Ba⁺ and Yb⁺ ions were trapped with buffer gas in a rf ion trap. The number and the storagetime of the trapped ions were determined by the rf resonance method. It was shown thatthe motion of the trapped ions was expressed by an external forced oscillation equation with anonlinear term in the case the fabricated trap was imperfect. Due to this nonlinear effect, thesubharmonic oscillation was induced, and thus the number and the storage time of the trappedions were decreased and shortened, respectively. The temperature and the spatial distributionof the trapped ions were determined by the fluorescence detection method.

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Optical disk storage density depends on laser wavelengths. Compact blue, green lasers areimportant for the future optical disk systems. Recent advancements of the second harmonicgeneration lasers including bulk and waveguide type are reviewed and evaluated from theaspects of those applications.

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Detailed insight into the dynamics of chemical reactions, nonreactive collisions, and molecular photofragmentation processes is provided by measurements of the translational-andinternal-energy, and spacial angular distributions of the products. With a tunable vacuumultravioletlaser, it becomes appealing to study the chemical reaction dynamics involving lightatoms (hydrogen, oxygen, sulfur, chlorine) and molecules. In this article, we have describedrecent progress in the field of chemical reactions (translational energy dependence of reactivecross sections, lifetime of the intermediate complex, stereochemistry, site-specificity), nonreactivecollisions (velocity and spacial anisotropy relaxation, intersystem crossing, intramultiplettransition), photodissociation (site-specificity, primary processes, adiabaticity of potentialcurves, vector correlation), and nonadiabatic coupling among electronic states.

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Deposition of a diamond-like carbon (DLC) film on glass substrates in atmosphere atambient temperature using the laser physical vapor deposition (PVD) method has been investigated. The output from Nd-YAG laser is focused on a highly purified graphite carbontarget. The effect of the laser beam is to eject the ablation plume and to ensure only carbonions. By placing a glass substrate within the ablation plume created by irradiating a carbontarget with a Nd-YAG laser.
The following conclusions were obtained: (1) The laser beam is aimed vertically in relationto the target and the substrate is set parallel to the target. Then substarte should be used thetransparent material with laser beam. (2) The quality of DLC film is improved by using a relativelylong pulse width laser (msec order). (3) The optimal setting distance of substrate fromthe target to obtain the higher quality DLC film is typically 20 mm.

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We analyzed luminescence generated by Kr F excimer laser ablation of untreated, deorganizedand decalcified femurs of pig using time-resolved spectroscopy. The time-resolvedmeasurement was carried out for 8μs after the irradiation in the range of 350-700 nm with astreak camera system. The almost same luminescence spectra were obtained in the cases of theuntreated and deorganized bones, which differed from that of the decalcified bone. This resultindicates that these spectra are attributed to excited species of the inorganic components ofbone, which are Ca atom, Ca ion and HPO molecule. The life times of the emissions fromthese species were in the range of 0.6-1.5μs.

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Degenerate four-wave mixing method was employed to determine second molecular hyperpolarizabilities γ of a series of thiahetero [N] helicenes (N=3, 5, 7) and their methyl derivatives. γ values were calculated from the measured bulk susceptibility χ ⁽³⁾ of benzene solution. It was found that γ increases by about one order of magnitude with the addition of onebenzothiophene unit. The largest value of γ was about hundred times larger than that ofcarbon disulfide. The comparison of the optical absorption spectra measured before and afterlaser irradiation indicated that two chemical processes induced by photon absorption wereinvolved.

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