To address the need for compact, lightweight, and cost-effective high-magnification beam-expanding optics for missions such as NASA Langley Research Center’s Doppler Aerosol Wind (DAWN) lidar system, a Voxtel-led team—including Dr. Julie Bentley of Bentley Optical Design, collocated with the Institute of Optics at the University of Rochester—proposes to implement a novel distortion-free beam-expanding optical assembly based on 3D freeform gradient-index (GRIN) optical materials. Specifically in this effort, the goal is to implement a very compact folded-light-path four-mirror beam expander, optimized for 2,053-nm wavelength laser light, that implements a custom-engineered aberration-reducing 3D GRIN phase-corrector plate (PCP) to simultaneously minimize aberrations and maximize beam quality.
The PCP will be manufactured using Voxtel’s Volumetric Index-of-Refraction Gradient-Index Optics (VIRGO) technology platform, which deposits variable index-of-refraction transparent nanocomposite materials with optical properties that vary voxel by voxel in an additive manufacturing process to realize high-performance freeform GRIN optics. The ability to form freeform gradient optical-index functions enables the use of previously unavailable complex higher-order polynomial functions in optical path design, while also providing the capability to reduce geometric and chromatic aberrations.
The technology is applicable to the NASA Doppler Aerosol Wind (DAWN) lidar program employing pulsed laser to measure atmospheric wind profiles, the Differential Absorption Lidar (DIAL) program for atmospheric measurements of aerosol profiles in the visible and infrared band, the Thickness from Offbeam Returns (THOR) cloud measurement program, and the Near Earth Orbit (NEO) Nanosat-based Earth observation program.
Freeform GRIN lens technology will enable low-profile otherwise-impossible lenses, most notably for the cellphone camera market. Other markets include virtual-reality headsets, which will embody the technology in the form of light-field lens arrays, and medical optics, including endoscopy equipment, eyeglasses for patients with particularly difficult prescriptions, and contact lenses.