@inproceedings{afc2786cf70548808da22e70b18a0d4b,
title = "Generating electron beam lithography write parameters from the FORTIS holographic grating solution",
abstract = "The Far-UV Off Rowland-circle Telescope for Imaging and Spectroscopy (FORTIS) has been successful in maturing technologies for carrying out multi-object spectroscopy in the far-UV, including: The successful implementation of the Next Generation of Microshutter Arrays; large-Area microchannel plate refetectors; and an aspheric ual-order{"}holographically ruled diffraction grating with curved, variably-spaced grooves with a laminar (rectangular) profile. These optical elements were used to construct an efficient and minimalist wo-bounce{"}spectro-Telescope in a Gregorian configuration. However, the susceptibility to Lyman alpha (Ly) scatter inherent to the dual order design has been found to be intractably problematic, motivating our move to an ff-Axis{"}design. OAxFORTIS will mitigate its susceptibility to Ly by enclosing the optical path, so the detector only receives light from the grating. The new design reduces the collecting area by a factor of 2, but the overall effective area can be regained and improved through the use of new high efficiency reflective coatings, and with the use of a blazed diffraction grating. This latter key technology has been enabled by recent advancements in creating very high efficiency blazed gratings with impressive smoothness using electron beam lithography and chemical etching to create grooves in crystalline silicon. Here we discuss the derivation for the OAxFORTIS grating solution as well as methods used to transform the FORTIS holographic grating recording parameters (following the formalism of Noda et al.1974a,b), into curved and variably-spaced rulings required to drive the electron beam lithography write-head in three dimensions. We will also discuss the process for selecting silicon wafers with the proper orientation of the crystalline planes and give an update on our fabrication preparations.",
author = "Mackenzie Carlson and Stephan McCandliss and Randall McEntaffer and Fabien Grise and Nicholas Kruczek and Brian Fleming",
note = "Funding Information: This work is supported by NASA APRA grant NNX17AC26G to JHU entitled, Rocket and Laboratory Experiments in Astrophysics – Validation and Verification of the Next Generation FORTIS, and by a NASA SAT sub-award 80NSSC19K0450 to JHU entitled, Electron Beam Lithography Ruled Gratings for Future Ultraviolet/Optical Missions: High-Efficiency and Low-Scatter in the Vacuum Ultraviolet. Publisher Copyright: {\textcopyright} COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.; UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXII 2021 ; Conference date: 01-08-2021 Through 05-08-2021",
year = "2021",
doi = "10.1117/12.2594683",
language = "English (US)",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Siegmund, {Oswald H.}",
booktitle = "UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXII",
address = "United States",
}