Tuning of the Hanle effect from EIT to EIA using spatially separated probe and control beams

Abstract

We demonstrate a technique for continuous tuning of the Hanle effect from electromagnetically induced transparency (EIT) to electromagnetically induced absorption (EIA) by changing the polarization ellipticity of a control beam. In contrast to previous work in this field, we use spatially separated probe and control beams. The experiments are done using magnetic sublevels of the Fg = 4 → Fe = 5 closed hyperfine transition in the 852 nm D2 line of 133Cs. The atoms are contained in a room temperature vapor cell with anti-relaxation (paraffin) coating on the walls. The paraffin coating is necessary for the atomic coherence to be transported between the beams. The experimental results are supported by a density-matrix analysis of the system, which also explains the observed amplitude and zero-crossing of the resonances. Such continuous tuning of the sign of a resonance has important applications in quantum memory and other precision measurements.

Study of EIT resonances in an anti-relaxation coated Rb vapor cell

“…The experiments are done using magnetic sublevels of the ground state in the D 1 line (5S 1/2 → 5P 1/2 transition) of 87 Rb at 795 nm. The experimental results are supported by a two-region theoretical model [16,17] incorporating all the magnetic sublevels of the ground state.…”

“…The model is based on the multi-region density-matrix analysis given in Refs. [16] and [17]. The two interaction regions are labeled bright and dark.…”

Laser interferometry based on atomic coherence

“…This makes the use of a magnetic shield necessary. In fact with the magnetic shield we still have residual longitudinal and transverse fields of the order of 1 mG inside [19], which are small enough to be ignored. The number density in the cell is around 10 10 atoms/cm 3 at this temperature [20].…”

Robust Slow Light Enhancement Based on Flat Band States in the Continuum

“…Electromagnetic induced transparency (EIT), which is originally rooted in quantum physics system, has been widely used in the research of slow lights [48][49][50][51][52], sensors [53][54][55], absorbers [56][57][58], optical modulators [59,60], nonlinear enhancement [61,62], and other fields, due to its slow wave effect, strong dispersion, low absorption, and high-quality factor spectrum response. The analogue of EIT effect based on microwave metamaterials [52,[63][64][65], in particular, provides a new platform for the observation of slow wave effect, which not only is easy to adjust in structure, but also can visually reveal the strong dispersion effect caused by the EIT phenomenon.…”