Photon-assisted-tunneling in a coupled double quantum dot under high microwave excitation powers

We perform photon-assisted-tunneling (PAT) experiments on a GaAs double quantum dot device under high microwave excitation power. Photon-assisted absorption of up to 14 photons is observed, when electron temperature (>1 K) is far above the lattice temperature. Signatures of Landau-Zener-Stuckelberg interference are found even in this non-equilibrium PAT spectrum. In addition, the charge state relaxation time T1∼8ns measured in this out of thermal equilibrium double quantum dot is in agreement with other previous reports.