Overview

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1989 Excerpt: ...of all dielectric coatings measured degraded in response to 65min exposures of 248-or 351-nm light. HfCySiOg was found to be the most uv-resistant coating with a mean reflectivity loss of 0.21% when reflection losses for 248-and 351-nm light exposures were averaged. Furthermore, two uv light-induced reflectivity degradation mechanisms, probably attributable to defect (F-center) formation within the coating, were indicated from the experimental results. One mechanism correlates with a fast exponential decrease in reflectivity when a coating was first exposed to uv radiation, followed by a rapid rate of coating reflectivity recovery upon termination of irradiation. This mechanism is most prominent in the response of a coating to 351-nm irradiation and is virtually absent for 248nm coating exposures. The other mechanism is characterized by a slow exponential reflectivity decrease upon uv irradiation. Following the termination of irradiation, virtually no coating reflectivity recovery was observed from this damage mechanism. Finally, significant differences between various coatings were revealed in the dependency of reflectivity loss with 248-and 351-nm uv light fluence. The reflectivity of a TiOSiOHfOg coating was found to decrease monotonically with increasing 248-or 351-nm fluence. In fact, this coating was found to fail catastrophically at 248-nm fluences above 45 mJ/cm2. In contrast, the reflectivity loss for a HfCySiOg coating was found to saturate with increasing 248-and 351-nm fluence exposure. References: 1 Elleaume, P.; Velge, M.; Ortega, J. M. Diagnostic techniques and UV-induced degradation of mirrors used in the Orsay storage ring free-electron laser. Appl. Opt. 24(17): 2762-2770; 1985 September 1. 2 Velge, M.; Elleaume, P. FEL optics coating test ...

Full Product Details

9781236098191

Table of Contents

Reviews

Author Information

Tab Content 6

Customer Reviews

Recent Reviews

Countries Available