Open Accessλ~71 μm quantum cascade lasers with 19% wall-plug efficiency at room temperature
Author(s) -
Richard Maulini,
Arkadiy Lyakh,
Alexei Tsekoun,
C. K. N. Patel
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.017203
Subject(s) - materials science , cascade , laser , spark plug , quantum cascade laser , optics , resonance (particle physics) , quantum efficiency , optoelectronics , slope efficiency , voltage , injector , wavelength , atomic physics , physics , fiber laser , chemistry , chromatography , quantum mechanics , thermodynamics
Strain-balanced In0.6Ga0.4As/Al0.56In0.44As quantum cascade lasers emitting at a wavelength of 7.1 μm are reported. The active region is based on a three-phonon-resonance quantum design with a low voltage defect of 120 meV at injection resonance. A maximum wall-plug efficiency of 19% is demonstrated in pulsed mode at 293 K. Continuous-wave output power of 1.4 W and wall-plug efficiency of 10% are measured at the same temperature, as well as 1.2 W of average power in uncooled operation. A model for backfilling of the lower laser level which takes into account the number of subbands in the injector is presented and applied to determine the optimum value of the voltage defect to maximize wall-plug efficiency at room temperature, which is found to be ~100 meV, in good agreement with experimental results.