Gas-phase photoacoustic sensor at 8.41 μm using quartz tuning forks and amplitude-modulated quantum cascade lasers

Autor:	Michael D. Wojcik, Bret D. Cannon, Matthew S. Taubman, Mark C. Phillips
Rok vydání:	2006
Předmět:	Materials science Physics and Astronomy (miscellaneous) Microphone business.industry General Engineering General Physics and Astronomy Laser Noise floor law.invention Semiconductor laser theory Transducer Optics law Cascade Tuning fork business Quantum cascade laser
Zdroj:	Applied Physics B. 85:307-313
ISSN:	1432-0649 0946-2171
DOI:	10.1007/s00340-006-2394-8
Popis:	We demonstrate the performance of a novel infrared photoacoustic laser absorbance sensor for gas-phase species using an amplitude-modulated quantum cascade (QC) laser and a quartz tuning fork microphone. The photoacoustic signal was generated by focusing 5.3 mW of a Fabry–Perot QC laser operating at 8.41 μm between the tines of a quartz tuning fork which served as a transducer for the transient acoustic pressure wave. The sensitivity of this sensor was calibrated using the infrared absorber Freon 134a by performing a simultaneous absorption measurement using a 31-cm absorption cell. The power and bandwidth normalized noise equivalent absorption sensitivity (NEAS) of this sensor was determined to be D=2.0×10-8 W cm-1/Hz1/2. A corresponding theoretical analysis of the instrument sensitivity is presented and is capable of quantitatively reproducing the experimental NEAS, indicating that the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::0c450b6d28ab638f3e65523c052b4f43 https://doi.org/10.1007/s00340-006-2394-8 Zobrazit plný text záznamu Plný text ve formátu PDF