Search query: Exciton-polaritons in low dimensional structures

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abstract: Some special features of polaritons, quasi particles being normal modes of system of excitons interacting with photons in so called strong coupling regime, are theoretically and numerically analyze in low dimensional systems. In Chapter 1 is given a brief overview of 0D, 1D and 2D semiconductor structures with a general introduction to the polariton field. Chapter 2 is devoted to micro nano wires. The so called whispering gallery modes are studied in the general case of an anisotropic systems as well as polariton formation in ZnO wires. Theoretical model is compared with an experiment. In the Chapter 3 Josephson type dynamics with Bose Einstein condensates of polaritons is analyzed taking into account pseudospin degree of freedom. Chapter 4 start with an introduction to Aharonov Bohm effect, as the best known represent of geometrical phases. An another geometrical phase Berry phase, occurring for a wide class of systems performing adiabatic motion on a closed ring, is main subject of this section. We considered one proposition for an exciton polariton ring interferometer based on Berry phase effect. Chapter 5 concerns one 0D system strongly coupled quantum dot exciton to cavity photon. We have discussed possibility of obtaining entangled states from a quantum dot embedded in a photonic crystal in polariton regime.
author_names: Goran Pavlovic
title: Exciton polaritons in low dimensional structures
year: 2010

abstract: Along this thesis manuscript I shall present some emergent nonlinear phenomena in spinor exciton polariton condensates. After an introductory chapter bringing the necessary background, I will in a first part focus on half integer topological defects discussing their stability, acceleration and nucleation in the presence of effective magnetic fields. We will see that these objects behave as magnetic charges being fascinating dirac's monopole analogues. Remarkably we will see as well how they can be used as stable signals allowing to seed the physics acoustic black holes analogues. In a second part I will concentrate on low dimensional structures. Especially, I'll describe the formation of gap solitons and the Bloch oscillations of exciton polaritons in periodically patterned microwires, and besides, the room temperature Josephson oscillations within pairs of coupled micropillars.
author_names: Hugo Flayac
title: New trends in the physics of spinor exciton polariton condensates topological defects and low dimensional structures
year: 2012

abstract: A theory of the Anderson localization of light in randomly arranged ultrathin layers (quantum wells) uniform in lateral dimensions and possessing intrinsic optical resonances is put forward. To solve the multiple scattering problem, a model of layers with a d function resonance dielectric polarization is proposed. The model is an electromagnetic counterpart of the electronic model of zero radius potentials. Interlayer disorder is included under the assumption of a low average concentration of identical layers in order to calculate analytically the one and two photon characteristics of electromagnetic radiation transport, in particular, the average energy density and the Anderson localization length of light. The analysis is carried out for a structure with randomly distributed quantum wells in which quasi two dimensional excitons of different quantum wells are in resonance while their wave functions do not overlap. It is shown that the average electromagnetic field propagates through this disordered structure in the form of polaritons but are produced in exciton reemission between quantum wells. The localization length of light in the polariton spectral region decreases substantially, because the scattering (reflection) of light by individual quantum wells grows near the excitonic resonance.
author_names: Vladimir A Kosobukin
title: Exciton polaritons and their one dimensional localization in disordered quantum well structures
year: 2003

abstract: Cesium lead halide perovskite nanowires have emerged as promising low dimensional semiconductor structures for integrated photonic applications. Understanding light matter interactions in a nanowire cavity is of both fundamental and practical interest in designing low power consumption nanoscale light sources. In this work, high quality in plane aligned halide perovskite CsPbX3 (X Cl, Br, I) nanowires are synthesized by a vapor growth method on an annealed M plane sapphire substrate. Large area nanowire laser arrays have been achieved based on the as grown aligned CsPbX3 nanowires at room temperature with quite low pumping thresholds, very high quality factors, and a high degree of linear polarization. More importantly, it is found that exciton polaritons are formed in the nanowires under the excitation of a pulsed laser, indicating a strong exciton photon coupling in the optical microcavities made of cesium lead halide perovskites. The coupling strength in these CsPbX3 nanowires is dependent on the atomic composition, where the obtained room temperature Rabi splitting energy is ~210 13, 146 9, and 103 5 meV for the CsPbCl3, CsPbBr3, and CsPbI3 nanowires, respectively. This work provides fundamental insights for the practical applications of all inorganic perovskite CsPbX3 nanowires in designing light emitting devices and integrated nanophotonic systems.
author_names: Xiaoxia Wang

