title: Epoxy-based broadband antireflection coating for millimeter-wave optics.
abstract: We have developed epoxy-based, broadband antireflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixing three types of epoxy and doping with strontium titanate powder required for the high dielectric mixtures. At 140 K, the band-integrated absorption loss in the coatings was suppressed to less than 1% for the two-layer coating, and below 10% for the three-layer coating.
authors: Darin
authors: D
authors: Rosen
authors: Aritoki
authors: A
authors: Suzuki
authors: Brian
authors: B
authors: Keating
authors: William
authors: W
authors: Krantz
authors: Adrian T
authors: AT
authors: Lee
authors: Erin
authors: E
authors: Quealy
authors: Paul L
authors: PL
authors: Richards
authors: Praween
authors: P
authors: Siritanasak
authors: William
authors: W
authors: Walker