Narrowband coatings for the 100-105 nm range

Luis Rodríguez-de Marcos; José A. Méndez; Manuela Vidal-Dasilva; José A. Aznárez; Juan I. Larruquert

doi:10.1117/12.2017482

3 May 2013 Narrowband coatings for the 100-105 nm range

Luis Rodríguez-de Marcos, José A. Méndez, Manuela Vidal-Dasilva, José A. Aznárez, Juan I. Larruquert

Proceedings Volume 8777, Damage to VUV, EUV, and X-ray Optics IV; and EUV and X-ray Optics: Synergy between Laboratory and Space III; 87771E (2013) https://doi.org/10.1117/12.2017482
Event: SPIE Optics + Optoelectronics, 2013, Prague, Czech Republic

Abstract

Observations in the far ultraviolet (FUV) at wavelengths in the ~100-105 nm range, which include 102.6 nm (H Lyman β), 103.2 and 103.8 nm (O VI lines), are expected to unveil fundamental information for solar physics and astrophysics. Often the intensity of those lines is weak, and they may be masked by more intense lines, such as H Lyman α at 121.6 nm for observations of the solar corona. Narrowband multilayers peaked in the ~100-105 nm have not been available because of the absorption of materials at these wavelengths along with a strong influence of contamination in this range. When efficient narrowband coatings are not possible, an option is the use of coatings with high reflectance at the target wavelength and simultaneously low reflectance at the undesired wavelength, such as 121.6 nm. High-reflective-narrowband coatings peaked at 100-105 nm have been developed. We have designed a four-layer system (Al/LiF/SiC/LiF) that results in a high H Lyman β-to-Lyman α reflectance ratio. Three samples with slightly different film thicknesses were prepared and measured in the 50-190 nm spectral range. All samples showed a promising reflectance ratio when fresh; however, some sample ageing was observed after months of storage in a desiccator, probably due to the effect of reaction with water vapor among other contaminants at the outermost layer (LiF). All samples retained a narrowband performance over time. The reflectance at 121.6 nm, which was very low on fresh samples, typically increased over time, although keeping a high 102.6-to-121.6-nm reflectance ratio. The same system results in an efficient narrowband coating peaked in the target spectral range. We measured a reflectance as high as 63% at the peak wavelength of 100.3 nm, at near-normal incidence, the highest experimental reflectance reported in this range for a narrowband coating.

Citation Download Citation

Luis Rodríguez-de Marcos, José A. Méndez, Manuela Vidal-Dasilva, José A. Aznárez, and Juan I. Larruquert "Narrowband coatings for the 100-105 nm range", Proc. SPIE 8777, Damage to VUV, EUV, and X-ray Optics IV; and EUV and X-ray Optics: Synergy between Laboratory and Space III, 87771E (3 May 2013); https://doi.org/10.1117/12.2017482

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available