Sign reversal of Hanle electromagnetically induced absorption with orthogonal circularly polarized optical fields

Ram, Nibedita; Pattabiraman, M.

doi:10.1088/0953-4075/43/24/245503

Cited by 12 publications

(7 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effect is opposite in the co-propagating configuration. Reversal of the coherent resonances has been previously reported with co-propagating beams and only partial accumulation of atoms in the bright state [16]. In our work, by taking advantage of the overlapping of the K ground state hyperfine components and of the optical transitions of its D 1 line, we obtain the same efficiency of accumulation in states forming bright or dark resonances, depending on the experimental conditions, which can be easily tuned, as demonstrated in the following.…”

supporting

confidence: 70%

See 1 more Smart Citation

Tunable and polarization-controlled high-contrast bright and dark coherent resonances in potassium

et al. 2017

View full text Add to dashboard Cite

We demonstrate high-contrast Electromagnetically Induced Absorption (EIA) bright resonances on the D 1 line of 39 K with characteristics comparable to those of the Electromagnetically Induced Transparency (EIT) dark resonances observed in the same conditions. EIA is produced by the interaction of a weak probe beam with the atomic ground state driven in a degenerate coherent superposition by either a co-or counterpropagating pump beam. We have obtained an order of magnitude increase of the EIA's contrast with respect to previous similar experiments, performed with other alkalis, without compromising its linewidth. Furthermore, we show that the magneto-optic resonances can be continuously tuned from EIT to EIA by changing the relative handedness of circular polarizations of pump and probe beams, or depending on whether they co-or counter-propagate. This opens new perspectives in the use of EIA in a broad range of physical domains and in a large wealth of potential applications in optics and photonics. Contrary to Coherent Population Trapping and Electromagnetically Induced Transparency (EIT) with their ultra-narrow linewidths [1][2][3][4][5][6][7][8], Electromagnetically Induced Absorption (EIA) has found limited applications, mainly due to its broader linewidth and significantly smaller contrast. Nonetheless, an increasing interest in EIA was recently generated in view of potential applications, such as enhancement of the group velocity of light [9] and photonic metamaterials [10].EIA linewidths of several tens of kiloHertz have been reported, either with bichromatic excitation of Zeeman sublevels[11] or in Hanle configuration [12][13][14]. Bi-chromatic Hanle configuration has been explored by using Rb D 1 and D 2 lines [15]. Low-contrast EIA, resulting from EIT on D 2 line, was reported. Higher contrast EIA has been observed in [16], although overlapped to large background, which could be detrimental for highly-selective applications. More recently, sub-kHz EIA resonances were observed in Rb [17] and Cs [18,19]. In both cases, however, the contrast was of only a few percents. A pump/probe scheme in Hanle configuration for high-contrast EIA was proposed in a buffered vapor cell [20]. To date, however, no experimental demonstration has been reported. Highcontrast EIA has been observed on the 87 Rb D 2 line by using a complex excitation scheme with three separate photonic fields [21], and was theoretically investigated in [22]. EIA was also observed in the Paschen-Back regime in a purely non-degenerate three-level ladder system in 87 Rb [23]. Furthermore, while Rb and Cs have been widely investigated, this is the first observation of EIA in K, confirming our preliminary results [24].In this Letter, we report on an alternative and simpler approach for large contrast EIA in Hanle configuration using a pump/probe excitation scheme. We have observed EIA resonance contrast exceeding 50% in thermal K vapor. In this case, hyperfine optical pumping, which accumulates atoms to levels non interacting with the light [25,26], ...

show abstract

supporting

confidence: 70%

“…Low-contrast EIA, resulting from EIT on D 2 line, was reported. Higher contrast EIA has been observed in [16], although overlapped to large background, which could be detrimental for highly-selective applications. More recently, sub-kHz EIA resonances were observed in Rb [17] and Cs [18,19].…”

mentioning

confidence: 99%

Tunable and polarization-controlled high-contrast bright and dark coherent resonances in potassium

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In this case, one often refers to the phenomenon as a nonlinear magneto-optical resonance, which can be bright or dark, as the absorption at zero magnetic field represents a local maximum or minimum, respectively. Recently, attention has been focused on the conversion of EIT to EIA as a function of the properties of the pump field, such as polarization [4] and laser power density [5][6][7][8]. In this work we describe the conversion of a bright nonlinear magnetooptical resonance to a dark resonance as a function of the laser power density of the single optical field and the temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Working with two coherent laser fields, Kim et al observed the conversion of EIT to EIA as a function of the coupling laser power in the D 1 line of rubidium [5]. Other groups have also studied the influence of coupling laser power on EIT and EIA in different systems and for different polarizations of the coherent fields [6][7][8]22]. Brazhnikov et al have studied the effect of the polarization of counterpropagating fields on EIT and EIA [4].…”

Section: Introductionmentioning

confidence: 99%

Conversion of bright magneto-optical resonances into dark resonances at fixed laser frequency forD2excitation of atomic rubidium

et al. 2012

View full text Add to dashboard Cite

Nonlinear magneto-optical resonances on the hyperfine transitions belonging to the D2 line of rubidium were changed from bright to dark resonances by changing the laser power density of the single exciting laser field or by changing the vapor temperature in the cell. In one set of experiments atoms were excited by linearly polarized light from an extended cavity diode laser with polarization vector perpendicular to the light's propagation direction and magnetic field, and laser induced fluorescence (LIF) was observed along the direction of the magnetic field, which was scanned. A low-contrast bright resonance was observed at low laser power densities when the laser was tuned to the Fg = 2 −→ Fe = 3 transition of 87 Rb and near to the Fg = 3 −→ Fe = 4 transition of 85 Rb. The bright resonance became dark as the laser power density was increased above 0.6mW/cm 2 or 0.8 mW/cm 2 , respectively. When the Fg = 2 −→ Fe = 3 transition of 87 Rb was excited with circularly polarized light in a second set of experiments, a bright resonance was observed, which became dark when the temperature was increased to around 50 o C. The experimental observations at room temperature could be reproduced with good agreement by calculations based on a theoretical model, although the theoretical model was not able to describe measurements at elevated temperatures, where reabsorption was thought to play a decisive role. The model was derived from the optical Bloch equations and included all nearby hyperfine components, averaging over the Doppler profile, mixing of magnetic sublevels in the external magnetic field, and a treatment of the coherence properties of the exciting radiation field.

show abstract

“…1. MIT and MIA have been studied before, but only separately [8][9][10][11] 2. Only the transformation from MIA to MIT (using transitions in the D 1 line of Rb) has been studied before [12,13].…”

Section: Introductionmentioning

confidence: 99%

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

Ravi

Bhattarai

Bharti

et al. 2017

EPL

View full text Add to dashboard Cite

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 D 2 line of 133 Cs -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.

show abstract

Sign reversal of Hanle electromagnetically induced absorption with orthogonal circularly polarized optical fields

Cited by 12 publications

References 13 publications

Tunable and polarization-controlled high-contrast bright and dark coherent resonances in potassium

Tunable and polarization-controlled high-contrast bright and dark coherent resonances in potassium

Conversion of bright magneto-optical resonances into dark resonances at fixed laser frequency forD2excitation of atomic rubidium

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

Contact Info

Product

Resources

About