6 research outputs found
On the possibility of a terahertz light emitting diode based on a dressed quantum well
We consider theoretically the realization of a tunable terahertz light
emitting diode from a quantum well with dressed electrons placed in a highly
doped p-n junction. In the considered system the strong resonant dressing field
forms dynamic Stark gaps in the valence and conduction bands and the electric
field inside the p-n junction makes the QW asymmetric. It is shown that the
electrons transiting through the light induced Stark gaps in the conduction
band emit photons with energy directly proportional to the dressing field. This
scheme is tunable, compact, and shows a fair efficiency.Comment: 6 pages, 5 figure
Quantum Rings in Electromagnetic Fields
This is the author accepted manuscript. The final version is available from Springer via the DOI in this recordThis chapter is devoted to optical properties of so-called Aharonov-Bohm
quantum rings (quantum rings pierced by a magnetic flux resulting in AharonovBohm
oscillations of their electronic spectra) in external electromagnetic fields.
It studies two problems. The first problem deals with a single-electron AharonovBohm
quantum ring pierced by a magnetic flux and subjected to an in-plane (lateral)
electric field. We predict magneto-oscillations of the ring electric dipole moment.
These oscillations are accompanied by periodic changes in the selection rules for
inter-level optical transitions in the ring allowing control of polarization properties
of the associated terahertz radiation. The second problem treats a single-mode microcavity
with an embedded Aharonov-Bohm quantum ring which is pierced by a
magnetic flux and subjected to a lateral electric field. We show that external electric
and magnetic fields provide additional means of control of the emission spectrum
of the system. In particular, when the magnetic flux through the quantum ring is
equal to a half-integer number of the magnetic flux quanta, a small change in the
lateral electric field allows for tuning of the energy levels of the quantum ring into
resonance with the microcavity mode, thus providing an efficient way to control
the quantum ring-microcavity coupling strength. Emission spectra of the system are
discussed for several combinations of the applied magnetic and electric fields