Flexible lock-in detection system based on synchronized computer plug-in boards applied in sensitive gas spectroscopy
Författare
Summary, in English
We present a flexible and compact, digital, lock-in detection system and its use in high-resolution
tunable diode laser spectroscopy. The system involves coherent sampling, and is based on the
synchronization of two data acquisition cards running on a single standard computer. A
software-controlled arbitrary waveform generator is used for laser modulation, and a four-channel
analog/digital board records detector signals. Gas spectroscopy is performed in the wavelength
modulation regime. The coherently detected signal is averaged a selected number of times before it
is stored or analyzed by software-based, lock-in techniques. Multiple harmonics of the modulation
signal 1f, 2f, 3f, 4f, etc. are available in each single data set. The sensitivity is of the order of 10−5,
being limited by interference fringes in the measurement setup. The capabilities of the system are
demonstrated by measurements of molecular oxygen in ambient air, as well as dispersed gas in
scattering materials, such as plants and human tissue.
tunable diode laser spectroscopy. The system involves coherent sampling, and is based on the
synchronization of two data acquisition cards running on a single standard computer. A
software-controlled arbitrary waveform generator is used for laser modulation, and a four-channel
analog/digital board records detector signals. Gas spectroscopy is performed in the wavelength
modulation regime. The coherently detected signal is averaged a selected number of times before it
is stored or analyzed by software-based, lock-in techniques. Multiple harmonics of the modulation
signal 1f, 2f, 3f, 4f, etc. are available in each single data set. The sensitivity is of the order of 10−5,
being limited by interference fringes in the measurement setup. The capabilities of the system are
demonstrated by measurements of molecular oxygen in ambient air, as well as dispersed gas in
scattering materials, such as plants and human tissue.
Avdelning/ar
Publiceringsår
2007
Språk
Engelska
Publikation/Tidskrift/Serie
Review of Scientific Instruments
Volym
78
Issue
11
Fulltext
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Dokumenttyp
Artikel i tidskrift
Förlag
American Institute of Physics (AIP)
Ämne
- Atom and Molecular Physics and Optics
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1089-7623