Photopumped phonon-assisted laser operation (77 K) of In0.5(AlxGa1-x)0.5P quantum well heterostructures

The photopumped phonon-assisted laser operation (612 nm, 77 K) of a high-gap In1−y(AlxGa1−x)yP quantum well heterostructure (QWH) lattice matched to GaAs (y≊0.5) is identified using a single rectangular sample that is shifted in its heat sinking from (a) low Q when clamped onto Au (bare edges) to (b) high Q when further compressed into Au with all four edges reflecting. For the low-Q QWH sample photopumped in a spot (partially photopumped), phonon-assisted laser operation (abrupt threshold, narrow spectrum) is observed on closely spaced end-to-end laser modes ΔE=ℏωLO≊45–47 meV below the lowest confined-particle transitions. For the same sample shifted to high Q, edge-to-edge laser operation across the sample on confined-particle transitions is ‘‘turned on’’ also, thus providing an unambiguous experimental reference (ℏωLO≊45–47 meV) for the phonon sideband.