We used laser ablation to fabricate sub-wavelength structure anti-reflection coating (SWS-ARC) on a 5 cm diameter alumina lens. With an aspect ratio of 2.5, the SWS-ARC are designed to give a broad-band low reflectance response between 110 and 290 GHz. SWS shape measurements conducted on both sides of the lens give 303 μm pitch and total height between 750 and 790 μm, matching or exceeding the aspect ratio design values. Millimeter-wave transmittance measurements in a band between 140 and 260 GHz show the increase in transmittance expected with the ARC when compared to finite element analysis electromagnetic simulations. To our knowledge, this is the first demonstration of SWS-ARC on an alumina lens, opening the path for implementing the technique for larger diameter lenses.
@article{arxiv.2506.13042,
title = {Laser ablated sub-wavelength structure anti-reflection coating on an alumina lens},
author = {Shaul Hanany and Scott Cray and Samuel Dietterich and Jan Dusing and Calvin Firth and Jurgen Koch and Rex Lam and Tomotake Matsumura and Haruyuki Sakurai and Yuki Sakurai and Aritoki Suzuki and Ryota Takaku and Qi Wen and Alexander Wienke and Andrew Y. Yan},
journal= {arXiv preprint arXiv:2506.13042},
year = {2025}
}
Comments
9 pages, 7 figures, updated and improved version of paper presented at SPIE's Astronomical Telescopes and Instrumentation 2024