Efficient and uniform Aluminum-based broadband mirrors are essential components for far-ultraviolet (FUV) astronomy. Plasma-enhanced atomic layer deposition (PEALD) is a low temperature, highly conformal coating process that has previously been demonstrated to produce high quality AlF3 films, although little has been reported on their performance in FUV applications. An ongoing collaboration between the US Naval Research Laboratory (NRL) and NASA Goddard Space Flight Center (GSFC) focuses on optimizing material properties of PEALD AlF3 coatings on Al mirrors to enhance FUV optical performance.
PEALD AlF3 films were deposited using trimethylaluminum and SF6 plasma precursors in a modified Veeco Fiji G2 reactor. ALD growth windows (the range of process parameters resulting in ideal growth) were established using an in situ ellipsometer to monitor the fluoride growth rate directly on Al substrates and supplemented with post-deposition x-ray photoelectron spectroscopy to elucidate process-structure property relationships. Optimal AlF3 films had a growth rate of 0.75-0.8Å/cycle, F/Al ratio of ≈3, < 2 at% O, indicating that PEALD is a beneficial process technique towards achieving optical coatings on a variety of potential mirror materials. The influence of PEALD parameters on the FUV optical performance of Al mirrors overcoated with PEALD-AlF3 will be also discussed.
Calcite is a birefringent material with optical anisotropy that becomes extreme in the infrared, allowing for the excitation of highly-directional, sub-diffractional hyperbolic modes. In this talk, I will discuss our recent work that focuses on understanding the optical behavior of hyperbolic modes supported within asymmetric nanostructures formed in calcite crystals with in-plane anisotropy, including our recent findings that demonstrate how the resonant frequency and directional power flow can be tuned by simply rotating gratings with respect to the crystal axes of calcite – without changing the shape of the gratings.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
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.