通过研究双色场中三维氢原子的高次谐波,发现当作为驱动源的两束光频率比为3:5, 且附加光相对于 基本光的强度比落在某个特殊值(0.35)时,叠加截止区的高次谐波能直接得到单个的短脉冲。 提出利用双色场获取单个短脉冲的新方案,该方案的要点是:作为驱动源的两束光,频率要是比较接近的奇数比; 附加光的相对强度要是一个特殊值,使不同通道间的干涉相消抑制其它脉冲。在进一步的研究中可选取 束缚能更高的原子,扩展截止区的位置,使得到单脉冲的脉宽更窄。

The high order harmonic generations (HHG) of three-dimensional hydrogen atom which exposed to the combination of two laser pulses were studied. When the combined field has a proper frequency ratio of 3:5, and the relative intensity of the additional laser field reaches a specific value (0.35), the single short pulse can be obtained directly. A new method to obtain the single short pulse is proposed, the main points of the method are the following. Frequency ratio of the two lasers should be adjacent odd, and the relative intensity of the additional laser to basic laser should fall on a particular value. In future research, the atoms with a higher binding energy can be chosen, and the width of HHG’s plateau will be enlarged, so the width of pulse will be reduced.