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

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.

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

An increase has been observed in the conversion efficiency (η_k) from laser energy to K_α X-ray energy produced by 60 fs frequency-doubled high-contrast laser pulses focused on a Cu foil. comparedto the case with fundamental laser pulses. The value of η_k shows 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 η_k. This demonstrates that high-contrast lasers are an effective tool for optimizing η_k, through increasing the quantity of hot electrons by vacuum heating. These results have been published in Phys. Rev. Lett. ,2008,100:045004 .