Mar 31, 2020
With the rapid development of laser technology, ultrafast laser appears in people's eyes. It has a unique ultrashort pulse, super-strong characteristics, and can obtain high peak light intensity with low pulse energy. The appearance of chirped pulse amplification (CPA) technology greatly improves the intensity of the ultrafast laser. Different from the traditional long-pulse laser and continuous laser, the ultrafast laser has an ultrashort laser pulse, which makes the spectrum width of the laser pulse very large. Such a wide spectrum has important applications in the study of atomic energy levels, laser bonding chemistry, and so on. According to the characteristics of the ultrafast laser pulse, we can use the pump-probe method to photograph the interaction between laser pulse and matter at different times, in order to obtain the characteristics of the whole process. This method has been applied to various fields, such as in the study of atom and molecule reaction dynamics and the observation of electron motion, using femtosecond laser pulse or even attosecond pulse to observe the reaction process by the pump-probe method. When the peak power density of the focused ultrafast laser is more than 1012w / cm2, the electric field intensity is greater than that of the atom. It provides a very strong and extremely high electric field, which can exceed the binding force of valence band electrons, making the electronic system of molecules and atoms change greatly. By using this property, we can study the peculiar phenomena inside the atom caused by the ultrafast laser. In addition, the ultrafast laser also shows other different characteristics, such as small heat affected area, the effect can exceed the optical diffraction limit and excellent spatial selection characteristics.
The interaction between ultrafast and super intense laser pulses and the matter is one of the most active research topics at present. It has a wide range of applications in new particle accelerators, ultrafast high energy X-ray sources, and so on. At the same time, it contains many theoretical and experimental research topics, involving many important branches of physics, such as laser physics, atomic and molecular physics, nonlinear optics, plasma physics, thermodynamics, and so on. With the continuous development of ultrashort laser pulse technology, high-intensity periodic ultrashort pulses have been produced experimentally, which provides unprecedented experimental means and extreme physical conditions for the study of the interaction between light and matter, It has opened up a new research field of the interaction between light and matter, produced the so-called extreme nonlinear optics, greatly enriched the research content of optics, and expanded the research of the interaction between laser and various forms of matter such as atoms, molecules, ions, electronic clusters and plasmas to the strong field range of highly nonlinear and relativity.
In the process of interaction between ultrafast super intense laser and matter, with the continuous improvement of laser intensity, all kinds of nonlinear effects are increasing, such as high-order harmonics, threshold ionization, tunneling ionization, and so on. Moreover, the periodic ultrashort laser pulse loses the unique periodic characteristics of the wave phenomenon, which leads to a series of new physical phenomena and laws. It provides a new experimental tool for coherent control, nonlinear optics, and the control of the newly arisen SUBPERIODIC electronic wave packet. It also provides a new time measurement scale, attosecond, which may have an important impact on many disciplines.
In the aspect of material processing, since the appearance of an ultrafast laser, because of its ultrafast time and high peak value characteristics, it can quickly and accurately concentrate energy in the action area, and realize the non-hot melt cold treatment of almost all materials. The advantages of high precision and low damage that traditional laser can't match are obtained. These unique advantages of microsecond laser have been widely used in material microprocessing, nanostructure fabrication, photon devices, high-density storage, Medical Bioengineering, and so on.
Ultra-fast laser science is a very young new subject, which is on the eve of a major breakthrough. In recent years, with the breakthrough and commercialization of high-power picosecond, femtosecond laser, and fiber ultrafast laser technology, the ultrafast laser has moved from laboratory to practical industrial production and application, becoming a hot direction in academia and laser application industry.
The ultrafast laser can solve many processing problems that are difficult to be achieved by conventional methods, such as high, precise, sharp, hard, difficult, etc., achieve amazing processing capacity, processing quality and processing efficiency, and generate significant economic and social benefits.
With the launch and development of "industry 4.0" and "made in China 2025" in Germany, the demand for high-end manufacturing, intelligent manufacturing, and high-precision manufacturing will increase significantly in the future, and ultrafast laser and advanced micro-nano processing technology will usher in new opportunities for rapid development. It is estimated that the total market volume of the ultrafast laser will exceed 1.5 billion US dollars by 2020.