Aging of Al thin film extreme ultraviolet filters

0518278 - ÚFP 2020 RIV US eng C - Conference Paper (international conference)
Koláček, Karel - Frolov, Oleksandr - Schmidt, Jiří - Štraus, Jaroslav - Hoffer, Petr - Stelmashuk, Vitaliy - Lukeš, Petr - Juha, Libor
Aging of Al thin film extreme ultraviolet filters.
Proceedings of SPIE. In: Proceedings of SPIE - The International Society for Optical Engineering. Vol. 11032. Bellingham: SPIE, 2019, Roč. 11035 (2019), č. článku 110350O. ISBN 9781510627307. ISSN 0277-786X.
[Optics Damage and Materials Processing by EUV/X-ray Radiation VII. Praha (CZ), 01.04.2019-03.04.2019]
R&D Projects: GA MŠMT LTT17015
Institutional support: RVO:61389021
Keywords : influence of aging of materials on their XUV characteristics * aging of thin film Al filters * changes of transmission of Al filters in due time
OECD category: Optics (including laser optics and quantum optics)

Thin film Al filters, very popular for their high transmittance in the wavelength range 17 to 67 nm and simultaneously low transmittance in the visible and near UV region, are prone to oxidation. The amorphous Al2O3 layers on the Al surfaces have much smaller transmittance than the bulk Al material, and, therefore, they strongly influence the total transmittance of the filter. This paper gives not only the transmittance of very old Al filters, but also maps the transmittance development of Al filters in two years span since their delivery in not controlled atmosphere. Surprisingly, it turned out that while the transmission of surface layers (present on filters since the very beginning) slightly increases with time, the average attenuation rate per unit filter thickness of the bulk material (Al) with time dramatically rises.
Permanent Link: http://hdl.handle.net/11104/0303434