Physical Society Colloquium

Ultralow-noise optomechanical sensors and mechanical motion defined by light

Jack Sankey (Childress)

Department of Physics
McGill University

Mechanical systems are everywhere in society, from oscillators in timekeeping devices to electronic filters and accelerometers in automobiles and cell phones. They also represent an indispensable set of tools for fundamental science, providing a means of sensing atom-scale forces and masses, or even the minuscule spacetime distortions from passing gravitational waves. In the modern field of optomechanics, we exploit the forces exerted by light to gain unique control over these systems at all size scales. In this talk I will discuss our ongoing efforts to fabricate delicate micromechanical elements and incorporate them into optical microcavities such that their motion can be profoundly influenced by an average of a single photon in the apparatus. These devices are ideally suited for sensing the “quantum hiss” of the radiation force over the entire acoustic range, and we hope to use this response to squeeze the sensitivity of interferometers (such as LIGO) below the so-called standard quantum limit. I will also discuss progress toward a related system in which radiation forces create a tunable defect in a periodic mechanical structure, thereby strongly controlling the distribution of oscillating mass in a mechanical mechanical system.