Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Phys Rev Lett. 2010 Jan 8;104(1):013601. doi: 10.1103/PhysRevLett.104.013601. Epub 2010 Jan 5.
We describe an experimental study of spin-projection noise in a high sensitivity alkali-metal magnetometer. We demonstrate a fourfold improvement in the measurement bandwidth of the magnetometer using continuous quantum nondemolition measurements. Operating in the scalar mode with a measurement volume of 2 cm3 we achieve magnetic field sensitivity of 22 fT/Hz(1/2) and a bandwidth of 1.9 kHz with a spin polarization of only 1%. Our experimental arrangement is naturally backaction evading and can be used to realize sub-fT sensitivity with a highly polarized spin-squeezed atomic vapor.
我们描述了一种在高灵敏度碱金属磁力计中自旋投影噪声的实验研究。我们通过连续量子非破坏测量证明了磁力计测量带宽提高了四倍。在测量体积为 2 立方厘米的标量模式下，我们仅用 1%的自旋极化实现了 22 fT/Hz(1/2)的磁场灵敏度和 1.9 kHz 的带宽。我们的实验装置自然地避免了反作用，并可用于实现具有高度极化的自旋压缩原子蒸气的亚 fT 灵敏度。
