Complex Broadband Millimeter Wave Response of a Double Quantum Dot: Rabi Oscillations in an Artificial Molecule

Complex photoconductive measurements of the current through a double quantum dot enable us to monitor effects of coherent electron transport in the suppression of the rabi oscillations of this ``artificial molecule.'' The current is induced by a new broadband millimeter wave source functioning as a heterodyne interferometer, which consists of two nonlinear transmission lines generating harmonic outputs in the range 2--400 GHz, and, being coherent, allows tracking the induced current through the sample in both magnitude and phase.