The extraction efficiency is one of the key parameters of an oscillator-type free electron laser (FEL). An extraction efficiency higher than 5% was observed with the midinfrared (MIR) FEL at Kyoto University using a dynamic cavity desynchronization method. The observed efficiency is the highest extraction efficiency realized in MIR-FEL oscillators driven by normal conducting linacs. A numerical simulation was performed, and the evolution of the electron energy distribution in the macropulse was compared with the experimental result. The details of the evolution of the electron energy distribution were investigated to reveal the physics of this high-efficiency lasing.

中文翻译：

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动态腔不同步实现中红外自由电子激光器的高提取效率操作

提取效率是振荡器型自由电子激光器（FEL）的关键参数之一。使用动态腔去同步方法，在京都大学的中红外（MIR）FEL观察到提取效率高于5％。观察到的效率是在正常导电直线加速器驱动的MIR-FEL振荡器中实现的最高提取效率。进行了数值模拟，并将大脉冲中电子能量分布的变化与实验结果进行了比较。研究了电子能量分布的演化细节，以揭示这种高效激光的物理原理。