المؤلفون: Auzinsh, M., Sargsyan, A., Tonoyan, A., Leroy, C., Momier, R., Sarkisyan, D., Papoyan, A.

مصطلحات موضوعية: Physics - Atomic Physics

الوصف: $^{39}$K atoms have the smallest ground state ($^2S_{1/2}$) hyperfine splitting of all the most naturally abundent alkali isotopes and, consequently, the smallest characteristic magnetic field value $B_0 = A_{^2S_{1/2}}/\mu_B \approx 170$ G, where $A_{^2S_{1/2}}$ is the ground state's magnetic dipole interaction constant. In the hyperfine Paschen-Back regime ($B \gg B_0$, where $B$ is the magnitude of the external magnetic field applied on the atoms), only 8 Zeeman transitions are visible in the absorption spectrum of the $D_1$ line of $^{39}$K, while the probabilities of the remaining 16 Zeeman transitions tend to zero. In the case of $^{39}$K, this behavior is reached already at relatively low magnetic field $B > B_0$. For each circular polarization ($\sigma^-,\sigma^+$), 4 spectrally resolved atomic transitions having a sub-Doppler width are recorded using a sub-microsized vapor cell of thickness $L = 120 - 390$ nm. We present a method that allows to measure the magnetic field in the range $0.1 - 10$ kG with micrometer spatial resolution, which is relevant in particular for the determination of magnetic fields with a large gradient (up to 3 G$/\mu$m). The theoretical model describes well the experimental results.
Comment: 7 pages, 5 figures

الوصول الحر: http://arxiv.org/abs/2203.11553Test

المؤلفون: Mozers, A., Busaite, L., Osite, D., Auzinsh, M.

المصدر: Phys. Rev. A 102, 053102 (2020)

مصطلحات موضوعية: Physics - Atomic Physics

الوصف: We investigated experimentally and theoretically angular momentum alignment-to-orientation conversion created by the joint interaction of laser radiation and an external magnetic field with atomic rubidium at room temperature. In particular we were interested in alignment-to-orientation conversion in atomic ground state. Experimentally the laser frequency was fixed to the hyperfine transitions of $D_1$ line of rubidium. We used a theoretical model for signal simulations that takes into account all neighboring hyperfine levels, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. The experiments were carried out by exciting the atoms with linearly polarized laser radiation. Two oppositely circularly polarized laser induced fluorescence (LIF) components were detected and afterwards their difference was taken. The combined LIF signals originating from the hyperfine magnetic sublevel transitions of $^{85}$Rb and $^{87}$Rb rubidium isotopes were included. The alignment-to-orientation conversion can be undoubtedly identified in the difference signals for various laser frequencies as well as change in signal shapes can be observed when the laser power density is increased. We studied the formation and the underlying physical processes of the observed signal of the LIF components and their difference by performing the analysis of the influence of incoherent and coherent effects. We performed simulations of theoretical signals that showed the influence of ground-state coherent effects on the LIF difference signal.
Comment: 11 pages, 11 figures

الوصول الحر: http://arxiv.org/abs/2006.15019Test

المؤلفون: Tonoyan, A., Sargsyan, A., Klinger, E., Hakhumyan, G., Leroy, C., Auzinsh, M., Papoyan, A., Sarkisyan, D.

مصطلحات موضوعية: Physics - Atomic Physics

الوصف: In this letter we demonstrate universal symmetry breaking by means of magnetically induced circular dichroism. Magnetic field induces forbidden at zero field atomic transitions between $\Delta F = \pm2$ hyperfine levels. In a particular range of magnetic field, intensities of these transitions experience significant enhancement. We have deduced a general rule applicable for the $D_2$ lines of all bosonic alkali atoms, that is transition intensity enhancement is larger for the case of $\sigma^+$ than for $\sigma^-$ excitation for $\Delta F = +2$, whereas it is larger (e.g. up to $10^{11}$ times for $^{85}$Rb atoms) in the case of $\sigma^-$ than for $\sigma^+$ polarization for $\Delta F = -2$. This asymmetric behaviour results in an explicit circular dichroism. For experimental verification we employed half-wavelength-thick atomic vapor nanocells using a derivative of selective reflection technique, which provides sub-Doppler spectroscopic linewidth ($\sim$50 MHz). The presented theoretical curves well describe the experimental results. This effect can find applications particularly in parity violation experiments.
Comment: 5 pages, 5 figures

الوصول الحر: http://arxiv.org/abs/1707.00688Test

المؤلفون: Jarmola, A., Berzins, A., Smits, J., Smits, K., Prikulis, J., Gahbauer, F., Ferber, R., Erts, D., Auzinsh, M., Budker, D.

