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Presents a study that investigated the second harmonic generation (SHG) from silica glasses doped with sodium or water to clarify the effects of the impurities on the second-order nonlinearity. Why second-order nonlinearity is forbidden for amorphous materials; Experimental procedure used in the study; Results and discussions.

Although there has been active research on the optical quadratic nonlinearity that appears in poled glass, its origin has not been clarified. There have been many reports on bulk glass but little research on poled glass thin film waveguides. Waveguide structures are important for future applications to optical IC devices, and clarifying the origin of the nonlinearity is very important. In this work we report experiments on phase-matched blue second-harmonic generation in a corona-poled Corning 7059 glass film waveguide with a titanium sapphire laser as a fundamental wave and investigate the origin of its nonlinearity. After relaxation of the nonlinearity optical constant once the poling has been measured, the analysis is performed using a biexponential function, and the origin is elucidated by separating the fast and the slow relaxation components. In particular, an etching experiment has been carried out noting the latter component, and it has been shown that the charge distribution generated in the waveguide by the poling and the interface between the glass film and glass substrate play important roles in generating quadratic nonlinearity. It has also been confirmed by X-ray photoelectron spectroscopy that sodium diffuses in Pyrex glass substrate as a result of poling. © 1999 Scripta Technica, Electron Comm Jpn Pt 2, 82(8): 53–61, 1999 [ABSTRACT FROM AUTHOR]

Several authors have reported the occurrence of extraforaminal L5 nerve root compression between lumbosacral transitional vertebrae (LSTV) and sacral ala, but reports on a lesion caused by an intervertebral osteophyte on the ventral and contralateral side of a unilateral abnormality by LSTV are hardly available. A 67-year-old woman presented with pain along the distribution of the L5 nerve root; straight leg raise test, femoral nerve stretch test, and Kemp test were positive on the left. Following plain radiographs, computerized tomography, magnetic resonance imaging, and selective nerve root block, an osteophyte bridging the L5 and S1 vertebral bodies in the ventral side was identified compressing the L5 nerve root. On account of resistance to conservative therapy and the delicate position of the lesion, surgical treatment was performed by an anterior decompression. Subsequently, the patient attained adequate relief from pain and could walk normally. We herein present a very rare case of extraforaminal L5 nerve root compression caused by an intervertebral osteophyte on the ventral and contralateral side of a unilateral abnormality by LSTV, which was managed by anterior decompression. [ABSTRACT FROM AUTHOR]

This study describes the preparation of biocompatible patterned surfaces by a two-photon absorption technique. We have synthesized poly(2-methoxyethyl acrylate) copolymers, which exhibit biocompatibility and photocrosslinking moiety. Fabrication resolution can be controlled in the sub-micrometer range by changing the laser power, photoinitiator concentration, and scanning speed. The patterned surfaces showed excellent human platelet compatibility. Biocompatible patterned surfaces can be used in various medical devices, implants, biosensor chips, and tissue engineering scaffolds. [ABSTRACT FROM AUTHOR]