Guarrera V, Gartman R, Bevilacqua G, Barontini G, Chalupczak W
Midlands Ultracold Atom Research Centre, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom.
Phys Rev Lett. 2019 Jul 19;123(3):033601. doi: 10.1103/PhysRevLett.123.033601.
We report on the use of parametric excitation to coherently manipulate the collective spin state of an atomic vapor at room temperature. Signatures of the parametric excitation are detected in the ground-state spin evolution. These include the excitation spectrum of the atomic coherences, which contains resonances at frequencies characteristic of the parametric process. The amplitudes of the signal quadratures show amplification and attenuation, and their noise distribution is characterized by a strong asymmetry, similar to those observed in mechanical oscillators. The parametric excitation is produced by periodic modulation of the pumping beam, exploiting a Bell-Bloom-like technique widely used in atomic magnetometry. Notably, we find that the noise squeezing obtained by this technique enhances the signal-to-noise ratio of the measurements up to a factor of 10, and improves the performance of a Bell-Bloom magnetometer by a factor of 3.
我们报告了利用参数激励在室温下相干操纵原子蒸汽集体自旋态的情况。在基态自旋演化中检测到了参数激励的特征。这些特征包括原子相干性的激发光谱，其中包含参数过程特征频率处的共振。信号正交分量的幅度呈现放大和衰减，并且它们的噪声分布具有强烈的不对称性，类似于在机械振荡器中观察到的情况。参数激励是通过泵浦光束的周期性调制产生的，采用了在原子磁力测量中广泛使用的类似贝尔 - 布鲁姆的技术。值得注意的是，我们发现通过该技术获得的噪声压缩将测量的信噪比提高了高达10倍，并将贝尔 - 布鲁姆磁力计的性能提高了3倍。
