Project title: Development of a Three Axis Accelerator using an Atom Interferometer

Supervisor: Professor Ed Hinds

Project description

Back in 1991 the first successful realisation of an atom interferometer for measuring gravitational forces was built by Mark Kasevich and Steven Chu [1,2]. Within this type of interferometer, a cloud of atoms (usually sodium or rubidium) are split using two-photon Raman transitions between two hyperfine ground states. The two spatially separated clouds are then reflected and recombined with subsequent Raman pulses. The acceleration,  parallel to the Raman beams, that the system undergoes will induce a path difference which amounts to a phase difference between the two atomic wavepackets. This phase difference is a measurable quantity and can be related back to the acceleration via , where  is the accumulated phase difference,  is the effective wavevector for the Raman beams,  is the acceleration of the system and  is the time between Raman pulses. To date, atom interferometers have focused on extreme sensitivity [2,3] or high repetition rate/transportability [4,5] in mind, usually at the expense of each other. With this in mind, we propose to build a three axis accelerometer that balances the trade-off between sensitivity and repetition rate which builds upon our current one axis system. The proposed level of sensitivity is 100ng/ÖHz with a dynamic operational range of ±0.3g and a repetition rate of 10Hz.

References

[1] Kasevich, M. and Chu, S., 1991. Atomic interferometry using stimulated Raman transitions. Physical review letters, 67(2), p.181.

[2] Biedermann, G.W., Wu, X., Deslauriers, L., Roy, S., Mahadeswaraswamy, C. and Kasevich, M.A., 2015. Testing gravity with cold-atom interferometers. Physical Review A, 91(3), p.033629.

[3] Rosi, G., Sorrentino, F., Cacciapuoti, L., Prevedelli, M. and Tino, G.M., 2014. Precision measurement of the Newtonian gravitational constant using cold atoms. Nature, 510(7506), pp.518-521.

[4] Farah, T., Guerlin, C., Landragin, A., Bouyer, P., Gaffet, S., Dos Santos, F.P. and Merlet, S., 2014. Underground operation at best sensitivity of the mobile LNE-SYRTE Cold Atom Gravimeter. Gyroscopy and Navigation, 5(4), pp.266-274

[5] Battelier, B., Barrett, B., Fouché, L., Chichet, L., Antoni-Micollier, L., Porte, H., Napolitano, F., Lautier, J., Landragin, A. and Bouyer, P., 2016. Development of compact cold-atom sensors for inertial navigation. arXiv preprint arXiv:1605.02454.