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Search Results: 1 - 10 of 53070 matches for " David Sarkisyan "
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An Alkali-Vapor Cell with Metal Coated Windows for Efficient Application of an Electric Field
David Sarkisyan,A. S. Sarkisyan,Jocelyne Guéna,Michel Lintz,Marie-Anne Bouchiat
Physics , 2005, DOI: 10.1063/1.1914780
Abstract: We describe the implementation of a cylindrical T-shaped alkali-vapor cell for laser spectroscopy in the presence of a longitudinal electric field. The two windows are used as two electrodes of the high-voltage assembly, which is made possible by a metallic coating which entirely covers the inner and outer sides of the windows except for a central area to let the laser beams in and out of the cell. This allows very efficient application of the electric field, up to 2 kV/cm in a rather dense superheated vapor, even when significant photoemission takes place at the windows during pulsed laser irradiation. The body of the cell is made of sapphire or alumina ceramic to prevent large currents resulting from surface conduction observed in cesiated glass cells. The technique used to attach the monocrystalline sapphire windows to the cell body causes minimal stress birefringence in the windows. In addition, reflection losses at the windows can be made very small. The vapor cell operates with no buffer gas and has no magnetic part. The use of this kind of cell has resulted in an improvement of the signal-to-noise ratio in the measurement of Parity Violation in cesium vapor underway at ENS, Paris. The technique can be applied to other situations where a brazed assembly would give rise to unacceptably large birefringence in the windows.
Effect of buffer gas on electromagnetically induced transparency in a ladder system using thermal rubidium vapor
Armen Sargsyan,David Sarkisyan,Ulrich Krohn,James Keaveney,Charles Adams
Physics , 2010, DOI: 10.1103/PhysRevA.82.045806
Abstract: We report on the first observation of electromagnetically induced transparency (EIT) in a ladder system in the presence of a buffer gas. In particular we study the 5S1/2 - 5P3/2 - 5D5/2 transition in thermal rubidium vapor with a neon buffer gas at a pressure of 6 Torr. In contrast to the line narrowing effect of buffer gas on {\Lambda}-systems we show that the presence of the buffer gas leads to an additional broadening of (32 +/- 5) MHz, which suggests a cross section for Rb(5D5/2)-Ne of {\sigma} = (7 +/- 1) x 10-19 m2. However, in the limit where the coupling Rabi frequency is larger than k the collisional dephasing a strong transparency feature can still be observed.
Nonlinear magneto-optical effects in Ba vapor
Irina Novikova,Alexander Khanbekyan,David Sarkisyan,George R. Welch
Physics , 2004,
Abstract: We report the first measurements of linear and nonlinear magneto-optical polarization rotation on an intercombination transition of Ba vapor (lambda= 791.1nm). We observe a maximum polarization rotation angle in Faraday configuration of 15mrad, accompanied by suppression of absorption. A theoretical treatment of the nonlinear Faraday effect in the limit of a strong interacting light field is developed.
N -resonances in a buffered micrometric Rb cell: splitting in a strong magnetic field
Armen Sargsyan,Rafayel Mirzoyan,Aram Papoyan,David Sarkisyan
Physics , 2012, DOI: 10.1364/OL.37.004871
Abstract: N -resonances excited in rubidium atoms confined in micrometric-thin cells with variable thickness from 1 {\mu}m 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 {\mu}m. The higher amplitude and sharper profile of N-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.
Selective Reflection Spectroscopy at the Interface between a Calcium Fluoride Window and Cs Vapour
Athanasios Laliotis,Isabelle Maurin,Michèle Fichet,Daniel Bloch,Martial Ducloy,Nikolay Balasanyan,Asphet Sarkisyan,David Sarkisyan
Physics , 2007, DOI: 10.1007/s00340-007-2927-9
Abstract: A special vapour cell has been built, that allows the measurement of the atom-surface van der Waals interaction exerted by a CaF2 window at the interface with Cs vapour. Mechanical and thermal fragility of fluoride windows make common designs of vapour cells unpractical, so that we have developed an all-sapphire sealed cell with an internal CaF2 window. Although impurities were accidentally introduced when filling-up the prototype cell, leading to a line-broadening and shift, the selective reflection spectrum on the Cs D1 line (894 nm) makes apparent the weak van der Waals surface interaction. The uncertainties introduced by the effects of these impurities in the van der Waals measurement are nearly eliminated when comparing the selective reflection signal at the CaF2 interface of interest, and at a sapphire window of the same cell. The ratio of the interaction respectively exerted by a sapphire interface and a CaF2 interface is found to be 0.55 $\pm$ 0.25, in good agreement with the theoretical evaluation of ~0.67.
