Polarization Micro-Optics: Circular Polarization From a Fresnel Rhomb 3D Printed on an Optical Fiber

High-resolution fabrication of three-dimensional polymeric structures with direct laser writing (DLW) holds a unique potential for the miniaturization of bulk optical elements. This has been so far mainly demonstrated for the fabrication of reflective, refractive, and phase-mask micro-optics. Here, we show the use of DLW for the fabrication of a miniaturized phase retarder element, a Fresnel Rhomb, which acts as a broadband quarter-wave plate. We show the integration of the Fresnel Rhomb onto a polarization-maintaining optical fiber, converting linearly polarized light from the fiber into circularly polarized light over a very broad spectral range.