Surface plasmon photonic structures in terahertz quantum cascade lasers.

The periodic scattering of the surface plasmon modes employed in the waveguide of terahertz quantum cascade lasers is shown to be an efficient method to control the properties of the laser emission. The scatterers are realized as thin slits in the metal and top contact layer carrying the surface plasmon. This technique provides larger coupling strengths than previously reported and can be used in various device implementations.