Zhong-Kun Hu, Bu-Liang Sun, Xiao-Chun Duan, Min-Kang Zhou, Le-Le Chen, Su Zhan, Qiao-Zhen Zhang, and Jun Luo
Phys. Rev. A88, 043610 – Published 8 October 2013
We present an ultrahigh-sensitivity gravimeter based on an
87
Rb atom interferometer using stimulated Raman transitions. Compared with our previous work, a two-dimensional magneto-optical trap is added in the new gravimeter to increase the atom number and improve the detection signal-to-noise ratio, and a better optical phase-locked loop system is used to reduce the phase noise of Raman beams. Benefiting from these efforts and the excellent performance of the active vibration isolator, a short-term sensitivity of about 4.2
μGal/
√
Hz
(
1μGal=1×10−8
m/s2
) is reached, which improves the sensitivity by a factor of 2 compared with the former best reported value. By a modulation experiment, we further indicate that the residual vibration noise contribution is about 1.2
μGal/
√
Hz
, which implies a possible improvement over the present absolute gravity measurement level by about one order of magnitude. Moreover, we demonstrate a calibration experiment to directly evaluate the sub-
μ
Gal resolution of our gravimeter.
