Development of widely tunable terahertz-wave generators and their possible applications are reviewed. The characteristics of an injection-seeded terahertz-wave parametric generator and the terahertz-wave applications in the industry and medical fields are reported.
Since laser-ablation plasmas have significant spatial distributions with transient properties, the diagnostic techniques should have temporal and spatial resolutions. Laser-induced fluorescence (LIF) imaging spectroscopy, which can visualize the distributions of particle densities in plasmas, is a suitable method for the diagnostics of laser ablation plasmas. This report describes our system of LIF imaging spectroscopy. Although LIF imaging spectroscopy is an excellent diagnostic technique, in this report, we dare to discuss some problems of LIF imaging spectroscopy to clarify the limitations in the application to laser-ablation plasmas.
Imaging and spectroscopic methods of two-dimensional laser-induced fluorescence (2D-LIF), ultraviolet rayleigh scattering (UV-RS) and re-decomposition laser-induced fluorescence (ReD-LIF) have been developed to observe the species in laser ablation process. These were applied to observed the laser ablation process of Si target, and it was shown that the atoms in ablation plume condense to molecules, clusters and finally to nanoparticles. The behavior of nanoparticles depended on by the viscosity of ambient gas. It was shown that these techniques are quite powerful to diagnose the condensation process in laser ablation.
Ion-induced secondary electron emission characteristics (γ_i) is very most important to evaluate protecting material for ac-Plasma Display. Automatic measuring system results in the repeatable result with stability, and expected to have new information about the protecting materials by the detailed analysis for the obtained results. In the present paper, we tried to make the measuring system, which is controlled by the personal computer. We examined the point on mounting, and designed nano-current circuit, which consist of I-V conversion circuit and isolation amplifier.
We developed the new electron gun, which can emit about twice electron in comparison with the conventional gun and could achieve the screen brightness of over 300cd/m^2 even if the ordinal driving circuit is applied. We tried two methods to improve the drive characteristics, and we chose to lower the cathode cut-off voltage (1). To maintain the resolution, we optimized the triode. And we used the tungsten-coated oxide cathode to guarantee the long life.
Cold cathode plates with gate structures were experimentally fabricated using graphite nanofibers (GNFs). A non fiber layer, which does not contribute to the emission of electrons, was remarkably suppressed by optimizing the conditions for the deposition. The plate had a threshold gate voltage of 30V. We confirmed the luminescence of the phosphor plate by line sequential driving for the GNF plate.
We study objective evaluation of moving images displayed on LCD panel using PSNR (Peak-Signal to Noise Ratio). The moving images with which we calculate PSNR are obtained via monochrome CCD camera. We assume a measurement is possible with not only test patterns but any arbitrary images by using this evaluation method. We are studying a validity of the evaluation using PSNR and correlation with subjective evaluation. In this paper, we examine this evaluation method by PSNR with a geometric pattern.
In order to clarify the relationship between the alignment and the surface energy, we investigate the phase transition droplets of liquid crystal on the surface. Various characteristics of phase transition droplet is observed and measured. From this results, it is clarified that the anchoring strength in a wide range is possible to measure.
Micro-groove substrate (MG) using a ruling engine was evaluated geometrically and optically. As the result, it was confirmed that the MG substrate had periodic structure. Uniform molecular alignment is observed partially. Precise control of the ruling engine promises uniform molecular alignment of LCDs.