Assessing Substrate-Transferred GaAs/AlGaAs Coatings for Gravitational-wave Detectors

Abstract

Substrate-transferred, 70-mm diameter AlGaAs coatings were tested for possible use in gravitational wave detectors by measuring the elastic loss [ϕbulk = (5.33±0.03)×10−4 and ϕ s h e a r = 0.0 − 0.0 + 5.2 × 10 − 7] and excess loss from bonding defects [≈ 5%].