LASER GENERATION AND DETECTION OF SURFACE ACOUSTIC WAVES USING GAS-COUPLED LASER ACOUSTIC DETECTION

摘要

GCLAD is an effective method for detection of SAWs in materials with both smooth and rough surfaces. Rayleigh and/or Lamb waves have been observed in metals, paper, thin films, and polymer/graphite composites. A six-line source array was used to limit the bandwidth of Lamb waves in the composite sample. We also have demonstrated the use of GCLAD as the detector element of a C-scanning system in which each pixel represents the amplitude of a SAW propagating through about one square centimeter of material. Implanted flaws in metal samples were clearly imaged in these tests.