Muhammad Shoaib

Xiao Wang

Xuehong Zhang

Mai He

Ziyu Luo

Weihao Zheng

Honglai Li

Tiefeng Yang

Xiaoli Zhu

Libo Ma

Anlian Pan
title: High Quality In Plane Aligned CsPbX3 Perovskite Nanowire Lasers with Composition Dependent Strong Exciton Photon Coupling.
venue: ACS nano
year: 2018

abstract: Hybrid Bose Fermi systems consist of a layer of fermions, usually two dimensional electron gas (2DEG) coupled to another layer of bosons, such as excitons, exciton polaritons, or Cooper pairs. The interplay between these layers leads to various novel and fascinating phenomena, interesting from both the technological and fundamental physics perspectives. Hybrid structures are used in light absorption studies of heterostructures, designing nano devices, realization of Majorana fermions, designing optically controlled superconductivity, and others. I will report on our work where the Bose layer is made up of condensed excitons and the Fermi layer is made up of electron gas. For the latter, we considered two types of electron dispersions: parabolic (GaAs) and linear (graphene) The electrons are coupled to the Bogoliubov excitations or bogolons from the Bose layer via Coulomb interaction. We developed a microscopic theory and derived the low and high temperature dependence of the resistivity. It is shown that the presence of the condensed excitons leads to novel scattering channels and can have a dominant contribution to the resistivity. This is contrary to the conventional wisdom that impurities and phonons have dominant effect at low and high temperatures, respectively.
author_names: Kristian Hauser A Villegas
title: Electronic transport in hybrid Fermi exciton Bose gas systems
year: 2019

abstract: A computational approach is taken to studying a range of light matter interactions which are interesting in terms of their potential applications as well as from a fundamental point of view. Two different types of polariton, part light, part matter quasiparticles, namely exciton polaritons and Tamm plasmon polaritons (a type of surface plasmon polariton) are considered. The conditions required for the strong coupling of optical whisperinggallery modes and bulk excitons in submicron spheres are ascertained for the materials gallium arsenide, gallium nitride and zinc oxide. It is shown that the strong coupling regime may be accessed by optical modes with a low decay constant, typically exhibited by those modes with higher angular momentum quantum numbers. Tamm plasmon polaritons have previously been shown to exist at the boundary between a metal and a planar Bragg reflector structure. The conditions required for the formation of Tamm plasmon polaritons in cylindrical multilayer structures with a metal core, cladding or metal in both of these locations are determined. The cylindrical Tamm plasmon polaritons are shown to have low effective masses and low group velocities. It is also shown that it is possible to obtain split polariton modes in structures containing metal in both the core and the cladding. The effect of disorder on a two dimensional photonic crystal structure consisting of air holes in a slab of dielectric material is studied. It is shown that the defined threshold disorder is not significantly affected by the different relative band widths of the ideal crystal structures considered.
author_names: Claire Elspeth Little
title: Computational studies of light matter interactions in two and three dimensional systems
year: 2011

