Midinfrared IV–VI vertical-cavity surface-emitting lasers with zero-, two-, and three-dimensional systems in the active regions

A comparison between IV–VI vertical-cavity surface-emitting midinfrared lasers containing active regions of different dimensionality is presented. Optically pumped laser emission is observed at wavelengths between 3.5 and 4.4 μm. The microcavities consist of high-reflectivity EuTe/PbEuTe Bragg mirrors, with active regions consisting either of a self-organized PbSe/PbEuTe quantum-dot superlattice, PbTe/PbEuTe multiquantum wells, or bulk-like PbTe. For the zero dimensional active medium, laser emission is obtained at temperatures up to 150 K. The results for the lasers with two-dimensional active region are similar to those with the three-dimensional bulk-like active region, for which lasing is observed up to 317 K. The threshold pump intensity is only 4 kW/cm2 at 195 K, and 15.6 kW/cm2 at room temperature.