Recently, the team of Prof. Mao Dong and Prof. Zhao Jianlin from Northwestern Polytechnical University (NWPU), in collaboration with Prof. Zhang Yong from Nanjing University and Prof. Sun Zhipei from Aalto University, Finland, have made important progress in Talbot soliton mode-locked lasers. The research results have been published in the top international academic journal Science Advances (a subset of Science) under the title of "The dissipative Talbot soliton fiber laser", and have been selected as the featured image of the issue. Featured image) of the issue. The first author of the paper is Heze Zhang, a current PhD student, and the corresponding author is Prof. Dong Mao.
As a typical dissipative system containing periodic gain, loss, dispersion and nonlinear effects, a superfiber laser provides an ideal research platform for exploring mode-locking in space-time, optical strange waves, novel solitons and their interactions. The Talbot effect refers to a class of self-imaging phenomena of a periodic light field or pulse at a specific location, which is dominated by diffraction and dispersion effects in the spatial and temporal domains, respectively. In conventional mode-locked lasers, the Talbot effect is seldom associated with the evolutionary behavior of mode-locked pulses due to the small longitudinal mode spacing and dispersion values of the resonant cavity, which cannot satisfy the Talbot self-imaging condition in the time domain.
(a, b) Steady-state and (c, d) breathing-state Talbot solitons in fiber lasers
The research team discovered for the first time soliton mode-locked pulses dominated by the Talbot effect, called Talbot solitons, in a multi-wavelength synchronous mode-locked fiber laser using pulse shaping techniques to modulate the frequency difference between adjacent spectra. It is found that when the number of mode-locked wavelengths is ≥3, the operating state of the fiber laser is determined by the time-domain Talbot effect - the laser outputs breathing solitons when the integer self-imaging distance deviates from the cavity length, and the laser outputs steady-state solitons when the integer self-imaging distance is equal to the cavity length; based on the spatio-temporal duality of the light wave, they proposed an improved Talbot theory that includes dispersion and nonlinearity , which accurately explains and describes the self-imaging phenomenon and steady-state-breathing behavior of Talbot solitons in the cavity, and provides a new platform and idea for the study of the nonlinear evolution of multicolor wave packets in dissipative optical systems.
This work was supported by the National Natural Science Foundation of China under the top-level project (12274344), the Natural Science Basic Research Program of Shaanxi Province (2021JC-09), and the Basic Research Operating Expenses of Central Universities (3102019JC008).
As an outstanding young teacher in the discipline of optical engineering in our university, Prof. Mao Dong, supported by the National Natural Science Foundation of China, the Outstanding Young Scientist Fund of Shaanxi Province, and the Fundamental Research Funds for the Central Universities, has carried out a lot of cutting-edge basic research work in the fields of ultrafast fiber lasers, spatio-temporal optical field modulation and other fields, and has been published in Nature Communications, Science He has published 62 papers in Nature Communications, Science Advances, Light: Science & Applications, Laser & Photonics Reviews and other journals as the first and corresponding author. The relevant papers have been cited more than 8800 times, and he has been selected as one of the Elsevier 2020 Highly Cited Scholars and Stanford University's top 2% of top scientists in the world, and this work is one of the representative results of the recent work.
