Abstract

We embed a nanomechanical-beam oscillator in a superconducting microwave cavity, realizing an interferometric measurement of the beam’s position. We achieve a displacement sensitivity within a factor of 20 of the standard quantum limit of motion and a sensitivity to forces acting on the beam better than 2 aN/Hz^1/2. Radiation pressure forces acting on the beam profoundly influence the beam’s motion. When the microwave excitation frequency is below the cavities resonance it damps and cools the beams motion. When the excitation frequency is above the cavity’s resonance, we observe mechanical amplification and opto-mechanical instability.

© 2008 Optical Society of America