We utilize the tools already presented in a previous publication [DeSavage, S.A; Gordon, K.H; Clifton, E.M.; Davis, J.P.; Narducci, F.A. J. Mod. Opt. 2011, 58 (21), 2028--2035] to theoretically and experimentally investigate in detail Raman transitions in a sample of laser cooled 85Rb. Using cross-linearly polarized Raman fields, we find that, for an arbitrarily oriented magnetic field, the Raman spectrum consists of up to eleven peaks. However, by judicious choice of magnetic field direction, the spectrum can be reduced to a five peaked spectrum (transverse magnetic field) or a six peaked spectrum (longitudinal magnetic field). We present cases in which the full spectrum can not be thought of as the incoherent sum of the five and six peaked spectra.
We present an experimental study of multi-Raman gain resonances in a hot rubidium vapor. The experiment is performed based on a high-efficiency four-wave mixing process due to the Raman-driven coherence in a double-Λ configuration. The Raman gain resonance for 85 Rb atoms under a bias magnetic field is shown to be split into five or six peaks, depending on the orientation of the magnetic field. The formed multi-Raman gain resonances have potential applications in measurement of magnetic fields and generation of multi-frequency correlated twin beams.
We present a method for magnetic field measurement by the weak magnetic-sensitive Zeeman splitting based on stimulated Raman transition. The magnetic field intensity measured by our proposed method is consistent with that by the magnetic-sensitive method in the error range of 0.5%. Compared with the traditional measurement, the contrast of the weak magnetic-sensitive resonance signal is improved significantly for gradient field. The dependence of the Raman transitions on polarization schemes is analyzed. The cancellation of the differential light shift between the separated peaks is demonstrated by proper choice of polarization configuration. The presented method is applicable to measuring the magnetic field with large gradient, such as 2–40 mG/mm in our clock, where the traditional method is unsuitable.
Precision magnetic field measurement is widely used for practical applications, fundamental research, and medical purposes, etc. We propose a novel quantum magnetometer based on atoms' multi-wave (3-wave and 5-wave) Ramsey interference. Our design features high phase sensitivity and can be applied to in situ measurements of the magnetic field inside vacuum chambers. The final state detection is designed to be achieved by Raman's two-photon transition. The analytical solution for applicable interference fringe is presented. Fringe contrast decay due to atom temperature and magnetic field gradient is simulated to estimate reasonable experimental conditions. Sensitivity functions for phase noise and magnetic field noise in a multi-wave system are derived to estimate the noise level required to reach the expected resolution. The validity of the model, dual-channel features on bias estimation, and the quasi-non-destructive detection feature are discussed.
The quantization axis defines the local interaction between the electromagnetic fields and the atoms. We studied both theoretically and experimentally the hyperfine Raman transition with different quantization axis and found a four-photon Raman transition which happened when the quantization axis is shifting from being parallel to perpendicular to the Raman beams' direction. It keeps the magnetic-field-insensitive feature like the two-photon Raman transition but can be used straightforwardly in multidimensional applications, like inertial sensors or even higher-dimensional quantum walk systems. In addition to inertial sensors, we also discuss the potential quantum sensing applications in magnetometers when the quantization axis is away from perpendicular due to magnetic-field perturbations.
We have investigated the two basic types of Hanle fluorescence spectra, distinguished by the direction of observation, from a V-type atom with a
Jg =0\ensuremath{\leftrightarrows}
Je =1 transition excited by a linearly polarized laser. In the absence of a magnetic field to lift the Zeeman degeneracy of the sublevels, the incoherent fluorescence spectrum
GXinc(\ensuremath{\omega}) is dark for all Rabi frequencies, while the incoherent fluorescence spectrum
GYinc(\ensuremath{\omega}) exhibits a single peak for small Rabi frequencies and a Mollow-like triplet for large Rabi frequencies. However, if a magnetic field is applied, the incoherent spectra are composed, in general, of five peaks. When ${\mathrm{\ensuremath{\omega}}}_{\mathrm{B}}$ \ensuremath{\ll}\ensuremath{\Omega}, the incoherent spectrum
GXinc(\ensuremath{\omega}) has four peaks, while
GYinc(\ensuremath{\omega}) has a Mollow-like triplet, and the integrated area (i.e., the fluorescence intensity) under the spectrum
GXinc(\ensuremath{\omega}) is much less than that of
GYinc(\ensuremath{\omega}). When ${\mathrm{\ensuremath{\omega}}}_{\mathrm{B}}$ \ensuremath{\gg}:\ensuremath{\Omega}, both incoherent spectra have a two-peak structure similar to that of a two-level atom far off resonance, but the integrated area under the spectrum
GXinc(\ensuremath{\omega}) is much greater than that of
GYinc(\ensuremath{\omega}). When ${\mathrm{\ensuremath{\omega}}}_{\mathrm{B}}$ =\ensuremath{\Omega}\ensuremath{\gg}:\ensuremath{\gamma}, both spectra have a similar five-peak structure, and the same integrated area. The results obtained are interpreted in the dressed atomic state representation. In the strong-field limit, the secular approximation is invoked, and analytical expressions of the resonance fluorescence spectra are derived which demonstrate the dependence of the peak heights and widths of the resonance fluorescence spectra on the intensities of the magnetic and linear polarized laser fields in a more transparent way.