Tuning terahertz transitions in a double-gated quantum ring
Physical review B: Condensed matter and materials physics
American Physical Society
© 2017 American Physical Society
We theoretically investigate the optical functionality of a semiconducting quantum ring manipulated by two electrostatic lateral gates used to induce a double quantum well along the ring. The well parameters and corresponding interlevel spacings, which lie in the THz range, are highly sensitive to the gate voltages. Our analysis shows that selection rules for interlevel dipole transitions, caused by linearly polarized excitations, depend on the polarization vector angle with respect to the gates. In striking difference from the conventional symmetric double well potential, the ring geometry permits polarization-dependent transitions between the ground and second excited states, allowing the use of this structure in a three-level lasing scheme.
We acknowledge support from the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom, via the EPSRC Centre for Doctoral Training in Metamaterials XM2 (Grant No. EP/L015331/1). This work was also supported by the EU FP7 ITN NOTEDEV (Grant No. FP7-607521); EU H2020 RISE project CoExAN (Grant No. H2020-644076); and FP7 IRSES projects CANTOR (Grant No. FP7-612285), QOCaN (Grant No FP7-316432), and InterNoM (Grant No FP7-612624).
This is the final version of the article. Available from American Physical Society via the DOI in this record.
Vol. 96 (23), article 235430