In spite of its recognized potential, studies on thin film deposition of organic systems by laser ablation are so far limited in number. In this paper, experimental results of the fabrication of polymer and non-polymer organic thin films by pulsed laser ablation are described. We succeeded in fabrication of crystalline thin films of polytetrafluoroethylene (PTFE) with an F₂ laser (157 nm). In this fluoropolymer deposition, cluster formation in the ablation plume under-200 mTorr Ar ambient gas keeps the bulk composition of the target in the films. PTFE thin films containing semiconductor CdTe microcrystallites, which exhibit a 3rd-order optical nonlinearity, were also fabricated in all ablation processes. These techniques were extended to non-polymer organic materials such as copper-phthalocyanine (CuPc) and 4-dialkylamino-4-nitrostilbene (DANS).

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Ion cyclotron resonance Fourier transform mass spectrometry which is a mass analysis method with feasibility of fast measurement of big molecules like organic and bio-molecules is reviewed. The mass-resolution reaches as high as 140, 000. The pulsed detection technique is easily combined with a pulsed ionization technique, for example, pulse-laser desorptiOn and pulse-laser ablation. The experimental results on Si3N4 ablation with ArF excimer laser are shown.

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Optical interconnections are expected to alleviate the “interconnection bottleneck” in developments of large-scale computing and switching systems using high-density and -speed synchronous parallel optical transmissions. Intra-and inter-module skew control, DC-coupled and error-free transmission, and compact, low-power, reliable and inexpensive modules are main technical issues. A monolithically integrated low-threshold, efficient and uniform LD array is a key device. This paper reviews summary of recent work on optical interconnections and our developed compact 200-Mbit/s/ch 10-ch optical interconnections we developed by using single-mode fiber and 3-mA-threshold current 1.3 μm LD arrays.

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New phenomena are reviewed on the multiple scattering of laser light waves propagating through random media. Coherent wave interference occurring inside or outside the scattering media leads to weak localization of photons and the enhancement of scattered intensity in the backward direction. When the strength of scattering increases, photon trajectories in a medium tend to be correlated with each other. This effect results in long-range intensity correlations in near and far field speckle patterns and non-Rayleigh statistics of the intensity distributions. Diffusing-wave spectroscopy and some possible applications of the multiple scattering phenomena are also discussed.

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Amixture of SF₆ and rare gas was solidified on a Ge substrate at 30 K to form a matrix sample. The thickness of the matrix was measured by interferometry using a He-Ne laser. From the number and the pattern of Newton rings appearing on the sample, the thickness and the crosssectional form of the matrix was derived. By using the value of the thickness with the IR spectrum of the sample, the absorption coefficient of SF₆ in a Kr matrix was estimated at 7.6×10⁷cm²/mol for the sample of dilution (Kr/SF₆) 5000.

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A new technique for machining three dimensional micro structure using a laser ablation has been developed. In this technique the works are rotating, while the laser pulses are focused and irradiated upon the works. The laser operations are controlled by a personal computer, to which the data of the final machined shape and the programs for the machining process are instolled. It was demonstrated that the machining of the arbitrary three dimensional micro structure having the typical dimension of less than 1 mm was possible by using this new technique.

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For achieving tunable and single longitudinal mode oscillation, a Fox-Smith type mode selector with a Fabry-Perot etalon was incorporated in a TEA CO₂ laser. The etalon was inserted in the optical path taken out from the main cavity of the CO₂ laser for protecting the etalon from damage on the surface. According to the longitudinal mode resulting from the etalon and the Fox-Smith optical path, the single mode oscillation of purities of more than 99% and 95% was performed with the probabilities of 55% and 100%, respectively. The tunability of a laser frequency was obtained with the purity of more than 75% over the whole gain region of the TEA CO₂ laser by controlling the tilting angle of the etalon or the optical path length of the Fox-Smith system.

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Dye lasers are used to high resolution spectroscopy such as resonance scattering, electronic Raman scattering and two photon resonace excitation, as well as a laser isotope separation, for its excellent tunability from near ultraviolet to near infrared. Beside these merits, flashlamppumped dye lasers are inexpensive and highly energetic, so that it can be used to a laser radar and laser processing or annealing which require high power and high energy. The lifetime of the flashlamp-pumped dye lasers is limitted by not only a dye moleculer photo-dissociation but also by the lifetime of the flashlamp and the spark gap switch. We report a highly energetic flashlamp-pumped dye laser without a spark gap switch, as a transmitter of a Mie scattering laser radar for fog and snow cloud observation.

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