0000000000002012
AUTHOR
David Sarkisyan
showing 19 related works from this author
Nonlinear magneto-optical resonances atD1excitation ofRb85andRb87in an extremely thin cell
2010
Nonlinear magneto-optical resonances have been measured in an extremely thin cell (ETC) for the ${D}_{1}$ transition of rubidium in an atomic vapor of natural isotopic composition. All hyperfine transitions of both isotopes have been studied for a wide range of laser power densities, laser detunings, and ETC wall separations. Dark resonances in the laser induced fluorescence (LIF) were observed as expected when the ground-state total angular momentum ${F}_{g}$ was greater than or equal to the excited-state total angular momentum ${F}_{e}$. Unlike the case of ordinary cells, the width and contrast of dark resonances formed in the ETC dramatically depended on the detuning of the laser from th…
Hyperfine Paschen-Back regime realized in Rb nanocell
2012
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 D1 line in 0.5 - 0.7 T magnetic field. Experimental results are perfectly consistent with the theory. In particular, with sigma+ laser excitation, the slopes of B-field dependence of frequency shift for all the 10 individual transitions of 85,87Rb 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.
Magnetic Field Gradiometer with Sub-Micron Spatial Resolution Based on Caesium Vapour in an Extremely Thin Cell
2015
Abstract In this paper we present a device for measuring the magnetic field and its gradient with a spatial resolution of several hundred nanometres. This device is based on caesium metal vapour confined to an extremely thin cell (ETC). To measure magnetic signals, we use absorption and very low laser powers, which might be appealing for modern fabrication techniques. A portable, fully automated device was constructed.
Circular dichroism in atomic vapors: magnetically induced transitions responsible for two distinct behaviors
2021
Atomic transitions of alkali metals for which the condition $F_e-F_g = \pm2$ is satisfied have null probability in a zero magnetic field, while a giant increase can occur when an external field is applied. Such transitions, often referred to as magnetically-induced (MI) transitions, have received interest because their high probabilities in wide ranges of external magnetic fields which, in some cases, are even higher than that of usual atomic transitions. Previously, the following rule was established: the intensities of MI transitions with $\Delta F=\pm2$ are maximum when using respectively $\sigma^\pm$ radiation. Within the same ground state, the difference in intensity for $\sigma^+$ and…
SELECTIVE AMPLIFICATION OF NARROW RESONANCE FORMED IN TRANSMISSION SPECTRUM OF Rb NANO-CELL IN MAGNETIC FIELD
2012
Recently it was shown that "λ-Zeeman Technique" (λ-ZT) is a convenient tool to study individual transitions between the Zeeman sublevels of hyperfine levels in an external magnetic field. λ-ZT is based on resonant transmission spectrum of nanometric thin cell (NTC) of thickness L = λ, where λ is the resonant wavelength 794 nm for Rb D1 line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field. Examination of VSOP resonances allows one to identify and investigate an atomic transition in the range of magnetic fields 10 - 5000 G. Here we present a new method for selective addressing of VSOP r…
Circular dichroism of magnetically induced transitions for D 2 lines of alkali atoms
2018
In this letter we study magnetic circular dichroism in alkali atoms exhibiting asymmetric behaviour of magnetically induced transitions. The magnetic field induces transitions between hyperfine levels of alkali atoms and in the range of magnetic field, the intensities of these transitions experience significant enhancement. We have inferred a general rule applicable for the D 2 lines of all alkali atoms, that is the transition intensity enhancement is around four times larger for the case of than for excitation for , whereas it is several hundreds of thousand times larger in the case of than that for polarization for . This asymmetric behaviour results in circular dichroism. For experimenta…
High-contrast dark resonances on the D1 line in cesium nanocell: the advantages compared with the other alkali D lines
2015
Electromagnetically induced transparency (EIT) effect in a -system formed by Cs atoms line, enclosed in nanometric-thin cells, is studied both experimentally and theoretically for the first time. T...
