Optically pumped laser oscillation at 3.9 microns from Al(o. 5)Ga(0.5)Sb/InAs(0.91)Sb(0.09/Al(0.5)Ga(0.5)Sb double heterostructure grown by molecular beam epitaxy on GaSb.

Double heterostructures consisting of InAs(0.91)Sb(0.09) active layers with Al(0.5)Ga(0.5)Sb cladding layers were grown by molecular beam epitaxy on GaSb substrates. Optically pumped laser emission at 3.9 microns was observed from 80K to 135K with an exponentially dependent threshold with T(0) = 17K. At 80K the threshold corresponds to an effective current of 4 kA/cm(2). This value represents a significant reduction when compared with previous results. For a 1 micron thick active layer the full angular width of the far field at the half intensity point normal to the junction is 40degrees and is in reasonable agreement with the width calculated from the guide and cladding refractive indices.