Polydiacetylene Langmuir-Blodgett Films Research Articles

Optical Characterization of Polydiacetylene Langmuir Blodgett Film on Silicon Substrates

ABSTRACTA bilayer of a surfactive polydiacetylene (15–8 PDA) has been deposited by Langmuir-Blodgett technique on a smooth Silicon substrate using a commercial Lauda film balance [1] . The morphology of the deposited film has been studied by cross-polarized optical microscopy, and laser light scattering microscopy. Usual crystalline domains with size ranging from 5 to 50 μm can be seen between cross polarizers. Nonuniformities and voids in the film are observed by imaging the scattered light from a visible laser beam incident at grazing angle onto the film.Raman scattering study on these bilayers have been carried out to investigate their vibronic structure. Information about vibronic levels from PDA has been used to define the extent of disorder and crystalline phase of the bilayer.

Saturation absorption and Kerr susceptibility in polydiacetylene Langmuir-Blodgett film

Abstract Direct measurements of the saturation absorption from Langmuir-Blodgett films of a polydiacetylene have been carried out in picosecond time domain. Using a photoacoustic technique, we have obtained directly the imaginary part of Kerr susceptibility, χ (3) (-ω;ω,ω, -ω). The magnitude of χ (3) is found to be in excess of 10 -8 esu and the associated ground state recovery time is less than the laser pulse width of 3 ps. These results are discussed in terms of a phase space filling model for a one dimensional exciton.

All-optical bistabilities of polydiacetylene Langmuir–Blodgett film waveguides

Two types of all-optical bistability were observed in polydiacetylene Langmuir–Blodgett (PDALB) films layered on rf-sputtered Corning 7059 slab-type waveguides with fused-quartz substrates. One bistability originating from optical nonlinear coupling between a prism and a PDALB-Corning hybrid waveguide produced input and output curves with hysteresis characteristics. The other type of bistability was observed in the hybrid waveguide with a nonlinear distributed-Bragg reflector of the PDALB top layer. We cannot yet determine whether the origins of both bistabilities are electronic or thermal.

ポリジアセチレンＬＢ膜の色相転移と熱処理特性

ポリジアセチレンＬＢ膜の色相転移と熱処理特性

Photo-induced structural disorder in Langmuir-Blodgett films of polydiacetylenes

Molecular vibration spectra were measured on Langmuir-Blodgett films of polydiacetylene, PDA-(12, 8), by the grazing-incidence reflection method. Structural disorders in the side-group conformation were found to occur at photo-induced phase-transition in the polymer backbone structure.