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We report the generation of quasi-continuous-wave vacuum-ultraviolet (VUV) coherent light based on a Ti:sapphire laser with two successive frequency doubling stages. In the first stage, UV light at 399 nm with power of 1.1 W was obtained by exploiting an enhanced cavity. With a KBBF crystal as nonlinear material, quasi-continuous-wave VUV coherent light with power of about 25 mW at 199.5 nm and 4.7 mW at 193.5 nm were achieved through a single-pass SHG configuration, respectively, in the second stage.

Polarization holographic gratings transform the polarization state of an incident wavefront. We have studied the diffraction properties of polarization gratings, formed with two orthogonal linearly or circularly polarized waves. For a polarization modulation recorded in the organic material bacteriorhodopsin, the diffraction efficiency and the diffracted wave polarization strongly depend on the polarization state of the read- out wave. We have given a simple theoretical treatment using the Fraun- hofer diffraction integral. The experimental results have been interpreted in terms of this simplified model. © 2002 Society of Photo-Optical Instrumentation Engineers. (DOI: 10.1117/1.1510746)

A flexible numerical method for analyzing diffraction of real- time holograms written in bacteriorhodopsin films is described. The method calculates the propagation of writing and reading beams in bac- teriorhodopsin films using the finite-differential beam propagation method. The changes of the films in refractive index and absorption are deduced from rate equations for B-state and M-state molecules. We ap- ply this method to a real-time holographic lens and calculate the spot profile on the focal plane and the diffraction efficiencies for various pa- rameter values. We also measured diffraction efficiencies experimentally and compared the values with numerical results. © 1999 Society of Photo- Optical Instrumentation Engineers. (S0091-3286(99)01601-3)

Polarization properties of the phase conjugate beam in biological photochrome bacteriorhodopsin with photoinduced anisotropic nonlinearity are studied. We derived the polarization state and reflectivity of the phase conjugate beam in degenerate four-wave mixing (DFWM) where two pump beams have the same or orthogonal polarization and a probe beam has arbitrary polarization. Theoretical results are proved by experiments.

脳卒中とくに脳血栓は, 脳動脈の粥状硬化症を基盤として発症する疾病である。脳動脈粥状硬化症発症の三大因子は加令, 高血圧, 糖尿病である。そこで, この三大因子の終着像を心機図法による血行力学的因子について観察し, 脳血栓発症の近接危険因子あるいはトリガー因子を検討してみることにした。その結果, 三大因子のいずれにおいても, 終着像としては全末梢血管抵抗そして動脈硬化度の増大と心不全の進展とを推定することができた。そして, この心不全が発症のトリガーとして重要であることが考察された。なお, 三大危険因子が終着像にいたる過程において, 血液脂質の増加とたん白質の減少がみられるということもわかった。脂質/たん白質比の増大の持続は, やがて脳梗塞の基盤となる粥状硬化症の進展にかかわるものと思えるのである。農村においては, 都市よりも脳卒中が多発するが, これは農村の高血圧者は同年代の都市の高血圧者の場合よりも, 心機能の低下がいちじるしいことに, その原因をもとめうるものと考えることができた。そして, その心機能低下の要因は栄養の問題にもとめうるものと思えた。したがって, 脳梗塞発症の近接的予防法としては, 高令者, 高血圧者, 糖尿病者等, 脳卒中素因のある者における心不全の早期発見とその予防および治療が重要であると考えるものである。

In 1949, 376 boys and girls in a certain primary school in Tokyo, who were aged 7 to 10 who were dispersed on account of the present World War II, and those non-dispersed in 1944 to 1946, the dispersions of which are further classified according to the districts such as cities, towns and farming fishing villages and their ages; and the caries of deciduous teeth (surface caries, deep-seated caries, root stump caries) and def in 1949 and the condition of 1950 and the increase and decrease during the year in these boys and girls was observed, which resulted as follows: -1. Those dispersed compared to non-dispersed are generally under aged 9 in 1949, especially aged 7 in 1949 and 1950 show a high degree contraction in both deciduous caries and def, but aged 10 show a low degree one in both 1949 and 1950.2. Those who were dispersed to farming and fishing villages, compared to those dispersed to cities and towns were generally under aged 9 in 1949, especially aged 7 show a low degree contraction in both deciduous caries and def, but show a high degree one in both 1949 and 1950.3. At the period of dispersion we can guess that the boys and girls dispersed in cities and towns, farming and fishing villages were in the circumstances of being easily attacked by deciduous caries than those in Tokyo, and between farming, fishing villages, and cities, towns, this suffering tendency was remarkable in the former than in the latter from a standpoint of dispersion districts.

Optical pulse delay technique is important in such fields as time-resolved spectroscopy, optical sampling and very high speed time division multiplexing of digital data. This paper reports a proposal to assemble an optical pulse delay unit with a reduced number of components by using a composite zone plate and its successful implementation with a dynamic range of 300 ps delay of 40 ps diode laser pulses.