Femtosecond laser fabrication of hybrid micro-optical elements and their integration on the fiber tip

Mangirdas Malinauskas, Holger Gilbergs, Albertas Zukauskas, Kastytis Belazaras, Vytautas Purlys, Marius Rutkauskas, Gabija Bickauskaite, Andrej Momot, Domas Paipulas, Roaldas Gadonas, Saulius Juodkazis, Algis Piskarskas (+4 others)
2010 Micro-Optics 2010  
Femtosecond laser photo-polymerization of zirconium-silicon based sol-gel photopolymer SZ2080 is used to fabricate micro-optical elements with a single and hybrid optical functions. We demonstrate photo-polymerization of the solid immersion and Fresnel lenses. Gratings can be added onto the surface of lenses. The effective refractive index of polymerized structures can be controlled via the volume fraction of polymer. We used woodpile structure with volume fraction of 0.65-0.8. Tailoring of
more » ... ersion properties of micro-optical elements by changing filling ratio of polymer are discussed. Direct write approach is used to form such structures on a cover glass and on the tip of an optical fiber. Close matching of refractive indices between the polymer and substrate in visible and near infra red spectral regions (n SZ2080 = 1.504, n glass = 1.52) is favorable for such integration. The surface roughness of laser-polymerized resits was ∼30 nm (min-max value), which is acceptable for optical applications in the visible range. For the bulk micro-optical elements the efficiency of 3D laser polymerization is increased by a factor ∼ (2 − 4) × 10 2 times (depends on the design) by the shell-formation polymerization: (i) contour scanning for definition of shell-surface, (ii) development for removal of nonfunctional resist, and (iii) UV exposure for the final volumetric polymerization of an enclosed volume.
doi:10.1117/12.854396 fatcat:2y3qjqfb2jdyzaalye7qh2ve2u