Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 57: Poster IIa
HL 57.20: Poster
Dienstag, 8. März 2005, 16:30–19:00, Poster TU E
Properties of quantum-cascade lasers with metallic mirror coatings and metallic distributed feedback gratings in the 10 µm spectral range — •S. Höfling1, J. Seufert2, M. Fischer2, J. Koeth2, P. Eugster1, J.P. Reithmaier1, and A. Forchel1 — 1Technische Physik, Universität Würzburg, Würzburg — 2nanoplus, Nanosystems and Technology GmbH, Gerbrunn
Manufacturing highly reflective coatings in the 10 µm spectral region is challenging due to the lack of dielectric materials with low absorption. A way to overcome this problem is the application of metallic coatings deposited on the insulated facet. We fabricated these types of mirrors on GaAs based bound-to-continuum quantum-cascade (QC) lasers and observed a reduction by 15 % of the threshold current densities, increased quantum efficiencies, and an increase in maximum operation temperatures by 20 K to 359 K (86 ∘C).
In addition, based on different cascade structures we fabricated single mode QC lasers with distributed feedback metal gratings on top of the laser ridge. Operating these devices at 280 K (240 K), which is readily available with thermoelectric coolers, single mode output powers exceeding 15 mW at 11.1 µm (9.5 µm) were achieved. Furthermore, we report device properties such as the wavelength tuning behavior depending on both the grating period and the heat sink temperature, far field patterns and the high duty cycle performance depending on different packaging techniques.