SLIDE 1 Stability and spatial coherence of nonresonantly pumped exciton-polariton condensates
Nataliya Bobrovska1, Elena A. Ostrovskaya2, Michał Matuszewski1
1Institute of Physics, Polish Academy of Sciences, Warsaw 2Nonlinear Physics Centre, Research School of Physical Sciences
and Engineering, The Australian National University, Canberra
SLIDE 2 EXCITON-POLARITON CONDESATE
(105 times smaller than exciton mass)
- Strong interparticle interactions
SLIDE 3
THE MODEL
EXCITON-POLARITON CONDESATE
Kasprzak et al., Nature 2006
Resonant pumping Nonresonant pumping Polariton condensates are the nonequlibrium systems where continuous pumping is necessary to maintain the condensate population
SLIDE 4
HOMOGENEOUS PUMPING
OUTLINE
Model system (open-dissipative Gross-Pitaevskii equation) Stability and coherence of exciton-polariton condensate under homogeneous pumping Stability and coherence of exciton-polariton condensate under inhomogeneous pumping
SLIDE 5
INHOMOGENEOUS PUMPING
THE MODEL
Wouters & Carusotto, PRL 2007
SLIDE 6
INHOMOGENEOUS PUMPING
OPEN-DISSIPATIVE GROSS-PITAEVSKII MODEL
Wouters & Carusotto, PRL 2007
Rate equation for the reservoir density Open-dissipative Gross-Pitaevskii equation
SLIDE 7
- Bogoliubov-de Gennes method
- Direct numerical integration
ℏ=m=1
Dimensionless units
METHODS
One-dimensional exciton-polariton condensate
Bobrovska et al., PRB 2014
SLIDE 8 INHOMOGENEOUS PUMPING
HOMOGENEOUS PUMPING
Below threshold Above threshold No condensate! Condesate! ODGP model Threshold pumping:
SLIDE 9
INHOMOGENEOUS PUMPING
HOMOGENEOUS PUMPING
stability limit Periodic boundary conditions The analytical condition for condensate stability
Smirnov et al., PRB 2014
Density evolution of the condensate
Bobrovska et al., PRB 2014
SLIDE 10
INHOMOGENEOUS PUMPING
HOMOGENEOUS PUMPING
First-order correlation First-order correlation function TWA – truncated Wigner Approximation Density evolution of the condensate
Bobrovska et al., PRB 2014
SLIDE 11
INHOMOGENEOUS PUMPING
HOMOGENEOUS PUMPING
Uniform flow waves
Bobrovska et al., PRB 2014
SLIDE 12
INHOMOGENEOUS PUMPING
HOMOGENEOUS PUMPING
Effect of polariton energy relaxation Relaxation term
Tanese et al, Nat. Commun 2013 Bobrovska et al., PRB 2014
SLIDE 13 INHOMOGENEOUS PUMPING
INHOMOGENEOUS PUMPING
Gaussian profile
- Narrow (W = 15.8)
- Wider (W = 44.7)
Large spot Small spot
Bobrovska et al., PRB 2014
SLIDE 14
INHOMOGENEOUS PUMPING
HOMOGENEOUS PUMPING
Experimental evidence of influence of the pumping profile on the stability and condensate coherence in 2D are recently shown in the organic condensates. Courtesy of S. Kena-Cohen
Kena-Cohen et al., Nat. Phot, 2010 Daskalakis et al. ArXiv:1503.01373v
2D simulations experiment Numerical simulations
SLIDE 15 CONCLUSIONS
Homogeneous pumping Inhomogeneous pumping
- Instability in steady state leads to a significant reduction of the condensate coherence
- The polariton energy relaxation has a little effect on the condensate stability
- Pumping profile has significant effect on the condensate stability
and changes the condensate coherence length
