High-order harmonic generation in liquids in bicircularly polarized laser fields
Zhuang-Wei Ding, Yi-Ben Wang, Zhengliang Li, Xue-Bin Bian
Abstract
It is a nonlinear and nonperturbative optical phenomenon that high-order harmonic generation (HHG) can be produced by the interaction of intense laser pulses with liquid targets. The theoretical studies on HHG in liquids based on full dimensional simulations meet the difficulty of very low computational efficiency. Here, we develop an efficient numerical method based on the statistical mechanics in two-dimensional space, which reproduces the experimental HHG measurements very well. We also study the HHG in bicircularly polarized $1\ensuremath{\omega}$ $+$ $3\ensuremath{\omega}$ laser fields with the same field strength. It is found that near-circularly-polarized harmonics with different ellipticities can be generated in the counterrotating driving lasers. The cutoff energy of HHG in counter- and corotating driving lasers demonstrates a similar dependence of laser field strength and wavelength as that in the case of a linearly polarized driving laser field. This work paves the way for controlling the ultrafast electron dynamics in liquids by manipulating the laser fields.