Strong light-matter coupling: coherent parametric interactions in a cavity and free space

Strong light-matter coupling: coherent parametric interactions in a cavity and free space

V. S. Egorov1, V. N. Lebedev1, I. B. Mekhov1, P. V. Moroshkin2, I. A. Chekhonin1, and S. N. Bagayev3

1St. Petersburg State University, V.A. Fock Institute of Physics, St. Petersburg, Russia2Universite de Fribourg, Fribourg, Switzerland

3Institute of Laser Physics, Siberian Branch of RAS, Novosibirsk, Russia

V. S. Egorov1, V. N. Lebedev1, I. B. Mekhov1, P. V. Moroshkin2, I. A. Chekhonin1, and S. N. Bagayev3

1St. Petersburg State University, V.A. Fock Institute of Physics, St. Petersburg, Russia2Universite de Fribourg, Fribourg, Switzerland

3Institute of Laser Physics, Siberian Branch of RAS, Novosibirsk, Russia

The report is focused on

• Coherent interaction between an optically dense resonant medium and near-resonant laser light

• Influence of intrinsic light-matter dynamics on nonlinear parametric processes

• Role of the dispersion of a strongly coupled light-matter system (polaritons)

• Peculiarities of the strong-coupling regime in a free-space in contrast to cavity interactions

Strong-coupling regime of light-matter interactionStrong-coupling regime of light-matter interaction

Two coupled oscillators: field and polarization of a medium

I. Energy exchange is faster than decoherence

High coupling coefficient, small relaxation(dynamical effects may be significant)

Coherence of both field and matter is important(adiabatic elimination cannot be applied)

II. Weak external field

Key role of reemission (reaction) field(constant-field approximation does not work)

External field does not destroy collective behavior of an atomic ensemble(beyond the framework of a single-atom model,in contrast to Rabi flopping, Mollow-Boyd, and other strong-field effects)

Photons and matter excitations are presented by nearly equal contributions (polaritons)

Strong-coupling regime has attracted attention in

Atomic and molecular opticsAtomic and molecular optics Solid-state opticsSolid-state optics

Dicke superradiance(oscillatory regime)

Cavity QED (up to single atom / photon interactions)

Dicke superradiance(oscillatory regime)

Cavity QED (up to single atom / photon interactions)

Exciton-polaritons in semiconductor microcavities with nanostructures(single and multiple QWs and QDs)

- Stimulated scattering- Parametric interactions- Squeezing, entanglement- Bose-Einstein condensation

Exciton-polaritons in semiconductor microcavities with nanostructures(single and multiple QWs and QDs)

- Stimulated scattering- Parametric interactions- Squeezing, entanglement- Bose-Einstein condensation

It is important for quantum information processing with bothdiscrete and continuous variables

Interactions in a cavityInteractions in a cavity

Splitting of a cavity mode (collective vacuum Rabi oscillations)

Spatial spectrum is fixed by a cavity

Polariton dispersion in a cavity

Quantum beats in a two-level medium

“Spectrum condensation” in active systems“Spectrum condensation” in active systems

Pumping Broadband gain medium

Narrow-bandabsorbing medium

Spectrum condensation of a multimode dye laser with an intracavity absorbing cell (Ne discharge)

Spectrum condensation of a multimode dye laser with an intracavity absorbing cell (Ne discharge)

Weak coupling:Saturated absorption line

Strong coupling: Bright doublet

Strong-coupling regime in a free spaceStrong-coupling regime in a free space

Short broadband pulse

Under linear interactions, frequency spectrum is entirely determined by the input spectrum

No coherent density-dependent features in the output spectrum(in contrast to vacuum Rabi oscillations in a cavity)

Spectrum

Coherent collective oscillations in temporal evolution

Possibility to observe collective features in nonlinear parametric interactions

Time

Spatial spectrum is NOT fixed by a cavity(continuos)

D+1

D-1p-1

D0

Nonlinear interaction:

D+2p+2

Nonlinear pump-probe interactionNonlinear pump-probe interaction

pump

probe

Bloch equations:

Two intersected pulses:

Probe

Coupled Maxwell-Bloch system

Pump

Collective optical ringing in an extended mediumCollective optical ringing in an extended medium

frequency:

Strong coupling condition:

Propagation of a probe pulse in the presence of a pumpPropagation of a probe pulse in the presence of a pump

Coherent density- and coordinate- dependent features under nonlinear

parametric interaction

Experiments in a Ne discharge(588.2 nm)

Resonant atom density is n=1013 cm-3

Transition from strong-couplingto strong-field regime

ConclusionsConclusions

Nonstationary interaction of laser pulses with a dense resonant medium was considered under the strong-coupling regime of light-matter interaction

Internal collective light-matter dynamics was shown to significantly affect nonlinear parametric interactions between short laser pulses

Efficient parametric processes in the strong coupling regime were proved even for the free-space conditions

Contrary to stationary strong-field effects, the density- and coordinate-dependent transmission spectra of the probe manifest the importance of collective oscillations and cannot be obtained in the framework of a single-atom model

ReferencesReferences

S.N. Bagayev, V.S. Egorov, I.B. Mekhov, P.V. Moroshkin, I.A. Chekhonin, E.M. Davliatchine, and E. Kindel, Phys. Rev. A 68, 043812 (2003)

V.S. Egorov, V.N. Lebedev, I.B. Mekhov, P.V. Moroshkin, I.A. Chekhonin, and S.N. Bagayev, Phys. Rev. A 69, 033804 (2004)