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Photoacoustic Microcantilevers for Spectroscopy

Oak Ridge National Laboratory

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Technology Marketing SummaryORNL researchers invented a unique microcantilever design that can identify the
chemical structure of minute sample materials using photoacoustic and photothermal
spectroscopy. The design advances current technology, which cannot identify specific
chemicals, and furthers the detection of vapors, cells, and tissues. The technology can
also characterize biomass, biomaterials, and pharmaceuticals.

DescriptionIn this invention, a beam of light is directed at a target substance on a base in an
environment with reduced noise. The base supports a cantilever that measures the
acoustic waves generated as the chopped/pulsed light is absorbed by the sample; the
wavelengths of light can then be detected and measured.

As the wavelength changes, the target either absorbs or rejects each optical frequency.
Rejection decreases the photoacoustic intensity, and absorption increases it; both
affect the vibrating cantilever. By monitoring the variations of vibration intensity as
a function of the changing wavelengths of light, researchers detect a spectrum that
identifies the chemical structure of the target material.
  • Identifies chemicals in extremely small sample quantities
  • Improves current technology, which cannot identify specific chemicals
  • Increases the amount of chemical sample adsorbed on the sensor without losing sensitivity
  • Can be made compact
Applications and Industries
  • Detection of chemical vapors, adsorbates, immobilized cells, and tissues
  • Characterization of biomass, tissues and cells, and pharmaceuticals
  • Fourier transform infrared spectroscopy to obtain an infrared spectrum of absorption, emission, photoconductivity or Raman scattering of a solid, liquid or gas
More InformationPatent
Thomas G Thundat, Charles W. Van Neste, Gilbert M. Brown, and Lawrence R. Senesac, Photoacoustic Microcantilevers, U.S. Patent Application 12/488,238, filed June 19, 2009.

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
Patent 8,194,246
Photoacoustic microcantilevers
A system generates a photoacoustic spectrum in an open or closed environment with reduced noise. A source focuses a beam on a target substance disposed on a base. The base supports a cantilever that measures acoustic waves generated as light is absorbed by the target substance. By focusing a chopped/pulsed light beam on the target substance, a range of optical absorbance may be measured as the wavelength of light changes. An identifying spectrum of the target may detected by monitoring the vibration intensity variation of the cantilever as a function of illuminating wavelength or color.
Oak Ridge National Laboratory 06/05/2012
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated

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To: Nestor Fronco<>