Wavelength modulated photoacoustic spectrometer
U. S. Patent 6,552,792, issued April 22, 2003
Wavelength modulation spectroscopy is efficiently combined with photoacoustic spectroscopy using diode lasers. Diode lasers naturally tune wavelength with injection current, facilitating this combination with photoacoustic detection. Because the differential absorption over the depth of the wavelength modulation generates the detected acoustic wave, broadband absorbing noise sources are suppressed.
The invention by Jeff Pilgrim and David Bomse of Southwest Sciences enhances
signal-to-noise in wavelength modulated photoacoustic systems by modulating
the optical source with square and modified square waveforms. These waveforms
enhance photoacoustic signals by providing proportionately longer heating
and cooling periods for a given frequency through operation solely on the
peak and wings of the absorption feature.
You may view a PDF image of the full patent (13 pages, 750 kb). You will need the free Acrobat Reader available from Adobe.
Contact Information
e-mail sciences@swsciences.com