Colloquium on October 19, 2009

Florian Marquardt,
Center for NanoScience, Arnold Sommerfeld Center for Theoretical Physics, and Department of Physics, Ludwig-Maximilians-University Munich,

Optomechanics - The interaction between light and mechanical motion

In this talk I will review recent progress in the physics of the interaction between radiation and mechanical motion. The paradigmatic system in this field of 'optomechanics' consists of an optical cavity with a movable mirror attached to a cantilever or other micro- and nanomechanical structures. During the past five years, rapid progress has been made in this field, both on the theoretical and the experimental side.

I will discuss how the coupled dynamics of the light field inside the cavity and the cantilever motion gives rise to a series of interesting effects. On the level of classical dynamics, I will present the theory of nonlinear oscillations and the corresponding attractor diagram. Nonlinear effects may permit sensitive detection and signal processing.

Furthermore, it is possible to cool the cantilever by irradiating the cavity with a red-detuned laser beam. I will present the quantum theory of optomechanical cooling and discuss the progress in reaching the ground state of the cantilever's center-of-mass motion. Several interesting opportunities will open up in the quantum regime. I will discuss the quantum nonlinear dynamics of an optomechanical system and present a possible scheme for detecting Fock states of mechanical motion. Finally, I will comment on the possibility of obtaining strong coupling between the motion of a single atom and a mechanical oscillator.