Abstract
Single-crystal diamond optomechanical devices have the potential to enable fundamental studies and technologies coupling mechanical vibrations to both light and electronic quantum systems. Here, we demonstrate a single-crystal diamond optomechanical system and show that it allows excitation of diamond mechanical resonances into self-oscillations with amplitude . The resulting internal stress field is predicted to allow driving of electron spin transitions of diamond nitrogen-vacancy centers. The mechanical resonances have a quality factor and can be tuned via nonlinear frequency renormalization, while the optomechanical interface has a 150 nm bandwidth and sensitivity. In combination, these features make this system a promising platform for interfacing light, nanomechanics, and electron spins.
6 More- Received 28 April 2015
DOI:https://doi.org/10.1103/PhysRevX.5.041051
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Published by the American Physical Society
Popular Summary
The superior optical, mechanical, and thermal properties of single-crystal diamond make it an attractive platform for technologies ranging from lasers to x-ray optics. Single-crystal diamond also has applications in optomechanics and quantum optics research. Intriguingly, single-crystal diamond is host to defects such as nitrogen-vacancy color centers with excellent quantum characteristics that act as sensors and quantum information storage elements. The electronic and nuclear states of these defects can be manipulated using optical and microwave photons and, as shown recently, phonons. On-chip optomechanical technology has the potential to provide control and measurement of phonons of individual devices using light, the preferred medium for transmitting quantum information. Here, we use a scalable fabrication technique to create a single-crystal diamond optomechanical system based on waveguide coupling to the nanobeams.
Optomechanical devices enhance optical forces, allowing low-power actuation and high-sensitivity readout of mechanical structures. They can simultaneously provide photon-phonon and phonon-spin coupling, enabling new hybrid approaches for optical control of spins and transferring quantum information between disparate systems. The nanobeams we employ double as optical waveguides, enabling sensitive optomechanical readout of their mechanical characteristics via phase-matched coherent coupling to an optical fiber. We are able to amplify the nanobeam thermal motion into self-oscillations greater than 200 nanometers in amplitude in cryogenic conditions (5 K). A comprehensive study of the nonlinear nanobeam dynamics reveals that the photothermal force in these devices is enhanced by the presence of compressive stress so that only 100 nW of absorbed optical power is needed to excite the self-oscillations.
These oscillations are predicted to enable strong phonon-spin coupling within the diamond nanobeam, paving the way for the future development of hybrid quantum devices that may be useful for sensing.