The self-amplification mechanism of coherent energy modulation was proposed by the free electron laser team of Shanghai Synchrotron Radiation Facility, and the experimental verification based on shanghai soft X-ray free electron laser was completed. Through the self-amplification of the small energy modulation introduced by the seed laser, the 30^th harmonic amplification, which is the world record of "amplified harmonic to laser modulation ratio" at present, is successfully achieved. This result paves the way for the external seeded free electron laser of MHz repetition rate, and is expected to bring new breakthroughs in high resolution spectroscopy and extreme ultraviolet lithography. The result published in Physical Review Letters was co-authored by Dr. Jiawei Yan, Professor Haixiao Deng, and Professor Zhentang Zhao. 

The award for China’s Top 10 Optical Breakthroughs was initiated by China Laser Press, and this event aims to disseminate innovative and important achievements by Chinese researchers and further boost the development of optics in China. This year, 20 results among 162 optical candidates were awarded, including 10 fundamental researches and 10 applied researches. It is reported that, “the first lasing of echo-enabled harmonic generation” achieved by the Shanghai Synchrotron Radiation Facility was awarded China’s Top 10 Optical Breakthroughs in 2012.

Meanwhile, the achievement of "the first observation of laser-beam interaction in a dipole magnetic field" of the Shanghai Synchrotron Radiation Facility was selected as the fundamental research nomination award of the 2021 China’s Top 10 Optical Breakthroughs.