Enhanced fully optically pumped magnetic resonance with optical sideband auxiliary pumping

Abstract

We have proposed a new technique to obtain highly polarized atoms for improving the sensitivity of the all-optical Cs atomic magnetometer. In a Bell–Bloom magnetometer, the resonance pumping from the ground state F g = 3 to the excited state F e = 4 at the D1 line is used to polarize the Cs atoms and populate the sublevels of the | F g = 4 , m F = 4 ⟩ partly as the transition F g = 4 → F e = 3 remains leaking. Here we utilize a modulation technique to generate a sideband frequency to pump both transitions simultaneously, which drives more atoms to the target state | F g = 4 , m F = 4 ⟩ . This improvement significantly increases the magnetic resonance signal but with little effect on its linewidth. It is very suitable for the miniaturization of the atomic magnetometer in the future.

Quantum magnetic gradiometer with entangled twin light beams

“…To measure the gradient magnetic field, two isotopically enriched 87 Rb vapor cells are used as the two sensors (S a and S b ) of the gradiometer. The atomic spins of S a and S b are synchronously oriented along yfalse^ (polarized to the │5 S 1/2 , F = 2, m F = 2〉 state) by two circularly polarized laser beams (P2a/P3a.1emand.1emP2b/P3b) with modulation frequency Ω m ( 45 , 46 ). Here, P2a and P3a are optical pumping and repumping for sensor S a ; P2b and P3b are optical pumping and repumping for sensor S b .…”

Quantum-limit-breaking Magnetic Gradiometer with Entangled Light

“…The atomic spins of S a and S b are both synchronously stretched along ŷ (polarized to the 5 S 1/2 , F = 2, m F = 2 state) by circularly polarized optical pumping and repumping with modulation frequency Ω m [38,39]. With the existence of a leading magnetic field B L along the x-direction, the atomic spins of S a and S b start to undergo Larmor precession with Larmor frequencies of Ω a L and Ω b L , respectively.…”

“…To generate CMM field and magnetic field gradient on two sensors we add a set of Helmholtz coil and a set of anti-Helmholtz coil with a diameter of 92 mm outside of two 87 Rb vapor cells. For each sensor, the atoms are fully polarized to 5 S 1/2 , F = 2, m F = 2 state by two circularly polarized, ŷ-directed laser beams (P a 2 /P a 3 and P b 2 /P b 3 ) [38,39], where P a 2 and P a 3 are optical pumping and repumping for sensor S a ; P b 2 and P b 3 are optical pumping and repumping for sensor S b . The optical pumping beam is resonant with 5 S 1/2 , F = 2 to 5 P 1/2 , F ′ = 2 transition to polarize the atoms.…”