HIGHLY ABSORPTIVE COATING FOR THE VACUUM-ULTRAVIOLET RANGE

We have developed new, highly absorptive coatings for the vacuum UV wa velength range. These coatings display two distinct granularity scales : large structures of a 10-100-mu m scale form efficient light traps, upon which are superimposed structures of a submicrometer scale. We pr esent results for the total hemispherical reflectivity at normal incid ence for 121.6 nm and at a grazing angle incidence for 17.1, 30.4, 58. 4, and 121.6 nm. These measurements were made for the new coatings as well as for various coatings in common use. Absorption of the new coat ings is in some cases higher than for the best-known coatings and, in contrast to the latter, they are mechanically robust. (C) 1998 Optical Society of America.