Optical studies of a two-dimensional electron system in a cavity: quantum Hall polaritons
Light-matter interaction has played a central role in understanding and engineering new states of matter. Reversible coupling of excitons and photons enabled groundbreaking results in condensation and superfluidity of nonequilibrium quasiparticles with a photonic component. In this work, we combine the physics of correlated many-body states in a two-dimensional electron system with the methods of cavity quantum electrodynamics. By coupling the cavity photon of an AlGaAs based DBR micro-cavity structure to optical inter-band excitations of a 20 nm GaAs quantum well we observe the emergence of novel many-body polariton modes. In the presence of a magnetic field, polaritons show distinct signatures of integer and fractional quantum Hall ground states. We use the strong coupling of the cavity mode to bound trion states of inter-Landau level transitions to perform the spectroscopy of many-body correlated states in the quantum Hall regime. These quantum Hall polaritons provide a direct way to study the spin-polarization of quantum Hall states by measuring the polarization dependent normal-mode splitting. Our technique is also well suited to study the compressibility of the electron system and constitutes a powerful method to complement transport spectroscopy with the advantages of a minimally invasive local probe.
Host: Luis A. Orozco
Subscribe to A Quantum Bit
Quantum physics began with revolutionary discoveries in the early twentieth century and continues to be central in today’s physics research. Learn about quantum physics, bit by bit. From definitions to the latest research, this is your portal. Subscribe to receive regular emails from the quantum world. Previous Issues...
Sign Up Now
Sign up to receive A Quantum Bit in your email!