利用调制的偏振态门控制阿秒脉冲的产生

提出一种利用多光周期驱动脉冲获得极紫外宽带超连续谱的新方法.利用波长为1600nm的基频场组成的偏振态门增强高次谐波产生效率对椭扁率的依赖，并叠加上波长为800nm的倍频场来调制电离比率.计算结果表明，采用脉冲宽度为6个光周期(32.4fs)的基频脉冲就能够将高次谐波辐射限制在0.5个光周期内，获得了带宽为280eV的超连续谱，这个谱宽支持傅里叶极限为10as的单个脉冲输出.直接选取超连续谱上的一段，可以获得100as的脉冲输出.此外，在调制的偏振态门中可以使用相对延迟较小的两束基频光组成偏振态门，提高了 关键词： 阿秒脉冲 超连续谱 偏振态门

Control of attosecond pulse generation with modulated polarization gating

A new method is proposed to generate extreme ultraviolet supercontinuum. The polarization gating at 1600nm is employed to intensify the ellipticity dependence of high harmonic signal， and the addition of a second harmonic field is used for modulating the ionization ratio. Calculations show that a fundamental pulse up to 6 optical cycles (32.4fs) in duration can be applied to confine the efficient high harmonic generation to half an optical cycle. This feature allows us to produce an extreme ultraviolet supercontinuum with the bandwidth of about 280eV which supports generating a Fourier-transform-limited pulse of 10as. By selecting one part of the supercontinuum， a 100as pulse is obtained directly. In addition， the intensity utilizing efficiency of fundamental pulses can be increased by making the delay between the two pulses which compose the polarization gating smaller，when the modulated polarization gating is employed.