高对比度飞秒激光与固体薄膜相互作用硬X射线源的研究

Hard X-ray source based on a high-Contrast femtosecond laser interacting with a solid foil

文章作者使用60 fs倍频高对比度激光脉冲聚焦到Cu膜上,发现与基频激光脉冲相比,从激光到KαX射线的能量转化效率(ηk)明显增强.ηk对激光脉冲非线性啁啾上升沿呈现出很强的依赖性,它在激光为100fs负啁啾脉冲时达到最大值.实验表明对超热电子有效的加热导致了ηk的增强.这说明由于能够驱动真空加热机制来增强超热电子的产生,高对比度激光已成为优化ηk的有效工具.这些结果发表在Phys.Rev.Lett.,2008,100:045004上.

An increase has been observed in the conversion efficiency（ηk） from laser energy to Kα X-ray energy produced by 60 fs frequency-doubled high-contrast laser pulses focused on a Cu foil,compared to the case with fundamental laser pulses.The value of ηkshows a strong dependence on the nonlinearly modified rising edge of the laser pulse.It reaches a maximum for a 100 fs negatively modified pulse.The efficient heating of the hot electrons leads to the enhancement of ηk.This demonstrates that high-contrast lasers are an effective tool for optimizing ηk,through increasing the quantity of hot electrons by vacuum heating.These results have been published in Phys.Rev.Lett.,2008,100：045004.