Spatial coherence of polaritons in a 1D channel
- PDF / 281,419 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 32 Downloads / 212 Views
MOLECULES, OPTICS
Spatial Coherence of Polaritons in a 1D Channel I. G. Savenkoa,b,d, I. V. Iorshc, M.A. Kaliteevskia,e, and I. A. Shelykhb,d a
Academic University, Research and Education Center of Nanotechnologies, Russian Academy of Sciences, St. Petersburg, 194021 Russia b Science Institute, University of Iceland, Dunhagi, Reykjavik, Iceland c National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, 197001 Russia dDivision of Physics and Applied Physic, Nanyang Technological University, 637371 Singapore eIoffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia email: [email protected] Received July 9, 2012
Abstract—We analyze time evolution of spatial coherence of a polariton ensemble in a quantum wire (1D channel) under constant uniform resonant pumping. Using the theoretical approach based on the Lindblad equation for a oneparticle density matrix, which takes into account the polariton–phonon and exciton– exciton interactions, we study the behavior of the firstorder coherence function g1 for various pump intensi ties and temperatures in the range of 1–20 K. Bistability and hysteresis in the dependence of the firstorder coherence function on the pump intensity is demonstrated. DOI: 10.1134/S1063776113010135
1. INTRODUCTION
electrical) pumping of the system is required to attain the equilibrium state (condensate) [12]. It is also important to mention the fact that the observation of coherent radiation from a microcavity is not a sufficient confirmation (condition) of the BEC formation in the system [13]. For this reason, addi tional criteria were formulated for the emergence of polariton condensation (in particular, the condition of the decrease in the secondorder coherence function g(2) from 2 to 1 [14, 15]) as well as for spontaneous emergence of the linear polarization of polariton radi ation under nonpolarized pumping [16] and stabiliza tion of the offdiagonal longrange order (ODLRO), which is described by the asymptotic behavior of first order coherence function g(1)(r, r'). The latter criterion is the key object of investigation in a number of theo retical [17, 18] and experimental [19–21] works. In spite of the fact that the experimental setup for measuring spatial coherence (namely, Young’s double slit experiment on diffraction of light) was constructed long ago, a unified approach to the theoretical descrip tion and calculation of spatial coherence has not been worked out as yet. This can be explained by the lack of a method of description (formalism) which would take into account simultaneously the coherent evolution of a polariton wave packet in direct space, on the one hand, and dephasing processes associated with the interaction with thermalized reservoir of acoustic phonons, on the other hand. Until now, two approached have been used for describing the system of coupled polaritons: a completely coherent approach based on the solution of the Gross–Pitaevskii equation
Excitonpolaritons are bosonic quasipar
Data Loading...
