Surface Emitting Ring Quantum-cascade Lasers made by Focused Ion Beam Milling

The results on the fabrication and studies of ring quantum-cascade lasers with light output through a second-order diffraction grating are presented. The grating was formed over the entire surface of the ring cavity by the focused ion beam milling. Lasing in vertical direction to surface was observed near
$7.75\ \mu \mathrm{m}$
at room temperature.