Hyperfine Paschen–Back regime realized in Rb nanocell

Abstract

A simple and efficient scheme based on one-dimensional nanometric thin cell filled with Rb and strong permanent ring magnets allowed direct observation of hyperfine Paschen-Back regime on D 1 line in 0.5 − 0.7 T magnetic field. Experimental results are perfectly consistent with the theory. In particular, with σ + laser excitation, the slopes of B-field dependence of frequency shift for all the 10 individual transitions of 85,87 Rb are the same and equal to 18.6 MHz/mT. Possible applications for magnetometry with submicron spatial resolution and tunable atomic frequency references are discussed. c 2018 Optical Society of America OCIS codes: 020.1335, 300.6360Rubidium atoms are widely used in atomic cooling, information storage, spectroscopy, magnetometry etc [1,2]. Miniaturization of alkali vapor cells is important for many applications [3][4][5][6]. Atom located in magnetic field undergoes shift of the energy levels and change in transition probabilities, therefore precise knowledge of the behavior of atomic transitions is very important [7]. In case of alkali atomic vapor use a sub-Doppler resolution is needed to study separately each individual atomic transition between hyperfine (hf) Zeeman sub-levels of the ground and excited states (in case of a natural mixture of 85 Rb and 87 Rb the number of closely spaced atomic transitions can reach several tens). Recently it was shown that a one-dimensional nanometric-thin cell (NTC) with the thickness of Rb atomic vapor column L = λ, where λ = 794 nm is the wavelength of laser radiation resonant with D 1 line of Rb, is a good tool to obtain subDoppler spectral resolution. Spectrally narrow velocity- When NTC is placed in a weak magnetic field, the VSOPs are split into several components depending on total angular momentum quantum numbers F = I + J, with amplitudes and frequency positions depending on B-field, which makes it convenient to study separately each individual atomic transition.In this Letter we describe a simple and robust system based on NTC and permanent magnets, which allows of achieving magnetic field up to 0.7 T sufficient to observe a hyperfine Paschen-Back regime [9]. The magnetic field required to decouple the nuclear and electronic spins is given by B ≫ A hf s /µ B ∼ = 0.2 T for 87 Rb, and

Giant modification of atomic transition probabilities induced by a magnetic field: forbidden transitions become predominant

“…In this case the splitting of transitions is described by the projections m J and m I [13][14][15][16][17][18]. At B > 6000 G, sixteen transitions are observable in the absorption spectrum: by 8 starting from the ground states 6S 1/2 ,m J =-1/2 and and 6S 1/2 ,m J =+1/2.…”

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

“…The frequency slopes (the derivative of the frequency shifts) of all curves becomes positive at B > 1 kG and asymptotically approaches s ≈ 2.8 MHz/G. This behavior is due to the fact that at B > 1 kG the total angular momentum J of the electron and nuclear magnetic moment I starts to decouple and the behavior of atomic levels perturbed by the magnetic field are described by projections m J and m I (so-called Paschen-Back or Back-Goudsmit regime of the hyperfine structure (HPB)): the behavior of the Zeeman sublevels of F g = 2, 3 are shown, for example, in [22][23][24]. The values of the magnetic fields where the I-J decoupling is efficient are determined by the condition , where A HFS is the hyperfine coupling constant for the 5S 1/2 ground state of Rb and μ B is the Bohr magneton (appropriate values are given e.g.…”

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

“…This significantly facilitates identification of transitions in strong fields. Figure 4a shows the absorption spectrum of 6S 1/2 6P 3/2 transitions (components [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] in an MC filled with Cs vapor, measured for B = 8.45 kG using σ + polarized radiation at a laser power of 20 μW. Components 1-8 correspond to transitions 6S 1/2 , m J = -1/2 6P 3/2 , m J = 1/2, while compo nents 9-16 correspond to transitions 6S 1/2 , m J = 1/2 6P 3/2 , m J = 3/2 (see Fig.…”

“…It has been demonstrated [7][8][9] that the use of nanometer thin cells (NCs) with thicknesses L = λ or L = λ/2 makes it possible to successfully study the behavior of atomic transitions in the aforementioned metals in a broad range of magnetic fields. In the case of strongly inhomogeneous magnetic fields, NCs with L = λ give a better spectral resolution, while a cell with L = λ/2 ensures a better spatial resolution.…”