Coherent submillimeter-wave emission from charge oscillations in a double-well potential

We directly observe the electromagnetic radiation emitted by electrons coherently oscillating between the two wells of a semiconductor coupled-quantum- well structure. Using time-resolved coherent detection of the submillimeter-wave radiation from these spatial charge oscillations, we trace up to fourteen oscillations at 1.5 THz before phase relaxation destroys the coherence of the oscillating wave packet. In addition to the oscillatory electromagnetic signal, we also observe an instantaneous signal from electricfield-induced optical rectification in the semiconductor structure

Terahertz radiation from coherent electron oscillations in a double-quantum-well structure.

We detect the submillimeter-wave radiation from excitonic wave packets that, after excitation by an ultrashort laser pulse, oscillate coherently between the two wells of a semiconductor coupled-quantum-well structure. In addition, we identify a terahertz signal originating from the instantaneous polarization of photo-excited excitions in an electrical bias field