Buried heterostructure 2.9 THz quantum cascade lasers operating up to 77 K in continuous wave using two-dimensional surface plasmon confinement

We demonstrate the continuous wave operation of a 2.9 THz quantum cascade laser up to 77 K based on a novel buried waveguide geometry. A two dimensional surface plasmon mode is bound at the metal-semiconductor interface, therefore avoiding the usual lateral air confinement for the laser. This is combined with an independent electron channel via proton implantation to realise an embedded structure.