Selective reflection spectroscopy of a vapour at a calcium fluoride interface
Thierry Passerat De Silans,Athanasios Laliotis,Marco Romanelli,Pedro Chaves De Souza Segundo,Isabelle Maurin,Daniel Bloch,Martial Ducloy,Asphet Sarkisyan,David Sarkisyan
Physics , 2007, DOI: 10.1051/anphys:2008040
Abstract: Fluoride materials exhibit surface resonances located in the thermal infrared. This makes them interesting to search for a fundamental temperature dependence of the atom-surface interaction, originating in the near-field thermal emissivity of the surface. Preliminary selective reflection experiments performed on a special Cs vapour cell that includes a CaF2 interface show a temperature dependence, yet to be analyzed
A method for the quantitative study of atomic transitions in a magnetic field based on an atomic vapor cell with L=lambda
Armen Sargsyan,Grant Hakhumyan,Aram Papoyan,David Sarkisyan,Aigars Atvars,Marcis Auzinsh
Physics , 2008,
Abstract: We describe the so-called "Lambda-Zeeman method" to investigate individual hyperfine transitions between Zeeman sublevels of atoms in an external magnetic field of 0.1 mT - 0.25 T. Atoms are confined in a nanocell with thickness L = Lambda, where Lambda is the resonant wavelength (794 nm or 780 nm for D1 or D2 line of Rb). Narrow resonances in the transmission spectrum of the nanocell are split into several components in a magnetic field; their frequency positions and probabilities depend on the B-field. Possible applications are described, such as magnetometers with nanometric spatial resolution and tunable atomic frequency references.
Sub-Doppler spectroscopy of Rb atoms in a sub-micron vapor cell in the presence of a magnetic field
David Sarkisyan,Aram Papoyan,Tigran Varzhapetyan,Janis Alnis,Kaspars Blush,Marcis Auzinsh
Physics , 2003, DOI: 10.1088/1464-4258/6/3/023
Abstract: We report the first use of an extremely thin vapor cell (thickness ~ 400 nm) to study the magnetic-field dependence of laser-induced-fluorescence excitation spectra of alkali atoms. This thin cell allows for sub-Doppler resolution without the complexity of atomic beam or laser cooling techniques. This technique is used to study the laser-induced-fluorescence excitation spectra of Rb in a 50 G magnetic field. At this field strength the electronic angular momentum J and nuclear angular momentum I are only partially decoupled. As a result of the mixing of wavefunctions of different hyperfine states, we observe a nonlinear Zeeman effect for each sublevel, a substantial modification of the transition probabilities between different magnetic sublevels, and the appearance of transitions that are strictly forbidden in the absence of the magnetic field. For the case of right- and left- handed circularly polarized laser excitation, the fluorescence spectra differs qualitatively. Well pronounced magnetic field induced circular dichroism is observed. These observations are explained with a standard approach that describes the partial decoupling of I and J states.
Magnetic field-induced mixing of hyperfine states of Cs 6 2^P_{3/2} level observed with a sub-micron vapor cell
Aram Papoyan,David Sarkisyan,Kaspars Blush,Marcis Auzinsh,Daniel Bloch,Martial Ducloy
Physics , 2003,
Abstract: The fluorescence spectra of a sub-micron atomic cesium vapor layer observable under resonant excitation on D2 line have been studied in the presence of an external magnetic field. Substantial changes in amplitudes and frequency positions of the individual (resolved) hyperfine transitions have been recorded in moderate magnetic fields (up to ~ 50 Gauss). These features are caused by mixing of the hyperfine states of the upper level resulting from comparable values of the hyperfine splitting of the 62^P_{3/2} manifold and Larmor frequencies of the magnetic sublevels. The results of simulation show a good agreement with the experimental spectra. Possible application of the results for high spatial resolution magnetometry is discussed.
Optical transmission through a dipolar layer
James Keaveney,Armen Sargsyan,Ulrich Krohn,Julia Gontcharov,Ifan G. Hughes,David Sarkisyan,Charles S. Adams
Physics , 2011,
Abstract: The interaction between light and matter is fundamental to developments in quantum optics and information. Over recent years enormous progress has been made in controlling the interface between light and single emitters including ions, atoms, molecules, quantum dots and ensembles. For many systems, inter-particle interactions are typically negligible. However, if the emitters are separated by less than the emission wavelength, resonant dipole--dipole interactions modify the radiative decay rate and induce a splitting or shift of the resonance. Here we map out the transition between individual dipoles and a strongly interacting ensemble by increasing the density of atoms confined in a layer with thickness much less than the emission wavelength. We find two surprising results: whereas for a non-interacting ensemble the opacity increases linearly with atomic density, for an interacting ensemble the opacity saturates, i.e., a thin dipolar layer never becomes opaque regardless of how many scatterers are added. Secondly, the relative phase of the dipoles produces an abrupt change in the optical transmission around the thickness \lambda/4.
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