the brightness of laser is also a common description, because the greater the emission power of laser pen, the brighter and hotter it is. But for professionals, there is another important parameter to describe laser, that is pulse width, also referred to as pulse width. Pulse width refers to the interval of laser pulses, that is, the interval of laser emission.
At first, the laser was fired continuously, just like a water gun constantly spraying water. However, scientists have found that higher power can be obtained by emitting laser in stages, that is, pulsed laser. The smaller the pulse width of pulsed laser, the faster the emission frequency and the greater the energy of each laser pulse.