Gas Phase Photoacoustic Spectroscopy in the long-wave IR using Quartz Tuning Forks and Amplitude Modulated Quantum Cascade Lasers
A paper to accompany a 20 minute talk about the progress of a DARPA funded project called LPAS. ABSTRACT: We demonstrate the performance of a novel long-wave infrared photoacoustic laser absorbance spectrometer for gas-phase species using an amplitude modulated (AM) quantum cascade (QC) laser and a quartz tuning fork microphone. Photoacoustic signal was generated by focusing the output of a Fabry-Perot QC laser operating at 8.41 micron between the legs of a quartz tuning fork which served as a transducer for the transient acoustic pressure wave. The QC laser was modulated at the resonant frequency of the tuning fork (32.8 kHz). This sensor was calibrated using the infrared absorber Freon-134a by performing a simultanious absorption measurement using a 35 cm absorption cell. The NEAS of this instrument was determined to be 2 x 10^-8 W cm^-1 /Hz^1/2 and the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 907939
- Report Number(s):
- PNNL-SA-51528; 400403809; TRN: US200721%%470
- Resource Relation:
- Conference: Optically Based Biological and Chemical Detection for Defence III. Proceedings of SPIE, 6386:NIL_142 - NIL_150
- Country of Publication:
- United States
- Language:
- English
Similar Records
External Cavity Quantum Cascade Laser for Quartz Tuning Fork Photoacoustic Spectroscopy of Broad Absorption Features
Quartz-Enhanced Photoacoustic Spectroscopy for Field Calibration of Atmospheric Aerosol Absorption Properties