The reversible photoisomerization and consequent molecular orientation of azobenzene dyes are observed when these compounds are irradiated by specific wavelengths. Due to these attractive properties, these organic dyes have been the subject of several studies, aiming applications in optics and photonics devices. In this work, we functionalized acrylate resins with a series of azobenzene dyes to fabricate optically active devices which are sculpted via multiphoton absorption polymerization (MAP). For the experiments reported here, the host resin consists in two acrylate monomers namely tris(2-hydroxyethyl)isocyanurate triacrylate and ethoxylated(6) trimethylolpropane triacrylate, combined in equal proportion. These monomers are then mixed to a variety of azobenzene dyes: Disperse Red 1, Disperse Red 13, Disperse Red 19 and Disperse Orange 03. These dyes were added in weight percentages ranging from 0.05 to 1 wt%. In our experiment, a small amount of dye also works as a photoinitiator to start the polymerization process. In this case, the dominant reaction usually involves the loss of a molecule of N2 followed by reactions with the monomers. However, the remaining dye is unaffected by the laser beam, maintaining its optical properties, as can be observed after the complete fabrication procedure. Using a dedicated system we evaluate the photoinduced birefringence of these structures. To observe the light transmission through the device, placed between crossed polarizer and analyzer, we used a 0.25-NA microscope objective and a CCD camera. Through the analysis of the birefringence time-evolution curves, we observed significant residual optical memory, essential feature for micro-optical storage devices.
Femtosecond laser processing techniques have been widely employed to produce micro or nanodevices with special features. These devices can be selectively doped with organic dyes, biological agents, nanoparticles or carbon nanotubes, increasing the range of applications. Acrylate polymers can be easily doped with various compounds, and therefore, they are interesting materials for laser fabrication techniques. In this work, we use multiphoton absorption polymerization (MAP) and laser ablation to fabricate polymeric microdevices for optical applications. The polymeric sample used in this work is composed in equal proportions of two three-acrylate monomers; while tris(2-hydroxyethyl)isocyanurate triacrylate gives hardness to the structure, the ethoxylated(6) trimethyl-lolpropane triacrylate reduces the shrinkage tensions upon polymerization. These monomers are mixed with a photoinitiator, the 2,4,6-trimetilbenzoiletoxifenil phosphine oxide, enabling the sample polymerization after laser irradiation. Using MAP, we fabricate three-dimensional structures doped with fluorescent dyes. These structures can be used in several optical applications, such as, RGB fluorescent microdevices or microresonators. Using azo compounds like dopant in the host resin, we can apply these structures in optical data storage devices. Using laser ablation technique, we can fabricate periodic microstructures inside polymeric bulks doped with xanthene dyes and single-walled carbon nanotubes, aiming applications in random laser experiments. In structured bulks we observed multi-narrow emission peaks over the xanthene fluorescence emission. Furthermore, in comparison with non-structured bulks, we observed that the periodic structure decreased the degree of randomness, reducing the number of peaks, but defining their position.