Nonlinear Optical Rotation Magnetometry University of California, Berkeley

1. rot Bmax1.4 Gs eff1.3 Hz -40 -20 20 40 Magnetic Field, Gs Nonlinear Optical Rotation MagnetometryUniversity of California, Berkeley Scientific Issues: Assessment of ultimate attainable sensitivity in atomic magnetometry, 3-axis low-field magnetometry, control and characterization of ultra-low magnetic field environment, fundamental physics applications Objectives: Proof-of-principle demonstration of precision nonlinear optical rotation magnetometry with sensitivity ~10 pGs(Hz)-1/2, investigation of its ultimate performance limits • Approach: • Use large enhancement of optical rotation due to NLOR • Combine the eight orders of magn. rotation enhancement demonstrated in this work withprecision laser spectropolarimetrydeveloped for atomic parity violation experiments • Accomplishments: • Observation of ultra-narrow effective widths (1.3 Hz) in magneto-optics • Demonstration of an 8 orders of magnitude rotation enhancement compared to linear magneto-optics • Realization of a prototype low-field 3-axis magnetometer • Impact: • Demonstration of a new method to prepare, preserve and probe long-lived atomic Zeeman coherence (alignment) • Potential applications in related research involving EIT, coherent dark resonances, phaseonium; in experiments on P, T-violation

2. "Nested" Effects in Nonlinear Magneto-Optical Rotation Large Dynamic Range Magnetometry 5 s (mrad) "wall survival" Optical Rotation s (mrad) transit effect 1 0 5 -5 hole burning Bz (Gs) -1 -5 -1 0 1 Longitudinal Magnetic Field Bz (Gs) Light intensity: 100 W/cm2. Effective laser beam diameter: ~ 2 mm. Rb-cell at room temperature. The solid line is a fit to the developed model. The insert shows a detailed scan of the near-zero Bz-fieldregion.

3. Observed phenomenon: Dramaticchanges of the shape of NMOR in the presence of transverse magnetic fields Btr~Bz Idea for application: The found strong dependence can be used for: Three Dimensional Magnetometry First realization: Three Dimensional Magnetometry was used to compensate residual magnetic fields and to reach narrowest observed NLOR feature with effective resonance width: eff1.3 Hz Nonlinear Magneto-Optical Rotation in Arbitrarily-Directed Magnetic Fields Three Dimensional Magnetometry Bx2 Gs By0 Gs Bx3.7 Gs By0.7 Gs 2 1 0 0 -1 -2 By0.04 Gs Bx-1.2 Gs 2 1 Optical Rotation s (mrad) 0 0 -1 -2 By-0.5 Gs Bx0 Gs 2 1 Bz2.8 Gs 0 0 -1 -2 -10 0 10 0 10 -10 Longitudinal Magnetic Field Bz (Gs)