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Polariton Bose-Einstein condensate from a bound state in the continuum
V Ardizzone1,2, F Riminucci1,2,3, S Zanotti4
1CNR Nanotec, Institute of Nanotechnology, Lecce, Italy.
Nature
|May 18, 2022
Summary
Bound states in the continuum (BICs) enable non-equilibrium Bose-Einstein condensation of polaritons. This breakthrough leverages BICs
Area of Science:
- Topological photonics
- Quantum optics
- Condensed matter physics
Background:
- Bound states in the continuum (BICs) are symmetry-protected topological states.
- BICs exhibit theoretically infinite lifetimes and topological charges.
- Previous studies showed optical BICs with lasing, but their full potential remains untapped.
Purpose of the Study:
- To demonstrate non-equilibrium Bose-Einstein condensation of polaritons within a BIC.
- To exploit the non-radiative nature of BICs for enhanced polariton accumulation.
- To investigate the unique dispersion properties and topological aspects of this phenomenon.
Main Methods:
- Utilizing a planar photonic crystal lattice to realize symmetry-protected BICs.
- Confining polaritons (hybrid light-matter excitations) within a waveguide geometry.
- Observing polariton condensation at a saddle point in reciprocal space due to BIC properties.
Main Results:
- Achieved non-equilibrium Bose-Einstein condensation of polaritons in a BIC.
- Demonstrated an extremely low threshold density for condensation.
- Observed condensation at a saddle point, not the dispersion minimum, enabled by BIC lifetime and confinement.
Conclusions:
- Bridged bosonic condensation with symmetry-protected BICs, imparting topological properties onto macroscopic quantum states.
- Revealed unexplored dispersion features in polariton condensation.
- Opened avenues for energy-efficient polariton condensation in integrated photonic devices and hybrid light-matter optical circuits.
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