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arXiv · 2601.19627

Silicon-based vacuum window for millimeter and submillimeter-wave astrophysics

Ryota Takaku·Scott Cray·Kosuke Aizawa·Akira Endo·Shaul Hanany·Kenichi Karatsu·Jürgen Koch·Kuniaki Konishi·Tomotake Matsumura·Haruyuki Sakurai
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Abstract

We designed, fabricated, and characterized the properties of a silicon-based vacuum window suitable for millimeter-wave astrophysical applications. The window, which has a diameter of 124 mm, optically active diameter of 68 mm, and thickness of about 4 mm, gives an average transmittance and reflectance of 99% and 1%, respectively, a fractional bandwidth of 67%. Absorptive loss is below the detection limit of our measurement. The anti-reflection coating is made with laser ablated sub-wavelength structures (SWS), and the measured transmittance and reflectance values agree with modeling based on the measured SWS shapes. The window has been integrated into DESHIMA v2.0, an astrophysics instrument that took year-long observations with the Atacama Submillimeter Telescope Experiment.

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Ryota Takaku, Scott Cray, Kosuke Aizawa, Akira Endo, Shaul Hanany, Kenichi Karatsu, Jürgen Koch, Kuniaki Konishi, Tomotake Matsumura, Haruyuki Sakurai. 2026-01-27. Silicon-based vacuum window for millimeter and submillimeter-wave astrophysics. https://doi.org/10.1364/ao.591873

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