GaAs-AlGaAs based micro lasers emitting at 10 μm and 13 μm

The unipolar semiconductor lasers presented here are quantum cascade lasers (QCL). The lasing transition of the first QCLs occurs between 2 intersubband levels of 3-coupled quantum wells. Electrons are injected into the intersubband levels over a specially designed non-periodic superlattice. One period, consisting of injector and coupled quantum wells is repeated typically 30 times and acts as gain region. Besides coupled quantum wells a periodic or chirped superlattice can act as gain medium. In these miniband lasers the radiative transition takes place between two minibands of a periodic superlattice