Bright Cavity Polariton Solitons

Nature, 2002

Cavity solitons are localized intensity peaks that can form in a homogeneous background of radiation. They are generated by shining laser pulses into optical cavities that contain a nonlinear medium driven by a coherent field (holding beam). The ability to switch cavity solitons on ...

Photons and excitons in a semiconductor microcavity interact to form exciton-polariton condensates. These are governed by a nonlinear quantummechanical system involving exciton and photon wavefunctions. We calculate all non-traveling harmonic soliton solutions for the one-dimensional lossless system. There are two frequency bands of bright solitons when the inter-exciton interactions produce a repulsive nonlinearity and two frequency bands of dark solitons when the nonlinearity is attractive. In addition, there are two frequency bands for which the exciton wavefunction is discontinuous at its symmetry point, where it undergoes a phase jump of π. A band of continuous dark solitons merges with a band of discontinuous dark solitons, forming a larger band over which the soliton far-field amplitude varies from 0 to ∞; the discontinuity is initiated when the operating frequency exceeds the free exciton frequency. The far fields of the solitons in the lowest and highest frequency bands (one discontinuous and one continuous dark) are linearly unstable, whereas the other four bands have linearly stable far fields, including the merged band of dark solitons.

Journal of Luminescence, 2000

Recent work on strong coupling exciton}polariton phenomena in single and coupled microcavities is presented. We describe experiments for single cavities where the strong coupling nature of the excitations manifests itself. It is also shown that coupled cavities enable optically induced coupling between macroscopically separated exciton states to be achieved, and polaritons with strongly anisotropic properties to be realised. Results for both inorganic and organic microcavities are presented.

Physical Review B, 2013

We study the nonlinear dynamics of exciton-polaritons in semiconductor microcavities operating in the strongcoupling regime and driven by a coherent optical pump above the exciton resonance. Provided that the exciton dispersion is accounted for, parametric mixing of polaritons from the upper and the lower polariton branches gives rise to modulational instability of the homogeneous solution. This instability leads to the formation of quasiperiodic patterns. Our analytical analysis shows that there are domains in parameter space where these patterns and stable homogeneous solution may exist simultaneously. This is the prerequisite for the existence of cavity polariton solitons-single-peak solutions on a homogeneous background. Because they originate from parametric mixing of polaritons from both branches of the dispersion relation we term them hybrid parametric cavity solitons. There are two kinds of these resting solitons-stationary and breathing ones. Both types require for stability that the cavity resonance be redshifted to the exciton resonance.

2013

Propagation of long-lifetime polaritons in a semiconductor microcavity 1 GERMAN V. KOLMAKOV, OLEG L. BERMAN, ROMAN YA. KEZERASHVILI, the New York City College of Technology, the City University of New York -We study propagation of polaritons in a high-quality microcavity. The polaritons are formed by the cavity photons coupled with the excitons in a semiconductor quantum well. We focus on the long-lifetime polaritons (∼ 100 ps), which can spread in a semiconductor structure over a few mm distance before they damp. The case where the polaritons form a non-equilibrium Bose-Einstein condensate is considered. We discuss the changes in the spatial polariton distribution if the polaritons are accelerated by a constant force in the wedge-shaped microcavity.

2003

Abstract Microcavity exciton polaritons, the fundamental optical excitations of semiconductor microcavities with quantum wells inside, have been proposed as promising candidates for observing stimulated scattering, condensation and other phenomena related to the bosonic nature of excitons. Having a light mass, quantum degeneracy of polaritons can be reached at low densities and high temperatures.

Physical Review Letters, 2000

A massive redistribution of the polariton occupancy to two specific wave vectors, zero and ϳ3.9 3 10 4 cm 21 , is observed under conditions of continuous wave excitation of a semiconductor microcavity. The "condensation" of the polaritons to the two specific states arises from stimulated scattering at final state occupancies of order unity. The stimulation phenomena, arising due to the bosonic character of the polariton quasiparticles, occur for conditions of resonant excitation of the lower polariton branch. High energy nonresonant excitation, as in most previous work, instead leads to conventional lasing in the vertical cavity structure.

2011

Periodic incorporation of quantum wells inside a one-dimensional Bragg structure is shown to enhance coherent coupling of excitons to the electromagnetic Bloch waves. We demonstrate strong coupling of quantum well excitons to photonic crystal Bragg modes at the edge of the photonic band gap, which gives rise to mixed Bragg polariton eigenstates. The resulting Bragg polariton branches are in good agreement with the theory and allow demonstration of Bragg polariton parametric amplification.

Physical Review B, 2000

By exciting resonantly a microcavity with a pulsed laser beam, we have observed the in-plane propagation of excitonic cavity polaritons over distances much greater than the wavelength. The initial in-plane wave vector is conserved during the propagation, showing that it is a good quantum number for cavity polaritons. The polariton group velocities were measured as a function of both the in-plane wave vector and detuning. Propagation is faster for negative detunings where the polaritons have a light effective mass. The observations are in good agreement with a simple two-oscillator model.

2010

We report on the dynamics of confined zero-dimensional polaritons. We excite resonantly discrete polariton states optically with a tailored picosecond laser pulse and observe their emission time resolved in the twodimensional k space or real space. We are able to distinguish between three regimes. When the laser excites only one state no dynamics are observed. When a small number of well separated states are excited, the dynamics are described in terms of interference.