Hyperfine Paschen-Back regime in alkali metal atoms: consistency of two theoretical considerations and experiment
2013
Simple and efficient "\lambda-method" and "\lambda/2-method" (\lambda is the resonant wavelength of laser radiation) based on nanometric-thickness cell filled with rubidium are implemented to study the splitting of hyperfine transitions of 85Rb and 87Rb D_1 line in an external magnetic field in the range of B = 0.5 - 0.7 T. It is experimentally demonstrated from 20 (12) Zeeman transitions allowed at low B-field in 85Rb (87Rb) spectra in the case of \sigma+ polarized laser radiation, only 6 (4) remain at B > 0.5 T, caused by decoupling of the total electronic momentum J and the nuclear spin momentum I (hyperfine Paschen-Back regime). The expressions derived in the frame of completely uncoupl…
Fluorescence of rubidium in a submicrometer vapor cell: spectral resolution of atomic transitions between Zeeman sublevels in a moderate magnetic fie…
2005
It is experimentally demonstrated that use of an extremely thin cell (ETC) with the thickness of a Rb atomic vapor column of ∼400 nm allows one to resolve a large number of individual transitions between Zeeman sublevels of the D1 line of 87Rb and 85Rb in the sub-Doppler fluorescence excitation spectra in an external magnetic field of ∼200 G. It is revealed that due to the peculiarities of the Zeeman effect for different hyperfine levels of Rb, all allowed transitions between magnetic sublevels can be clearly resolved for 87RbF_g = 1 --> F_e = 1, 2 and F_g = 2 --> F_e = 1, 2 fluorescence excitation. Also, relatively good spectral resolution can be achieved for 85RbF_g = 2 --> F_e = 2, 3 flu…
Electromagnetically Induced Transparency and optical pumping processes formed in Cs sub-micron thin cell
2012
Abstract The Electromagnetically Induced Transparency (EIT) effect in a Λ -system formed by Cs atoms (6 S 1/2 − 6 P 3/2 − 6 S 1/2 ) confined in an extremely thin cell (ETC) (atomic column thickness L varies in the range of 800 nm –3 µm is studied both experimentally and theoretically. It is demonstrated that when the coupling laser frequency is in exact resonance with the corresponding atomic transition, the EIT resonance parameters weakly depend on L , which allows us to detect the effect at L = λ = 852 nm. EIT process reveals a striking peculiarity in case of the coupling laser detuned by Δ from the atomic transition, namely the width of the EIT resonance rapidly increases upon an in…
Complete hyperfine Paschen-Back regime at relatively small magnetic fields realized in potassium nano-cell
2015
A one-dimensional nano-metric-thin cell (NC) filled with potassium metal has been built and used to study optical atomic transitions in external magnetic fields. These studies benefit from the remarkable features of the NC allowing one to use $\lambda/2$- and $\lambda$-methods for effective investigations of individual transitions of the K D_1 line. The methods are based on strong narrowing of the absorption spectrum of the atomic column of thickness L equal to $\lambda/2$ and to $\lambda$(with $\lambda = 770\un{nm}$ being the resonant laser radiation wavelength). In particular, for a $\pi$-polarized radiation excitation the $\lambda$-method allows us to resolve eight atomic transitions (in…
Relaxation mechanisms affecting magneto-optical resonances in an extremely thin cell: Experiment and theory for the cesiumD1line
2015
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 wi…
High-Spatial-Resolution Monitoring of Strong Magnetic Field using Rb vapor Nanometric-Thin Cell
2011
We have implemented the so-called $\lambda$-Zeeman technique (LZT) to investigate individual hyperfine transitions between Zeeman sublevels of the Rb atoms in a strong external magnetic field $B$ in the range of $2500 - 5000$ G (recently it was established that LZT is very convenient for the range of $10 - 2500$ G). Atoms are confined in a nanometric thin cell (NTC) with the thickness $L = \lambda$, where $\lambda$ is the resonant wavelength 794 nm for Rb $D_1$ line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field with the frequency positions and transition probabilities depending on th…
Atomic transitions of Rb, D2 line in strong magnetic fields: Hyperfine Paschen–Back regime
2014
An efficient $\lambda/2$-method ($\lambda$ is the resonant wavelength of laser radiation) based on nanometric-thickness cell filled with rubidium is implemented to study the splitting of hyperfine transitions of $^{85}$Rb and $^{87}$Rb $D_2$ lines in an external magnetic field in the range of $B =3$~kG -- 7~kG. It is experimentally demonstrated that at $B > 3$~kG from 38 (22) Zeeman transitions allowed at low $B$-field in $^{85}$Rb ($^{87}$Rb) spectra in the case of $\sigma^+$ polarized laser radiation there remain only 12 (8) which is caused by decoupling of the total electronic momentum $\textbf{J}$ and the nuclear spin momentum $\textbf{I}$ (hyperfine Paschen-Back regime). Note that at $…
Electromagnetically induced transparency resonances inverted in magnetic field
2015
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. br…
Collapse and revival of a Dicke-type coherent narrowing in potassium vapor confined in a nanometric-thin cell
2015
A nanometer-thin-cell (in the direction of laser beam propagation) has been elaborated with the thickness of the atomic vapor column varying smoothly in the range of $L = \unit[50-1500]{nm}$. The cell allows one to study the behavior of the resonance absorption over the $D_1$ line of potassium atoms by varying the laser intensity and the cell thickness from $L = \lambda / 2$ to $L = 2 \lambda$ with the step $\lambda/2$ ($\lambda =\unit[770]{nm}$ is the resonant wavelength of the laser). It is shown that despite the huge Doppler broadening ($>\unit[0.9]{GHz}$ at the cell temperature $\unit[170]{^{\circ}C}$), at low laser intensities a narrowing of the resonance absorption spectrum is observe…
Essential features of optical processes in neon-buffered submicron-thin Rb vapor cell
2010
A new submicron thin cell (STC) filled with Rb and neon gas is developed and comparison of resonant absorption with STC containing pure Rb is provided. The effect of collapse and revival of Dicke-type narrowing is still observable for the thickness L = lambda /2 and L = lambda , where lambda is a resonant laser wavelength 794 nm (D(1) line). For an ordinary Rb cm-size cell with addition of buffer gas, the velocity selective optical pumping/saturation (VSOP) resonances in saturated absorption spectra are fully suppressed if neon pressure0.5 Torr. A spectacular difference is that for L = lambda , VSOP resonances are still observable even when neon pressure isor = 6 Torr. Narrow fluorescence s…
Magnetic field-induced mixing of hyperfine states of Cs 6 2^P_{3/2} level observed with a sub-micron vapor cell
2003
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 spa…
A method for the quantitative study of atomic transitions in a magnetic field based on an atomic vapor cell with L=lambda
2008
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.