Effects related to the temperature of atoms in an atom interferometry gravimeter based on ultra-cold atoms

Abstract

The temperature of atoms, coupled to several effects, plays an important role in high precision atom interferometry gravimeters. In this work, we present an ultra-cold 87Rb atom interferometry gravimeter, in which the atom source is produced by evaporative cooling in an all optical dipole trap to investigate the effects related to atom temperature. A condensate containing 4 × 104 atoms can be prepared within 3.2 s through an all-optical dipole trap composed of two reservoirs and a dimple. The fringe contrast of our atom interferometry gravimeter reaches up to 76(4)% due to the advantage of ultra-cold atom source even at a free evolution time of T=80 ms. A resolution of 6 μGal (1 μGal=1×10−8 m/s2) after 3000 s integration time with a sampling rate of 0.25 Hz is achieved in this atom gravimeter. The relationship between the fringe contrast and the atom temperature in the atom gravimeter is studied; in addition, the wavefront aberration effect in the atom gravimeter is also investigated by varying the temperature of atoms.

Precision Magnetic Field Sensing with Dual Multi-Wave Atom Interferometer

“…The facilities of atom cooling lasers and Raman lasers are reported in Ref. [ 46 ]. Atom clouds are freely falling during the sequence.…”

“…Due to the finite temperature of atoms [ 46 , 50 , 51 ], the expansion of the atom cloud and the magnetic field gradient are coupled to bring decoherence to the Ramsey interference, leading to a decrease in the fringe contrast. Because of the magnetic field gradient and the spatial distribution of the atoms in the atom cloud, each atom experiences a different variation of the magnetic field during the free fall.…”

“…The required atom number and temperature are conventional for results that achieved evaporation cooling producing BEC [ 46 , 53 , 54 ]. Still, there is plenty of room compared to the world’s top-level result [ 55 ].…”

“…The cycle time , including the duration for MOT-loading and atom evaporation is of the order of , as shown in Ref. [ 46 ]. The estimated resolution at is thus multiplied by .…”