Open AccessSpectroscopy of GaAs∕AlGaAs quantum-cascade lasers using hydrostatic pressure
Author(s) -
S. R. Jin,
C. N. Ahmad,
Stephen J. Sweeney,
A.R. Adams,
B. N. Murdin,
H. Page,
X. Marcadet,
Carlo Sirtori,
Stanko Tomić
Publication year - 2006
Publication title -
applied physics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 442
eISSN - 1077-3118
pISSN - 0003-6951
DOI - 10.1063/1.2364159
Subject(s) - hydrostatic pressure , lasing threshold , laser , cascade , quantum well , electron , atomic physics , semiconductor laser theory , delocalized electron , ambient pressure , gallium arsenide , materials science , optoelectronics , wavelength , chemistry , physics , optics , organic chemistry , chromatography , quantum mechanics , thermodynamics
The authors have measured the output spectrum and the threshold current in 9.2μm wavelength GaAs∕Al0.45Ga0.55As quantum-cascade lasers at 115K as a function of hydrostatic pressure up to 7.3kbars. By extrapolation back to ambient pressure, thermally activated escape of electrons from the upper lasing state up to delocalized states of the Γ valley is shown to be an important contribution to the threshold current. On the other hand leakage into the X valley, although it has a very high density of states and is nearly degenerate with the Γ band edge in the barrier, is insignificant at ambient pressure.
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