Cavity optomechanics with low-noise crystalline mirrors

Abstract

Cavity optomechanics is a rapidly evolving field operating at the intersection of solid-state physics and modern optics. The fundamental process at the heart of this interdisciplinary endeavor is the enhancement of radiation pressure within a high-finesse optical cavity. Isolating this weak interaction, i.e. the momentum transfer of photons onto the cavity boundaries, requires the development of mechanical resonators that simultaneously exhibit high reflectivity (requiring low absorption and scatter loss) and low mechanical dissipation. In a Fabry-Pérot implementation, this is realized by fabricating suspended micrometer-scale mechanical resonators directly from high-reflectivity multilayers. Thus, the properties of the mirror material—particularly the loss angle and optical absorption—drive the ultimate performance of the devices. Interestingly, similar requirements are found in a broad spectrum of applications, ranging from gravitational wave interferometers to stabilized lasers for optical atomic clocks. This overlap leads to an intimate link between advances in the seemingly disparate areas of macroscopic interferometry (e.g. precision measurement and spectroscopy) and micro- and nanoscale optomechanical systems. In this manuscript, I will outline the fascinating implications of cavity optomechanics and present proof-of-concept experiments including MHz-frequency resonators aimed at the demonstration of quantum states of mechanical systems, as well as low-frequency (<1 kHz) devices for the observation of quantum radiation pressure noise. Additionally, I will discuss off-shoot technologies developed in the course of this work, such as a numerical solver for the determination of support-mediated losses in mechanical resonators, as well as a new strategy for the realization of ultra-high-stability optical reference cavities based on transferred crystalline multilayers.