The Effect of Internal Relaxation on Optoacoustic Conversion in Liquids.

Abstract

In the optoacoustic effect, optical energy is adsorbed by a medium and converted to translational energy, creating an acoustic signal. In most liquids, the conversion process takes place very rapidly (ps or fs) and the nonradiative decay time is much shorter than the resulting acoustic signal. Theories have been developed, based purely on geometrical considerations, which accurately predict the optoacoustic signal in such cases. The results show that for a short pulse of optical energy the time dependence of the acoustic pressure is determined by the size and shape of the excitation zone. This research was concerned with the actual energy transfer process and how variations in the process which exist from one liquid to another will affect the optoacoustic signal. The purpose of this study was to observe the optoacoustic signal in a situation where nonradiative decay is slow enough to compete with the geometry of the excitation zone in determining the time dependence of the acoustic pressure, and to develop a model to predict the signal in such a situation.

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Document Details

Document Type
Technical Report
Publication Date
Feb 05, 1988
Accession Number
ADA191307

Entities

People

  • Charles Thompson
  • Henry E. Bass

Organizations

  • University of Mississippi

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Acoustic Signals
  • Acoustics
  • Classification
  • Conversion
  • Curve Fitting
  • Differential Equations
  • Energy
  • Energy Transfer
  • Equations
  • Excitation
  • Geometry
  • Optical Detection
  • Pressure Gradients
  • Refraction
  • Refractive Index
  • Wave Equations
  • Waveforms

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Materials Science and Engineering.
  • Systems Analysis and Design