Optical Fibers in Fluoropolymer Cladding Exhibiting Unixial Photomechanical Motion

Stable and repeatable uniaxial pistons at any scale are desirable simple machines for a variety of applications. This study examines photomechanical behavior of optical fibers to actuate the motion exclusively with laser light. Sample fibers were fabricated by doping a polydimethyl-siloxane resin solution with graphene nanoplates and drawing that solution into fluoropolymer tubing before the resin set. When pumped by a continuous-wave laser, the graphene absorbs the light, heating the cured resin which expands within the tube and protrudes out the ends with uniaxial motion. Some of the resulting motion was due to the tube cladding itself expanding and straining from the heat, where the core was pinned to the fluoropolymer cladding. Successive samples were lubricated with a non-refractive castor oil to reduce friction and allow free motion between the core and cladding. The results presented examine the efficacy of adding lubrication to the system on its reversibility, and the contribution of variables such as sample length, variations of inner diameter, and cladding material in repeatability.