image: Figure | simultaneous emissivity control over MWIR and LWIR bands. (a) Images of Newton and Leibniz are thermally encoded on MWIR and LWIR respectively (b) The metasurface unit cell. The resonances are created by an MIM structure, and are controlled by geometrical parameters such as radius and period of nanodisks. (c) Original and simulated thermal emission based on selected emissivity values (left) for both MWIR and LWIR channels, together with experimentally measured thermal images at different chip temperatures (32°C–112°C). As temperature increases, the encoded patterns become dominant over the background emission. (d) Thermal images acquired at 54°C and different incident angles (0°, 17°, 35°, 44°). The LWIR image stays remarkably stable for every measured angle and temperature, while the MWIR image remains distinguishable and distinct from the LWIR image.
Credit: Roy Maman et al.
Modern infrared imaging and security infrastructure increasingly rely on dual-band tracking, deploying both mid-wave infrared (MWIR) and long-wave infrared (LWIR) advanced sensors to maximize detection contrast and robustness. To bypass these sophisticated surveillance networks, engineering an object's thermal signature across both atmospheric windows is highly desirable. However, conventional thermal photonics cannot independently manipulate these separate bands at a localized, pixel level without one band disrupting the other.
In a new paper published in Light: Science & Applications, Roy Maman, a PhD student from the research group of Professor Uriel Levy at The Hebrew University of Jerusalem, led the development of a novel dual-band metasurface alongside Professor Ilya Goykhman and the nanofabrication expert Noa Mazurski. This breakthrough flat optical device breaks fundamental spectral dependencies by independently managing how a single chip emits thermal energy across separate infrared channels, unlocking a robust, fabrication-ready platform for advanced optical encryption and multi-band.
The platform is centered around a micro-scale pixel array optimized using an advanced mathematical framework. By smart control over the geometry of nano cavities, the platform manipulates light-matter interactions with extreme precision. It allows users to program independent grayscale values into individual pixels for both thermal bands simultaneously. The scientists summarize the core operating principle of their platform:
“Using a mathematical stability analysis rooted in control theory, we leveraged fundamental geometric degrees of freedom to independently tune optical resonances across both wavelength bands simultaneously. This approach allowed us to decouple the control over key resonance parameters, such as peak position and spectral width, achieving near-zero correlation between the two distinct infrared channels.”
This complete independence allows for unprecedented control over thermal signatures. In simple terms, if you look at the exact same physical structure with two different infrared cameras, you will see two entirely different images.
To demonstrate this mind-bending capability, the researchers executed a multi-channel image multiplexing experiment on a single chip. They encoded two completely different, detailed portraits into the exact same pixel area. When viewed under a mid-wave infrared camera, the chip displays a grayscale image of Sir Isaac Newton. Simultaneously, when the exact same chip is viewed through a long-wave infrared camera, the face of his historical calculus rival, Gottfried Wilhelm Leibniz, appears. In an alternate configuration, the platform can be programmed for advanced thermal camouflage, projecting identical signatures to blend seamlessly into an engineered background.
The team also proved that this technology is remarkably robust. The encoded images remain completely clear and stable across wide viewing angles and over a broad temperature, ensuring that high-frequency visual data never accidentally leaks between the two channels.
This breakthrough opens up a vast array of future possibilities for both security and thermal management. Because the design is fully compatible with standard photolithography, it can be easily scaled up for large-scale, low-cost industrial manufacturing. The scientists forecast the broad impact of their work:
“This platform could redefine next-generation anti-counterfeiting tags, secure optical data encryption, and multi-sensor military stealth. Looking even further ahead, incorporating active materials like graphene, electro-optic layers, or phase-change alloys could eventually unlock real-time, reconfigurable dual-band thermal animations - effectively turning static camouflage into dynamic, adaptable thermal displays.”
Journal
Light: Science & Applications
Article Title
Metasurface platform for simultaneous and uncorrelated emissivity control over MWIR and LWIR spectral bands