Research Background:
With the development of modern science and technology, the study of optics has achieved unprecedented precision in two dimensions of space and time. In the time scale, optics enters the range of femtosecond [10^-15 s] to attosecond [10^-18 s]. As the pulse is compressed in the time domain, the peak power can reach the level of terawatt [10^12 W] - petawatt [10^15 W]. The resulting ultrashort intense laser pulses greatly enhance the interaction between light and matters, thus giving rise to a new and promising discipline - Ultrafast Nonlinear Optics. Since its emerging in the 1990s, the connotation and research scope of ultrafast nonlinear optics have been constantly deepened and expanded, which is of great significance to the development of laser technology, spectroscopy and material structure analysis. At present, ultrafast nonlinear optics has become a cutting-edge subject and hot spot in the field of optics. Notably, the 2018 Nobel Prize in Physics was partially conferred to G. Mourou and D. Strickland for their ingenious approach to generating high-intensity, ultra-short optical pulses.
The field of ultrafast nonlinear optics is broad and multidisciplinary and encompasses areas concerned with both the generation and measurement of ultrashort pulses of light, as well as those concerned with the applications of such pulses. Ultrafast nonlinear optics research mainly includes femtosecond-attosecond pulse generation, THz-visible-XUV ultrafast laser technology, ultrafast spectroscopy, time-resolved sensitive detection, as well as information science, material science, life science and other cross-discipline applications. In the 13th Five-Year Plan for Shanghai's scientific and technological innovation released in 2016, ultrafast and ultra-intense laser devices and related physical research were regarded as an important part of consolidating the scientific and technological foundation.
Research Direction:
The ultrafast nonlinear optics team focuses on major scientific issues and key technical challenges in the field of optics with three main directions: ultrafast laser technology, ultrafast and ultra-intense laser physics, and ultrafast sensitive detection. These three research directions are relatively independent but closely related.
·Ultrafast Laser Technology: High-power femtosecond laser and its time-frequency precision control are the basis to drive cutting-edge scientific research on ultrafast laser physics and high-precision measurement, as well as to promote high-tech development of precision manufacturing equipment. It is also one of the competitive technologies that attract developed countries such as the United States. Fiber lasers are widely used in the fields of industry, medical industry, scientific research, national defence and military due to advantages such as good beam quality, small size, high efficiency, good heat dissipation, compact structure and flexible operation. The research of ultrafast laser technology mainly focuses on high-power fiber laser amplification, phase control, optical frequency comb, which provides valuable support for high-power coherent source generation, ultrafast ultra-intense laser physics, ultrafast spectroscopy and high-precision measurement.
·Ultrafast and Ultra-intense Laser Physics: This research direction focuses on the major scientific cutting-edge issues in the process of the interaction of ultra-intense femtosecond laser and matter, with an aim to provide a new concept of light source and scheme for optical remote sensing, and to explore the potential of ultrafast intense laser in air pollution analysis, remote electromagnetic field measurement, and trace biologics detection.
·Ultrafast Sensitive Detection: Ultrafast sensitive detection is not only widely used in free space communication, missile imaging tracking and positioning, infrared remote sensing and other major military and defence fields, but also plays a crucial role in civil industries such as air pollution monitoring, material processing and disease detection. Particular interests of the team are focused on optical trace detection and micro-nano sensitive detection. Many efforts have been made to explore and establish new principles, new methods, new instruments and new equipment in developing ultrafast detection with high precision and high sensitivity.
Infrastructure:
The Optical Instrument and System Engineering Center of the Ministry of Education, where the team is located, have public platforms and equipment including an atomic force microscope, scanning electron microscope, corrosion electrochemical system, multi-function vacuum coating machine, magnetron sputtering machine, plasma-etching machine, electron beam evaporator deposit system and so on. The team has conducted research in nonlinear optics and ultra-intense physics for a long time, and now possesses super clean laboratories, precision optical platforms, high-power fiber lasers, femtosecond lasers, polarization-maintaining fusion splicers, optical fiber spectrometers, high-precision spectrum analyzers and so on. In addition, the team has achieved the industrialization of fiber lasers, single-photon detectors and quantum cryptographic products.
Principal Investigator: Professor Liu Yi, doctoral supervisor, laureate of the National Thousand Young Talents Program, the Shanghai Thousand Talents Program, and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning. In 2001, he received the bachelor's degree in Physics from the Department of Physics of Lanzhou University. In 2006, he received the doctor's degree in Optics from Peking University. After that, he went to École Polytechnique for post-doctoral research and was appointed as tenured associate research scientist at Centre national de la recherche Scientifique (CNRS) in 2009. In 2014, he was appointed as a doctoral supervisor in Université Paris VI. In 2015, he joined in School of Optical Electrical and Computer Engineering, USST.
In the last ten years, he has been engaged in the research of ultrafast nonlinear optics. A total of 52 SCI papers were published, among which 10 were Physical Review Letters. The published papers were cited more than 1,350 times and the factor H was 21, among which 3 papers were cited more than 100 times. Three academic works were respectively reported by Physics Review Focus and by Laser Focus World. Up to date, he has given 16 invited talks in international conferences. In 2015, he was invited by Conference on Lasers and Electro-Optics (CLEO) as a session invited speaker. He has won the Third Prize of Excellent Researcher of CNRS.
Team Composition:
The team is comprised of 21 faculty members including 1 laureate of the National Thousand Young Talents Program, 1 laureate of the Shanghai Thousand Talents Program, 4 Eastern Scholar, 1 Shanghai "ChenGuang" talent. The team's work covers the development of ultrafast light source technology, ultrafast laser and material interactions, and ultrafast sensitive measurements. The ultrafast nonlinear optics team is one of the core teams of the "International Laboratory for Future Optics" in USST.
Honors (Achievements):
In recent years, the team has made tremendous achievements in the fields of high-power fiber laser, optical frequency comb, nonlinear propagation of ultra-intense femtosecond pulse, air laser, and ultrafast Raman spectroscopy. So far, more than 60 high-quality papers were published, including 4 in Physical Review Letters, 4 in Nature Photonics and 4 in Nature Communication. The team has established close cooperation with many prestigious universities, such as Ecole Polytechnique (France), Lund University (Sweden), National Institute of Advanced Industrial Science (Japan) and Technology, Peking University, Southeast University. Currently, the team is co-training doctoral students with Ecole Polytechnique. In the meanwhile, the biomedical micro-imaging system and compact high-energy fiber laser, based on optical coherence tomography and artificial intelligence algorithm, developed by the team have also been applied in the industry, which produces social benefits and economic value.
Contacts: yi.liu@usst.edu.cn
