Abstract Unusual magnetically-induced (MI) transitions Fg =1 → Fe = 3 of the 87Rb atoms, D2 lines, forbidden in the absence of magnetic field but becoming significant in magnetic fields >500 G have been studied. The effect of the buffer gas of neon on MI transitions was studied using the process of resonant absorption of laser radiation in a nanocell (NC) with Rb atomic vapors with an NC thickness L = 390 nm and a buffer gas of neon with the pressures of 6 and 20 Torr. The use of NC enables to achieve high spectral resolution and selectively study the MI transitions. It was found that the addition of neon to the cell results in a decrease in the amplitude of the MI transition and its spectral broadening (for some optical processes, the addition of a buffer gas results in an improvement of the parameters). The optimal power of a CW laser for the effective formation of the MI transitions was found to be equal to 10 μW.Abstract Unusual magnetically-induced (MI) transitions Fg =1 → Fe = 3 of the 87Rb atoms, D2 lines, forbidden in the absence of magnetic field but becoming significant in magnetic fields >500 G have been studied. The effect of the buffer gas of neon on MI transitions was studied using the process of resonant absorption of laser radiation in a nanocell (NC) with Rb atomic vapors with an NC thickness L = 390 nm and a buffer gas of neon with the pressures of 6 and 20 Torr. The use of NC enables to achieve high spectral resolution and selectively study the MI transitions. It was found that the addition of neon to the cell results in a decrease in the amplitude of the MI transition and its spectral broadening (for some optical processes, the addition of a buffer gas results in an improvement of the parameters). The optimal power of a CW laser for the effective formation of the MI transitions was found to be equal to 10 μW.

Journal of Contemporary Physics (Armenian Academy of Sciences)May 27, 20220 citations

A dual-pulse heterodyne detection scheme for tunable temporal weak-value amplification towards unshielded Faraday magnetometry

Md Tousif Alam, Surya Narayan Sahoo, Nandini Mondal +2 more

Abstract When a polarized optical pulse propagates through a Faraday medium, the two circular polarization eigenmodes accumulate differential phase shifts and differential group delay. These two eigenmodes thus become distinguishable by the arrival time of photons, which can serve as a pointer state in the weak-measurement (WM) framework. Here, we describe the Faraday effect as a von Neumann-type interaction, coupling the polarization degree of freedom of light to the temporal envelope of the pulse. Under suitable pre- and post-selection of nearly orthogonal linear polarizations, the two delayed circular components interfere spectrally. This produces an amplified spectral centroid shift, corresponding to the imaginary weak value of the circular polarization component, which is highly sensitive to the small phase shifts induced by the Faraday effect. We propose detecting this spectral shift using heterodyne detection by measuring the centroid of the radio-frequency beat spectrum, a method suitable for atomic magnetometry. While this single-pulse approach may be viable where steep dispersion near resonance yields considerable group delay, it would be ineffective in most far-off-resonant magnetometry where group delay is insignificant. We propose to overcome this challenge by employing two oppositely circularly polarized pulses with a controllable phase difference and a synthetic temporal delay. These engineered input pulses provide tunable sensitivity by allowing weak-value amplification for detecting small magnetic field variations, even in the presence of an ambient magnetic field. Crucially, because the post-selection process prevents detector saturation, it allows for the use of significantly higher optical power, up to the atomic saturation level. For far-off-resonant Faraday magnetometry, we estimate that this detection scheme could potentially allow 10–100 femtotesla-level ( fT Hz − 1 ) photon-shot-noise-limited sensitivity for thermal alkali-vapors depending on detuning, with microtesla-level tunable dynamic range. Hence, this WM-based heterodyne spectral centroid readout scheme can mitigate technical noise, paving the way for high-sensitivity alkali-vapor magnetometry in unshielded environments.Abstract When a polarized optical pulse propagates through a Faraday medium, the two circular polarization eigenmodes accumulate differential phase shifts and differential group delay. These two eigenmodes thus become distinguishable by the arrival time of photons, which can serve as a pointer state in the weak-measurement (WM) framework. Here, we describe the Faraday effect as a von Neumann-type interaction, coupling the polarization degree of freedom of light to the temporal envelope of the pulse. Under suitable pre- and post-selection of nearly orthogonal linear polarizations, the two delayed circular components interfere spectrally. This produces an amplified spectral centroid shift, corresponding to the imaginary weak value of the circular polarization component, which is highly sensitive to the small phase shifts induced by the Faraday effect. We propose detecting this spectral shift using heterodyne detection by measuring the centroid of the radio-frequency beat spectrum, a method suitable for atomic magnetometry. While this single-pulse approach may be viable where steep dispersion near resonance yields considerable group delay, it would be ineffective in most far-off-resonant magnetometry where group delay is insignificant. We propose to overcome this challenge by employing two oppositely circularly polarized pulses with a controllable phase difference and a synthetic temporal delay. These engineered input pulses provide tunable sensitivity by allowing weak-value amplification for detecting small magnetic field variations, even in the presence of an ambient magnetic field. Crucially, because the post-selection process prevents detector saturation, it allows for the use of significantly higher optical power, up to the atomic saturation level. For far-off-resonant Faraday magnetometry, we estimate that this detection scheme could potentially allow 10–100 femtotesla-level ( fT Hz − 1 ) photon-shot-noise-limited sensitivity for thermal alkali-vapors depending on detuning, with microtesla-level tunable dynamic range. Hence, this WM-based heterodyne spectral centroid readout scheme can mitigate technical noise, paving the way for high-sensitivity alkali-vapor magnetometry in unshielded environments.

