Continuous-wave mid-infrared VCSELs

We report the continuous-wave operation of an optically pumped mid-infrared (mid-IR) vertical-cavity surface-emitting laser (VCSEL). The active region consisting of type-II antimonide quantum wells with a "W" configuration occupies a cavity formed by a semiconductor bottom mirror and dielectric top mirror. The emission wavelength of 2.9 μm is nearly independent of temperature (d/spl lambda//dT/spl ap/0.09 nm/K) compared to type-II edge-emitters and the multimode linewidth is narrow (2.9 nm). At T=78 K, the threshold pump intensity is /spl ap/940 W/cm
²
, the peak output power from a 50-μm spot is 45 mW, and the differential power conversion efficiency is 4.5%. Lasing is observed up to T=160 K.