Application of Spin-Exchange Relaxation-Free Magnetometry to the Cosmic Axion Spin Precession Experiment

摘要: The Cosmic Axion Spin Precession Experiment (CASPEr) seeks to measure oscillating torques on nuclear spins caused by axion or axion-like-particle (ALP) dark matter via magnetic resonance (NMR) techniques. A sample spin-polarized along a leading field experiences when the Larmor frequency matches axion/ALP Compton frequency, generating precessing transverse magnetization. Here we demonstrate Spin-Exchange Relaxation-Free (SERF) magnetometer with sensitivity $\approx 1~{\rm fT/\sqrt{Hz}}$ and an effective sensing volume of 0.1 $\rm{cm^3}$ that may be useful for NMR detection in CASPEr. potential drawback SERF-magnetometer-based is SERF's limited dynamic range. Use flux transformer suppress considered as method expand range order probe higher frequencies.