Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Matched optical vortices of slow light using a tripod coherently prepared scheme

Hamid Reza Hamedi, Ite A. Yu, Emmanuel Paspalakis

Published Nov 30, 2023• 10 citations
Publisher

Abstract

This paper explores the propagation of optical vortices of slow light inside a four-level tripod atomic light-matter coupling system. Initially, the system is prepared in a coherent superposition of two out of the three lower levels by, for example, coherent population trapping, while the third lower state remains unoccupied. The unoccupied state is coupled to a strong control laser field with a constant Rabi frequency, lacking orbital angular momentum (OAM). Simultaneously, one of the remaining lower states interacts with a weak vortex beam. The third lower state has no initial coupling to any field. This arrangement effectively closes the level transitions, resulting in a phase-dependent configuration. By solving the Maxwell-Schr\"odinger equations, we provide analytical evidence that the application of a strong control field can generate an additional optical vortex of slow light. This vortex possesses the same OAM as the incident vortex beam. Furthermore, we explore the matching of optical vortices at different propagation distances, contingent upon the intensity of the control field. Additionally, our analysis extends to a more complex five-level tripod and $\mathrm{\ensuremath{\Lambda}}$ scheme, where we introduce two additional strong control fields to prepare the atoms in a coherent superposition of two lower levels.

DOI
10.1103/physreva.108.053719

Related papers

Propagation of optical vector vortices of slow light in a coherently prepared tripod configuration

Dharma P. Permana, Mažena Mackoit Sinkevičienė, Julius Ruseckas +1 more

We investigate the propagation of optical vector vortices of slow light in a coherently prepared four-level tripod atomic system. The vector vortex consists of superposed pulse pairs with opposite circular polarizations and orbital angular momentum (OAM) charges $\pm l$, weakly interacting with an atomic medium initially prepared in a coherent superposition of two ground states. A third unoccupied state is coupled to a stronger control laser without OAM, creating a phase-dependent configuration. In the linear regime, the vortex OAM is mapped onto the medium, producing symmetrical azimuthally structured absorption patterns, with losses significantly reduced by the control field. For small detunings, complementary spatially dependent amplification and absorption occur for the two circular polarization components. This OAM-structured coherence induces a dynamical anisotropy, affecting both the intensity and polarization of the slow-light vortex. Polarization states evolve periodically between left-circular, linear, and right-circular polarizations during propagation. Once the beam reaches a stationary regime, the ring-shaped intensity transforms into a petal-like structure, and the final polarization states stabilize according to the initial superposition. The rate of polarization transitions is tunable via the control field strength, demonstrating flexible control over slow-light vector vortex dynamics.

quant-pharXiv:2603.23097•Chaos Solitons & Fractals•Mar 25, 2026•0 citations

Transfer of optical vortices in coherently prepared media

Hamid Reza Hamedi, Julius Ruseckas, Emmanuel Paspalakis +1 more

We consider transfer of optical vortices between laser pulses carrying orbital angular momentum in a cloud of cold atoms characterized by the $\mathrm{\ensuremath{\Lambda}}$ configuration of the atom-light coupling. The atoms are initially prepared in a coherent superposition of the lower levels, creating a so-called phaseonium medium. If a single vortex beam initially acts on one transition of the scheme, an extra laser beam is subsequently generated with the same vorticity as that of the incident vortex beam. The absorption of the incident probe beam takes place mostly at the beginning of the atomic medium within the absorption length. The losses disappear as the probe beam propagates deeper into the medium where the atoms are transferred to their dark states. The method is extended to a tripod atom-light coupling scheme and a more general ($n+1$)-level scheme containing $n$ ground states and one excited state, allowing for creation of multiple twisted light beams. We also analyze generation of composite optical vortices in the scheme using a superposition of two initial vortex beams and study lossless propagation of such composite vortices.

arXiv:1811.10647•Physical Review A•Mar 6, 2019•80 citations

Optical vortices of slow light using tripod scheme

Julius Ruseckas, Algirdas Mekys

We consider propagation, storing and retrieval of slow light (probe beam) in a resonant atomic medium illuminated by two control laser beams of larger intensity. The probe and two control beams act on atoms in a tripod configuration of light–matter coupling. The first control beam is allowed to have an orbital angular momentum (OAM). Application of the second vortex-free control laser ensures the adiabatic (lossless) propagation of the probe beam at the vortex core where the intensity of the first control laser goes to zero. Storing and release of the probe beam is accomplished by switching off and on the control laser beams leading to the transfer of the optical vortex from the first control beam to the regenerated probe field. A part of the stored probe beam remains frozen in the medium in the form of atomic spin excitations, the number of which increases with increasing intensity of the second control laser. We analyze such losses in the regenerated probe beam and provide conditions for the optical vortex of the control beam to be transferred efficiently to the restored probe beam.

