Current Prospects for Free-Electron Lasers in the Extreme Ultraviolet*

Abstract

In the last few years, free-electron laser (FEL) oscillators and amplifiers have produced coherent radiation over a broad spectral range extending from 463 nm in the visible to millimeter wavelengths as summarized graphically in Fig. 1. These successful demonstrations have encouraged a number of research centers to boldly consider extension of this electron-accelerator-based technology to the extreme ultraviolet (XUV) below 100 nm where no powerful, tunable, coherent-radiation source presently exists. Here, the peak- and average-power output of FEL oscillators and amplifiers should surpass the capabilities of any existing, continuously tunable photon sources by many orders of magnitude.