Credit: © 2009 NPG

The vibrations of nanoscale beams can been used to measure small masses and detect single spins. These vibrations can be detected using electron flow, which gives a high sensitivity but low precision, or by using light, which gives a high precision but low sensitivity.

Now, Tobias Kippenberg and colleagues at the Max Planck Institute of Quantum Optics, Ludwig-Maximilians-Universität, and Ecole Polytechnique Fédérale de Lausanne have demonstrated the optical transduction of nanomechanical motion with both high sensitivity and record precision1. The researchers used the decaying evanescent field outside of a small optical resonator to probe an array of double-clamped nanoscale beams made from SiN. The frequency noise of the cavity allowed measurement of the array at room temperature to a precision limited only by quantum effects, reaching the standard quantum limit. Furthermore, the pressure exerted by radiation from the resonator affected the motion of the beams, and was even able to drive them into oscillations.

This unique coupling scheme can be applied to a variety of other nanomechanical oscillators, and may lead to new ways of controlling noise and measuring quantum effects in these systems.