Optics & Electro-Optics areas through areas like Day vision, Night Vision, Thermal Imaging are playing vital role in warfare due to their high resolution and covert passive operation. The Infrared Search and Track system uses the heat or infrared radiation emitted by the target to provide passive means of detecting and tracking as well as generate data for the weapon system of an aircraft. Hyperspectral imaging sensors look at many spectra of light in closely spaced bandwidths can provide many details about the target like the kind of metal it’s made from, the color and type of paint it has, or the amount of moisture it contains.
Current generation of imaging systems are being developed based on well established and seemingly immutable “laws” of optics design and physics Laws like Reflection and Snell’s Law. One widely considered pillar of optical design, for example, is that imaging systems must be built from a series of complex and precisely manufactured optical elements arranged linearly.
Therefore, current high resolution imaging systems may require dozens of large-area elements in order to achieve the desired spatial resolution requirements, making their design, manufacturing, assembly and alignment very difficult, and rendering optics and opto-mechanics heavy and sensitive to mechanical and thermal perturbations.
The goal of the EXTREME Program is to develop new optical components, devices, systems, architectures and design tools using Engineered Optical Materials (EnMats) to enable new functionality and/or vastly improve size, weight, and power characteristics of traditional optical systems. EnMats are broadly defined to include, but are not limited to, metamaterials (both metallic and dielectric), scattering surfaces and volumes, holographic structures, and diffractive elements.
Early examples of EnMats have been used to design and build multifunctional elements and to dynamically control light, seemingly going beyond standard “laws” of reflection and refraction. The EXTREME program will explore this optical design space and aims to understand the trade-offs, and harness the possibilities, afforded by EnMats.
“We’ve seen significant technical advances in recent years in the communities of optical system design, materials science and fabrication, and multiscale modeling and optimization,” said Predrag Milojkovic, DARPA program manager. “EXTREME seeks to capitalize on this momentum by uniting these separate communities to revolutionize optics and imaging as we know it.”
To achieve its objective, EXTREME is focused on developing new EnMats–both two-dimensional metasurfaces as well as 3D volumetric optics and holograms–that manipulate light in ways beyond classical rules of reflection and refraction. EXTREME also will address multiscale modeling to enable design and optimization of EnMats across vastly different scales, from nanometer to centimeter, for example.
A key program aim will be to demonstrate an optical system with engineered surfaces where control of light propagation is decoupled from a specific geometric shape, and can also be tuned. “EXTREME also seeks to demonstrate a volumetric optical element the size of a sugar cube or larger that can perform a multitude of functions simultaneously in [the visible] and infrared bands, such as imaging, spectrum analysis, and polarization measurements, among others,” announced the agency.
DARPA says that the project could introduce a new era in optics and imagers for national defense. EXTREME optical components would be lighter and smaller, enabling miniaturization of imaging systems for intelligence, surveillance, and reconnaissance (ISR) applications. The multifunctional nature of these devices could offer improvements in a wide variety of imaging systems by reducing size and weight without compromising performance for systems as diverse as night vision goggles, hyperspectral imagers, and IR search and track systems.
The project, says DARPA, will require formation of cross-cutting teams bringing together expertise from disparate communities and fields, including but not limited to engineered material design and fabrication, multiscale modeling/simulation/optimization, and optical system design.
EXTREME is divided into three technical areas (TAs):
TA1: Modifying the Principles of Conventional Optics – performers will analyze the limits to which EnMats can modify conventional light propagation laws defined as the laws typically used within the optical design process. This includes, but is not limited to, the Law of Reflection, Snell’s Law, and Fresnel refraction/reflection coefficients. Theories, concepts, and techniques will be developed to address current limitations of EnMats in terms of efficiency, wavelength, bandwidth, polarization, and working numerical aperture
TA2: Multifunctional Optics – performers will explore the limits and state-of-the-possible of multifunctional optical elements. As an example, an imager is considered to perform a single function, a spectrometer is considered to perform a single function, a hyperspectral imager would be considered to perform two functions, and a compressive hyperspectral imager would be considered to perform three functions
TA3: Modeling, Design, and Optimization – will develop novel concepts in the modeling, design, and optimization of optical systems based on EnMats, and is divided into two sub-TAs. TA3(a) focuses on physics-based models, and n TA3(b) will explore design concepts and optimization environments specifically tailored towards the development of disruptive EnMatbased optical system architectures
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