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

Cold atoms in light fields: from free space optical lattices to multimode optical cavities

Arne Wickenbrock

Published Jun 28, 2012• 0 citations
OpenAlex

Abstract

The electromagnetic mode density of the vacuum can be dramatically \nmodified by the presence of an optical resonator. In the strong coupling \nregime, spontaneous emission in a cavity becomes a reversible process and \nthe intracavity photon number undergoes Rabi oscillations. We load up \nto 200x10^3 ^133Cs atoms into a nearly confocal lossy cavity and reach the \ncollective strong coupling regime. Normal mode splitting, the hallmark of this regime, is observed and cooperativities up to C_coll = (186±5) are measured. In a second experiment we investigate for the first time \nthe multi-mode character of the coupled cavity-atom system. In a confocal \ncavity the higher-order transverse cavity modes are degenerate in frequency and accessible to the spontaneous emission of the atomic ensemble. \nWe observe an increase of the coupling constant measured via modal decomposed transmission analysis, which could be attributed to \nthe presence of the higher-order modes. Normal mode splitting proportional to the square root of the atom number was visible for all of the \ndifferent mode components. Furthermore, we observe a redistribution of the relative weights in the modal transmission composition, which scales with the atom number in the cavity mode. \nIn a second set of experiments, ^87Rb atoms were loaded into a dissipative \nlin ⊥ lin lattice. By driving the lattice with a biharmonic force, transport can be observed when the systems symmetries are broken: the so called ratchet effect. Research in this area is concerned with the appearance \nof current reversals. We were able to identify dissipation related symmetry breaking as the underlying cause of an observed current reversal, which occurs as a function of the driving frequency. Furthermore, in a \nsecond experiment, we use the ratchet effect as a probe of the optical potential depths. We show that an oscillating force with a frequency far above any other system-inherent timescale, can be used to renormalize \nthe optical potential. The ^87Rb atoms experience an average position dependent force, which becomes controllable over the amplitude of the \napplied driving.

Related papers

Transport of cold atoms in laser fields

NA Abdulwahhab

This thesis describes three experiments with cold rubidium atoms. The first experiment implements a rocking ratchet with cold atoms in driven dissipative optical lattices, and explores a fundamental feature of ratchets: current reversals. It precisely investigates current reversals as observed by varying the driving frequency. It is found that this kind of current reversal in the frequency domain is determined by dissipation-induced symmetry breaking. The second experiment explores vibrational mechanics for a system of cold atoms in an optical lattice. A high frequency strong driving field was applied in order to renormalise the optical potential. It was observed that the amplitude of the potential is indeed renormalised and can be controlled by the high frequency driving field. This is detected by two methods: via the study of the diffusion properties and via the observation of the directed transport. The final experiment is the realisation and characterisation of a Bose-Einstein condensate of rubidium atoms.

•Jan 28, 2015•1 citation

Cold atoms in a ring cavity

Lawrence Mudarikwa

An ensemble of atoms coupled to a high finesse optical cavity is an ideal test bed for the study of the cooperative behaviour of atom-photon systems. Dicke showed that an ensemble of excited atoms coupled to a light field interacts with the light in a collective and coherent fashion leading to the emission of highly directional spontaneous emission whose intensity scales with the square of the number of atoms, a phenomenon known as superradiance. \nThis thesis describes the build of an experiment to study cooperative atom-photon interactions in a ring cavity. Particular focus is given to the cavities used in the experiment. Firstly a transfer cavity used for transferring stability to off-resonant lasers in the experiment, this was developed with the capability of exploiting Gouy phase degeneracies to produce tightly spaced frequency discriminants to be used as lock points. Secondly the ring cavity for the experiment which is atypical in its design allowing for bidirectional probing of the cavity mode and dynamic manipulation of the intra-cavity optical lattice. An intra-cavity MOT was produced and collective strong coupling was observed in the cavity with an Neff=6400 atoms coupled to the cavity mode.

•Jul 1, 2015•0 citations

Cavity quantum electrodynamics with strong coupling in the optical domain

G. Rempe, R. J. Thompson, R. J. Brecha +1 more

The radiative properties of atoms inside an optical cavity can be dramatically changed with respect to those in free space. In the strong-coupling limit, the reversible dipole interaction between an atom and the cavity field dominates the irreversible decay resulting from spontaneous emission and cavity damping. In this limit the atom and field can no longer be regarded as separate quantities but instead form a composite dynamic system. To enhance the dipole coupling constant and increase the photon storage time, our experiments are performed with a small cavity 1 mm long, with a finesse of 8 × 104. On average, 0.4 photons are sufficient to saturate the resonance transition at 852 nm for the cesium atoms used, while the cooperativity parameter for a single atom is 2. Optical bistability is studied in this system over the range 3 < N < 65 atoms inside the cavity, with the semiclassical theory predicting bistability for N > 5. We report observations of manifestly quantum effects in this regime, including photon antibunching and sub-Poissonian photon statistics, with the magnitude of these nonclassical effects observed to be largely independent of the number of intracavity atoms.

