Exploring the Use of Magnetorheological Fluid Technology to Generate Optical Vortex Beams

Project Overview

A wide variety of optical applications rely upon accurate generation and manipulation of structured light states with space-variant polarization distributions. While many technologies exist, none are capable of operating at high fluence (more than 10 Joules/centimeters²), large aperture (up to ~40x40 cm), and with a high degree of accuracy. In this work, we demonstrated the feasibility of a new technology for high-fluence, large-aperture space-variant polarization control, in which freeform optic fabrication technology and magnetorheological finishing (MRF) tools are used to carve a prescribed thickness profile into a crystalline quartz waveplate. New tools have been developed to carve a spiral-shaped thickness pattern with a carve depth of over 100 microns. Fabrication of a 2-inch diameter fused silica test piece and a quartz spiral plate is nearing completion and will be used to generate a polarization vortex beam, which is expected to have an angular Stokes vector error of less than 2° compared to the ideal case. Additional demonstrations and validations will be performed as part of an upcoming research effort. This new technology is poised to support major advances in several areas related to core Lawrence Livermore National Laboratory missions, including generation of large magnetic fields for high-energy-density science experiments and reduction of depolarization losses in solid state laser architectures.

Mission Impact

Our work supports several of the Laboratory's core competency areas including laser and optical science and technology, high-energy-density science, and additive manufacturing. Our results enable a new class of experiments and laser operating regimes that will advance Livermore's inertial fusion science research in support of the NNSA mission.

Publications, Presentations, and Patents

Di Nicola, Jean-Michel, Alvin Erlandson, Joseph A. Menapace, and Gabriel Mennerat. 2021. Polarization manipulation of free-space electromagnetic radiation fields. U.S. Patent Application 2021/0239893 A1, filed September 1, 2020, and published August 5, 2021.