Mid-infrared pump-related electric-field domains in GaAs/(Al,Ga)As quantum-cascade structures for terahertz lasing without population inversion
Mid-infrared pump-related electric-field domains in GaAs/(Al,Ga)As quantum-cascade structures for terahertz lasing without population inversion
Giehler, M.; Wienold, M.; Schrottke, L.; Hey, R.; Grahn, H. T.; Pavlov, S. G.; Hübers, H.-W.; Winnerl, S.; Schneider, H.
We investigate the effect of mid-infrared (MIR) pumping on the transport properties of GaAs/(Al,Ga)As terahertz (THz) quantum lasers (TQLs), which rely on quantum coherence effects of intersubband transitions. Aiming at THz lasing at elevated temperatures, we extend the concept of THz gain with and without population inversion of a single, MIR-pumped, electrically driven THz stage proposed by Waldmueller et al. [Phys. Rev. Lett. 99, 117401 (2007)] to an entire TQL. However, experiments using a CO2 as well as a free-electron laser and numerical simulations show that this resonant MIR pumping causes a negative differential conductivity (NDC) in addition to the NDC caused by sequential tunneling. Lasing of these TQLs is prevented by the formation of electric-field domains below the resonance field strength for gain of each single THz stage.
Keywords: quantum cascade laer; intersubband transition; GaAs/AlGaAs; free-electron laser
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
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- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 16289) publication
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Journal of Applied Physics 110(2011), 103104
DOI: 10.1063/1.3660676
Cited 13 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-16289