Room temperature spasing of surface plasmon polaritons at 1.46 μm wavelength has been demonstrated by sandwiching a gold-film plasmonic waveguide between optically pumped InGaAs quantum-well gain media. The spaser exhibits gain narrowing, the expected transverse-magnetic polarization, and mirror feedback provided by cleaved facets in a 1-mm long cavity fabricated with a flip-chip approach. The 1.06-μm pump-threshold of ~60 kW/cm2 is in good agreement with calculations. The architecture is readily adaptable to all-electrical operation on an integrated microchip.
We report a five-stage interband cascade laser that operates at λ=3.75μm in cw mode up to a maximum temperature of 319K. With gold electroplating, epitaxial-side-up mounting, and one facet coated for high reflectivity, a 3mm×9.2μm ridge emits over 10mW of cw power at 300K.
Lifetimes and Auger coefficients for type-II W interband cascade lasers are deduced from correlations of the experimental threshold current densities and slope efficiencies with calculated threshold carrier densities and optical gains. The room-temperature Auger coefficients for a number of low-threshold devices emitting at wavelengths from 2.9 to 4.1 μm fall in the narrow range of (3–5)×10−28 cm6/s, which represents a much stronger suppression of Auger decay than was implied by most earlier experiments and theoretical projections. The Auger coefficient is nearly independent of the thicknesses and compositions of the layers in the W active region.
Dilute-nitride GaNSb bulk materials with up to 1.4% nitrogen were grown by molecular beam epitaxy on GaSb substrates. Hall measurements indicate residual hole concentrations of nearly 10 19 cm −3 at room temperature, but a decrease to below 10 16 cm −3 and a hole mobility of 1300 cm 2 / V s at 4.5 K for a sample with 0.6% nitrogen. Photoluminescence ͑PL͒ and optical absorption measurements demonstrate a bandgap reduction by up to 300 meV with increasing nitrogen incorporation. The experimental absorption spectra are well fit by a functional dependence corresponding to direct allowed optical transitions, and the PL spectra are also consistent with that interpretation. Room temperature carrier relaxation times in the picosecond range are measured using an ultrafast PL upconversion technique.
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