Optical poling of oligoether acrylate photopolymers doped by stilbene-benzoate derivative chromophores

Abstract

A large second harmonic generation (SHG) excited by an Nd:YAG laser (λ = 1.32 µm) has been observed during the investigation of the optical poling process in 2-(stilbene-4-yl)benzoxazole derivatives chromophores incorporated within oligoether acrylate photopolymer matrices. We have revealed that the maximum output SHG is observed for the chromophore derivatives molecule possessing the highest second-order hyperpolarizabilities and corresponding dipole moments. Due to the incorporation of the chromophore into photopolymer matrices, second-order microscopic susceptibilities of the composites substantially increase (from 0.24 up to 1.89 pm V−1). The investigated composites possess long-lived polarized states and after more than 106 laser pulses the output SHG did not decrease below 75% compared with the initial SHG one. Optimal conditions for optical poling corresponded to a power density of the doubled frequency beam of about 0.07 GW cm−2 and chromophore content about 6.5% (in weighting units).