Type-II mid-infrared lasers

摘要

Abstract: Recent progress towards the realization of high-power,non- cryogenic (quasi-)cw mid-IR lasers based on the`W' configuration of the active region is reported.Type-II diodes with AlGaAsSb broadened-waveguideseparate confinement regions are the first III-Vinterband lasers to achieve room-temperature pulsedoperation at a wavelength longer than 3 $mu@m. For cwoperation, T$-max$/ was 195 K and P$-out$/ $EQ 140 mWwas measured at 77 K. Optically- pumped W lasersrecently attained the highest cw operating temperatures(290 K) of any semiconductor laser emitting in the 3 -6 $mu@m range. For a $lambda $EQ 3.2 $mu@m device at 77K, the maximum cw output power was 0.54 W per uncoatedfacet. In order to maximize the absorption of the pumpin the active region, an optical pumping injectioncavity structure was used to create an etalon cavityfor the 2.1 $mu@m pump beam. The pulsed incident pumpintensity at threshold was only 8 kW/cm$+2$/ at 300 Kfor this edge- emitting mid-IR laser. The differentialpower conversion efficiency was 9% at 77 K and 4% at275 K, which indicates promising prospects forachieving high cw output powers at TE-coolertemperatures following further optimization.!30