Figure 1
The coupled triple QD system. (a) Schematic energy-level diagram of a triple QD system without a gate voltage. (b) With an applied gate voltage, the energy-level in the conduction-band could get into resonance in the triple QD system. (c) Excitation scheme of the triple QD system, as determined by the Rabi frequency Ω p (which is proportional to the probe-field strength), decoherence channels Γm1 (m = 2, 3, 4), energy-level difference ω4n (n = 1, 2, 3), probe-field detuning Δ p  = ω p  − ω41 from the energy-level difference ω41, and tunneling coupling T ek (k = 1, 2). Driven by a pulsed laser field, one electron can be excited from the valence band to the conduction band to form a direct exciton state |4〉 inside the central dot. The gate electric field allows the electron to tunnel from the central dot to the left (right) dot to form an indirect excitonic states |2〉 (|3〉). Here |1〉 denotes the state with no exciton inside this triple QD.
