Mixed films were produced by means of composite-multilayer method and co-evaporation method to obtain any specified refractive-index or stress of thin films. The refractive-index of mixed film with SiO2-ZrO2 was almost the same as the calculated value from Lorentz-Lorenz formula. Two-wavelength antireflection (AR) coatings with composite-multilayer method were produced for the first time by combining the mixed films with SiO2-ZrO2 and MgF2 on fused-silica and BK-7 glass substrates. The laser damage threshold of this AR coating was measured to be 10_??_12 J/cm2 at 1.064 μm (pulse-width τp=1 ns) and 10_??_11 J/cm2 at 0.532 μm (τp=1 ns), respectively. Also, the relation between laser damage threshold and stress of thin films were examined by using the SiO2-MgF2 mixed film and high reflectance mirror produced by mixed film with SiO2-MgF2 and ZrO2. As a result, it has become clear that the laser damage threshold with τp of less than 1 ns is not affected from stress of less than 3000 kgf/cm2 on thin films.
Investigations were carried out to clear the superposition effects of the silent discharge, the surface discharge and the discharge luminescence on ozone synthesis. A coaxial and cylindrical double layer discharge tube was used for ozone synthesis. The inner tube was made of quartz and the outer tube of hard glass. Outer and inner tubes were rolled by aluminum foil and nickel wire coil respectively, as electrodes, and a rod electrode was inserted at the center of the inner tube. Nitrogen gas filled the inner tube and oxygen flowed between the inner and the outer tubes. Silent discharges were generated in oxygen gas, and nitrogen discharges in the inner tube with surface discharge on its surface. The following results were obtained. Amounts of ozone generated by silent discharges and surface discharges were almost the same. The sum of the amounts of ozone generated by the silent discharge alone and by the surface discharge alone is approximately equivalent to the amount of ozone generated when both types of discharge occurred simultaneously in oxygen gas. The superposition effect of silent discharge and luminescence of nitrogen discharge was studied, but no remarkable effect was observed.