Summary form only given: It is demonstrated that the use of Selective Reflection process obtained with the help of a thin cells filled with the Cs atomic vapor allows one to detect seven Fg=3 → Fe=5 atomic transitions in an external magnetic field in the range of 0.5-3 kG.
Selective reflection of 852-nm laser radiation from the interface between cesium vapor and the sapphire window of a 30-micrometer-thick microcell was used to record an extreme increase in the probability of the Fg=3→Fe=5 transitions associated with the Cs-atom D2 lines in magnetic fields with inductions ranging from 300 to 3200 Gauss. We showed that a group of seven transitions Fg=3, mF=−3, −2, −1, 0, +1, +2, +3→Fe=5, mF=−2, −1, 0, +1, +2, +3, +4 was formed in accordance with the selection rules ΔmF=+1 for σ+-circularly-polarized radiation. These seven transitions have much higher probabilities in 500–1000 Gauss magnetic fields, with three of the transitions having probabilities higher than all of the other transitions originating from the level Fg=3. In magnetic fields with induction greater than 3000 Gauss, this group of seven transitions at the high-frequency end of the spectrum is completely separate from the group of transitions with Fg=3→Fe=4. Comparison of the frequencies and probabilities of these seven atomic transitions with those for the transitions Fg=3→Fe=5 showed good agreement between theory and experiment. We also discuss potential practical applications for these transitions.
Abstract Magnetically induced (MI) transitions of the D2 line of 39K atom in an external magnetic field of 10–600 G have been experimentally and theoretically investigated for the first time using circularly polarized σ+ and σ− radiations. According to the selection rules, the transitions between the sublevels of the ground and excited levels of a hyperfine structure with Fe – Fg = ΔF = ±2 are forbidden in the zero magnetic field, whereas their probabilities increase radically in a magnetic field. For the Fg = 1 → Fe = 3 (ΔF = +2) and Fg = 2 → Fe = 0 MI transitions, the highest probabilities are achieved using the σ+ and σ– radiations, respectively. The atomic transitions have been spectrally resolved using selective reflection of laser radiation from a nanocell filled with potassium atomic vapor, which makes it possible to investigate the behavior of the MI transitions. The experimental and theoretical data are shown to be in good agreement.
The magnetic field-induced giant modification of probabilities for seven components of 6S 1/2 , F g = 3 → 6P 3/2 , F e = 5 transition of the Cs D 2 line, forbidden by selection rules, is observed experimentally for the first time. For the case of excitation with circularly polarized laser radiation, the probability of a F g = 3, m F = −3 → F e = 5, m F = −2 transition becomes the largest of 25 transitions of the F g = 3 → F e = 2,3,4,5 group in a wide-range magnetic field of 200–3200 G. Moreover, the modification is the largest among D 2 lines of alkali metals. A half-wave-thick cell (the length along the beam propagation axis L = 426 nm) filled with Cs has been used in order to achieve sub-Doppler resolution, which allows the large number of atomic transitions that appear in the absorption spectrum to be separated when an external magnetic field is applied. For B > 3000 G the group of seven transitions F g = 3 → F e = 5 is completely resolved and is located at the high frequency level of F g = 3 → F e = 2,3,4 transitions. The applied theoretical model describes very well the experimental curves.
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 D 2 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 F g = 4, m F = 4 → F e = 5, m F = 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.
The so-called "λ/2-Zeeman technique" (HLZT) for studies of individual optical transition between Zeeman sublevels of atomic hyperfine structure in an external magnetic field of B = 10 - 2500 G is presented. Particularly, implementation of HLZT allows one to realize a direct determination of frequency shift and a strong modification of an optical transition probability between Zeeman components in a B-field. The main advantages of the method compared to "λ-Zeeman technique" (LZT) is that it allows one to study weak transitions. Particularly, with the help of fluorescence on 87Rb, D2 line, Fg = 1 → Fe = 3 transitions, three "forbidden" transitions in magnetic field B are detected and studied. Also, on 87Rb D1 line, Fg = 1, mF = 0 → Fe = 1, mF = 0 "forbidden" transition is detected when B ~ 400 G. A strong modification of the probability for these "forbidden" transitions is revealed. The theoretical model well describes the observed results.
Abstract Magnetically induced (MI) transitions Fg = 1 → Fe = 3 of 87Rb D2 line are among the most promising atomic transitions for applications in laser physics. They reach their maximum intensity in the 0.2–2 kG magnetic field range and are more intense than many conventional atomic transitions. An important feature of MI transitions is their large frequency shift with respect to the unperturbed hyperfine transitions which reaches ~12 GHz in magnetic fields of ~3 kG, while they are formed on the high-frequency wing of the spectrum and do not overlap with other transitions. Some important peculiarities have been demonstrated for the MI 5S1/2 → 5P3/2 transitions (λ = 780 nm). Particularly, it was shown that using a nanocell with thickness L = 100 nm it is possible to realize 1 μm-spatial resolution which is important when determining magnetic fields with strong spatial gradient (of >3G/μm). Earlier, our studies have been performed for 5S1/2 → nP3/2 transition with n = 5, while it is also theoretically shown to be promising for the transitions with n = 6, 7, 8 and 9, corresponding to the transition wavelengths of 420.2, 358.7, 334.9 and 322.8 nm, respectively.