•Aug 17, 2016•30 citations

Optical vortices of slow light using a tripod scheme

J Ruseckas, A Mekys, Gediminas Juzeliūnas

We consider propagation, storing and retrieval of slow light (probe beam) in a resonant atomic medium illuminated by two control laser beams of larger intensity.The probe and two control beams act on atoms in a tripod configuration of light-matter coupling.The first control beam is allowed to have an orbital angular momentum (OAM).Application of the second vortex-free control laser ensures the adiabatic (lossless) propagation of the probe beam at the vortex core where the intensity of the first control laser goes to zero.Storing and release of the probe beam is accomplished by switching off and on the control laser beams leading to the transfer of the optical vortex from the first control beam to the regenerated probe field.A part of the stored probe beam remains frozen in the medium in the form of atomic spin excitations, the number of which increases with increasing intensity of the second control laser.We analyze such losses in the regenerated probe beam and provide conditions for the optical vortex of the control beam to be transferred efficiently to the restored probe beam.

arXiv:1104.5536•Journal of Optics•Apr 27, 2011•32 citations

Exchange of optical vortices using an electromagnetically-induced-transparency–based four-wave-mixing setup

Hamid Reza Hamedi, Julius Ruseckas, Gediminas Juzeliūnas

We propose a scheme to exchange optical vortices of slow light using the phenomenon of electromagnetically induced transparency in a four-level double-$\mathrm{\ensuremath{\Lambda}}$ atom-light coupling scheme illuminated by a pair of probe fields as well as two control fields of larger intensity. We study the light-matter interaction under the situation where one control field carries an optical vortex, and another control field has no vortex. We show that the orbital angular momentum (OAM) of the vortex control beam can be transferred to a generated probe field through a four-wave-mixing process and without switching on and off of the control fields. Such a mechanism of OAM transfer is much simpler than in a double-tripod scheme in which the exchange of vortices is possible only when two control fields carry optical vortices of opposite helicity. The losses appearing during such OAM exchange are then calculated. It is found that the one-photon detuning plays an important role in minimizing the losses. An approximate analytical expression is obtained for the optimal one-photon detuning for which the losses are minimum while the intensity of generated probe field is maximum. The influence of phase mismatch on the exchange of optical vortices is also investigated. We show that in presence of phase mismatch the exchange of optical vortices can still be efficient.

arXiv:1807.01685•Physical Review A•Jul 26, 2018•96 citations

Coherent phase control of orbital-angular-momentum light-induced torque in a double-tripod atom-light coupling scheme

Hamid R. Hamedi, Viačeslav Kudriašov, Mažena Mackoit-Sinkevičienė +1 more

We investigate a phase-controllable mechanism for generating optical torque in a five-level double-tripod (DT) atom-light coupling scheme interacting with four strong coherent control fields as well as two weak optical vortex probe beams carrying orbital angular momentum (OAM). The spatial phase gradients of the OAM-carrying probes induce a quantized torque that is transferred to the atoms, rotating them and generating a directed atomic flow within an annular geometry. Analytical solutions of the optical Bloch equations under steady-state conditions show that the induced torque and resulting rotational motion exhibit high sensitivity to phase variations. We show that the DT system coherently reconfigures into either coupled Λ or double-Λ schemes depending on the relative phases, with each configuration exhibiting distinct quantized torque characteristics. This enables precise phase control of the atomic current flow, with potential applications in quantum control, precision measurement, and quantum information processing.

