Tunneling induced transparency and controllable group velocity in triple and multiple quantum-dot molecules

TL;DR

This paper investigates how tunneling in quantum-dot molecules can create transparency windows and control the group velocity of light, enabling slow light propagation and multiple transparency windows.

Contribution

It introduces a novel analysis of tunneling-controlled transparency and group velocity in triple and multiple quantum-dot molecules, replacing laser coupling with tunneling interactions.

Findings

Two transparency windows in triple quantum-dot molecules.

Group velocity can be as low as 300 m/s.

Multiple quantum-dot molecules can exhibit up to N-1 transparency windows.

Abstract

We analyze the interaction of a triple quantum dot molecules controlled by the tunneling coupling instead of coupling laser. A general analytic expression for the steady-state linear susceptibility for a probe-laser field is obtained and we show that the system can exhibit two transparency windows. The group velocity of the probe-laser pulse is also analyzed. By changing the tunneling couplings, two laser pulses with different central frequency can propagate with the same group velocity. And the group velocity can be as low as 300 m/s in our system. We extend our analysis to the case of multiple quantum dot molecules (the number of the quantum dots is N) and show that the system can exhibit at most N-1 transparency windows. And at most N-1 laser pulses with different central frequencies can be slowed down.