No abstract

A laser Thomson scattering technique has been used to directly measure the electron density (n e) and electron temperature (T e) profiles of a striated plasma in a plasma display panel (PDP)-like discharge. A modulation in n e was observed only on the anode side of an electrode substrate; this corresponds to a feature similar to that of the emission images obtained using an intensified charge-coupled device (ICCD) camera. Also, a modulation in T e was observed and it was found to be out of phase from the modulation in n e.

The speckle reduction for laser projectors has been vigorously studied because speckle causes a serious deterioration in image quality. Most speckle reduction methods can be categorized into wavelength diversity, angular diversity and polarization diversity, which are usually treated independently. In this paper, it is shown that the effect of wavelength diversity and angular diversity on speckle reduction is not independent, and that the effect of wavelength also depends on incidence and observation angles on screen. The speckle reduction effect by wavelength diversity is smaller when the angular diversity is larger. Also, the speckle reduction effect is investigated on various screens including matte and silver screens, and it is shown that the effect of wavelength diversity is larger on matte screen than on silver screen.

We have developed two high-efficiency, all-solid-state exciters for pumping TEA CO2 lasers, and experimentally proved their energy scalability, high-efficiency operation, and high repetition rate operation. The small-scale all-solid-state exciter of the two-stage magnetic pulse compressor was operated with an output transfer energy of 8.8 J/pulse and energy transfer efficiency of 78%, and the average CO2 laser power of 117 W was obtained at 250 pps using this exciter. The larger all-solid-state exciter of three-stage magnetic pulse compressor is ten times as large as the small one, and operated with an output transfer energy of 95 J/pulse and an energy transfer efficiency of 84%. With the larger exciter, a CO2 laser output of 9.1 J/pulse was obtained with a total laser efficiency of 8.1%. As a result, the scalability of the exciter for the CO2 laser has been demonstrated.

Ne-Kr gas mixtures with high Kr concentrations were applied to ac plasma display panels. Spatiotemporal behaviors of excited Kr atoms in the 1s 5 metastable state and the 1s 4 resonance state were measured by microscopic laser-absorption spectroscopy in the binary mixtures with Kr concentrations of 20% and 40%. A systematic comparison was done between the characteristics of Ne-Kr-filled panels and those of conventional Ne-Xe panels with the same structure but with lower Xe concentrations of 5% and 10%. For example, the total number of Kr * ͑1s 5 ͒ atoms in a unit cell ranged from 7.4ϫ 10 7 to 2.0ϫ 10 8 , at the peak was apparently smaller than the value of Xe * ͑1s 5 ͒ atoms. However, when the difference in the decay rate of the excited atoms by three-body collision processes is taken into account, the production efficiency of vacuum-ultraviolet ͑VUV͒ emission from Kr 2 * excimers is as large as that from Xe 2 * excimers in a usual panel since these processes lead directly to the formation of excimers. From the measured density of Kr * ͑1s 4 ͒ atoms, it is estimated that the contribution of the atomic resonance line is smaller than the excimer band at those high Kr concentrations. In any case, by summing up those two contributions to the VUV emission, the overall efficiency in the Ne-Kr͑40%͒ panel is estimated to be comparable to that in the Ne-Xe͑10%͒ one.