Field-enhanced optical amplification in GaAs/AlGaAs quantum cascade structures

Summary form only given. Since the invention of the quantum cascade laser (QCL), tremendous performance improvements have been attained. Recently, the first QCLs based on the GaAs/AlGaAs system were presented. There has been much effort to determine the gain characteristics, which are important in the design and fabrication of such structures. So far, a direct measurement of the current-induced transmission change in the amplifier portion of the QCL has not been performed. We report the first study of electrically-induced optical transmission changes of a disc-shaped GaAs/AlGaAs quantum cascade structure (QCS) without resonator. We demonstrate a strong field enhancement of optical amplification resonant to a mid-infrared intersubband transmitter.