quant-pharXiv:2512.17537•Physical Review A•Dec 22, 2025•1 citation
This paper explores the propagation of optical vortices of slow light inside a four-level tripod atomic light-matter coupling system. Initially, the system is prepared in a coherent superposition of two out of the three lower levels by, for example, coherent population trapping, while the third lower state remains unoccupied. The unoccupied state is coupled to a strong control laser field with a constant Rabi frequency, lacking orbital angular momentum (OAM). Simultaneously, one of the remaining lower states interacts with a weak vortex beam. The third lower state has no initial coupling to any field. This arrangement effectively closes the level transitions, resulting in a phase-dependent configuration. By solving the Maxwell-Schr"odinger equations, we provide analytical evidence that the application of a strong control field can generate an additional optical vortex of slow light. This vortex possesses the same OAM as the incident vortex beam. Furthermore, we explore the matching of optical vortices at different propagation distances, contingent upon the intensity of the control field. Additionally, our analysis extends to a more complex five-level tripod and \ensuremathΛ\mathrm{\ensuremath{\Lambda}}\ensuremathΛ scheme, where we introduce two additional strong control fields to prepare the atoms in a coherent superposition of two lower levels.
We investigate the propagation of optical vector vortices of slow light in a coherently prepared four-level tripod atomic system. The vector vortex consists of superposed pulse pairs with opposite circular polarizations and orbital angular momentum (OAM) charges ±l\pm l±l, weakly interacting with an atomic medium initially prepared in a coherent superposition of two ground states. A third unoccupied state is coupled to a stronger control laser without OAM, creating a phase-dependent configuration. In the linear regime, the vortex OAM is mapped onto the medium, producing symmetrical azimuthally structured absorption patterns, with losses significantly reduced by the control field. For small detunings, complementary spatially dependent amplification and absorption occur for the two circular polarization components. This OAM-structured coherence induces a dynamical anisotropy, affecting both the intensity and polarization of the slow-light vortex. Polarization states evolve periodically between left-circular, linear, and right-circular polarizations during propagation. Once the beam reaches a stationary regime, the ring-shaped intensity transforms into a petal-like structure, and the final polarization states stabilize according to the initial superposition. The rate of polarization transitions is tunable via the control field strength, demonstrating flexible control over slow-light vector vortex dynamics.
We consider transfer of optical vortices between laser pulses carrying orbital angular momentum in a cloud of cold atoms characterized by the $\mathrm{\ensuremath{\Lambda}}$ configuration of the atom-light coupling. The atoms are initially prepared in a coherent superposition of the lower levels, creating a so-called phaseonium medium. If a single vortex beam initially acts on one transition of the scheme, an extra laser beam is subsequently generated with the same vorticity as that of the incident vortex beam. The absorption of the incident probe beam takes place mostly at the beginning of the atomic medium within the absorption length. The losses disappear as the probe beam propagates deeper into the medium where the atoms are transferred to their dark states. The method is extended to a tripod atom-light coupling scheme and a more general (n+1n+1n+1)-level scheme containing nnn ground states and one excited state, allowing for creation of multiple twisted light beams. We also analyze generation of composite optical vortices in the scheme using a superposition of two initial vortex beams and study lossless propagation of such composite vortices.
We consider propagation, storing and retrieval of slow light (probe beam) in a resonant atomic medium illuminated by two control laser beams of larger intensity. The probe and two control beams act on atoms in a tripod configuration of light–matter coupling. The first control beam is allowed to have an orbital angular momentum (OAM). Application of the second vortex-free control laser ensures the adiabatic (lossless) propagation of the probe beam at the vortex core where the intensity of the first control laser goes to zero. Storing and release of the probe beam is accomplished by switching off and on the control laser beams leading to the transfer of the optical vortex from the first control beam to the regenerated probe field. A part of the stored probe beam remains frozen in the medium in the form of atomic spin excitations, the number of which increases with increasing intensity of the second control laser. We analyze such losses in the regenerated probe beam and provide conditions for the optical vortex of the control beam to be transferred efficiently to the restored probe beam.
We consider propagation, storing and retrieval of slow light (probe beam) in a resonant atomic medium illuminated by two control laser beams of larger intensity.The probe and two control beams act on atoms in a tripod configuration of light-matter coupling.The first control beam is allowed to have an orbital angular momentum (OAM).Application of the second vortex-free control laser ensures the adiabatic (lossless) propagation of the probe beam at the vortex core where the intensity of the first control laser goes to zero.Storing and release of the probe beam is accomplished by switching off and on the control laser beams leading to the transfer of the optical vortex from the first control beam to the regenerated probe field.A part of the stored probe beam remains frozen in the medium in the form of atomic spin excitations, the number of which increases with increasing intensity of the second control laser.We analyze such losses in the regenerated probe beam and provide conditions for the optical vortex of the control beam to be transferred efficiently to the restored probe beam.
We propose a scheme to exchange optical vortices of slow light using the phenomenon of electromagnetically induced transparency in a four-level double-$\mathrm{\ensuremath{\Lambda}}$ atom-light coupling scheme illuminated by a pair of probe fields as well as two control fields of larger intensity. We study the light-matter interaction under the situation where one control field carries an optical vortex, and another control field has no vortex. We show that the orbital angular momentum (OAM) of the vortex control beam can be transferred to a generated probe field through a four-wave-mixing process and without switching on and off of the control fields. Such a mechanism of OAM transfer is much simpler than in a double-tripod scheme in which the exchange of vortices is possible only when two control fields carry optical vortices of opposite helicity. The losses appearing during such OAM exchange are then calculated. It is found that the one-photon detuning plays an important role in minimizing the losses. An approximate analytical expression is obtained for the optimal one-photon detuning for which the losses are minimum while the intensity of generated probe field is maximum. The influence of phase mismatch on the exchange of optical vortices is also investigated. We show that in presence of phase mismatch the exchange of optical vortices can still be efficient.
We investigate a phase-controllable mechanism for generating optical torque in a five-level double-tripod (DT) atom-light coupling scheme interacting with four strong coherent control fields as well as two weak optical vortex probe beams carrying orbital angular momentum (OAM). The spatial phase gradients of the OAM-carrying probes induce a quantized torque that is transferred to the atoms, rotating them and generating a directed atomic flow within an annular geometry. Analytical solutions of the optical Bloch equations under steady-state conditions show that the induced torque and resulting rotational motion exhibit high sensitivity to phase variations. We show that the DT system coherently reconfigures into either coupled Λ or double-Λ schemes depending on the relative phases, with each configuration exhibiting distinct quantized torque characteristics. This enables precise phase control of the atomic current flow, with potential applications in quantum control, precision measurement, and quantum information processing.