Low threshold THz QC lasers with thin core regions

It is demonstrated that the active region thickness of THz quantum cascade lasers can be reduced by a factor of 2 without effects on the threshold current density and maximum operating temperature of the laser. Pulsed and continuous-wave operation, with a low threshold Jth= 71 A/cm2, are obtained for a 5.86 µm-thick THz QC laser. The emission is peaked at λ≃115 µm and the waveguide resonator is based on a metal-metal geometry.