Extreme-ultraviolet filters for 58.4 and 83.4 nm

Muamer Zukic; Douglas G. Torr; Jongmin Kim; Marsha R. Torr

doi:10.1117/12.60591

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1 June 1992 Extreme-ultraviolet filters for 58.4 and 83.4 nm

Muamer Zukic, Douglas G. Torr, Jongmin Kim, Marsha R. Torr

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Proceedings Volume 1744, Instrumentation for Magnetospheric Imagery; (1992) https://doi.org/10.1117/12.60591
Event: San Diego '92, 1992, San Diego, CA, United States

Abstract

We report the design of an extreme ultraviolet (EUV) filter for He I at 58.4 nm and the design and fabrication of an EUV filter for O II at 83.4 nm. Both filters are designed as combinations of three narrow-band reflection filters. The net transmittance through both EUV filters is close to 10% with bandwidths less than 10 nm, and blocking better than 0.005% for out-of-band wavelengths. A theoretical calculation of the 83.4 nm filter predicts higher values for the peak transmittance than the measured spectral performance of the fabricated filter. Since aluminum is one of the film materials used for the fabrication of EUV filters, the aluminum film oxidation can be modeled in order to explain the discrepancy between the theory and experiment. The 83.4 nm filters were deposited in a conventional high vacuum coater with pressure of 10^-6 torr. In order to avoid aluminum oxidation and improve the performance of the narrow-band filters, an ultrahigh vacuum coater must be used with deposition pressures of less than 10^-10 torr. Since the filters operate at angles of incidence up to 50 degree(s), the optical components of a system can serve as both the filtering and imaging elements.

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Muamer Zukic, Douglas G. Torr, Jongmin Kim, and Marsha R. Torr "Extreme-ultraviolet filters for 58.4 and 83.4 nm", Proc. SPIE 1744, Instrumentation for Magnetospheric Imagery, (1 June 1992); https://doi.org/10.1117/12.60591

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