Room-temperature low-threshold type-II quantum-well lasers at 4.5 μm

We report optically pumped InAs-InGaSb-InAs-AlSb type-II quantum-well lasers at 3.84-4.48 μm. Lasing was observed at temperatures up to 300 K with a characteristic temperature T
₀
of 61.6 K. The average absorbed threshold power was only 0.7 mW at 220 K, and 2.7 mW at 300 K with a pulselength of 650 ns and a repetition rate of 2 kHz. At 49 K, the continuous-wave (CW) output power was 4.2 mW/facet with an absorbed threshold pump power of 31.5 mW and an absorbed pump power of 62 mW, indicating a differential quantum efficiency of 54% for two facets.