Polarization-dependent tuning of the Hanle effect in the ground state of Cs

Department of Physics, Indian Institute of Science - Bangalore, 560012, India

Received: 11 April 2017
Accepted: 4 May 2017

Abstract

We demonstrate that the Hanle effect can be tuned between magnetically induced absorption (MIA) and magnetically induced transmission (MIT) simply by changing the polarization of the input laser beam. The experiments are done using closed hyperfine transitions of the D₂ line of ¹³³Cs —F_g = 3 → F_e = 2 and F_g = 4 → F_e = 5. The former shows a transformation from MIT to MIA, while the latter shows the opposite behavior. A qualitative explanation based on optical pumping and coherences among the magnetic sublevels of the ground state is borne out by a detailed density-matrix calculation. To increase the coherence time, the experiments are done in a Cs vapor cell with paraffin coating on the walls. The observed linewidth is extremely narrow (∼ 0.1 mG) compared to previous work in this area, making this a promising technique for all kinds of precision measurements.