| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
A novel technique for evaluating a variety of newly developed chemical materials has been required to develope nowadays. From the above-mentioned view point, we have tried to apply a laser -induced ultrasonic to them. That is, using two laser beams of the same frequencies,interference pattern is produced inside materials by intersecting the two beams. In the interference region optical properties ( ie, refractive index, light absorption strength ) of the material are also spatially modulated through the interaction between light and material. In the case of light absorbing materials, the same pattern arises from the heat generated by nonradiative relaxation processes of the excited states. The spatial modulation of the heat gives rise to thermal grating and also counterpropagating acoustic waves through expansion and contraction of the heated region. A diffraction grating generated inside the materials is detected through the Bragg diffraction of another probe beam. Using the above-mentioned laser-induced thermal grating, we demonstrated some experimental results that this technique can be successfully applied to trace analysis of materials and ultrasonic spectroscopy.
That is, using thermal grating, quantitative analysis of <KMnO_4> solutions in <H_2O> was carried out down to the order of <10^(-7)> M concentration. Ultrasinc waves could be generated and detected over the ranges from some MH to 100 MHz without restriction of any contact with samples and its ultrasoniz velocity was measured in liquid samples.
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