Simulation on the nonuniform electrical pumping efficiency of THz quantum-cascade lasers

Abstract

The efficiency of electric pumping of THz quantum-cascade lasers (QCLs) with strip geometry is studied depending on the number and position of contact pads. The numerical simulation of the electric potential distribution in the THz QCL active region is used to determine the required thicknesses of the upper metallisation layers of the THz QCLs to minimize the voltage drop along the laser structure in the case of nonuniform current supply. It is found that the efficiency of electric pumping in the case of a centrally located contact is significantly higher than when the contact pads are located near the laser structure edges. From the calculated dependence of the THz QCL integral power on the thickness of the upper metal layer, it is shown that for effective current injection, the contact pads must be located at a distance of less than 0.5 mm from each other.

Electron beam pumping improves the conversion efficiency of low-frequency photons radiated by perovskite quantum dots

“…3(d) and decrease the pumping current density needed for self-saturation lasing in thin PQD films. Although the EB pumping source's bandwidth has reached the THz band, [32] electron focusing will still exhaust its bandwidth. The great utilization rate of pumping current density to trigger random lasing is extremely advantageous to the design of power-type EB devices at the THz level.…”