Experimental Investigation of the Pulsed Photoacoustic Effect Produced on a Solid Surface
Abstract
The purpose of this investigation was to determine the characteristics of the photoacoustic signal generated from the surface of a solid material. The important characteristics considered were the dependence of the signal upon (1) the pump-laser power level, (2) the absorption coefficient and specific heat of the material, (3) the radial and axial sound distribution, and (4) the distribution of sound with laser focal characteristics. The model of peak sound pressure for the photoacoustic effect employed in this study was developed by Patel and Tam for liquids. The divergence angles of cylindrical and spherical sound waves were calculated by means of the lateral sound pressure distribution. Throughout the study the peak pressure of the photoacoustic sound pulse was measured through the use of the linear deflection of a HeNe probe beam. The results indicate that the Patel model for the peak pressure of a photoacoustic signal gives an adequate description of the dependence of the sound pressure upon radial distance and pump-laser power level. The results indicate that a cylindrical wave generated by titanium is optimum for applications to the measurement of flame temperatures. Originator-supplied keywords include: Photoacoustics, Sound Propagation, Sound Generation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1984
- Accession Number
- ADA152114
Entities
People
- Hyun Chul Yoon
Organizations
- Air Force Institute of Technology