Lasing and high intensity photoluminescence in InGaAsGaAs strained layer superlattices

A pulsed nitrogen laser was used to excite lasing and photoluminescence (PL) in InGaAsGaAs strained-layer superlattices (SLS). At moderate excitation intensities the PL spectrum consisted of a single narrow peak. But at higher intensities a second peak, up to 16 meV lower in energy, was also seen due to optical gain induced in the waveguiding SLS structure. In a laser geometry gain could also be seen at an intermediate wavelength, about 4 meV below the spontaneous emission line center.