Quantum Cavity Optomechanics

Yale University, New Haven CT

Investigators

Abstract

This work is aimed at bringing a micromechanical system into the fully quantum regime, which would result in a breakthrough in the field of opto/nanomechanical systems. It would greatly broaden our notion of which physical systems can exhibit quantum effects and allow us to explore the physics associated with quantum optics and mesoscopic condensed matter in an entirely new type of system (i.e., mechanical), whose coupling to readout devices and the environment is qualitatively different from present-day quantum systems. The project uses ultrasensitive millimeter-scale membranes dispersively coupled to high-finesse optical cavities. This coupling is strong enough to laser-cool the membrane to its vibrational ground state, to observe the quantum back-action of displacement measurements, and to produce squeezed light. At the same time this coupling can be tuned to coax especially subtle quantum effects from the optomechanical system; by realizing a strong "position squared" readout we will observe the quantization of energy in the membrane's vibration and quantum jumps between the membrane's energy eigenstates. These goals cover a wide conceptual range, but they represent different facets of the same optomechanical coupling which can be realized in a single device. These experiments are relevant to ultrasensitive instruments in a variety of fields. Quantum limited displacement measurements are relevant to astrophysical gravitational wave searches, as is the production of squeezed light. Micromechanical devices cooled to their ground state could serve as exceptionally sensitive detectors, particularly when coupled to a readout capable of registering the devices' individual quantum excitations. The conceptual simplicity of these systems, combined with the possibility of using them to explore exotic quantum phenomena on a macroscopic scale makes them appealing. The past few years have seen a rapid increase in the number of students, postdocs, and PIs working in this field, and an increased level of interest from scientific and general audiences. This work will serve as an excellent basis for training undergraduate, graduate, and postdoctoral students in important scientific techniques, and will prepare them for a wide range of careers in applied or fundamental research.