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Saturated absorption and electromagnetically induced transparency of residual rubidium in dense cesium vapor
Authors:
Armen Sargsyan,
Anahit Gogyan,
David Sarkisyan
Abstract:
In the sealed-off cesium vapor cell studied in this work, a residual rubidium fraction of approximately $\sim$1\% was observed. We investigate the optical response of these trace Rb atoms in a sealed 1~cm long Cs-filled vapor cell. Despite the low concentration, laser excitation at 795~nm allows the observation of saturated absorption and electromagnetically induced transparency (EIT) resonances.…
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In the sealed-off cesium vapor cell studied in this work, a residual rubidium fraction of approximately $\sim$1\% was observed. We investigate the optical response of these trace Rb atoms in a sealed 1~cm long Cs-filled vapor cell. Despite the low concentration, laser excitation at 795~nm allows the observation of saturated absorption and electromagnetically induced transparency (EIT) resonances. The surrounding Cs vapor effectively acts as a buffer medium, reducing the Rb atomic velocity and increasing the interaction time with the laser field, which improves the EIT signal. The experiments are performed in an all-sapphire cell that can be heated up to 500$^{\circ}$C without window blackening, unlike conventional glass cells. From the measured spectra, Cs--Rb collisional cross sections are estimated. These results show that residual atomic species in high-temperature vapor cells can be exploited for spectroscopic and nonlinear-optical studies.
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Submitted 10 March, 2026;
originally announced March 2026.
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Features of the van der Waals Interaction on the Cesium $6S_{1/2} \rightarrow 7P_{3/2}$ Transition in an Optical Nanocell
Authors:
Armen Sargsyan,
Anahit Gogyan,
David Sarkisyan
Abstract:
We report the first experimental study of the influence of a dielectric surface on the transmission spectrum of cesium atoms for the $6S_{1/2} \rightarrow 7P_{3/2}$ ($D_2$) transition in vapor cells with thicknesses in the range $50$-$250\,$nm. The measurements were performed using a homemade optical nanocell filled with atomic cesium and featuring a wedge-shaped gap between the inner surfaces of…
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We report the first experimental study of the influence of a dielectric surface on the transmission spectrum of cesium atoms for the $6S_{1/2} \rightarrow 7P_{3/2}$ ($D_2$) transition in vapor cells with thicknesses in the range $50$-$250\,$nm. The measurements were performed using a homemade optical nanocell filled with atomic cesium and featuring a wedge-shaped gap between the inner surfaces of sapphire windows. For atom-surface distances below approximately $300$\,nm, a significant red shift of the atomic transition frequency is observed due to van der Waals (vdW) interactions with the dielectric surface. An additional red shift arises at high vapor pressures owing to Cs-Cs interactions, with a measured contribution of $15$\,MHz/Torr, which must be accounted for in order to correctly determine the vdW coefficient $C_3$. By recording transmission spectra of the nanocell at different thicknesses, we determine for the first time the vdW coefficient for the Cs $6S_{1/2} \rightarrow 7P_{3/2}$ transition, obtaining values in the range $C_3 \sim 2- 20$\,kHz\,$μ$m$^3$. These results are of interest for fundamental studies of atom-surface interactions and are also relevant for the development of miniature sensors based on atomic vapors, in particular compact frequency references exploiting atomic transitions in the blue spectral region.
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Submitted 8 January, 2026;
originally announced January 2026.
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Second-order correlations in directed emissions in sodium atoms
Authors:
Ara Tonoyan,
Sushree Subhadarshinee Sahoo,
Anahit Gogyan,
Oleg Tretiak,
Razmik Aramyan,
Alexander Akulshin,
Dmitry Budker
Abstract:
We report on measurements of second-order intensity correlations $g^{(2)}(τ)$ of infrared emission under bichromatic excitation at 589.2\,nm and 569.0\,nm of sodium atoms contained in a buffer-gas-free and uncoated 10-cm-long vapor cell. Directional emissions at $2.34\,μ$m in the forward direction and $2.21\,μ$m in both forward and backward directions under different experimental parameters are co…
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We report on measurements of second-order intensity correlations $g^{(2)}(τ)$ of infrared emission under bichromatic excitation at 589.2\,nm and 569.0\,nm of sodium atoms contained in a buffer-gas-free and uncoated 10-cm-long vapor cell. Directional emissions at $2.34\,μ$m in the forward direction and $2.21\,μ$m in both forward and backward directions under different experimental parameters are considered for this study. The measured values of $g^{(2)}(0)$ in all cases are found to exceed unity, while remaining significantly below the thermal light limit of 2. Cross-correlation measurements reveal that forward- and backward-propagating $2.21\,μ$m radiations are correlated. Oscillatory features in $g^{(2)}(τ)$ are observed over a broad range of excitation powers, and the dependence of the oscillation frequency on laser power can be attributed to AC Stark shifts, with contributions from hyperfine atomic structure in selected atomic velocity groups even in the presence of Doppler broadening. Our study establishes that the observed mid-infrared emission arises from a phase-matched, continuous-wave cooperative process that combines features of lasing and collective amplified spontaneous emission. The results highlight the buildup of long-range dipole coherence and velocity-selective coupling of atomic groups, which together govern the observed photon correlations and forward-backward emission symmetry. The demonstrated backward emission is of particular interest for applications in laser guidestar generation and mesospheric remote sensing, where understanding the statistical properties of the emitted light is essential for optimizing sodium-based light sources.
