Mid-infrared (8.5 μm) semiconductor lasers operating at room temperature

The room-temperature pulsed operation of a semiconductor laser emitting at 8.5 μm is reported. This device is an optimized vertical transition quantum cascade (QC) laser. At 300 K the peak output power from a single facet is 15 mW, and the current density at threshold is /spl sim/8 kA/cm
²
. The temperature dependence of the threshold current density is described by a high T
₀
(107 K) in the 200-320 K temperature range.