Increase of SRG modulation depth in azopolymers-nanoparticles hybrid materials

TL;DR

This study demonstrates that incorporating silver and gold nanoparticles into azopolymer films enhances surface relief grating modulation depth and diffraction efficiency, with optimal nanoparticle concentrations significantly improving performance.

Contribution

It introduces a hybrid azopolymer-nanoparticle material that increases SRG modulation depth and diffraction efficiency compared to pure azopolymer films.

Findings

NP doping increases diffraction efficiency more than twofold.

Optimal NP concentrations enhance SRG modulation depth.

Surface relief gratings are more efficient in hybrid materials.

Abstract

Thin films of azopolymer-nanoparticles hybrid materials were fabricated with poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl] (PAZO) and different concentrations of Ag and AgAu nanoparticles (NPs). By illuminating the films with polarized interference patterns, surface relief gratings (SRGs) were recorded. It was found that for some concentrations of NPs their modulations and diffraction efficiency were higher than the obtained for PAZO films without NPs. The effect was mainly explained by the increase of the free volume available for the photoisomerization for certain concentrations of NPs. The dependence of the diffraction efficiency on concentration was directly related to changes in modulation depth. When doping with NPs, the maximum efficiency increases more than two times the efficiency without NPs.