2019.06.04 Lecture: An atom interferometer for inertial sensing

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Speaker: Dr. Xiaxi Cheng, Centre for Cold Matter (CCM), Imperial College London, UK

Time: 10:00 am, June 4, 2019
Venue: Transient Building, 3rd floor conference room

Abstract: During the absence of Global navigation satellite systems signal, conventional accelerometers and gyroscopes are used instead. The accuracy and stability of these devices in inertial sensing are limited primarily by their electronic and mechanical bias drift. Laser cooled atoms promise an attractive solution to this problem. Inertial sensing based on cold atom interferometry not only benefits from the long-term stability of atoms, but also from a significantly higher sensitivity to inertial forces than conventional sensors.

I present our work towards a 3-axis cold atom accelerometer using laser cooled Rubidium-87 atoms. A three pulse Mach-Zehnder interferometer using stimulated Raman transitions is used to measure the acceleration with high sensitivity.

  We aim to achieve a repetition rate of 10 Hz to reduce the dead-times while maintaining a good signal-to-noise ratio. We have reached a sensitivity of 500 ng/Hz^(-1/2) in an one-axis acceleration sensor to measure horizontal acceleration, which is comparable with the state-of-art classical accelerometers. Currently, we are testing the system to reach a sensitivity of 100 ng/Hz^(-1/2) and a dynamic range of +/- 0.3g. This will eventually be working as a stand-alone inertial navigation unit.


Biography: Xiaxi Cheng has received a M.Sc. in Physics at University of Vienna in 2014, working on matter wave interferometry for large molecules. In 2015, he joined the Centre for Cold Matter (CCM) at Imperial College London with a UK’s Ministry of Defense PhD scholarship working on building an atom interferometer for navigation. Currently, he works as a research associate in the CCM and collaborates closely with M Squared Lasers to build a transportable quantum accelerometer.