Jiang Lan, born in 1972, is a native of Zigong, Sichuan Province. He is one of the first chair professors of Beijing Institute of Technology, and has long been engaged in the research of femtosecond laser fabrication, and is one of the main academic leaders in the field of laser fabrication in China. He was awarded the second prize of the National Natural Science Award and the He Liang He Li Science and Technology Innovation Award, etc. In May 2023, he was awarded the Third National Innovation Prize, and in November 2023, he was elected as an academician of the Chinese Academy of Sciences.
1 femtosecond is one trillionth of a second. The energy of a laser pulse is compressed into a few femtoseconds and released at a very high speed, and its peak power can be increased by millions of billions of times, which can theoretically process any solid material. Femtosecond laser, this indestructible "super strong and ultra-fast light knife", has a broad application prospects.
Focusing on femtosecond laser manufacturing research for more than 20 years, Jiang Lan team realized a number of major breakthroughs, he took the lead in writing a number of important plans in the direction of laser manufacturing, to promote China's first echelon in the field of international.
The first prediction of the shape of femtosecond laser processing
With such a short time and high energy, how will the femtosecond laser be utilized? Although there are many advantages at the theoretical level, but for a long time, femtosecond laser manufacturing applications remain at the conceptual level.
From concept to application, where is the difficulty of femtosecond laser manufacturing? Jiang Lan introduced, the classical theory is difficult to predict the shape of the femtosecond laser processing, processing mechanism is also difficult to describe, this is the team more than 20 years of research to study the dilemma faced.
"Must open the femtosecond laser and material interaction 'black box', in order to completely understand the femtosecond laser processing mechanism." Jiang Lan said.
When femtosecond laser processing, the local transient properties of the material will change drastically, in order to explore this change, Jiang Lan and his team have established a plasma quantum model to predict the shape of femtosecond laser processing for the first time, and successfully predicted a series of important anomalous effects. Initially, the academic community was skeptical, but as the main assumptions and predictions of the model proposed by Jiang Lan were widely verified around the world, the research results gradually gained recognition.
After verifying the model, there is still a need for intuitive observations to support the results, i.e., to "film" the process of femtosecond laser manufacturing. Due to the traditional observation technology has a single perspective, and is still two-dimensional imaging, can not capture the multi-dimensional information involved in the process of femtosecond laser processing. Jiang Lan led the team to develop a cross-scale quasi-three-dimensional ultrafast continuous camera system, which for the first time realized a panoramic observation across 15 time scales in the process of femtosecond laser-material interaction.
With a series of original results, Jiang Lan has become a leader in the field of femtosecond laser manufacturing research. In fact, during his postdoctoral work, Jiang Lan started to carry out research on femtosecond laser fabrication. At that time, there was no femtosecond laser equipment, project funding and laboratory, only relying on a computer, Jiang Lan began a difficult exploration.
Femtosecond laser fabrication involves multiple disciplines such as mechanics, physics, optics, materials, chemistry, etc. For the unfamiliar fields, Jiang Lan made breakthroughs in many disciplines other than mechanics through self-study or consulting relevant experts, which also laid the foundation for the next research.
The characteristics of femtosecond lasers lead to low processing efficiency, low depth-to-diameter ratio, and processing accuracy worse than the diffraction limit. Another hurdle to overcome is to find a way to regulate the manufacturing process of femtosecond lasers.
Based on his model prediction, Jiang Lan pioneered a new principle and method of electronic dynamic control manufacturing, thus realizing the control of processing results.
Jiang Lan led the team to verify while groping, and finally, based on the new principle of electronic dynamic regulation, the processing efficiency has been increased by 56 times, the depth-to-diameter ratio has been increased by 260 times, so that the repeatable processing accuracy up to 1/14 of the wavelength and so on.
"Any more advanced processing technology, if it only stays on paper, it can't achieve good application development." Jiang Lan said.
Based on the new principles and methods of electronic dynamic regulation, Jiang Lan led the team to break through a series of bottlenecks in the manufacture of three-dimensional complex microfabrication of difficult-to-machine materials one after another, invented new technologies such as electronic dynamic regulation of control holes, cutting, leveling, and engraving, developed a series of new equipment, and took the lead in realizing the major engineering applications of femtosecond laser manufacturing and large-scale industrial applications.
"The well-known cell phone full-screen shaped cutting and other technologies are also one of the technologies we focus on." Jiang Lan introduced, the application of electronic dynamic modulation manufacturing new principles, new technologies, the team and the enterprise jointly developed a femtosecond laser electronic dynamic modulation cutting / hole making new equipment, the performance of the overall international leading level.
Laboratory technology to industrial applications, although the technology path is clear, but still need to consider the cost, practicality and other constraints. To this end, Jiang Lan's team, together with partner companies, repeatedly verify the process and adjust the parameters. "Often soaked in the laboratory, sometimes in order to perfect a certain performance, before and after a whole year of busy work." Jiang Lan's team member, Hu Jie, a professor at Beijing Institute of Technology, recalled.
Tackling high-quality processing of composite materials, preparing new materials and new devices, and developing high-precision manufacturing equipment ...... Nowadays, Jiang Lan's team, with its high-quality and original work, is continuing to open up the application scenarios of laser manufacturing. "Scientific research, we have to do really valuable work, do 'top of the sky' scientific research, do not pick green fruit." Jiang Lan's requirements for the team's teachers and students have become part of the team's culture.
Years ago, laser manufacturing was only a tertiary branch of the mechanical engineering field, with no systematic support from related departments. There were few researchers, little research funding, small industrial scale, and the gap was obvious compared with the world's advanced level.
Jiang Lan realized that to catch up, relying on one or two teams alone will not work, "to make the discipline bigger and stronger, we must unite the scientific research community and industry together, and work together".
In 2008, the National Natural Science Foundation of China listed the field of high-energy beams and special energy field manufacturing as a priority direction of support, laser manufacturing is an important aspect of it, and Jiang Lan as the person in charge of the field. Under the guidance of former scholars, Jiang Lan has led the writing of two parts of the planning of the high-energy beam and special energy field area of the Fund Committee within 12 years, and in the field of laser manufacturing, he has achieved certain theoretical results.
Jiang Lan led the expert group to invest a lot of time and energy to sort out the short boards of the industrial chain and prepare the development plan of the industry, so as to promote the national or ministry science and technology programs in the field of laser manufacturing. He has taken the lead in writing 12 national medium- and long-term science and technology development plans for laser manufacturing and other directions, as well as five-year ministerial science and technology plans of the Ministry of Science and Technology and the Foundation Commission.
Among them, the "13th Five-Year Plan" national key research and development program - "additive manufacturing and laser manufacturing", the project justification took two and a half years. "At that time, I and the expert group members often work and discuss until the early morning." Jiang Lan recalls.
More than 30 thematic discussion, research visits to more than 70 enterprises, writing millions of words of argumentation materials ...... Jiang Lan and the expert group to go all out. Afterwards, the special access to the "14th Five-Year Plan" rolling support, become the only manufacturing field "build a long board" of national key specialties.
Hundreds of scientific research institutions, thousands of companies engaged in laser manufacturing-related research, we have different expertise, interest, how to bring everyone together? "Jiang Lan has always stood in the country, the industry's development position to prepare the plan, and gained everyone's recognition." An industry expert said.
"In the era of big science, the development of technology can't rely on solo efforts." Jiang Lan said that there are still many problems to be solved in the field of laser manufacturing, the team will be based on the "four oriented", united with the industry, academia and research of the attack force, and strive to make due contributions to the manufacturing country, education and science and technology.
