Micrometric Thin Cells Research Articles

Saturated absorption spectrum of cesium micrometric-thin cell with suppressed crossover spectral lines

Micrometric-thin cells (MCs) with alkali vapor atoms have been valuable for research and applications of hyperfine Zeeman splitting and atomic magnetometers under strong magnetic fields. We theoretically and experimentally study the saturated absorption spectra using a 100-μm cesium MC, where the pump and probe beams are linearly polarized with mutually perpendicular polarizations, and the magnetic field is along the pump beam. Because of the distinctive thin chamber of the MC, crossover spectral lines in saturated absorption spectra are largely suppressed leading to clear splittings of hyperfine Zeeman transitions in experiments, and the effect of spatial magnetic field gradient is expected to be reduced. A calculation method is proposed to achieve good agreements between theoretical calculations and experimental results. This method successfully explains the suppression of crossover lines in MCs, as well as the effects of magnetic field direction, propagation and polarization directions of the pump/probe beam on saturated absorption spectrum. The saturated absorption spectrum with suppressed crossover lines is used for laser frequency stabilization, which may provide the potential value of MCs for high spatial resolution strong-field magnetometry with high sensitivity.

Measurement of the size of micrometric voids in dielectric media

We have developed a method to measure the characteristic interstice size of transparent porous dielectric media. The method is based upon the observation of the transient decay of alkali atoms contained in the medium pores and excited to a sufficiently long-lived state. We present a simple model describing the dependence of the decay transients on the distance L traveled by the atoms between interstice walls. Fitting of the observed transient data to the model predictions allows the determination of L. The method is tested with two well-characterized micrometric thin cells and used to measure the characteristic interstice size of several porous glass samples.

Micron-thick spectroscopic cells for studying the Paschen-Back regime on the hyperfine structure of cesium atoms

It is shown that the use of spectroscopic cells of micron thickness (L = 10–50 μm) allows one to effectively study the behavior of individual levels of the Cs D2 line in strong magnetic fields up to 9 kG. In particular, the absorption spectrum of Cs excited by circularly polarized light in fields above 8 kG consists of two fully separated groups, each containing eight atomic transitions. The intensities of atomic transitions and their frequency slopes (vs. magnetic field) in each group are almost the same. The physical explanation for the observed features is given; in particular, it is shown that one of the 54 possible atomic transitions in moderate magnetic fields (denoted Fg = 4, mF = 4 → Fe = 5, mF = 5) has unique characteristics that make it possible to predict the intensities and frequency slopes of seven atomic transitions in the same group. Practical applications of devices based on micrometric-thin cells in strong magnetic fields are considered.

N-type resonances in a buffered micrometric Rb cell: splitting in a strong magnetic field

N-type resonances excited in rubidium atoms confined in micrometric-thin cells with variable thickness from 1 μm to 2 mm are studied experimentally for the cases of a pure Rb atomic vapor and of a vapor with neon buffer gas. Good contrast and narrow linewidth were obtained for thicknesses as low as 30 μm. The higher amplitude and sharper profile of N-type resonances in the case of a buffered cell was exploited to study the splitting of the 85Rb D1 N-resonance in a magnetic field of up to 2200 G. The results are fully consistent with the theory. The mechanism responsible for forming N-resonances is discussed. Possible applications are addressed.

Dressed Four-Wave Mixing Spectroscopy Modified by Polarization Interference and Atom-Wall Collision in Micrometric Thin Cells

Dressed four-wave mixing (DFWM) spectroscopy is investigated theoretically in some micrometric thin cells. It is found that DFWM spectra can be modified by polarization interference of atoms and transient effects induced by atom-wall collision. This modification can lead to width-narrowing of DFWM lines and facilitates to implement experiment of high resolution DFWM spectroscopy in a confined atomic system.

Population Loss in Closed Optical Transitions οf Rb and Cs Atoms Confined in Micrometric Thin Cells

V. Biancalana, S. Cartaleva, Y. Dancheva, P.N. Gosh, E. Mariotti, S. Mitra, L. Moi, N. Petrov, B. Ray, D. Sarkisyan and D. Slavov CNISM — Unita di Siena, Dipartimento di Fisica and CSC Universita di Siena, via Roma 56, 53100 Siena, Italy Institute of Electronics, BAS, boul. Tzarigradsko shosse 72, 1784 Sofia, Bulgaria Jadavpur University, Kolkata 700032, India Department of Physics, University of Calcutta, 92 APC Road, Calcutta 700009, India Institute for Physical Research, NAS of Armenia, Ashtarak-2, 378410, Armenia

Theoretical study of dark resonances in micrometric thin cells

We investigate theoretically dark resonance spectroscopy for a dilute atomic vapor confined in a thin (micrometric) cell. We identify the physical parameters characterizing the spectra and study their influence. We focus on a Hanle-type situation, with an optical irradiation under normal incidence and resonant with the atomic transition. The dark resonance spectrum is predicted to combine broad wings with a sharp maximum at line center, which can be singled out when detecting a derivative of the dark resonance spectrum. This narrow signal derivative, shown to broaden only sublinearly with the cell length, is a signature of the contribution of atoms slow enough to fly between the cell windows in a time as long as the characteristic ground state optical pumping time. We suggest that this dark resonance spectroscopy in micrometric thin cells could be a suitable tool for probing the effective velocity distribution in the thin cell arising from the atomic desorption processes, and notably to identify the limiting factors affecting desorption under a grazing incidence.