Trial construction of a non-contacting measurement system of elastic constants for tiny crystals

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A new apparatus for measuring elastic, constants of tiny crystals has been developed. The appa rates is based on the Brillouin scattering that is frequently applied to the measurement of non-metallic materials, for example ceramics or organic materials. The most of apparatus for measuring the Brillouin scattering in uses Ar-ion laser that has very large volume and electrical power required is quite large to obtain enough output power. We adopt a new light source that is diode pumped solid state (DPSS) laser, which has very small volume and high efficiency of conversion from electrical to light. The most important point of the light source for the Brillouin scattering is the line width (purity) of the light. We have checked the purity and confirmed that the line width is enough narrow for the Brillouin scatteringAnother key part of the apparatus is light detector ; the detector must has high sensitivity, stability and low noise feature. A photo multiplier is frequently used to the detector, however, conventional one has low quantum efficiency. We adopt a new type of photo multiplier that has a different material to emitter with high quantum efficiency of about 40% for the light of 532nmBy using such newly developed parts, we have succeeded to construct a new apparatus having small volume and high efficiency