Invited talk at Kings College for P&N Seminar

On Wednesday 6th February I spoke at the Photonics & Nanotechnology seminar held at Kings College! I had a great day including visiting some laboratories - there’s a new group led by Dr. James Millen looking into levitated optomechanics using rods, spheres and non-optical methods of cooling to a macroscopic quantum state.

Here’s my talk title and abstract:
Optomechanical sensors: an ally of quantum technology, fit for commercialisation

Many cavity optomechanical systems are capable of ultraprecise measurements of displacement, surpassing the performance of commercial sensors such as accelerometers. Such systems respond to mechanical changes of the cavity length/size, resulting in a measurable shift and/or broadening of the cavity optical resonance. In this talk I discuss an optomechanical accelerometer that uses optical whispering gallery mode (WGM) resonances within a spherical cavity, attached to movable cantilever [1]. The optomechanical coupling of the WGM to the cantilever motion allows for detection of accelerations at the micro-g Hz-1/2 level (g=9.81ms-2), with future designs predicted to operate at the current limits of bench-top ultracold atomic systems. As a precursor to commercialisation, we performed feasibility studies outside the laboratory environment by assembling a portable, battery powered, prototype. By mounting the prototype onto a vehicle driven over rough terrain, we verify operation and survival, even during high shocks (+/- 60 g) [2]. I will conclude with a brief discussion on the detection limits, the enabling role these systems can play for quantum sensor development [3], and the route towards sensing beyond the standard quantum limit.

[1] Characterization and Testing of a Micro-g Whispering Gallery Mode Optomechanical Accelerometer, Y. L. Li & P.F. Barker, Journal of Lightwave Technology, 38(16), (2018)
[2] Field Evaluation of a Portable Whispering Gallery Mode Accelerometer, Y.L. Li & P.F. Barker, Sensors 18 (12), (2018)
[3] Don’t hesitate, innovate, Y. L. Li, Nature Nanotechnology 11 (7) (2016)