FEASIBILITY OF FAR-INFRARED LASERS USING MULTIPLE SEMICONDUCTOR QUANTUM-WELLS

A feasibility study is performed for a new semiconductor multiple quantum well far-infrared (THz) laser device, based on selective injection of electrons into an upper subband, and selective removal from a lower subband of a quantum well, using quantum-well energy filters. Photon confinement is achieved between doped injector and collector semiconductor contacts which also serve as good photon reflectors. The lasing threshold current density is estimated to be in the range of J(th) approximately 130 A/cm2 at 5 THz. Thus the feasibility of a far-infrared laser based on this design and operating at cryogenic temperatures (less-than-or-equal-to 10 K) seems quite promising.