InGaAsSb(Gd)/InAsSbP double heterostructure lasers /spl lambda/=3.0-3.3 /spl mu/m for diode laser spectroscopy

Summary form only given. Double heterostructures, consisting of an undoped n-InAs [111]A substrate (n=2/spl middot/10/sup 16/ cm/sup -3/) and three epitaxial layers, were grown by liquid-phase epitaxy: the widegap cladding layer adjacent to the substrate is n-InAs/sub 1-x-y/Sb/sub x/P/sub y/ (0.05/spl les/x/spl les/0.09; 0.09/spl les/y/spl les/0.18); the active layer of the laser is n-In/sub 1-v/Ga/sub v/As/sub 1-w/Sb/sub w/ (v/spl les/0.07; w/spl les/0.07) and the widegap emitter is p(Zn)-InAs/sub 1-x-y/Sb/sub x/P/sub y/ (0.05/spl les/x/spl les/0.09; 0.09/spl les/y/spl les/0.18). The half-width of photoluminescence spectra decreases down to 12 meV and the intensity increases 10-fold. The thickness of the widegap layers were 4 /spl mu/m, and of the active layer /spl sim/1 /spl mu/m. Mesa-stripe lasers with stripe width 20 /spl mu/m and cavity length 70-150 /spl mu/m were fabricated using photolithography. The lasers are operating in the 50-107 K temperature range. The main loss mechanism in the lasers is intraband absorption by holes with their transition to the spin-orbit split-off band due to the closeness of the bandgap energy and spin-orbit splitting energy. In short-cavity lasers the internal losses at threshold become comparable with the gain attained in semiconductor lasers and maximum working temperature is governed by intraband absorption rather than by Auger recombination. A total optical output power of 0.5 mW/facet, single mode power of 0.43 mW/facet and threshold current less than 10 mA are observed at 77 K at CW-operation. Single mode emission is measured with a spectral purity as high as 650:1, tuning rate and range are 210 cm/sup -1//A and 10 cm/sup -1/. Methane gas detection at 3028.75 cm/sup -1/ is demonstrated.