Quantum-dot cascade laser: proposal for an ultralow-threshold semiconductor laser

We propose a quantum-dot version of the quantum-well cascade laser of Faist et al., see Science, vol. 264, p. 553, 1994. The elimination of single phonon decays by the three-dimensional confinement implies a several order-of-magnitude reduction in the threshold current. The requirements on dot size (10-20 nm) and on dot density and uniformity [one coupled pair of dots per (200 nm/sup 3/) with 5% nonuniformity] are close to current technology.