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 Cs-133 - Fg = 3 -> F-e = 2 and F-g = 4 -> Fe = 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 C-s vapor cell with paraffin coating on the walls. The observed linewidth is extremely narrow (similar to 0.1mG) compared to previous work in this area, making this a promising technique for all kinds of precision measurements. Copyright (C) EPLA, 2017We 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 Cs-133 - Fg = 3 -> F-e = 2 and F-g = 4 -> Fe = 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 C-s vapor cell with paraffin coating on the walls. The observed linewidth is extremely narrow (similar to 0.1mG) compared to previous work in this area, making this a promising technique for all kinds of precision measurements. Copyright (C) EPLA, 2017

Jan 1, 201716 citations

Tuning from enhanced absorption to transparency in the Hanle effect

Harish Ravi, Sapam Ranjita Chanu, Vasant Natarajan A

We demonstrate that the Hanle effect can be tuned from enhanced absorption to enhanced transmission simply by changing the polarization of the laser beam from linear to circular. The experiments are done on the D $_2$ line of Cs at 852 nm, using the closed hyperfine transition $ F_g = 4 \rightarrow F_e = 5 $. The transformation can be understood qualitatively based on optical pumping and coherences among the magnetic sublevels of the levels involved. To increase the coherence time, the experiments done in a paraffin-coated Cs vapor cell (at room temperature). The observed linewidth is extremely narrow (about 1 mG or 175 Hz), making this a promising technique for all kinds of precision measurements.We demonstrate that the Hanle effect can be tuned from enhanced absorption to enhanced transmission simply by changing the polarization of the laser beam from linear to circular. The experiments are done on the D$_2$ line of Cs at 852 nm, using the closed hyperfine transition $ F_g = 4 \rightarrow F_e = 5 $. The transformation can be understood qualitatively based on optical pumping and coherences among the magnetic sublevels of the levels involved. To increase the coherence time, the experiments done in a paraffin-coated Cs vapor cell (at room temperature). The observed linewidth is extremely narrow (about 1 mG or 175 Hz), making this a promising technique for all kinds of precision measurements.

Oct 13, 20150 citations

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

Mangesh Bhattarai, Vineet Bharti, Vasant Natarajan A

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.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.

arXiv:1710.04378Scientific ReportsMay 8, 201826 citations

Magnetic-field-induced absorption with sub-milligauss spectral width in paraffin-coated rubidium vapor cell

Hyun Joon Lee, Han Seb Moon

We investigated the switching between the transmittance and absorption of the 5S1/2(F=2)→5P1/2(F′=1) transition of Rb87 in a paraffin-coated Rb vapor cell in the Hanle configuration. When the laser polarization was changed from linear to circular, the coherent population trapping (CPT) spectrum, with a spectral width of 0.12 mG due to the Ramsey effect, transformed into a narrow absorption spectrum with a sub-milligauss spectral width of 0.2 mG. The CPT and narrow absorption spectra were numerically calculated for both polarizations by considering the degenerate magnetic sublevels of the 5S1/2–5P1/2 transition in the antirelaxation-coated atomic vapor cell. This narrow absorption spectrum was revealed to be magnetic-field-induced absorption due to the residual transverse magnetic field and preservation time of the ground-state coherent spin states.We investigated the switching between the transmittance and absorption of the 5S1/2(F=2)→5P1/2(F′=1) transition of Rb87 in a paraffin-coated Rb vapor cell in the Hanle configuration. When the laser polarization was changed from linear to circular, the coherent population trapping (CPT) spectrum, with a spectral width of 0.12 mG due to the Ramsey effect, transformed into a narrow absorption spectrum with a sub-milligauss spectral width of 0.2 mG. The CPT and narrow absorption spectra were numerically calculated for both polarizations by considering the degenerate magnetic sublevels of the 5S1/2–5P1/2 transition in the antirelaxation-coated atomic vapor cell. This narrow absorption spectrum was revealed to be magnetic-field-induced absorption due to the residual transverse magnetic field and preservation time of the ground-state coherent spin states.

