A research group led by Professor Zhao Zengxiu from College of Science collaborated with Professor S. Ghimire from Stanford University propose a novel approach based on the subcycle injection of carriers to extend the high-energy cutoff in solid-state high harmonics generation. The researchers verify that the previously generated high harmonics in a real solid can participate in the latter nonlinear dynamics as it propagates with the fundamental field and find a significant high-energy cutoff extension, from around 20th order to around 50th order, in harmonics emitted from the backside of the sample.
The research is published in Physical Review Letters, entitled "Proposal for high-energy cutoff extension of optical harmonics of solid materials using the example of a one-dimensional ZnO crystal". The first author of the article is doctoral candidate Lang Yue from College of Sciences. The corresponding authors are Associate Professor Liu Jinlei, Professor Zhao Zengxiu from National University of Defense Technology and Professor S. Ghimire from Stanford University.