Abstract

Highly reflecting multilayer coatings (MLC), used to form resonant cavities for soft x-ray lasers(1) in which double- and triple-pass amplification occurs, can be destroyed by strong electric fields generated at the multilayer boundaries by intense soft x-ray radiation, rather than plasma debris from which the coatings are shielded. Any multilayer coating used in high field strength applications, FEL, x-ray projection lithography, etc., are subject to such damage. Electric field strengths can be reduced at the boundaries in MLCs by altering slightly the layer thicknesses of the final, or topmost, layers. Calculations are presented showing reduced field strengths caused by altering final layer thicknesses. The optical constants used in the calculations were obtained from Henke et al(2) and Palik(3) so similar computations may vary depending on the actual n,k values used but the basic concepts discussed herein are independent of the optical constants.

© 1992 Optical Society of America