SBIR-STTR Award

To demonstrate the ability of freeform gradient optics to achieve compact lightweight high-performance beam-expanding optics, working with NASA subject matter experts and other stakeholders, the requirements for the lidar beam-expanding optical system will be refined. Design trade studies will be performed before various lidar beam-expander optics are designed and modeled. On-axis and off-axis afocal beam expanders will be designed that provide accurate, unobstructed and achromatic expansion of the collimated input source. The designs considered will include 15-cm- to 60-cm-diameter beam-expander telescope optical systems, with magnifications of 20x to 65x respectively. After optimizing designs, optical components will be fabricated, characterized, and demonstrated. The optics obtics will be shown to maintain high optical performance over a wide range of temperatures (e.g., at least -100° C to +100° C) and to be compatible with respect to environmental, atmospheric oxygen and radiation tolerance, and outgassing conditions typical of space-based payloads launched and operating in space. Potential NASA Applications (Limit 1500 characters, approximately 150 words) The innovation has widespread application for NASA missions requiring compact, high-performance optics, including those for small satellites, laser-ranging and lidar instruments, integral imaging spectroscopy, and demanding optical instruments. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) The innovation has widespread use in amateur astronomy, cell-phone cameras, holographic displays, integral imaging devices, optical microscopy, and consumer and industrial optical systems.

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. Potential NASA Applications (Limit 1500 characters, approximately 150 words) 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. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) 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.