Ricerc@Sapienza

Semiconductor quantum dots proved to be an extremely interesting source for single and entangled photons for the emerging fields of quantum information and quantum communication. The possibility to tune their light emission properties via strain engineering, to integrate them in the mature semiconductor technology, and the potential to work on-demand raised a high interest from the quantum optics community. Still, the amazing properties of these physics toy-models remain unexploited due to few current limitations. Most of the light emitted by a quantum dot is confined inside the semiconductor host matrix due to refraction index mismatch; moreover, static and dynamic fluctuations in the electronic structure of the individual quantum dot negatively impact the signal repeatability. This hinders optimal match between different emitters, a fundamental requirement for distant nodes in communication networks.
After discovering their fundamental properties, the efforts of the quantum dot community all concentrated in facing the above-mentioned challenges. These efforts recently produced a novel photonic device, i.e. the circular Bragg resonator or Bullseye, which finally helped to unlock the full potential of this promising quantum emitter.
The Nanophotonics group at Sapienza University of Rome already achieved experimental demonstrations of entanglement-based quantum information protocols with semiconductor quantum dots. We at the Nanophotonics group believe to be eligible candidates to implement a Bullseye photonic structure around a single quantum dot coupled with piezoelectric strain engineering to tune its emission energy to the one of another quantum dot. This would allow the demonstration of fundamental quantum information protocols such as quantum teleportation and entanglement swapping with remote quantum dots, a task never reached before.