We conducted preliminary experiments for developing a new ultrasonic method of evaluating resistivity distributions in ZnO single crystals using the line-beam ultrasonic material characterization system. We measured velocities of leaky surface acoustic waves at 225 MHz on three Z-cut ZnO specimens A, B, and C with low, high, and unknown resistivites. We obtained the great velocity changes of more than 50 m/s from the results of 2616 m/s for specimen A and 2669 m/s for specimen B, and evaluated specimen C with velocity distributions from 2612 m/s around the seed part to 2672 m/s for the outside part associated with the crystal growth, corresponding to the resistivity variations of 1-1000 Ω・m.

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In the present paper, we calculated the transmittance of phonons in a NWSL with a defect layer. It is shown that resonant peaks appear within the frequency gaps. These peaks originate from the resonance with vibrational modes localized at the defect layer. In particular, we examined how the resonant frequency depends on the width of the defect layer. The radial confinement of the phonons generates a critical frequency. Our results show that the localized modes can be generated only obove the critical frequency.

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The application of the Acousto-Optic Tunable Filter (AOTF) device to the wavelength monitor in the fiber-optic sensing system using Fiber Bragg Gratings (FBGs) was reported. But this sensing requires a good temperature characteristic. This time, the system having a good temperature characteristic has been realized by using two light wavelength as references. The accuracy of the measured wavelength was realized approximately 0.63 pm in temperature range from -20 to 70℃.

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Long period fiber gratings (LPFGs) are known to exhibit higher sensitivity to an applied strain than fiber Bragg gratings (FBGs). In this paper we report an application of LPFGs to vibration measurement based on the intensity modulation scheme. After characterizing strain dependence of a LPFG, which is written in a photosensitive optical fiber with an excimer laser, mechanical vibration of solid is measured with the developed LPFG vibration sensor. The sensor outputs clear waveforms and has good linearity with the dynamic range more than 100 dB.

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Dielectric, ferroelectric and piezoelectric properties of perovskite ferroelectric and bismuth layered-structured ferroelectric (BLSF) ceramics are described as superior candidates for lead-free piezoelectric materials to reduce environmental damages. Perovskite type ceramics seem to be suitable for actuator and high power applications that are required a large piezoelectric constant, d_<33> (>300 pC/N) and a relatively high Curie temperature, Tc (>200℃). On the other hand, BLSF ceramics seem to be excellent candidates as piezoelectric sensors for high temperatures and piezoelectric ceramic resonators with high mechanical quality factor, Ωm and low temperature coefficient of resonance frequency, TC-f.

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Alpha synthetic quartz crystals were cultivated with various growing rates. And we have evaluated its relation between impurities, and transmittance in the range of the VUV, the optical damage induced of laser irradiating. In order to good tolerance of the range of the VUV, the impurity content of quartz crystals is necessary to inhibit in ppb level.

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The GaInNAs/GaAs single quantum well (SQW) structure is remarked as a suitable material of an optical fiber communication. We have carried out the piezoelectric photothermal (PPT) and the surface photovoltage (SPV) measurements for Ga_<0.65>In_<0.35>N_<0.995>/GaAs single quantum well (SQW). Since only the PPT measurement at 100K could observe the signal from the first quantized level, but not for the SPV we conclude that the observed PPT signal is related to the leak of the photogenerated carriers from GaInNAs/GaAs SQW.

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