Dr. Charles Woffinden

Postdoctoral Research Fellow

Charles joins the BEC group from 10 years of experience in industry with Teledyne e2v, where he worked on electrical and electronic manufacturing, systems engineering, earth observation, and R&D of semiconductors and process engineering. Charles completed his Doctor of Philosophy (PhD) in Physics from University of York. 
Charles' research was focussed on quantum sensing and investigating quantum thermodynamics using Bose-Einstein condensates.

c.woffinden@uq.edu.au

Pre-prints

The list below includes current pre-prints published on the arXiv.
Pre-Prints
A high-speed, large-aperture 3D printed laser shutter for cold atom experiments
A high-speed, large-aperture 3D printed laser shutter for cold atom experiments

Cold atom experiments require optical shutters with rapid and repeatable actuation. Existing solutions often involve high cost, limited aperture diameter and slow transitioning. We present a 3D-printable shutter design featuring a large aperture of 4.5 mm diameter, low-cost assembly, and robust performance. The device achieves switching times of 399±8 μs with delays of 2.7±0.2 ms for a fully illuminated aperture, with four different shutters demonstrating repeatable performance. We measure the shutter speed to be 7.0±0.1 m/s. This approach offers an accessible, scalable solution for cold atom and other optical experiments requiring multiple shutters with precise light control and avoids the need to resize or precision-align a beam through an aperture.

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Publications

The list below includes all publications associated with the UQ BEC lab. For a full list of publications, please click here.
Publications
Viability of rotation sensing using phonon interferometry in Bose-Einstein condensates
Viability of rotation sensing using phonon interferometry in Bose-Einstein condensates

Charles W. Woffinden, Andrew J. Groszek, Guillaume Gauthier, Bradley J. Mommers, Michael. W. J. Bromley, Simon A. Haine, Halina Rubinsztein-Dunlop, Matthew J. Davis, Tyler W. Neely, Mark Baker, SciPost Phys. 15, 128 (2023) - Published 2 October 2023

In this work, we cool down rubidium atoms to close to absolute zero to form a Bose Einstein Condensate. We form this condensate into a ring, then create sound waves travelling around the circumference of the ring. These sound waves (or phonons) create a standing wave in the density of the condensate, with high- and low-density points around the ring which act as markers. Due to the superfluid nature of the condensate, these markers stay in the same location of the ring and don’t rotate, even if the lab frame of reference is rotating (e.g. due to Earth’s rotation). This means that these markers act as an absolute frame of reference - like the north-seeking pole on a compass and so could potentially be used for navigation in situations where satellite navigation is not available e.g. under water.

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