Annual Meeting Optical Society of America•Jan 1, 1991•0 citations

Normal Mode Splitting and Mechanical Effects of an Optical Lattice in a Ring Cavity

Julian Klinner, M. Lindholdt, Boris Nagorny +1 more

A novel regime of atom-cavity physics is explored, arising when large atom samples dispersively interact with high-finesse optical cavities. A stable far-detuned optical lattice of several million rubidium atoms is formed inside an optical ring resonator by coupling equal amounts of laser light to each propagation direction of a longitudinal cavity mode. An adjacent longitudinal mode, detuned by about 3 GHz, is used to perform probe transmission spectroscopy of the system. The atom-cavity coupling for the lattice beams and the probe is dispersive and dissipation results only from the finite photon-storage time. The observation of two well-resolved normal modes demonstrates the regime of strong cooperative coupling. The details of the normal mode spectrum reveal mechanical effects associated with the retroaction of the probe upon the optical lattice.

arXiv:quant-ph/0512121•Physical Review Letters•Jan 19, 2006•94 citations

Mechanical effects of light in optical resonators

P. Domokos, Helmut Ritsch

We review the modifications and implications of the effect of light forces on atoms when the field is enclosed in an optical resonator of high finesse. The systems considered range from a single atom strongly coupled to a single mode of a high-Q microcavity to a large ensemble of atoms in a highly degenerate quasi-confocal resonator. We set up general models that allow us to obtain analytic expressions for the optical potential, friction, and diffusion. In the bad-cavity limit the modified cooling properties can be attributed to the spectral modifications of light absorption and spontaneous emission in a form of generalized and enhanced Doppler cooling. For the strong coupling regime in a good cavity, we identify the dynamical coupling between the light field intensity and the atomic motion as the central mechanism underlying the cavity-induced cooling. The dynamical cavity cooling, which does not rely on spontaneous emission, can be enhanced by multimode cavity geometries because of the effect of coherent photon redistribution between different modes. The model is then generalized to include several distinct frequencies to account for more general trap geometries. Finally we show that the field-induced buildup of correlations between the motion of different particles plays a central role in the scaling behavior of the system. Depending on the geometry and parameters, its effect ranges from strong destructive interference, slowing down the cooling process, to self-organized crystallization, implying atomic self-trapping and faster cooling to lower temperatures by cooperative coherent scattering.

Journal of the Optical Society of America B•May 1, 2003•191 citations

Normal-mode splitting of four-level atom-cavity system under collective strong coupling

Zheng Tan, Liyong Wang, Min Liu +3 more

We investigate the transmission spectrum of an optical cavity coupled with four-level atoms. Multiple normal-mode splitting peaks of the strongly coupled atom-cavity system are obtained as single cavity mode couples three separated atomic transitions simultaneously. We employ a confocal optical cavity and an ensemble of cold Rb-85 atoms for cavity quantum electrodynamics. We observe four normal-mode splitting peaks of the cavity transmission in the strong coupling regime due to collective enhancement of the atom-cavity coupling strength by ensemble of cold atoms. The experimental observations are consistent with the theoretical analysis. The multiple normal-mode excitation in the strongly coupled multi-level atom-cavity system may lead to practical application for realizing multi-channel all-optical devices.

