WARF: P04199US

Intersubband Semiconductor Lasers That Operate Reliably at Room Temperature and in the Mid-Infrared


Dan Botez, Ali Mirabedini, Dapeng Xu, Luke Mawst

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing the first reliable semiconductor laser operating in the mid-infrared region.
OVERVIEWIntersubband semiconductor lasers represent a new type of laser that emits photons when electrons within a quantum-well structure release their energy during transit from high- to low-energy states. Achieving room temperature continuous wave (CW) operation of these lasers at mid-infrared wavelengths (3-5 microns) involves the use of multiple-stage devices called quantum-cascade lasers (QCLs). However, conventional QCLs emitting in the mid-infrared, which are made of InP-based materials, tend to leak carriers. This in turn causes thermal runaway and quick device degradation at room temperature. In addition, in GaAs-based QC devices at high transition energies, the laser’s active region is depopulated due to resonant tunneling between the X valleys of the surrounding barriers, a problem that limits the laser’s room temperature operation to wavelengths longer than 8 microns.
THE INVENTIONUW-Madison researchers have now developed a GaAs-based, quantum-cascade, intersubband semiconductor laser that suppresses virtually all carrier leakage, a feature that makes this device thermally stable during CW operation at room temperature and thus provides the first reliable semiconductor laser operating in the mid-infrared region. The device consists of very deep InGaAs quantum wells sandwiched between very high AlGaAs barrier layers, a structure that tightly confines injected carriers. This structure also prevents resonant tunneling between the X valleys of the surrounding barriers at high transition energies, a feature that also makes room temperature, mid-infrared emission possible in a GaAs device for the very first time.
  • Room temperature operation of GaAs-based lasers
  • Makes room temperature operation of GaAs-based lasers in the mid-infrared (3-5 micron) possible for the first time
  • Also makes reliable CW operation of semiconductor lasers in the mid-infrared possible for the first time
  • Promises to increase the efficiency of far-infrared (8-12 micron) laser emission
  • Simpler and less expensive to manufacture: Devices can be fabricated with low-pressure MOCVD (metal organic chemical vapor deposition) rather than molecular beam epitaxy (MBE)
  • GaAs-based laser technology is significantly more mature than InP-based technology
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Contact Information
For current licensing status, please contact Jeanine Burmania at or 608-960-9846.
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