He performed groundbreaking research in synchrotron radiation and free-electron lasers, both in high-gain amplifier and low-gain oscillator.He published >300 papers and a book Synchrotron Radiation and Free Electron Lasers(Cambridge University Press, 2017) in collaboration with two other authors. He became an APS Fellow in 1995, received the International FEL Award in 1997, the USPAS Award in 2013, and the Robert Wilson Prize in 2014.