Fig. 10: Scheme for the facet damage of long-wave mid-infrared QCL.

a Schematic of a QCL with an electrically isolated tapered output structure. b Cross-sectional view of the QCL using the electrically isolated taper structure scheme. c Current spreading into the tapered out-coupler along the laser cavity direction with an isolation channel depth of 2 um. d Output power of the fundamental mode (TM00) as a function of the taper width on the output facet65