Light can interact with mechanical systems in interesting and useful ways, not only probing the mechanical motion with spectacular sensitivity, but also driving the mechanics via radiation pressure forces or by coupling to embedded quantum systems. We are exploring a variety of such systems for use in practical sensors and quantum measurement science.
Our primary current research direction involves the use of fabricated devices with sub-wavelength periodicity (photonic crystals) as optomechanical elements. Such structures enable a rich variety of devices, including mirrors, polarizers, and filters, in a configuration that couples naturally to free-space optics. We have optically cooled these devices to cryogenic temperatures and are interested in cooling them further, into the quantum domain. We have used them as a key element of a "phonon laser," for which we are interested in developing useful applications. In other recent work, we have created engineered optical potentials to force controllable bistable and tristable static behavior in a micromechanical system. We have started to explore the use of active media in optomechanics and further novel functionality enabled by sub-wavelength devices, as well as the use of embedded quantum dots as sensors of mechanical displacement.