Optomechanics & Accelerometers
Developments in optomechanical devices have yielded compact high-Q optomechanical resonators capable of sensitive displacement measurements, and by extension accelerations [1,2]. At a macroscopic scale, these resonators utilize an integrated a Fabry-Perot cavity which can be optically interrogated test-mass displacement, yielding applications to gravitational wave detection, gravimetry and hybrid sensing with atom interferometers. At a mesoscopic scale, extremely high-Q resonators fabricated from high-stress silicon nitride films can be integrated with optical cavities  used to observe quantum effects such as radiation pressure shot noise or cooling a mechanical resonator near its motional ground state . In this work, we focus on development, improvement, and application of compact optomechanical systems. We model the performance of these devices using finite element analysis, and subsequently, experimentally verify the results. Small displacement signal is enhanced through the use of an optical Michaelson interferometer.
- Guzmán F., Kumanchik L., Pratt J., and Taylor J. M. (2014). “High sensitivity optomechanical reference accelerometer over 10 kHz”. In: Applied Physics Letters Vol. 104, No. 22, p. 221111. doi: 10.1063/1.4881936.
- Gerberding O., Guzmán F., Melcher J., Pratt J. R., and Taylor J. M. (2015). “Optomechanical reference accelerometer”. In: Metrologia Vol. 52, No. 5, p. 654. doi: 10.1088/0026-1394/52/5/654.
- D. Wilson et al. Phys. Rev. Let.. 103 (2009), 207204. https://doi.org/10.1103/PhysRevLett.103.207204
- D. Wilson et al. Nature 524 (2015) 325-329. https://doi.org/10.1038/nature14672
Utilization of the matter-wave properties of atoms have lead to the creation of atom interferometers capable of performing absolute measurements of inertial effects, such as accelerations and rotations. Current commercially inertial measurement devices are susceptible to long term drifts or are currently limited in the portability and sensitivity. Atom interferometry yields the possibility to develop compact drift-free inertial measurement devices. To build such a device requires hybrid sensing to address the dominant noise contribution in inertially sensitive atom interferometers; vibrational noise coupling to the inertial reference mirror. Utilization of novel compact opto-mechanical resonators for hybrid sensing eliminates limitations presented by commercially available motion sensors. This work was performed in collaboration with Quantum Sensing Group at the Institute of Quantum Optics – Leibniz Universität Hannover.
Gravimetric Optomechanical Laser (GOL)
We seek to create a high sensitivity gravimetric optomechanical laser through the combination of a Vertical External Cavity Surface Emitting Laser (VECSEL) and a fused-silica mechanical resonator. This system will allow accurate measurements of acceleration, which currently has applications in geodesy, gravimetry, seismometry, and inertial navigation. In addition to being a high sensitivity system, we hope to improve upon current gravimetric measurement devices by making this system more compact, increasing it’s overall utility. The VECSEL is crucial in shrinking the system. Current systems have the gravimetric sensor as a part of an overall system, requiring the use of external optics that all must be stabilized together. This system eliminates that by making the laser apart of the oscillator itself. The VECSEL’s silicon chip will be mounted on the frame of the oscillator, while the mirror for the VECSEL will be incorporated into the test mass. As the test mass moves, the frequency of the laser will change due to the changing cavity length. The mounting method of VECSEL components will ensure that the motion of the test mass will be the only motion encoded into the laser’s output frequency. This will allow the system to be more compact and portable compared to current systems.
Gravitational Wave Astronomy
LASSO is currently a member of both the LIGO Scientific Collaboration and the LISA Consortium.
Check back soon for further updates on our roles in both projects.