[11a-Z16-1~9] 4.3 Lasers and laser materials processing

▲ [11a-Z16-2] Optical vortex induced flower-shaped surface relief of azo-polymers

〇(M1)Ami Shiraishi¹, Keigo Masuda¹, Katsuhiko Miyamoto^1,2, Takashige Omatsu^1,2 (1.Chiba Univ., 2.MCRC, Chiba Univ.)

Keywords:optical vortex, azo-polymer

Surface relief formation of azo-polymers occurs via a single-photon or two-photon induced trans-cis isomerization, and it has the potential to develop rewritable optical data storages with high data capacity. Optical vortex possesses an orbital angular momentum associated with its helical wavefront, and its orbital angular momentum enables us to create helical surface relief of azo-polymers with the help of spin angular momentum of circular polarization. We report on, for the first time, a new class of optical vortex induced surface relief with 3 (or 6) petals along an azimuthal direction, that is an optical vortex induced flower-shaped surface relief. A micron-scale flower-shaped surface relief along an azimuthal direction was then created. Such flower-shaped surface relief manifests the spatial modal instability originating from optical nonlinearities, such as photo-bleaching effects of the azo-polymer film.