المصدر: Applied Physics Letters 107(24), 242403 (2015)

مصطلحات موضوعية: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science

الوصف: We present systematic measurements of longitudinal relaxation rates ($1/T_1$) of spin polarization in the ground state of the nitrogen-vacancy (NV$^-$) color center in synthetic diamond as a function of NV$^-$ concentration and magnetic field $B$. NV$^-$ centers were created by irradiating a Type 1b single-crystal diamond along the [100] axis with 200 keV electrons from a transmission electron microscope with varying doses to achieve spots of different NV$^-$ center concentrations. Values of ($1/T_1$) were measured for each spot as a function of $B$.
Comment: 4 pages, 8 figures

الوصول الحر: http://arxiv.org/abs/1511.06189Test

المؤلفون: Pustelny, S., Busaite, L., Akulshin, A., Auzinsh, M., Leefer, N., Budker, D.

مصطلحات موضوعية: Physics - Optics, Physics - Atomic Physics

الوصف: We present experimental and numerical studies of nonlinear magneto-optical rotation (NMOR) in rubidium vapor excited with resonant light tuned to the $5^2\!S_{1/2}\rightarrow 6^2\!P_{1/2}$ absorption line (421~nm). Contrary to the experiments performed to date on the strong $D_1$ or $D_2$ lines, in this case, the spontaneous decay of the excited state $6^2\!P_{1/2}$ may occur via multiple intermediate states, affecting the dynamics, magnitude and other characteristics of NMOR. Comparing the experimental results with the results of modelling based on Auzinsh et al., Phys. Rev. A 80, 1 (2009), we demonstrate that despite the complexity of the structure, NMOR can be adequately described with a model, where only a single excited-state relaxation rate is used.
Comment: 10 pages, 7 figures

الوصول الحر: http://arxiv.org/abs/1506.09171Test

المؤلفون: Sargsyan, A., Sarkisyan, D., Pashayan-Leroy, Y., Leroy, C., Cartaleva, S., Wilson-Gordon, A. D., Auzinsh, M.

مصطلحات موضوعية: Physics - Atomic Physics, Physics - Optics

الوصف: The electromagnetically induced transparency (EIT) phenomenon has been investigated in a $\Lambda$-system of the $^{87}$Rb D$_1$ line in an external transverse magnetic field. Two spectroscopic cells having strongly different values of the relaxation rates $\gamma_{rel}$ are used: a Rb cell with antirelaxation coating ($L\sim$1 cm) and a Rb nanometric-thin cell (nano-cell) with thickness of the atomic vapor column $L$=795nm. For the EIT in the nano-cell, we have the usual EIT resonances characterized by a reduction in the absorption (i.e. dark resonance (DR)), whereas for the EIT in the Rb cell with an antirelaxation coating, the resonances demonstrate an increase in the absorption (i.e. bright resonances). We suppose that such unusual behavior of the EIT resonances (i.e. the reversal of the sign from DR to BR) is caused by the influence of alignment process. The influence of alignment strongly depends on the configuration of the coupling and probe frequencies as well as on the configuration of the magnetic field.
Comment: 9 pages,23 figures

الوصول الحر: http://arxiv.org/abs/1505.03856Test

المؤلفون: Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalvans, L., Mozers, A., Spiss, A.

المصدر: Phys. Rev. A 91, 053418 (2015)

مصطلحات موضوعية: Physics - Atomic Physics

الوصف: We studied alignment-to-orientation conversion caused by excited-state level crossings in a nonzero magnetic field of both atomic rubidium isotopes. Experimental measurements were performed on the transitions of the $D_2$ line of rubidium. These measured signals were described by a theoretical model that takes into account all neighboring hyperfine transitions, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. In the experiments laser induced fluorescence (LIF) components were observed at linearly polarized excitation and their difference was taken afterwards. By observing the two oppositely circularly polarized components we were able to see structures not visible in the difference graphs, which yields deeper insight into the processes responsible for these signals. We studied how these signals are dependent on laser power density and how they are affected when the exciting laser is tuned to different hyperfine transitions. The comparison between experiment and theory was carried out fulfilling the nonlinear absorption conditions.
Comment: 11 pages, 13 figures

الوصول الحر: http://arxiv.org/abs/1503.03334Test

المؤلفون: Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalnins, U., Kalvans, L., Rundans, R., Sarkisyan, D.

