Photopolymerization with light fields possessing orbital angular momentum: Generation of helical microfibers

Yoshihiko Arita, Junhyung Lee, Shunsuke Toyoshima, Katsuhiko Miyamoto, Paris Panagiotopoulos, Ewan Wright, Kishan Dholakia, and Takashige Omatsu

ACS Photonics 5(10), 4156-4163 (2018)

doi: 10.1021/acsphotonics.8b00959

Photopolymerization is a powerful technique to create arbitrary micro-objects with a high spatial resolution. Importantly, to date all photopolymerization studies have been performed with incident light fields with planar wavefronts and have solely exploited the intensity profile of the incident beam. We investigate photopolymerization with light fields possessing orbital angular momentum, characterized by the topological charge l. We show both experimentally and theoretically that as a consequence of nonlinear self-focusing of the optical field, photopolymerization creates an annular-shaped vortex-soliton and an associated optical fiber, which breaks up into |l| solitons or microfibers. These microfibers exhibit helical trajectories with a chirality determined by the sign of l due to the orbital angular momentum of the light field, and form a bundle of helical-microfibers. This research opens up a new application for light fields with orbital angular momentum, and our generated microfibers may have applications in optical communications and micromanipulation.