Mid-infrared InAs∕AlGaSb superlattice quantum-cascade lasers

We report on the demonstration of mid-infrared InAs∕AlGaSb superlattice quantum-cascade lasers operating at 10μm. The laser structures are grown on n-InAs (100) substrate by solid-source molecular-beam epitaxy. An InAs∕AlGaSb chirped superlattice structure providing a large oscillator strength and fast carrier depopulation is employed as the active part. The observed minimum threshold current density at 80K is 0.7kA∕cm2, and the maximum operation temperature in pulse mode is 270K. The waveguide loss of an InAs plasmon waveguide is estimated, and the factors that determine the operation temperature are discussed.