Chipperfield L E, Robinson J S, Tisch J W G, Marangos J P
Imperial College London, London SW7 2BW.
Phys Rev Lett. 2009 Feb 13;102(6):063003. doi: 10.1103/PhysRevLett.102.063003. Epub 2009 Feb 12.
We present the perfect waveform which, during a strong field interaction, generates the maximum possible electron recollision energy for any given oscillation period, over 3 times as high as that for a pure sinusoidal wave. This ideal waveform has the form of a linear ramp with a dc offset. A genetic algorithm was employed to find an optimized practically achievable waveform composed of a longer wavelength field, to provide the offset, in addition to higher frequency components. This second waveform is found to be capable of generating electron recollision energies as high as those for the perfect waveform while retaining the high recollision amplitudes of a pure sinusoidal wave. Calculations of high harmonic generation demonstrate this enhancement, by increasing the cutoff energy by a factor of 2.5 while maintaining the harmonic yield, providing an enhanced tool for attosecond science.
我们展示了一种完美波形，在强场相互作用期间，对于任何给定的振荡周期，它能产生尽可能高的电子再碰撞能量，比纯正弦波产生的能量高出3倍多。这种理想波形具有带直流偏移的线性斜坡形式。采用遗传算法来寻找一种优化的、实际可实现的波形，该波形由一个更长波长的场组成，用于提供偏移，此外还有更高频率的分量。发现第二种波形能够产生与完美波形一样高的电子再碰撞能量，同时保留纯正弦波的高再碰撞幅度。高次谐波产生的计算证明了这种增强效果，通过将截止能量提高2.5倍，同时保持谐波产率，为阿秒科学提供了一种增强工具。