Physica ScriptaOct 16, 20260 citations

Reversal of Neon Lines excited at Radiofrequency.

Hantaro Nagaoka, Tadao MISHIMA

Proceedings of the Imperial AcademyJan 1, 19270 citations

Comments on the Resonance Fluorescence in Gases

C. Alden Mead, Hendrik F. Hameka

The Journal of Chemical PhysicsJan 15, 19641 citation

Nonlinear Faraday rotation and detection of superposition states in cold atoms

Adam M. Wojciechowski, Eric Corsini, Jerzy Zachorowski +1 more

We report on the observation of nonlinear Faraday rotation with cold atoms at a temperature of $~100$ $\ensuremath{\mu}$K. The observed nonlinear rotation of the light polarization plane is up to $0.1$ rad over the $1$ -mm-size atomic cloud in approximately $10$ -mG magnetic field. The nonlinearity of rotation results from long-lived coherence of ground-state Zeeman sublevels created by a near-resonant light. The method allows for creation, detection, and control of atomic superposition states. It also allows applications for precision magnetometry with high spatial and temporal resolution.We report on the observation of nonlinear Faraday rotation with cold atoms at a temperature of $~100$ $\ensuremath{\mu}$K. The observed nonlinear rotation of the light polarization plane is up to $0.1$ rad over the $1$-mm-size atomic cloud in approximately $10$-mG magnetic field. The nonlinearity of rotation results from long-lived coherence of ground-state Zeeman sublevels created by a near-resonant light. The method allows for creation, detection, and control of atomic superposition states. It also allows applications for precision magnetometry with high spatial and temporal resolution.

arXiv:1001.1629Physical Review AMay 24, 201029 citations

We report on the observation of nonlinear Faraday rotation with cold atoms at a temperature of

~100

$\ensuremath{\mu}$K. The observed nonlinear rotation of the light polarization plane is up to

0.1

rad over the

1

-mm-size atomic cloud in approximately

10

-mG magnetic field. The nonlinearity of rotation results from long-lived coherence of ground-state Zeeman sublevels created by a near-resonant light. The method allows for creation, detection, and control of atomic superposition states. It also allows applications for precision magnetometry with high spatial and temporal resolution.