Shift of zero-field level-crossing resonance in the Cs D₁ line and its use in vector magnetometry

We examine the level-crossing resonance in a cesium vapor cell filled with a buffer gas under counterpropagating pump and probe light waves with orthogonal linear polarizations. An optical transition F g = 4 → F e = 3 is excited in the D 1 line. Probe-wave transmission is analyzed versus a static magnetic field applied along the wave vectors. This configuration can provide ultrahigh-contrast electromagnetically induced absorption resonances. We report here a new, to the best of our knowledge, magneto-optical effect in the resonance shift caused by a transverse magnetic field and discuss how it can be applied in vector magnetometry.</jats:p

Application of directly modulated laser and polarimetric technique to observation of sub-Doppler resonances in small Cs vapor cell

International audience• The frequency standards are widely used in high-resolution spectroscopy, precision physics experiments<br&gt• Metrology, location, geophysics, space exploration<br&gt• One of the main methods of laser spectroscopy is method of saturated absorption in a gas of alkali metal atom

Electromagnetically Induced Absorption for a Cesium Vapor-Cell Microwave Frequency Reference

International audienceThe coherent population trapping (CPT) phenomenon1 has been widely used for the development of cell-based microwave frequency references, including the demonstration and even commercialization of chip-scale atomic clocks (MACs)2. In CPT physics, atoms are driven into adark state uncoupled from the excited state by making the atoms interact with a dual-frequency optical field such that the Raman detuning is null. CPT induces a reduction of the light field absorption in the vapor cell, leading to the detection of a resonance peak (increased transmission) in the bottom of the absorption line. The CPT dark resonance is usually excited in commercial MACs with a simple circularly polarized dualfrequency light field. Alternative excitation schemes have also been proposed

Electromagnetically induced absorption scheme for vapor-cell atomic clock

International audienceA dual-frequency light field scheme, composed of counterpropagating pump and probe light waves with equal circular polarizations and different intensities, is proposed for the detection of subnatural-linewidth electromagnetically induced absorption (EIA) resonances. In this scheme, the bright-type EIA resonance is obtained at fixed static magnetic field by tuning the frequency difference between both optical fields and can be used as a frequency reference in an atomic clock. Using a 5-mm long buffer-gas-filled Cs vapor cell, an EIA-based atomic clock with a short-term fractional frequency stability of 5.8 × 10−12 τ−1/2 until 20 s integration time is reported. These performances are found to be in correct agreement with the signal-to-noise/linewidth ratio of the resonance. The proposed EIA scheme can be considered as an alternative approach to the coherent population trapping (CPT) technique for the development of compact atomic clocks and sensors

Two-frequency sub-Doppler spectroscopy of the caesium D1 line in various configurations of counterpropagating laser beams

International audienceSub-Doppler resonances in caesium vapours are studied in a laser field produced by counterpropagating two-frequency light beams with mutually orthogonal linear polarisations. The beams are in resonance with optical transitions in the D<sub&gt1</sub&gt line, the frequency difference of the field spectral components being equal to the hyperfine ground-state splitting in the Cs atom (≈9.2 GHz). It has already been shown that in this configuration, the hypercontrast effect can be observed for sub-Doppler resonances, which makes this configuration promising for the employment in newgeneration miniature optical frequency standards. In the present work, two different two-frequency configurations are compared with each other and with the single-frequency configuration widely used in practice for observing saturated absorption resonances. The parameters of nonlinear resonances are measured at various temperatures of caesium vapours and at different optical field intensities. The results of the investigations performed make it possible to find an optimal two-frequency scheme for exciting nonlinear resonances and to estimate a potential of the scheme for its applications in quantum metrology