On November 22, 2021, the ultrafast optical group published an online paper entitled as "Huygens-Fresnel Picture for High Harmonic Generation in Solids" in the journal of Physical Review Letters.
High Harmonic Generation (HHG) is usually described by the laser-induced recollision of particlelike electrons, which lies at the heart of attosecond physics and also inspires numerous attosecond spectroscopic methods. Here, we demonstrate that the wavelike behavior of electrons plays an important role in solid HHG. By taking an analogy to the Huygens-Fresnel principle, an electron wave perspective on solid HHG is proposed by using the wavelet stationary-phase method. From this perspective, we have explained the deviation between the cutoff law predicted by the particlelike recollision model and the numerical simulation of semiconductor Bloch equations. Moreover, the emission times of HHG can be well predicted with our method involving the wave property of electrons. However, in contrast, the prediction with the particlelike recollision model shows obvious deviations compared to the semiconductor Bloch equations simulation. The wavelike properties of the electron motion can also be revealed by the HHG in a two-color field.
Figure Sketch for HHG analogy to the Huygens-Fresnel principle.
Prof. Lu Peixiang and Prof. Lan Pengfei are the co-corresponding authors of the paper. The first author is Associate Prof. Li Liang from Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology.
Link to this paper: https://doi.org/10.1103/PhysRevLett.127.223201