arXiv:1901.00127•Jan 1, 2019•5 citations
The electromagnetic mode density of the vacuum can be dramatically \nmodified by the presence of an optical resonator. In the strong coupling \nregime, spontaneous emission in a cavity becomes a reversible process and \nthe intracavity photon number undergoes Rabi oscillations. We load up \nto 200x10^3 ^133Cs atoms into a nearly confocal lossy cavity and reach the \ncollective strong coupling regime. Normal mode splitting, the hallmark of this regime, is observed and cooperativities up to C_coll = (186±5) are measured. In a second experiment we investigate for the first time \nthe multi-mode character of the coupled cavity-atom system. In a confocal \ncavity the higher-order transverse cavity modes are degenerate in frequency and accessible to the spontaneous emission of the atomic ensemble. \nWe observe an increase of the coupling constant measured via modal decomposed transmission analysis, which could be attributed to \nthe presence of the higher-order modes. Normal mode splitting proportional to the square root of the atom number was visible for all of the \ndifferent mode components. Furthermore, we observe a redistribution of the relative weights in the modal transmission composition, which scales with the atom number in the cavity mode. \nIn a second set of experiments, ^87Rb atoms were loaded into a dissipative \nlin ⊥ lin lattice. By driving the lattice with a biharmonic force, transport can be observed when the systems symmetries are broken: the so called ratchet effect. Research in this area is concerned with the appearance \nof current reversals. We were able to identify dissipation related symmetry breaking as the underlying cause of an observed current reversal, which occurs as a function of the driving frequency. Furthermore, in a \nsecond experiment, we use the ratchet effect as a probe of the optical potential depths. We show that an oscillating force with a frequency far above any other system-inherent timescale, can be used to renormalize \nthe optical potential. The ^87Rb atoms experience an average position dependent force, which becomes controllable over the amplitude of the \napplied driving.
This thesis describes three experiments with cold rubidium atoms. The first experiment implements a rocking ratchet with cold atoms in driven dissipative optical lattices, and explores a fundamental feature of ratchets: current reversals. It precisely investigates current reversals as observed by varying the driving frequency. It is found that this kind of current reversal in the frequency domain is determined by dissipation-induced symmetry breaking. The second experiment explores vibrational mechanics for a system of cold atoms in an optical lattice. A high frequency strong driving field was applied in order to renormalise the optical potential. It was observed that the amplitude of the potential is indeed renormalised and can be controlled by the high frequency driving field. This is detected by two methods: via the study of the diffusion properties and via the observation of the directed transport. The final experiment is the realisation and characterisation of a Bose-Einstein condensate of rubidium atoms.
An ensemble of atoms coupled to a high finesse optical cavity is an ideal test bed for the study of the cooperative behaviour of atom-photon systems. Dicke showed that an ensemble of excited atoms coupled to a light field interacts with the light in a collective and coherent fashion leading to the emission of highly directional spontaneous emission whose intensity scales with the square of the number of atoms, a phenomenon known as superradiance. \nThis thesis describes the build of an experiment to study cooperative atom-photon interactions in a ring cavity. Particular focus is given to the cavities used in the experiment. Firstly a transfer cavity used for transferring stability to off-resonant lasers in the experiment, this was developed with the capability of exploiting Gouy phase degeneracies to produce tightly spaced frequency discriminants to be used as lock points. Secondly the ring cavity for the experiment which is atypical in its design allowing for bidirectional probing of the cavity mode and dynamic manipulation of the intra-cavity optical lattice. An intra-cavity MOT was produced and collective strong coupling was observed in the cavity with an Neff=6400 atoms coupled to the cavity mode.
The radiative properties of atoms inside an optical cavity can be dramatically changed with respect to those in free space. In the strong-coupling limit, the reversible dipole interaction between an atom and the cavity field dominates the irreversible decay resulting from spontaneous emission and cavity damping. In this limit the atom and field can no longer be regarded as separate quantities but instead form a composite dynamic system. To enhance the dipole coupling constant and increase the photon storage time, our experiments are performed with a small cavity 1 mm long, with a finesse of 8 × 104. On average, 0.4 photons are sufficient to saturate the resonance transition at 852 nm for the cesium atoms used, while the cooperativity parameter for a single atom is 2. Optical bistability is studied in this system over the range 3 < N < 65 atoms inside the cavity, with the semiclassical theory predicting bistability for N > 5. We report observations of manifestly quantum effects in this regime, including photon antibunching and sub-Poissonian photon statistics, with the magnitude of these nonclassical effects observed to be largely independent of the number of intracavity atoms.
A novel regime of atom-cavity physics is explored, arising when large atom samples dispersively interact with high-finesse optical cavities. A stable far-detuned optical lattice of several million rubidium atoms is formed inside an optical ring resonator by coupling equal amounts of laser light to each propagation direction of a longitudinal cavity mode. An adjacent longitudinal mode, detuned by about 3 GHz, is used to perform probe transmission spectroscopy of the system. The atom-cavity coupling for the lattice beams and the probe is dispersive and dissipation results only from the finite photon-storage time. The observation of two well-resolved normal modes demonstrates the regime of strong cooperative coupling. The details of the normal mode spectrum reveal mechanical effects associated with the retroaction of the probe upon the optical lattice.
We review the modifications and implications of the effect of light forces on atoms when the field is enclosed in an optical resonator of high finesse. The systems considered range from a single atom strongly coupled to a single mode of a high-Q microcavity to a large ensemble of atoms in a highly degenerate quasi-confocal resonator. We set up general models that allow us to obtain analytic expressions for the optical potential, friction, and diffusion. In the bad-cavity limit the modified cooling properties can be attributed to the spectral modifications of light absorption and spontaneous emission in a form of generalized and enhanced Doppler cooling. For the strong coupling regime in a good cavity, we identify the dynamical coupling between the light field intensity and the atomic motion as the central mechanism underlying the cavity-induced cooling. The dynamical cavity cooling, which does not rely on spontaneous emission, can be enhanced by multimode cavity geometries because of the effect of coherent photon redistribution between different modes. The model is then generalized to include several distinct frequencies to account for more general trap geometries. Finally we show that the field-induced buildup of correlations between the motion of different particles plays a central role in the scaling behavior of the system. Depending on the geometry and parameters, its effect ranges from strong destructive interference, slowing down the cooling process, to self-organized crystallization, implying atomic self-trapping and faster cooling to lower temperatures by cooperative coherent scattering.
We investigate the transmission spectrum of an optical cavity coupled with four-level atoms. Multiple normal-mode splitting peaks of the strongly coupled atom-cavity system are obtained as single cavity mode couples three separated atomic transitions simultaneously. We employ a confocal optical cavity and an ensemble of cold Rb-85 atoms for cavity quantum electrodynamics. We observe four normal-mode splitting peaks of the cavity transmission in the strong coupling regime due to collective enhancement of the atom-cavity coupling strength by ensemble of cold atoms. The experimental observations are consistent with the theoretical analysis. The multiple normal-mode excitation in the strongly coupled multi-level atom-cavity system may lead to practical application for realizing multi-channel all-optical devices.