Terahertz Lasing at Roomtemperature: Numerical Study of a Vertical-Emitting Quantum Cascade Laser Based on a Quantum Dot Superlattice

TL;DR

This paper presents a numerical study demonstrating the potential for room-temperature terahertz lasing using a quantum dot superlattice in a quantum cascade laser, highlighting novel design and reduced operational thresholds.

Contribution

It introduces a new 'linear combination of quantum dot orbitals' method for bandstructure calculations and shows its effectiveness in achieving room-temperature lasing.

Findings

Strong vertical emission observed in coupled quantum dots

Reduced phonon coupling and in-plane scattering

Lasing achievable at room temperature with lower threshold currents

Abstract

We investigate room temperature lasing of terahertz quantum cascade lasers using quantum dot chains as active material suitable for wireless communication and imaging technologies. Bandstructure calculations for such extended systems of coupled quantum dots are made possible by a novel 'linear combination of quantum dot orbitals'--method, based on single quantum dot wavefunctions. Our results demonstrate strong vertical-emission of coupled quantum dots, reduced phonon coupling and in-plane scattering, enabling room-temperature lasing with significantly reduced threshold current densities.