Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Basic Theory of Bose–Einstein Condensation of Excitons
- 3 The Interaction of Condensed Excitons with Lattice Phonons
- 4 Bose–Einstein Condensation of Biexcitons
- 5 Phase Transitions and Thermodynamics of High-Density of Excitons
- 6 The Optical Stark Effect and the Virtual Bose Condensate
- 7 Bose–Einstein Condensation of Mixed States of Excitons and Photons
- 8 Nonequilibrium Kinetics of High-Density Excitons
- 9 Coherent Nonlinear Optics with Excitons
- 10 New Directions
- Appendix A: Properties of Excitons in Cu2O
- Author Index
- Subject Index
7 - Bose–Einstein Condensation of Mixed States of Excitons and Photons
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Basic Theory of Bose–Einstein Condensation of Excitons
- 3 The Interaction of Condensed Excitons with Lattice Phonons
- 4 Bose–Einstein Condensation of Biexcitons
- 5 Phase Transitions and Thermodynamics of High-Density of Excitons
- 6 The Optical Stark Effect and the Virtual Bose Condensate
- 7 Bose–Einstein Condensation of Mixed States of Excitons and Photons
- 8 Nonequilibrium Kinetics of High-Density Excitons
- 9 Coherent Nonlinear Optics with Excitons
- 10 New Directions
- Appendix A: Properties of Excitons in Cu2O
- Author Index
- Subject Index
Summary
Introduction. Polaritons and Semiconductor Microcavities
As we have mentioned previously, BEC of excitons or biexcitons and lasing can be seen as two limits of the same theory. Lasing occurs in the case of strong electron-photon coupling (recombination rate fast compared with interparticle-scattering rate) while excitonic BEC occurs in the case of weak electron-photon coupling (recombination rate slow compared with the interparticle-scattering rate.) A laser can be seen as a Bose condensate in which the long-range phase coherence exists in the photon states [1], while in the exciton condensate the coherence exists in the electronic states. This is one of the reasons for some of the confusing debates in the early history of excitonic Bose condensation – in many systems there is not a sharp distinction between an excitonic condensate and supperradiance, i.e., luminescence with enhanced intensity due to stimulated emission [2-4].
In the previous chapters, we have so far considered a laser light source only as a source of excitons by means of quantum transitions. In Chapter 6, the laser radiation was taken into account as a given external factor. This chapter is dedicated to phenomena related to a strong and noticeable exciton-photon interaction, when the light significantly influences the energy spectrum of the high-density excitons [5-9]. As we will see, this leads to many fascinating effects related to instabilities.
A strong exciton-photon interaction implies a strong polariton effect, in which photon and exciton states are mixed (as in Fig. 1.3). When this mixing is strong, it is not obvious how to define the ground state of the system.
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- Bose-Einstein Condensation of Excitons and BiexcitonsAnd Coherent Nonlinear Optics with Excitons, pp. 249 - 294Publisher: Cambridge University PressPrint publication year: 2000
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