Saturated-absorption spectroscopy revisited: atomic transitions in strong magnetic fields (>20  mT) with a micrometer-thin cell

Abstract

The existence of crossover resonances makes saturated-absorption (SA) spectra very complicated when external magnetic field B is applied. It is demonstrated for the first time, to the best of our knowledge, that the use of micrometric-thin cells (MTCs, L ≈ 40 μm) allows application of SA for quantitative studies of frequency splitting and shifts of the Rb atomic transitions in a wide range of external magnetic fields, from 0.2 up to 6 kG (20-600 mT). We compare the SA spectra obtained with the MTC with those obtained with other techniques and present applications for optical magnetometry with micrometer spatial resolution and a broadly tunable optical frequency lock.

EIT resonance features in strong magnetic fields in rubidium atomic columns with length varying by 4 orders

“…A part of the probe ν P radiation was directed to an auxiliary Rb NC (6). This cell was used as a frequency reference as described in [14].…”

“…From a practical standpoint the use of 30-μm cell allows one to form narrow optical resonances strongly frequency shifted (relative to the unperturbed atomic transitions) which can be used, particularly, for the laser frequency stabilization [6].…”

“…In particular, EIT resonances in strong magnetic fields allow one to form tunable narrow optical reference resonances (displaced by several GHz) from the unperturbed atomic transitions. This can be used in laser frequency stabilization, which is often necessary in practice [6], and also for the construction of secondary tunable frequency references with a spectral resolution of a few MHz.…”

Stabilization of a laser on a large-detuned atomic-reference frequency by resonant interferometry

“…The reference signal is shown to exhibit a spectral oscillatory behaviour in the wings of the resonance and is used to stabilize the laser frequency. Sargsyan and co-authors [12] used a strong magnetic field (B > 20 mT) in a micrometer-thin cell to displace the atomic resonance by a few GHz and performed a saturated absorption on this displaced resonance to stabilize the laser frequency. Here we describe a magnetic field-free technique to obtain a reference signal directly from a single laser beam transmitted through a warm atomic vapour.…”

Study of the Rb D 2-line splitting in a strong transverse magnetic field with Doppler-free spectroscopy in a nanocell

“…An important advantage of the NTC is sub-Doppler spectral resolution in the linear mode. The latter is required to assign individual transitions, because spectra consist of numerous close-lying lines, which are overlapped due to the Doppler broadening [7][8][9][10]. For example, studies [9] performed with a Cs-filled NTC with a thickness of L = λ/2, where λ is the wavelength of laser radiation tuned to the resonance with the D 2 transition (λ/2-method), demonstrated a giant enhancement of the 6S 1/2 (F g = 3) → 6P 3/2 (F e = 5) transition probabilities in an external magnetic field (in the absence of magnetic field, these transition are forbidden).…”