OSE Seminar by Dr. Chengyong Feng, OSE Alumnus, on Nonlinearity-tunable regenerative amplifier for high-power ultrashort pulse generation

Departmental News

Dr. Chengyong Feng

Posted: November 15, 2022

Date: Thursday, November 17, 2022

Time:  12:15 PM - 1:15 PM

Location:  at CHTM, Room 103 and via Zoom


Ultrafast lasers have seen significant increase in average power over the past decade, thanks to the use of Ytterbium-ion-doped gain materials in geometries (fibers, slabs, thin-disks) that are advantageous for heat extraction. The Yb:YAG thin-disk technology has been particularly remarkable in developing high-average power ultrafast lasers with average power exceeding 1 kW and pulse energy up to 1 J. Due to the limited gain bandwidth in conjunction with spectral gain narrowing, Yb:YAG thin-disk lasers can only support pulses of ~1 ps, which may not be short enough for some applications. This limitation has stimulated a wave of research during last five years on nonlinear post-compression of the high-average power ps-pulses.

In this talk I will discuss our progress made on the development of high-average power ultrafast laser technologies at LLE. I will start with a brief review of the Yb:YAG thin-disk technology before describing briefly the development of a high-average power Yb:YAG thin-disk regen and the demonstration of energy-scaling of nonlinear post-compression using divided-pulse nonlinear compression. I will then discuss in detail our very recent progress on demonstrating a nonlinearity-tunable regenerative amplifier for high-average power ultrashort pulse generation, a technique that is fundamentally different from the chirped-pulse amplification. This technique is particularly suitable for developing compact and cost-effective high-average power ultrafast lasers.


Chengyong Feng is a Laser Scientist at the University of Rochester’s Laboratory for Laser Energetics (LLE), where his work has been focused on the development of high-power laser technologies. In 2012, he was a Marie-Curie Early Career Researcher working with Profs. Mauro Nisoli and Giuseppe Sansone on ultrafast lasers and attosecond science at the Politecnico di Milano in Milan, Italy. He obtained his PhD in 2016 from the University of New Mexico under the guidance of Prof. Jean-Claude Diels. His dissertation work was focused on the development of a unique UV laser with 2-GW peak power for various applications. After a short post-doc at UNM, Dr. Feng joined LLE in Rochester in 2017. He is part of a team which has recently completed a mid-scale 0.5-PW all-OPCPA system MTW-OPAL. He continues leading the development of next-generation ultrabroadband front end suitable for a large-scale laser facility EP-OPAL (2´ 25 PW) that is under planning. He also leads a team including PhD students on developing high-average power laser technologies at LLE. His very recent research is on demonstrating the nonlinearity-tunable regenerative amplifier for high-average power ultrashort pulse generation.