Modeling and Optimization of Longwave Infrared Quantum Cascade Lasers

Abstract

AFOSR Award No. FA9550-18-1-0340 Modeling and Optimization of Longwave Infrared Quantum Cascade Lasers PI: Irena Knezevic, University of Wisconsin Madison, iknezevic@wisc.edu The midinfrared (mid-IR) part of the electromagnetic spectrum, with wavelengths in the 320 m range, is of great industrial, medical, and military importance. The atmospheric low-absorption windows at 35 m and 813 m enable free-space applications, such as remote sensing of chemical and biological species, hard-target imaging, range finding, target illumination, and free-space communication. Quantum cascade lasers (QCLs) are the highest-power monolithic coherent light sources in the mid-IR. Today, room temperature (RT), continuous-wave (CW) lasing has been demonstrated throughout the mid-IR using QCLs based on the InGaAs/InAlAs material system on the InP substrate. Under high power, CW operation, the electron and phonon systems in QCLs are both very far from equilibrium and strongly coupled to one another. The problem of their coupled dynamics is both multi-physics (coupled electronic and thermal) and multiscale (bridging between a single stage and device level. Large amounts of energy are pumped into the electronic system, of which a small fraction is given back through the desired optical transitions, while the bulk of it is deposited into the optical-phonon system. The fast relaxation of electrons into optical phonons, followed by the optical phonon slower decay into acoustic phonons, results in excess nonequilibrium phonons that can have appreciable feedback on electronic transport, population inversion, and the QCL figures of merit. To accurately describe QCL performance in the far-from-equilibrium conditions of CW operation, a multiscale electrothermal simulation is needed. We developed a multi-physics and multiscale simulation framework capable of capturing the highly nonequilibrium physics of the strongly coupled electron and phonon systems in QCLs [1-5].

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Document Details

Document Type
Technical Report
Publication Date
Jul 27, 2022
Accession Number
AD1230677

Entities

People

  • I. Knežević

Organizations

  • University of Wisconsin–Madison

Tags

Fields of Study

  • Physics

Readers

  • Computational Fluid Dynamics (CFD)
  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.

Technology Areas

  • Directed Energy
  • Microelectronics
  • Quantum Computing
  • Space
  • Space - Hall-Effect Thruster