以貝氏方法最佳化控制高階諧波產生超短阿秒雷射

Abstract

我們用一個精確及有效率的方法來計算氦原子的高階諧和光譜，是第一次成功的使用貝氏優化來對雷射場作最佳化控制並且產生超短的阿秒雷射，氦原子在被優化的雷射場中所產生的高階諧和光譜的強度比被優化前的強了好幾個次方，並且可以有效率的產生超短阿秒雷射。我們用TDGPS方法精確且有效率的解隨時變得薛丁格方程式，並且用小波分析來計算電子的時間及頻率的資料。

We present an efficient and powerful method to determine the high-order harmonic generation (HHG) of the helium atoms that are exposed to the combination of chirped two-color mid-IR laser field and its 34th harmonics. We extend the machine-learning based optimization method, called Bayesian optimization (BO), to optimize the incident laser pulse to generate ultrashort attosecond laser pulse successfully for the first time. It is shown that the intensity of HHG power spectrum from the plateau region to the cutoff is enhanced by the optimized laser field by several orders of magnitude. Further, an ultrashort isolated attosecond pulse can be generated efficiently by superposing the plateau harmonics. The time-dependent Schrödinger equation is solved accurately and efficiently by means of the time-dependent generalized pseudospectral method and the time-frequency spectrum is obtained by the wavelet transform.