Sensitive absorption spectroscopy with a room-temperature distributed-feedback quantum-cascade laser.
We report what we believe are the first spectroscopic measurements to be made with a room-temperature quantum-cascade distributed-feedback laser. Using wavelength modulation spectroscopy, we detected N(2)O and CH(4) in the chemical fingerprint wavelength range near 8microm . The noise equivalent absorbance for our measurement was 5 parts in 10(5), limited by excess amplitude modulation on the laser output, which corresponds to a 1-Hz bandwidth detection limit of 250 parts N(2)O in 10(9) parts N(2) in a 1-m path length.
Namjou
K
K
Cai
S
S
Whittaker
E A
EA
Faist
J
J
Gmachl
C
C
Capasso
F
F
Sivco
D L
DL
Cho
A Y
AY