Continuous wave operation of midinfrared (7.4-8.6 mu m) quantum cascade lasers up to 110 K temperature

The continuous wave (cw) operation of quantum cascade lasers operating at wavelengths in the 7.4-8.6 mu m range is reported. The GaInAS/AlInAs structures, grown by molecular beam epitaxy, are based on a vertical intersubband transition scheme and use a plasmon-enhanced waveguide geometry to reduce losses and increase the confinement factor. The single mode cw optical power from one facet is 2 mW up to a maximum temperature of 110 K. In pulsed operation, the highest temperature is 210 K and the threshold shows a weak temperature dependence typical of these class of lasers, with a T-0 = 110 K. (C) 1996 American Institute of Physics.