  Broadband laser ultrasonics and two dimensional Fourier transformation are
used to characterize the properties of varieties of foils and plates. Laser
ultrasonics generation is achieved by use of a pulsed laser which deposits
pulsed laser energy on the surface of the specimen. The displacement amplitude
of the resulting broadband ultrasonic modes are monitored using a two wave
mixing photo-refractive interferometer. By applying a two dimensional Fourier
transformation to the detected spatial and temporal displacement waveforms, the
images of density of state (DOS) for the excited ultrasounds are obtained.
Results are presented for a 150 um thick paper sample, a 52.8 um stainless
steel foil and a 1.27 mm thick aluminum plate. The DOS image demonstrates the
ability to measure the properties of each generated ultrasonic modes and
provides a direct, non destructive, measure of elastic moduli of the tested
specimens
