Abstract

Successful operation of cavity free electron lasers in the extreme ultraviolet and soft x-ray spectral regions requires mirrors having high normal incidence reflectance, as well as other optical elements standard in the visible spectral range. Such optics become increasingly difficult to realize as wavelengths decrease from ~1000 A in the far ultraviolet into the soft x-ray region, because of the changing optical properties of materials with decreasing wavelength into the x-ray region. Recent developments in multilayer and multifacet total reflection mirrors show promise as cavity-defining mirrors in selected wavelength regions. Potential degradation of optical performance from absorbed radiation and surface contamination are important concerns in extreme ultraviolet and soft x-ray optics.

© 1989 Optical Society of America