TI-QCL Energy Band Diagram.

Mid-wave infrared (MWIR) emissions are useful for a variety of applications ranging from communication to remote chemical sensing. The ability to produce efficient, modulatable, and coherent MWIR sources can help propel current technologies in these fields and enable new innovations. While standard quantum cascade lasers (QCLs) are one common solution for MWIR lasers, the transistor-injected quantum cascade laser (TI-QCL) presents a novel approach with several key advantages over conventional QCL devices. The added capability of the TI-QCL to separably control output power and emission wavelength enable or enhance more applications, such as spectroscopic measurements. Previous designs of the TI-QCL have demonstrated proper transistor function but have failed to produce coherent MWIR light. Recent focus has been put on improving both device design and processing control in pursuit of a fully functional and efficient device.

Related News + Publications

• Anik Presents TI-QCL Optimization Work at CS MANTECH
  Anik Mazumder presents his poster titled “Design Optimization for Carrier Injection and Optical Mode Profile in Mid-Infrared Transistor Injected-Quantum Cascade Lasers” at CS MANTECH 2026.
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  Negative differential resistance, self-oscillations, and light emission in transistor-injected quantum cascade structures
  We experimentally demonstrate negative differential resistance, collector current oscillations, and light emission in a transistor-injected quantum cascade structure. Distinct transport regimes are accessed by varying the reverse bias across the base-collector junction while independently controlling emitter injection. The collector current shows pronounced oscillations and alternating high–low levels as the reverse bias changes, indicating quantum transport… Read more: Negative differential resistance, self-oscillations, and light emission in transistor-injected quantum cascade structures
• Robert Presents QCL Work at CS MANTECH 2025
  Robert Kaufman presents his talk titled, “Impurity-Induced Disordering of InGaAs/InAlAs Superlattices by Zinc Diffusion for Electrical Confinement in Quantum Cascade Lasers” at CS MANTECH 2025.
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  Robert Presents TI-QCS Research at CS MANTECH 2024
  At the 2024 CS MANTECH conference, Robert presents his work finding unique device physics in his transistor injected quantum cascade structure (TI-QCS).
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  Ultra-sensitive current bistability and light switching in a resonant tunneling superlattice transistor
  Bistability in the current–voltage characteristics of semiconductor superlattices and quantum cascade laser structures has the potential for wide-ranging applications, particularly in sensing systems. However, the interdependency of applied bias and current injection in conventional two-terminal structures has led to complications in analysis and rendered the bistability phenomenon difficult to implement in practical applications. Here, we… Read more: Ultra-sensitive current bistability and light switching in a resonant tunneling superlattice transistor