abstract: Semiconducting nanocrystals in open access microcavities are promising systems in which enhanced light matter interactions lead to quantum effects such as the modulation of the spontaneous emission process and exciton polariton formation. In this thesis I present improvements of the open cavity platform which serves to confine the electromagnetic field with mode volumes down to the l3 regime and demonstrate results in both the weak and strong coupling regimes of cavity quantum electrodynamics with a range of different low dimensional materials. I report cavity fabrication details allowing a peak finesse of 5 x 104 and advanced photonic structures such as coupled cavities in the open cavity geometry. By incorporating two dimensional materials and nanoplatelets in the cavity I demonstrate the strong coupling regime of light matter interaction with the formation of exciton polaritons, quasi particles composed of both photon and exciton, at room temperature. In the perturbative weak coupling regime I show pronounced modulation of the single photon emission from CdSe/ZnS quantum dots and the two dimensional material WSe2 and demonstrate Purcell enhancement of the spontaneous emission rate by factors of 2 at room temperature and 8 at low temperature. The findings presented in this thesis pave the way to establish open microcavities as a platform for a wide range of applications in nanophotonics and quantum information technologies.
author_names: Lucas C Flatten
title: Quantum electrodynamics of semiconducting nanomaterials in optical microcavities
year: 2017

abstract: This volume contains some of the papers presented at the Third International Conference on Physics of Light Matter Coupling in Nanostructures (PLMCN3) which took place in Acireale, Sicily, from 1 to 4 October 2003. This meeting was fourth in the series started by PLMCN (St. Nectaire, 2000) and continued by PLMCN1 (Rome, 2001) and PLMCN2 (Rithymnon, 2002) All four conferences had the same format (about 70 participants) similar subject scope (interface between fundamental physics of light matter coupling phenomena and applied research on new semiconductor materials and low dimensional structures) and the proceedings of all of them have been published in physica status solidi. During these four years, a huge progress has been achieved in the understanding of exciton polariton effects in microcavities. From the discovery of stimulated scattering of polaritons in 1999 to the first experimental reports of polariton Bose condensation and lasing, attention to this rapidly developing research area has been increased drastically. It is clear now that realization of a new generation of opto electronic devices, referred to as polariton devices, is a realistic task for the coming decade. To achieve this target, much work has to be done both in fundamental research on dynamics of exciton polaritons in microcavities and experimental realization of high quality microcavities presumably based on wide band gap semiconductors like GaN, ZnO, ZnSe, suitable for the observation of strong exciton light coupling at room temperature. Forty nine research teams from twelve European countries have created a Polariton Consortium aimed at integration of the European research effort towards fabrication of polariton devices. PLMCN3 was not only an international conference devoted, in particular, to the research on polariton devices, but also the first scientific meeting of this community. The PLMCN meetings since the very first one have been sponsored by the US Army European Research Office (ERO) This time, with the initiative of Jim Harvey from ERO, a special session has been organized on the devices of 21st century, where a number of intriguing ideas have been proposed on new light sources, polariton lasers, and quantum memory elements based on microcavities. A special prize for the most crazy but realizable idea has been won by Misha Portnoi (Exeter) for the concept of a white diode based on a microcavity. Each PLMCN meeting brings participants from new countries. This time, the traditionally strong participation from Japan, Russia, the European Union and the USA has been enforced by a representative delegation from Israel and two speakers from Mexico. We are looking forward for new comers from other countries not yet involved in the PLMCN community, to join us for the next meeting to be held in St. Petersburg on 29 June 3 July 2004. Sergey Ivanov from the A. F. Ioffe Institute chairs the local Organizing Committee of this future conference. We are going to keep a unique informal and creative atmosphere being characteristic of the PLMCN meetings. We invite all those who wish to know more about light matter coupling in solids or to present any new interesting results in this area and at the same time to enjoy the beautiful city of St. Petersburg, to contact Sergey Ivanov (ivan@beam.ioffe.rssi.ru) or myself (kavokin@lasmea.univ bpclermont.fr) We are looking forward to welcoming you in St. Petersburg!
author_names: Alexey Vitalievich Kavokin
title: Preface: phys. stat. sol. (c) 1/6
year: 2004

