| High performance atomic devices play an important role in precise measurement based on atomic spectroscopy.We focus on atomic magnetometers and nuclear magnetic resonance(NMR)gyroscope in this thesis.Atomic magnetometers have been widely used due to their high magnetic field sensitivity.At the same time,it serves as the basis of atomic comagnetometers,which are used to applications beyond the magnetic field detections.One important development of atomic comagnetometers in inertial sensing is the NMR gyroscope.Currently,the mainstream research on NMR gyroscopes focus on the miniaturization and new schemes to improve the performance.On the atomic magneotmeter part,we performed research on spin-exchangerelaxation-free(SERF)magnetometers,which include both pump-probe and singlebeam experiment configurations.The single-beam SERF magneotmeter,which is driven by a non-resonant rf field,is used to develop a miniaturized version due to its compact configuration.This miniaturized SERF magnetometer has a cylindrical shape with a diameter of 20 mm and a length of 36 mm.Its magnetic field sensitivity reaches 26 fT/Hz1/2 at frequencies above 10 Hz,and can be used in bio-magnetic applications.In order to investigate the effect of non-resonant rf fields on the atomic spin precessions,we study the interactions between oscillating non-resonant rf fields and atoms with strong spin-exchange collisions in the presence of a weak dc magnetic field.We find that the atomic Larmor precession frequency shows a new functional form to the rf field parameters when the spin-exchange collision rate is tuned.In the weak rf field amplitude regime,a strong modification of atomic Larmor frequency appears when the spin-exchange rate is comparable to the rf field frequency.This effect has been neglected before due to its narrow observation window.We compare the experimental results with density matrix calculations,and explain the data by a damped oscillator model.When the rf field amplitude is large,there is a minimum atomic gyromagnetic ratio point due to the rf photon dressing,and we find that strong spin-exchange interactions modify the position of such a point.We also used the single-beam SERF magneotmeter for the global network of optical magnetometers(GNOME).Using such an apparatus,we participated in two rounds of measurements in 2017 and 2018 for dark matter detection.The NMR gyroscope utilizes the 129Xe-131Xe-Rb system,in which the sensitivity of the rubidium atomic magnetometer is limited by the collision between Rb-Xe.We use the multi-pass cavity technique to improve detection sensitivity while avoiding potential interference caused by large external magnetic field modulation.We realized a Herriott-cavity-assisted NMR gyroscope using the MEMS techniques developed specifically for cell fabrications.In this system,129Xe and 131Xe atoms are hyperpolarized and probed by polarized Rb atoms and continuously driven by oscillating magnetic fields,whose frequencies are kept on resonance by phase-locked loops.After optimizing the experimental parameters,the closed-loop NMR gyroscope reaches a bias instability of 0.2°/h(0.15 μHz),an angle random walk as 0.06°/h1/2,and a bandwidth of 1.5 Hz.Currently,this bias stability is limited by the fluctuations of the cell temperature and the pump beam wavelength.By improving such experiment conditions,the bias stability of the NMR gyroscope is promising to be improved by one order of magnitude. |
