Photoacoustic spectroscopy with quantum cascade distributed-feedback lasers.

We present photoacoustic (PA) spectroscopy measurements of carbon dioxide, methanol, and ammonia. The light source for the excitation was a single-mode quantum cascade distributed-feedback laser, which was operated in pulsed mode at moderate duty cycle and slightly below room temperature. Temperature tuning resulted in a typical wavelength range of 3cm(-1)at a linewidth of 0.2cm(-1). The setup was based on a Herriott multipass arrangement around the PA cell; the cell was equipped with a radial 16-microphone array to increase sensitivity. Despite the relatively small average laser power, the ammonia detection limit was 300 parts in 10(9)by volume.

[1]  Frank K. Tittel,et al.  Compact mid-infrared trace gas sensor based on difference-frequency generation of two diode lasers in periodically poled LiNbO3 , 1998 .

[2]  Mads Hammerich,et al.  Photoacoustic detection of NH3 in power plant emission with a CO2 laser , 1989 .

[3]  A. Karbach,et al.  Photoacoustic signal in a cylindrical resonator: Theory and laser experiments for CH4 and C2H6 , 1986 .

[4]  M. Sigrist,et al.  Continuously tunable high-pressure CO/sub 2/ laser for spectroscopic studies on trace gases , 1996 .

[5]  Federico Capasso,et al.  Single-mode tunable, pulsed, and continuous wave quantum-cascade distributed feedback lasers at λ≅4.6-4.7 μm , 2000 .

[6]  Federico Capasso,et al.  Continuous-wave and high-power pulsed operation of index-coupled distributed feedback quantum cascade laser at λ≈8.5 μm , 1998 .

[7]  M. Sigrist,et al.  Co-laser photoacoustic spectroscopy of gases and vapours for trace gas analysis , 1990 .

[8]  Herwig Kogelnik,et al.  Off-Axis Paths in Spherical Mirror Interferometers , 1964 .

[9]  Federico Capasso,et al.  Self-mode-locking of quantum cascade lasers with giant ultrafast optical nonlinearities. , 2000, Science.

[10]  R. Zare,et al.  Photoacoustic spectroscopy using quantum-cascade lasers. , 1999, Optics letters.

[11]  Erich Gornik,et al.  GaAs/AlGaAs distributed feedback quantum cascade lasers , 2000 .

[12]  Mattias Beck,et al.  High-temperature operation of distributed feedback quantum-cascade lasers at 5.3 μm , 2001 .