Although the luster of the Pinctada fucata pearls is one of main factors in estimating their quality, the equipment for measuring their luster has not yet been sufficiently developed. Thus, we fabricated a pearl-luster measuring equipment, consisting of a light source, lenses and a charge-coupled-device (CCD line sensor). By using the equipment, the luster LID of white, yellow, black and green pearls with diameter 8mm were measured. As a result, it was found that there was a fairly strong correlation between LID and the psy-chological luster of pearls, LpH; the coefficient of correlation being γ=0.78_??_0.96. The error ΔL of the luster caused by the deviation from normal pearl-holding-positon was also estimated by computer simulation. The value of ΔL was found to be relatively small; ΔL <<10% for deviation of 1.4mm, in the case of the pearl of 8mm diameter.
Cathodoluminescence properties of CuGaS2 crystals grown by the iodine transport method are described. Four emission peaks are observed at about 497. 5nm, 520nm, 550nm and near infrared (700_??_750nm) region at 110K for as grown crystals. The appearance of these peaks is affected by the annealing in various atmospheres such as S, Ga, Cu and the vacuum, and by the deviations from the stoichiometric composition of the raw materials. It is supposed that the emission observed near 520nm arises from the transition from donor to acceptor related to VGa or CUGa and the emission near 550nm arises from the transition from level related to Vs to level related to VGa. The origin of the emission observed at 497.5nm is still uncertain. A tentative energy band model is proposed to explain the transitions observed as the above emissions.
Temporal resolution of 360 fs with a new design of the electron-optical streak camera (femtosecond streak camera; FESCA) has been achieved for the first time with 110 fs pulses from a passively mode-locked ring dye laser. The femtosecond streak tube used in FESCA is characterized by the property of electro-magnetic focussing, strong electrostatic field strength in front of the photocathode; _??_6×106 V/m, and high deflection sensitivity of _??_60 mm/kV. The ultimate temporal resolution of FESCA is estimated to be 200 fs, by extrapolating data obtained under the dynamic measurement of intensity dependent temporal resolution at various streak speeds with femtosecond laser pulses. In this paper, structure and operation, static and dynamic performances and its measuring methods, and relationship between dynamic range and temporal resolution of the system are described.