abstract: Semiconductor microcavities are micron scale photonic structures in which quantum wells are embedded within a high finesse Fabry Perot cavity, the whole structure being prepared by high precision, modern crystal growth techniques [1] In such structures vertical confinement of both excitons in the quantum wells and of light within the Fabry Perot cavity results in strong and controllable light matter interactions unachievable in quantum wells or bulk semiconductors. This control has opened up a new field of exciton polariton physics, where key features of the interacting exciton photon system can be tailored by sample design. Most importantly for the physics described here, the dispersion curves of the coupled two dimensional (2D) exciton photon modes, exciton polaritons (termed cavity polaritons) differ from those of their bulk analogues since the confinement of light results in a finite energy at k=0. This property, combined with the controllable dispersion and the extremely low density of polariton states [1] has recently allowed a variety of new phenomena to be observed, including final state stimulation and a new condensed phase with macroscopic coherence, which have the potential to lead to new devices including very low threshold optical parametric oscillators and a coherent light source based on stimulated polariton scattering.
author_names: M S Skolnick

Alexander I Tartakovskii

Raphael Butte

R Mark Stevenson

Jeremy J Baumberg

D M Whittaker
title: High Occupancy Effects and Condensation Phenomena in Semiconductor Microcavities and Bulk Semiconductors
year: 2002

abstract: Bosonic particles placed in a lattice are powerful tool for fundamental studies of quantum phenomena. The remarkable progress in this area are connected with exciton polaritons formed inside a high quality semiconductor microcavity in the regime of the strong light mater coupling. Exciton polaritons are subject to a rapid radiative decay and its population should be maintained by pumping. This nonequilibrium driven dissipative nature of polaritonic system together with the nonlinear effects substantially affects its properties. Nowadays there are several experimental proofs of the spontaneous coherency building up in the systems of polariton placed in artificial lattices [1 4] For instance, besides a conventional in phase ground state (when condensates locate in the neighboring potentials wells are in phase) a spontaneous buildup of antiphase (p state) "superfluid" states was observed in both weak contrast periodical lattice [2] as well as in chains of deep trapping potentials [1, 2] We consider the incoherently pumped periodical systems of exciton polaritons, which assumes that a reservoir of hot excitons is created. In particular, basing on the open dissipative Gross Pitaevskii model for wave function of coherent polaritons and exciton reservoir density we predict the existence of persistent oscillatory dynamics of polariton condensate. Such a behavior results in a persistent oscillations of the condensate density which are accompanied by periodical transitions between states located at the different bands of the condensate band structure [5] We have observed that such oscillations are developed when the condensate is both in phase and in anti phase (p states. In the latter case such oscillations resembles Josephson oscillations but it occur in the reciprocal space. Besides, we study the nonlinear modification of condensate steady states which have a structure of Bloch waves in periodical potential. It is well known that due to the presence of exciton component polaritons possess strong nonlinearities. We have demonstrated that strong Kerr like nonlinearity leads to the formation of the dynamically stable "current state" which are characterized by the non zero polariton flux through the lattice [6] The most intriguing feature of these states is that it exists even when the condensate quasi momentum lies at the boundaries of the Brillouin zone. According to main concepts of solid state physics the existence of a current in the Brillouin zone edge is forbidden due to Bragg scattering on the lattice. However we have shown that strongly polariton nonlinearities can effectively screen the influence of the periodic potential. An experimental scheme allowing observation of polariton nonlinear current states is also proposed. Finally, we consider the influence of the finiteness of the pump on the states formed in polariton condensation process. In we demonstrated that the formation of both in phase and anti phase states formed in finite structures can be explained in terms of the stability of such states. For this purpose we used a simple discrete model for incoherently pumped polariton condensate, which is valid in the case of strongly contrast lattices. Our analysis explains the phenomena observed in experiments within the framework of a simple phenomenological theory.
author_names: Yu A Chestnov

A V Yulin

Oleg A Egorov

Alexander Alodjants
title: Dynamics of Microcavity Polaritons in Low Dimensional Lattices
year: 2017