From Single Quanta to Macro Coherence

Quantum mechanics is the language in the microscopic world where single or few particles and quasi-particles are fully described by their complex wavefunctions and a Hermitian system Hamiltonian. When the number of particles grows large, phase correlation among the particles is lost due to interaction with the environment — and we enter the classical world of human scales. In some special systems, however, phase correlations survive among a macroscopic number of particles over macroscopic distances, and remarkable collective quantum phenomena emerge. Those are the systems that we study.

Earlier examples of such studies have led to tremendous advances in modern science and technology, such as stimulated scattering and lasers, Bardeen-Cooper-Schrieffer state and superconductors, Bose-Einstein Condensation and precision measurement. Our current interest centers on the discovery, creation, control and applications of both single quantum state and collective quantum phenomena in solid and light systems.


Collective Quantum States of Matter and Light in Open Systems


Polariton BEC.

  • Dynamic condensation and lasing of semiconductor microcavity polaritons.
  • Strong-coupling and polariton condensation in novel structures and materials
  • Low-dimensional and coupled quantum gasses of polaritons.
  • Dispersion and spin engineering of polaritons.
  • Lattice cavity quantum electrodynamics.
  • Searching for vortices in a polariton quasi-condensate
  • Understanding coherence dynamics in a nonequilibrium polariton system

A poster about this project is available here.


Quantum Photonics & Plasmonics with Wide Bandgap Materials


(Left) Dot Array, (Right) Dot PL.

  • Site-controlled (In)GaN nanostructures and quantum dots.
  • High temperature single photon source.
  • Plasmon and quantum dot coupling.
  • Single- and few-emitter QED.

A poster about this project is available here.


Optical Vortices


(Top) Vortex Images, (Bottom) Zeno Sorter.

A poster about this project is available here.

  • Generation and propagation of high purity optical vortices.
  • High fidelity, compact optical vortex sorters.
  • High-dimensional quantum information processing with optical vortices.