Past events

Coherent Laser Beam Combining: Past, Present, and Future

Prof James R. Leger, University of Minnesota, Minneapolis, USA


Laser beam combining is currently seen as the primary route to high optical radiance in many laser systems. A wide variety of approaches have been developed since the early designs of the 1980’s, resulting in a wealth of optical techniques and architectures. In addition, the fundamental requirements and limitations of both coherent and incoherent beam combining systems are now largely understood.

In this talk, we will review the fundamental elements of laser beam combining technology, including beam shaping, mode control, laser phasing requirements and methods, spatial and temporal coherence effects, and resonator architecture.

Special emphasis will be placed on new methods of spatial beam shaping and an exploration of self-phasing phenomena in fibre lasers. A new theory that allows for optimization of self-phasing and accurately predicts observations of bistability and hysteresis in coupled resonators will be presented.


Prof. James Leger received his BS degree in Applied Physics from the California Institute of Technology (1974) and Ph.D. degree in Electrical Engineering from the University of California, San Diego (1980). He has held previous positions at the 3M Company and MIT Lincoln Laboratory.

He is currently professor of Electrical Engineering at the University of Minnesota, where he holds both the Cymer Professorship for research in Electrical Engineering and the Mr. and Mrs. George W. Taylor distinguished teaching professorship.

His research group works in the area of optical design, including laser mode control and beam shaping optics, coherent laser beam combining, optical metrology, design of nonclassical imaging systems, and microoptical systems. Prof. Leger is currently serving as senior deputy editor of Optics Express and has served on the Board of Directors of the Optical Society of America.

Prof. Leger has been awarded the 1998 Joseph Fraunhofer Award/Robert M. Burley Prize by the Optical Society of America for his work in microoptical design, and the 2000 George Taylor Award for Outstanding Research at the University of Minnesota. He has received a number of awards for teaching, resulting in his induction into the academy of distinguished teachers at the University of Minnesota.

He is a Fellow of the Optical Society of America, Fellow of the Institute of Electrical and Electronic Engineers (IEEE), and Fellow of the International Society of Optical Engineers (SPIE).