Femtotesla direct magnetic gradiometer using a single multipass cell

Abstract

We describe a direct gradiometer using optical pumping with opposite circular polarization in two ${}^{87}$Rb atomic ensembles within a single multipass cell. A far-detuned probe laser undergoes a near-zero paramagnetic Faraday rotation due to the intrinsic subtraction of two contributions exceeding 3.5 rad from the highly-polarized ensembles. We develop analysis methods for the direct gradiometer signal and measure a gradiometer sensitivity of $10.1$ fT/cm$\sqrt{\mathrm{Hz}}$. We also demonstrate that our multipass design, in addition to increasing the optical depth, provides a fundamental advantage due to the significantly reduced effect of atomic diffusion on the spin noise time-correlation, in excellent agreement with theoretical estimate.

5 pages, 4 figures

References in corpus (18)

• Optical Magnetometry
• Ultra-high sensitivity magnetic field and magnetization measurements with an atomic magnetometer
• Quantum noise limited and entanglement-assisted magnetometry
• Sub-femtotesla scalar atomic magnetometer using multipass cells
• Portable magnetometry for detection of biomagnetism in ambient environments
• A microfabricated optically-pumped magnetic gradiometer
• Measurements with prediction and retrodiction on the collective spin of 10^{11} atoms beat the standard quantum limit
• High Bandwidth Atomic Magnetometery with Continuous Quantum Non-demolition Measurements
• A Low-Noise High-Density Alkali Metal Scalar Magnetometer
• Ultra-sensitive magnetometry based on free precession of nuclear spins
• Measurement-induced nonlocal entanglement in a hot, strongly-interacting atomic system
• Squeezed-light spin noise spectroscopy
• Stroboscopic back-action evasion in a dense alkali-metal vapor
• Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity
• Portable Intrinsic Gradiometer for Ultra-Sensitive Detection of Magnetic Gradient in Unshielded Environment
• Correlation function of spin noise due to atomic diffusion
• Cavity enhanced atomic magnetometry
• Sensitivity, quantum limits, and quantum enhancement of noise spectroscopies

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