Open AccessHeterodyne interferometric signal retrieval in photoacoustic spectroscopy
Author(s) -
Karol Krzempek,
Grzegorz Dudzik,
Krzysztof M. Abramski,
Gerard Wysocki,
Piotr Jaworski,
Michał Nikodem
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.001125
Subject(s) - optics , photoacoustic spectroscopy , interferometry , heterodyne (poetry) , materials science , laser , heterodyne detection , signal (programming language) , spectroscopy , optical path , optical path length , photoacoustic effect , refractive index , physics , computer science , quantum mechanics , acoustics , programming language
A new heterodyne interferometric method for optical signal detection in photoacoustic or photothermal spectroscopy is demonstrated and characterized. It relies on using one laser beam for the photoacoustic excitation of the gas sample that creates refractive index changes along the beam path, while another laser beam is used to measure these changes. A heterodyne-based detection of path-length changes is presented that does not require the interferometer to be balanced or stabilized, which significantly simplifies the optical design. We discuss advantages of this new approach to photoacoustic signal detection and the new sensing arrangements that it enables. An open-path photoacoustic spectroscopy of carbon dioxide at 2003 nm and a novel sensing configuration that enables three-dimensional spatial gas distribution measurement are experimentally demonstrated.