A geometrically scalable method for manufacturing high quality factor mechanical resonators

We present what we believe to be a novel, geometrically scalable manufacturing method for creating compact, low-resonance frequency, and high quality factor fused silica resonators. These resonators are intended to be used in inertial sensors for measuring external disturbances of sensitive physics experiments. The novel method uses direct bonding and chemical-mechanical polishing (CMP) in order to overcome the limitations of current subtractive manufacturing methods, which face prohibitive cost and complexity as material removal increases, inherently restricting the design flexibility of the resonator. We demonstrate a prototype with a test mass of only 3 g that reaches a quality factor of Q = 118 000 ± 400 at a resonance frequency of below 20 Hz. This advancement is particularly significant for future gravitational wave observatories, such as the Einstein Telescope.