Light-Induced Dynamic Holography

Abstract

Holographic photomobile polymers (H-PMP) are a novel class of photomobile materials in which holograms can be optically recorded. They can be used in a large variety of applications, including optical switches and color selectors. In this work, we show one of the most important properties of the photomobile film, which is the photophobicity of the unpolymerized parts of the photomobile mixture. In order to investigate this property, we recorded a transmission phase grating on an H-PMP film, and used a different experimental technique to measure the diffraction efficiency, surface tension, and mixture properties. The results allowed for a better understanding of the mechanism of the light-controlled bending observed in these compounds.

Keywords: all-optical control; holography; photomobile polymer; photophobicity.

Figure 1

Effects of post-polymerization on the diffraction efficiency of the transmission grating written in the photomobile polymer material.

Figure 2

Surface tension as function of time under light irradiation ($\lambda$ = 405 nm; P = 25 mW).

Figure 3

A droplet of unpolymerized material on a glass surface (a). Under laser irradiation, the droplet tends to escape away from the irradiated area (b,c). When the laser is switched off, the material returns in its original position (d).

Figure 4

Scheme of the hypothesized reaction mechanism of NVP and 4-AP in oxidative conditions: formation of the phenoxy radical by PbO${}_2$ on 4-AP; attack of the phenoxy radical on NVP and oligomer formation.