Journal of the Optical Society of America BJul 27, 20139 citations

Measurement of longitudinal and transverse spin relaxation rates using the ground-state Hanle effect

N. Castagna, Antoine Weis

We present a theoretical and experimental study of the resonant circularly-polarized-light-induced Hanle effect in the ground state of Cs vapor atoms in a paraffin-coated cell. The effect manifests itself as a narrow resonance (centered at $B=0$ ) in the dependence of the optical transmission coefficient of the vapor on the magnitude of an external magnetic field $\stackrel{P\vec}{B}$. We develop a theoretical model that yields an algebraic expression for the shape of these resonances for arbitrary field orientations and arbitrary angular momenta of the states coupled by the exciting light, provided that the light power is kept sufficiently small. An experimental procedure for assessing the range of validity of the model is given. Experiments were carried out on the laser-driven Cs ${D}_{1}$ transition both in longitudinal and transverse field geometries, and the observed line shapes of the corresponding bright and dark resonances give an excellent confirmation of the model predictions. The method is applied for determining the intrinsic longitudinal and transverse relaxation rates of the vector magnetization in the vapor and their dependence on light power.We present a theoretical and experimental study of the resonant circularly-polarized-light-induced Hanle effect in the ground state of Cs vapor atoms in a paraffin-coated cell. The effect manifests itself as a narrow resonance (centered at $B=0$) in the dependence of the optical transmission coefficient of the vapor on the magnitude of an external magnetic field $\stackrel{P\vec}{B}$. We develop a theoretical model that yields an algebraic expression for the shape of these resonances for arbitrary field orientations and arbitrary angular momenta of the states coupled by the exciting light, provided that the light power is kept sufficiently small. An experimental procedure for assessing the range of validity of the model is given. Experiments were carried out on the laser-driven Cs ${D}_{1}$ transition both in longitudinal and transverse field geometries, and the observed line shapes of the corresponding bright and dark resonances give an excellent confirmation of the model predictions. The method is applied for determining the intrinsic longitudinal and transverse relaxation rates of the vector magnetization in the vapor and their dependence on light power.

Physical Review ANov 17, 201165 citations

Absorption of elliptically polarized light in closed transitions of Rb vapor

Marina M. Mijailović, Jelena Dimitrijević, Z. D. Grujić +4 more

We have studied experimentally and theoretically Hanle EIA on the closed Fg = 3 goes to Fe = 4 D2 transition of 85Rb. Atoms were excited by the laser light with different polarization, from linear to circular. Results of the theoretical calculations of the laser transmission, based on optical Bloch equations for density matrix elements for the same atomic system, show important effects of magnetic field transverse to the laser light. We were not able to control transverse magnetic field in the experiment but the theoretical results are still applicable to our experimental data due the presence of laboratory stray magnetic field in the vicinity of the Rb cell, occurring because of imperfect magnetic shielding.We have studied experimentally and theoretically Hanle EIA on the closed Fg = 3 goes to Fe = 4 D2 transition of 85Rb. Atoms were excited by the laser light with different polarization, from linear to circular. Results of the theoretical calculations of the laser transmission, based on optical Bloch equations for density matrix elements for the same atomic system, show important effects of magnetic field transverse to the laser light. We were not able to control transverse magnetic field in the experiment but the theoretical results are still applicable to our experimental data due the presence of laboratory stray magnetic field in the vicinity of the Rb cell, occurring because of imperfect magnetic shielding.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEMar 2, 20070 citations

_2

line of Cs at 852 nm, using the closed hyperfine transition $ F_g = 4 \rightarrow F_e = 5 $. The transformation can be understood qualitatively based on optical pumping and coherences among the magnetic sublevels of the levels involved. To increase the coherence time, the experiments done in a paraffin-coated Cs vapor cell (at room temperature). The observed linewidth is extremely narrow (about 1 mG or 175 Hz), making this a promising technique for all kinds of precision measurements.

B=0

) in the dependence of the optical transmission coefficient of the vapor on the magnitude of an external magnetic field $\stackrel{P\vec}{B}$. We develop a theoretical model that yields an algebraic expression for the shape of these resonances for arbitrary field orientations and arbitrary angular momenta of the states coupled by the exciting light, provided that the light power is kept sufficiently small. An experimental procedure for assessing the range of validity of the model is given. Experiments were carried out on the laser-driven Cs

{D}_{1}

transition both in longitudinal and transverse field geometries, and the observed line shapes of the corresponding bright and dark resonances give an excellent confirmation of the model predictions. The method is applied for determining the intrinsic longitudinal and transverse relaxation rates of the vector magnetization in the vapor and their dependence on light power.