Continuous Faraday measurement of spin precession without light shifts
Continuous Faraday measurement of spin precession without light shifts
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DOI：
10.1103/physreva.96.063402
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发表时间：
2017-12-01
影响因子：
2.9
通讯作者：
Turner, L. D.
中科院分区：
文献类型：
--
作者：
Jasperse, M.;Kewming, M. J.;Turner, L. D.
我们描述了一种原子自旋色散法拉第光学探针，它可以连续测量量子气体的自旋投影超过一秒。迄今为止，将明亮的远共振探针聚焦到量子气体上，由于强烈的标量和矢量光位移施加偶极子和斯特恩-格拉赫力，已经证明是侵入性的。我们发现，在87Rb的精细结构双重态之间的790 nm处，将探针调谐到神奇零波长附近，可以抵消标量光移，而仔细控制偏振可以消除矢量光移。由于每个精细结构线的法拉第旋转在该波长增强，提高了固定速率的探测器诱导退相干的信噪比。使用这种微创自旋探针，我们在高时间分辨率下进行微尺度原子磁强计。单旋子玻色-爱因斯坦凝聚体的拉莫尔进动信号的谱图分析测量了时变磁场强度，每5 ms精度为1 μ G；或者，等效地，以10 pT根Hz的灵敏度进行200多次连续测量。
We describe a dispersive Faraday optical probe of atomic spin which performs a weak measurement of spin projection of a quantum gas continuously for more than one second. To date, focusing bright far-off-resonance probes onto quantum gases has proved invasive due to strong scalar and vector light shifts exerting dipole and Stern-Gerlach forces. We show that tuning the probe near the magic-zero wavelength at 790 nm between the fine-structure doublet of 87Rb cancels the scalar light shift, and careful control of polarization eliminates the vector light shift. Faraday rotations due to each fine-structure line reinforce at this wavelength, enhancing the signal-to-noise ratio for a fixed rate of probe-induced decoherence. Using this minimally invasive spin probe, we perform microscale atomic magnetometry at high temporal resolution. Spectrogram analysis of the Larmor precession signal of a single spinor Bose-Einstein condensate measures a time-varying magnetic field strength with 1 mu G accuracy every 5 ms; or, equivalently, makes more than 200 successive measurements each at 10 pT root Hz sensitivity.