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Tetsuya AOYAMA Emi TAKABAYASHI Yadong ZHANG Hiroyuki SASABE Tatsuo WADA
Angle-multiplexed holography using four-wave mixing (4WM) was demonstrated with a monolithic photorefractive carbazole trimer. We measured the diffraction efficiency as a function of incident angle of the read beam. The cross-talk was almost negligible at the Bragg angle mismatch of 1. Two figure images were recorded with the different incident angle of the reference beam in the photorefractive carbazole trimer film, and were read out independently by illuminating with the read beam which counter-propagated to the corresponding reference beam.
Tatsuo WADA Yoshihiko MATSUOKA Motoyoshi SEKIYA Keisuke SASAKI Hiroyuki SASABE
The optical waveguides containing phthalocyanine as an optically active material were fabricated and transmission properties were investigated experimentally and numerically. The positive refractive index change was observed in the glass waveguide with a vanadyl phthalocyanine thin film as a top layer. The thermal influence on refractive index change was estimated by surface plasmon measurements.
Akimasa KANEKO Akira ITO Osamu FURUKAWA Tatsuo WADA Hiroyuki SASABE Keisuke SASAKI
We report the dispersion of two-photon absorption (TPA) coefficient, (β), in polydiacetylene (12, 8) thin film waveguides in the wavelength range less than the one-photon band-gap with a 100 femtosecond mode-locked Ti: Sapphire laser pulses. The TPA coefficient was found to be 4 cm/GW for TE polarization at 900 nm (1.38 eV) by taking into account a Gaussian intensity distribution as well as a temporal pulse shape. We observed a sharp resonance in β above the first one-photon allowed transition with a full width at half maximum (FWHM) of 90 meV.
Akimasa KANEKO Takashi KUWABARA Tatsuo WADA Hiroyuki SASABE Keisuke SASAKI
Optical Kerr effect were applied to all-optical switching devices in the form of nonlinear waveguide directional couplers. The nonlinear waveguide directional coupler consists of a quartz thin gap between two Corning 7059 guided layers on a pyrex substrate with ion-milled grating and organic thin film as a top layer. The vacuum-deposited polydiacetylene (12, 8) film was used as an organic nonlinear material. Power-dependent switching phenomenon in this asymmetrical nonlinear directional coupler was observed by 100 fs pulse duration of mode-locked Ti: Sapphire laser.