Long-wavelength (∼15.5μm) unipolar semiconductor laser in GaAS quantum wells

A unipolar semiconductor laser emitting in the mid-infrared spectral region is demonstrated. The laser scheme relies on a simple three-level system in GaAs/AlGaAs asymmetric coupled quantum wells. Population inversion between excited states is achieved by optical pumping of electrons from the ground state with a CO2 laser. Long-wavelength (approximate to 15.5 mu m) laser emission is demonstrated, The laser is operated in the pulsed regime up to a temperature of 110 K and with an output peak power approximate to 0.4 W at 77 K, Unipolar quantum well semiconductor lasers based on this principle are capable of covering the long wavelength mid-infrared spectral region above 12 mu m. (C) 1997 American Institute of Physics. [S0003-6951(97)00851-6].