The continuous wave (cw) operation of quantum cascade lasers operating at wavelengths in the 7.4–8.6 &mgr;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 aT0=110 K. ©1996 American Institute of Physics.