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Submitted 15 November, 2025;
originally announced November 2025.
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Blue laser induced bright red fluorescence in hot cesium vapor
Authors:
Armen Sargsyan,
Anahit Gogyan,
David Sarkisyan
Abstract:
We have observed laser-induced fluorescence using 456 nm laser radiation, resonant with the 6S1/2-7P3/2 transition in Cs atoms. It includes red emission lines in the range of 580-730 nm and a prominent line at 852 nm corresponding to the 6P3/2-6S1/2 transition. A T-shaped all-sapphire cell with a length of 1 cm, containing Cs atomic vapor and capable of being heated up to 500 oC, was used. The las…
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We have observed laser-induced fluorescence using 456 nm laser radiation, resonant with the 6S1/2-7P3/2 transition in Cs atoms. It includes red emission lines in the range of 580-730 nm and a prominent line at 852 nm corresponding to the 6P3/2-6S1/2 transition. A T-shaped all-sapphire cell with a length of 1 cm, containing Cs atomic vapor and capable of being heated up to 500 oC, was used. The laser-induced fluorescence (LIF) power at 852 nm was investigated as a function of the cell temperature. The maximum LIF power was achieved at 130 oC, while a significant decrease was observed around 300 oC. At 130 oC, the Doppler-broadened LIF spectrum at 852 nm exhibited self-conversion, resulting in the formation of two distinct peaks within the spectrum. The LIF power at 852 nm was also studied as a function of the 456 nm radiation power. The Cs cell demonstrated potential as an efficient optical filter and down-converter, effectively transforming 456 nm radiation into 852 nm radiation.
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Submitted 26 December, 2024;
originally announced December 2024.
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Experimental Investigation of Electromagnetically Induced Transparency in Selective Reflection Spectra
Authors:
Armen Sargsyan,
Anahit Gogyan,
David Sarkisyan
Abstract:
We have investigated electromagnetically induced transparency in the spectrum of selective reflection at the interface of Rb atom vapors and a dielectric nanocell window. A nanocell with atomic vapor column thicknesses ranging from 150 to 1200 nm, as well as a 50~$μ$m thickness microcell were used. We have compared electromagnetically induced transparency observed for the cases of the selective re…
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We have investigated electromagnetically induced transparency in the spectrum of selective reflection at the interface of Rb atom vapors and a dielectric nanocell window. A nanocell with atomic vapor column thicknesses ranging from 150 to 1200 nm, as well as a 50~$μ$m thickness microcell were used. We have compared electromagnetically induced transparency observed for the cases of the selective reflection and transmission. It was demonstrated that for the thicknesses of below $\leq 1000$ nm selective reflection technique is more favorable. In contrast, for wider cells and microcells, using transmitted radiation as probe field is more effective.
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Submitted 22 June, 2024;
originally announced June 2024.
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Shaping coherent excitation of atoms and molecules by a train of ultrashort laser pulses
Authors:
Anahit Gogyan,
Stephane Guerin,
Yuri Malakyan
Abstract:
We propose a mechanism to produce a superposition of atomic and molecular states by a train of ultrashort laser pulses combined with weak control fields. By adjusting the repetition rate of the pump pulses and the intensity of the coupling laser, one can suppress a transition while simultaneously enhancing the desired transitions. As an example, various superpositions of vibrational states of the…
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We propose a mechanism to produce a superposition of atomic and molecular states by a train of ultrashort laser pulses combined with weak control fields. By adjusting the repetition rate of the pump pulses and the intensity of the coupling laser, one can suppress a transition while simultaneously enhancing the desired transitions. As an example, various superpositions of vibrational states of the $K_2$ molecule are shown.
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Submitted 17 November, 2014;
originally announced November 2014.
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Deterministic production of free-propagating Fock states of programmable photon number from a single atom-cavity system
Authors:
A. Gogyan,
S. Guerin,
C. Leroy,
Yu. Malakyan
Abstract:
We propose a mechanism for producing Fock states on demand leaking from a single mode optical cavity interacting with a single atom and a laser pulse. The number of photons can be chosen, as it is determined by the Zeeman substructure of the ground state of the atom and its initial state. The deterministic generation of a free-propagating Fock state of $1\leq n\leq2F$ photons is achieved, when a c…
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We propose a mechanism for producing Fock states on demand leaking from a single mode optical cavity interacting with a single atom and a laser pulse. The number of photons can be chosen, as it is determined by the Zeeman substructure of the ground state of the atom and its initial state. The deterministic generation of a free-propagating Fock state of $1\leq n\leq2F$ photons is achieved, when a circularly polarized laser pulse completely transfers the atomic population between Zeeman sublevels of the ground hyperfine state $F$ through far-detuned Raman scattering thus producing linearly polarized cavity photons. We describe analytically the evolution of optical field taking into account the spontaneous losses and the cavity damping. We demonstrate the possibility of production of Fock-state with different numbers of photons by using different transitions of the same atom. We show also that this technique provides a deterministic source of a train of identical multiphoton Fock-states, if a sequence of left- and right-circularly polarized laser pulses is applied. The resulting states have potential applications in quantum computation and simulation.
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Submitted 21 February, 2012;
originally announced February 2012.