High-quality electromagnetically-induced absorption resonances in a buffer-gas-filled vapour cell

Abstract

A new configuration for observation of magneto-optical subnatural-linewidth resonances of electromagnetically induced absorption (EIA) in alkali vapor has been verified experimentally. The configuration includes using two counter-propagating pump and probe light waves with mutually orthogonal linear polarizations, exciting an open optical transition of an alkali atom in the presence of a buffer gas. The main advantage of the novel observation scheme consists in the possibility of obtaining simultaneously high-contrast and quite narrow nonlinear signals. Here a 2.5-cm long rubidium-87 vapor cell filled with Ar buffer gas is used, and the excited optical transition is the Fg=2→Fe=1 of the D1 line. The signals registered reach a contrast of 57.7% with a FWHM of 7.2 mG. The contrast with respect to a wide Doppler pedestal well exceeds 100%. To our knowledge, to date this is the best result for EIA resonances in terms of contrast-to-width ratio. In general, the results demonstrate that the new magneto-optical scheme has very good prospects for various applications in quantum metrology, nonlinear optics and photonics.

High-quality level-crossing resonances under counterpropagating circularly polarized light waves for applications in atomic magnetometry

“…In [20], we proposed an idea of adding a second (pump) light wave to improve the parameters of the GSHE resonances. The idea was successfully verified experimentally with Rb [21] and Cs [22] buffer-gas vapor cells of cm dimension. Counterpropagating waves with orthogonal linear polarizations were used (lin⊥lin configuration), leading to observation of an EIA-type LC resonance in the probe wave transmission.…”

Level-crossing resonances on open atomic transitions in a buffered Cs vapor cell: Linewidth narrowing, high contrast and applications to atomic magnetometry

“…Such "pump-probe" light field configurations have been studied in several works, expanding capabilities of the standard Hanle scheme. Most of them utilize two separate light waves [30][31][32][33][34][35][36][71][72][73]. However, it is obvious that a single light wave configuration is much more preferable for developing a miniaturized magnetic field sensor.…”

“…Other types of AMs based on nonlinear Faraday rotation also require a relatively large vapor cell volume to achieve a sub-pT sensitivity at a low temperature of vapors [27,28]. Various pump-probe cw [29][30][31][32][33][34] or pulsed [35,36] light field configurations could help to overcome this problem. For instance, high-quality Hanle resonances have recently been observed in our pump-probe scheme with cesium vapors [34]: C≈ 80% was achieved at FWHM ≈ 2 mG, yielding large CWR of around 40 %/mG.…”

Zero-field level-crossing resonances in a small low-temperature cesium vapor cell for atomic magnetometry applications

“…Both beams are of the same optical frequency ω and are in resonance with the D 1 line. The similar pump-probe scheme composed of two counterpropagating linearly polarized light waves, here referred to as "lin⊥lin", has already demonstrated high-quality LCRs in rubidium [23] as well as in cesium [24,25] buffered vapor cells. The observation of high-contrast electromagnetically induced absorption (EIA) resonances in the probe wave transmission was powered by the creation of a coherent-population-trapping (CPT) state [26] that was a "dark" state for the pump beam, while it was a "bright" state for the probe one [27,28,29].…”