Injection locking of a levitated optomechanical oscillator for precision force sensing

Abstract

We report on the injection locking of an optically levitated nanomechanical oscillator (a silica nanosphere) to resonant intensity modulations of an external optical signal. We explore the characteristic features of injection locking in this system, e.g. the phase pull-in effect and the injection-induced reduction of the oscillation linewidth. Our measurements are in good agreement with theoretical predictions and deepen the analogy of injection locking in levitated optomechanical systems to that in optical systems (lasers). By measuring the force noise of our feedback cooled free-running oscillator, we attain a force sensitivity of $\sim 23\mathrm{zN}/\sqrt{\mathrm{Hz}}$. This can readily allow, in fairly short integration times, for tests of violations of Newtonian gravity and searching for new small-scale forces. As a proof of concept, we show that the injection locking can be exploited to measure the forces optically induced on levitated nanoparticles, with potential applications in explorations of optical binding and entanglement between optically coupled nanomechanical oscillators.

7 pages, 4 figures

References in corpus (8)

• A Mechanical Mass Sensor with Yoctogram Resolution
• Millikelvin cooling of an optically trapped microsphere in vacuum
• Nanomechanical motion measured with precision beyond the standard quantum limit
• Testing the limits of quantum mechanical superpositions
• Improved constraints on non-Newtonian forces at 10 microns
• Search for Millicharged Particles Using Optically Levitated Microspheres
• A microelectromechanically controlled cavity optomechanical sensing system
• Entangling levitated nanoparticles by coherent scattering