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Photoacoustic Point Spectroscopy

Oak Ridge National Laboratory

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Technology Marketing SummaryORNL researchers invented a detector that uses photoacoustic waves to excite a
vibratory sensor coated with unknown molecules. This invention can be used to
identify these molecules and study solid, gas, or liquid samples.

DescriptionThe device is an advance over other photoacoustic spectroscopy techniques,
because it uses a vibratory sensor instead of a resonant chamber and microphone.
This approach is effective in an open environment and also increases the sensitivity
of detection.

BenefitsTo identify the molecules, pulsed/chopped light is shown on a sensor. Acoustic waves
are produced at the light’s frequency, mechanically oscillating the vibratory sensor.
As the molecules absorb or reflect the impelling light, the amplitude of the acoustic
waves and the vibrating sensor increases or decreases. Identification of the molecule is
based on the vibrational amplitude of the sensor verses optical wavelength.

  • Increased range and sensitivity
  • Compact size
Applications and Industries
  • Open environment photoacoustic spectroscopy
  • Molecular analysis
More InformationPatent
Charles W. Van Neste, Lawrence R. Senesac, and Thomas G. Thundat, Photoacoustic Point Spectroscopy, U.S. Patent Application 12/189,652, filed August 11, 2008.

Lead Inventor
Charles W. Van Neste
Measurement Science and Systems Engineering Division
Oak Ridge National Laboratory

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Application 20100033722
A system and method are disclosed for generating a photoacoustic spectrum in an open or closed environment with reduced noise. A source may emit a beam to a target substance coated on a detector that measures acoustic waves generated as a result of a light beam being absorbed by the target substance. By emitting a chopped/pulsed light beam to the target substance on the detector, it may be possible to determine the target's optical absorbance as the wavelength of light is changed. Rejection may decrease the intensity of the acoustic waves on the detector while absorption may increase the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.
Oak Ridge National Laboratory 08/11/2008
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated

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To: Nestor Fronco<>