The hardware and software of Scanning Photoacoustic Microscope (SPAM) composed of low price parts are described. From the obtained images it is found that our SPAM can be used well to understand fundamental characteristics of a surface flaw on a machinable ceramic, surface and subsurface flaws in epoxy and the distribution of carbon fiber in the CFRP (Carbon Fiber Reinforced Plastic) as an equipment of nondestructive testing.

In this short note, a new technique for three-dimensional (3-D) high-speed imaging of the subsurface crack of an opaque material is proposed. First, the theoretical explanation and principle of simultaneous measurement of multiple frequencies (SMMF) method are given. The 3-D image and the elapsed time of a drill hole beneath the surface of graphite have also been described.

This paper describes improved models derived from an experiment in generation and propagation of photoacoustic signals in a drilled hole of an epoxy resin with different backing materials, a white polypropylene and a black one. The major difference between the improved and the old models is as follows. The photoacoustic signal at the top edge of the hole was generated not only due to absorbed incident light, but also due to absorbed and scattered light at the top edge of the hole. In addition, we show the propagation paths of the PA signals generated at the top edge of the hole.

We developed a technique for simultaneous measurement of multiple frequencies that allows rapid image build-up. The elapsed time required for measurement of the ω-1 dependence of the photoacoustic signal in the frequency range of 10 to 100 Hz in a graphite was 1/5 that required for a conventional technique employing a lock-in amplifier.

No abstract