Spectroscopy in the gas phase with GaAs/AlGaAs quantum-cascade lasers.
We demonstrate what we believe is the first application of the recently developed electrically pumped GaAs/AlGaAs quantum-cascade lasers in a spectroscopic gas-sensing system by use of hollow waveguides. Laser light with an emission maximum at 10.009 microm is used to investigate the mid-infrared absorption of ethene at atmospheric pressure. We used a 434-mm-long silver-coated silica hollow waveguide as a sensing element, which served as a gas absorption cell. Different mixtures of helium and ethene with known concentrations are flushed through the waveguide while the laser radiation that passes through the waveguide is analyzed with a Fourier-transform infrared spectrometer. The experimentally obtained discrete ethene spectrum agrees well with the calculated spectrum. A detection threshold of 250 parts per million is achieved with the current setup.
Hvozdara
L
L
Institute for Solid State Electronics, Technical University of Vienna, Gusshausstrasse 25-29y362, A-1040 Vienna, Austria.
Gianordoli
S
S
Strasser
G
G
Schrenk
W
W
Unterrainer
K
K
Gornik
E
E
Murthy
C S
CS
Kraft
M
M
Pustogow
V
V
Mizaikoff
B
B
Inberg
A
A
Croitoru
N
N