Limitations on maximum achievable enhancement in sensitivity using large momentum transfer for point source atom interferometry

A point source interferometer (PSI) is a device where atoms are split and recombined by applying a temporal sequence of Raman pulses. During the pulse sequence, an initially trapped cloud of cold atoms is released and allowed to expand, behaving approximately as a point source. The PSI can work as a sensitive multi-axes gyroscope that can automatically filter out the signal from accelerations. The phase shift arising from rotations is proportional to the momentum transferred to each atom from the Raman pulses. Therefore, by increasing the momentum transfer, it should be possibly to enhance the sensitivity of the PSI. Here, we investigate the degree of enhancement in sensitivity that could be achieved by augmenting the PSI with large momentum transfer (LMT) employing a sequence of many Raman pulses with alternating directions. Contrary to typical approaches used for describing a PSI, we employ a model under which the motion of the center of mass of each atom is described quantum mechanically. We show how increasing Doppler shifts lead to imperfections, thereby limiting the visibility of the signal fringes, and identify ways to suppress this effect by increasing the effective, two-photon Rabi frequencies of the Raman pulses. Considering the effect of spontaneous emission, we show that for a given value of the one-photon Rabi frequency, there is an optimum value for the number of pulses employed, beyond which the net enhancement in sensitivity begins to decrease. For a one-photon Rabi frequency of 200 MHz, for example, the peak value of the factor of enhancement in sensitivity is ~39, for a momentum transfer that is ~69 times as large as that for a conventional PSI. We also find that this peak value scales as the one-photon Rabi frequency to the power of 4/5.

[1]  M. Kasevich,et al.  Large area light-pulse atom interferometry , 2000, Physical review letters.

[2]  M. Kasevich,et al.  Enhanced atom interferometer readout through the application of phase shear. , 2013, Physical review letters.

[3]  T. Freegarde,et al.  Optimal control of mirror pulses for cold-atom interferometry , 2018, Physical Review A.

[4]  M. Kasevich,et al.  Effective Inertial Frame in an Atom Interferometric Test of the Equivalence Principle. , 2017, Physical review letters.

[5]  S. Chiow,et al.  102ℏk large area atom interferometers. , 2011, Physical review letters.

[6]  Eugene Ivanov,et al.  Single-Source Multiaxis Cold-Atom Interferometer in a Centimeter-Scale Cell , 2019, Physical Review Applied.

[7]  S. Lamoreaux,et al.  Elucidation of the neutron coherence length and a matter-wave sideband interferometer , 1992 .

[8]  Krish Kotru,et al.  Large-Area Atom Interferometry with Frequency-Swept Raman Adiabatic Passage. , 2015, Physical review letters.

[9]  Claus Lämmerzahl,et al.  Twin-lattice atom interferometry , 2019, Nature Communications.

[10]  A. Miffre,et al.  Atom interferometry , 2006, quant-ph/0605055.

[11]  J. Kinast,et al.  Efficient broadband Raman pulses for large-area atom interferometry , 2013 .

[12]  S. Chiow,et al.  Atom interferometers with scalable enclosed area. , 2009, Physical review letters.

[13]  M. Kasevich,et al.  Quantum superposition at the half-metre scale , 2015, Nature.

[14]  Ac Stark shifts in a two-zone Raman interaction , 2002 .

[15]  Chu,et al.  Atomic interferometry using stimulated Raman transitions. , 1991, Physical review letters.

[16]  C. Bordé.  Atomic interferometry with internal state labelling , 1989 .

[17]  Hunter Swan,et al.  Large Momentum Transfer Clock Atom Interferometry on the 689 nm Intercombination Line of Strontium. , 2020, Physical review letters.

[18]  J. Kitching,et al.  Point source atom interferometry with a cloud of finite size , 2016 .

[19]  P. Cladé,et al.  Large momentum beam splitter using Bloch oscillations. , 2009, Physical review letters.

[20]  M. Kasevich,et al.  Phase Shift in an Atom Interferometer due to Spacetime Curvature across its Wave Function. , 2017, Physical review letters.

[21]  J. Kitching,et al.  Trade-offs in size and performance for a point source interferometer gyroscope , 2017, 2017 IEEE International Symposium on Inertial Sensors and Systems (INERTIAL).

[22]  Steven Chu,et al.  Atom interferometry with up to 24-photon-momentum-transfer beam splitters. , 2007, Physical review letters.

[23]  M. Kasevich,et al.  Multiaxis inertial sensing with long-time point source atom interferometry. , 2013, Physical review letters.

[24]  Mattias Johnsson,et al.  80hk momentum separation with Bloch oscillations in an optically guided atom interferometer , 2013, 1307.0268.

[25]  Holland,et al.  Ballistic expansion of trapped thermal atoms. , 1996, Physical review. A, Atomic, molecular, and optical physics.