المصدر: Phys. Rev. A 91, 023410 (2015)

مصطلحات موضوعية: Physics - Atomic Physics

الوصف: We have measured magneto-optical signals obtained by exciting the $D_1$ line of cesium atoms confined to an extremely thin cell (ETC), whose walls are separated by less than one micrometer, and developed an improved theoretical model to describe these signals with experimental precision. The theoretical model was based on the optical Bloch equations and included all neighboring hyperfine transitions, the mixing of the magnetic sublevels in an external magnetic field, and the Doppler effect, as in previous studies. However, in order to model the extreme conditions in the ETC more realistically, the model was extended to include a unified treatment of transit relaxation and wall collisions with relaxation rates that were obtained directly from the thermal velocities of the atoms and the length scales involved. Furthermore, the interaction of the atoms with different regions of the laser beam were modeled separately to account for the varying laser beam intensity over the beam profile as well as saturation effects that become important near the center of the beam at the relatively high laser intensities used during the experiments in order to obtain measurable signals. The model described the experimentally measured signals for laser intensities for magnetic fields up to 55~G and laser intensities up to 1~W/cm$^2$ with excellent agreement.
Comment: 9 pages, 7 figures

الوصول الحر: http://arxiv.org/abs/1411.2750Test

المؤلفون: Bergmann, K, Nägerl, HC, Panda, C, Gabrielse, G, Miloglyadov, E, Quack, M, Seyfang, G, Wichmann, G, Ospelkaus, S, Kuhn, A, Longhi, S, Szameit, A, Pirro, P, Hillebrands, B, Zhu, XF, Zhu, J, Drewsen, M, Hensinger, WK, Weidt, S, Halfmann, T, Wang, HL, Paraoanu, GS, Vitanov, NV, Mompart, J, Busch, T, Barnum, TJ, Grimes, DD, Field, RW, Raizen, MG, Narevicius, E, Auzinsh, M, Budker, D, Pálffy, A, Keitel, CH

المساهمون: Department of Mechanical Engineering

مصطلحات موضوعية: Acoustic waves, Molecular Rydberg states, Nuclear coherent population transfer, Parity violation, Spin waves, Stimulated Raman adiabatic passage (STIRAP), Ultracold molecules

الوصف: 202209 bckw ; Version of Record ; RGC ; Others ; National Natural Science Foundation of China ; Published ; CC

العلاقة: http://hdl.handle.net/10397/95316Test; 52; 20; 2-s2.0-85075640126; 202001; RGC-B2-1468

الإتاحة: https://doi.org/10.1088/1361-6455/ab3995Test
http://hdl.handle.net/10397/95316Test

المؤلفون: Rochester, S, Pustelny, S, Szymański, K, Raizen, M, Auzinsh, M, Budker, D

المصدر: Proceedings of SPIE - The International Society for Optical Engineering. 9763(4)

مصطلحات موضوعية: physics.atom-ph

الوصف: We present a novel technique of efficient optical pumping of open, high-angular-momentum systems. The method combines two well-established approaches of population manipulation (conventional optical pumping and coherent population transfer), offering the ability to achieve higher population of a sublevel with the highest or lowest quantum number m (the "end state") than obtainable with either of the techniques. To accomplish this task, we propose to use coherent-population-transfer technique (e.g., adiabatic fast passage) to arrange the system in such a way that spontaneously emitted photon (conventional optical pumping) carries away more entropy than in conventional schemes. This enables reduction of a number of spontaneous decays Nsd required to pump the system with the total angular momentum J from Nsd = J decays in the conventional scheme to Nsd ≤ log2(2J) decays in the proposed scheme. Since each spontaneous-emission event is potentially burdened with a loss of population (population is transferred to a dark state), this enables increasing population accumulated in the "end state", which is important for many applications.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/3zd3k2b8Test