Mid-infrared pump-related electric-field domains in GaAs/(Al,Ga)As quantum-cascade structures for terahertz lasing without population inversion

Journal Article · Tue Nov 15 00:00:00 EST 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3660676· OSTI ID:22036771

Giehler, M; Wienold, M; Schrottke, L; Hey, R; Grahn, H T ^[1]; Pavlov, S G ^[2]; Huebers, H -W ^[2]; Winnerl, S; Schneider, H ^[3]

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1. Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)
2. Deutsches Zentrum fuer Luft- und Raumfahrt, Rutherfordstr. 2, 12489 Berlin (Germany)
3. Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany)

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 CO{sub 2} 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.

• OSTI ID: 22036771
• Journal Information: Journal of Applied Physics, Vol. 110, Issue 10; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
CARBON DIOXIDE
COMPUTERIZED SIMULATION
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
FREE ELECTRON LASERS
GAIN
GALLIUM ARSENIDES
GAS LASERS
NUMERICAL ANALYSIS
OPTICAL PUMPING
POPULATION INVERSION
SEMICONDUCTOR MATERIALS
THZ RANGE
TUNNEL EFFECT