Dimensional resonances in wide parabolic quantum wells

The direct observation of dimensional resonances in wide parabolic quantum wells is reported. Using a grating-coupler technique, we are able to excite and detect these resonances without the mediation of a magnetic field. The ability to tune electrically the carrier density in the well and—though not independently—the shape of the confining potential, enables us to compare directly our results with those of a recent theoretical prediction.