The concept behind the new work is known as infrared-to-visible upconversion. Instead of detecting infrared photons electronically, an upconversion device absorbs them and re-emits their energy at shorter, visible wavelengths, where ordinary silicon sensors and even the naked eye can see it. The trick has been demonstrated before in bulk crystals and optical fibers, but those systems typically demand intense laser pumping, operate only in narrow spectral bands, and offer little spatial control over the conversion process. The result is a technology that has remained largely confined to laboratory demonstrations rather than practical imaging systems. The new study tackles each of these limitations by rethinking the device at the level of nanostructure design.

At the heart of the approach are lanthanide-doped upconversion nanoparticles, most commonly built from a sodium yttrium fluoride host lattice doped with ions such as ytterbium and erbium or ytterbium and thulium. These ions form a cascade: the sensitizer ion, typically ytterbium, absorbs a near-infrared photon around 980 nanometers and transfers that energy stepwise to an activator ion, which accumulates the excitation and finally emits a visible photon. Because the energy levels of lanthanide ions are shielded by outer electron shells, the emission is sharp, stable, and remarkably resistant to photobleaching. The nanoparticles can be synthesized with controlled sizes and shell architectures, and core-shell designs that physically separate dopant ions suppress a major loss channel known as surface quenching, in which excitation energy leaks away at particle surfaces before it can produce light.

On their own, however, these nanoparticles are inefficient. The transitions that lanthanide ions undergo are formally forbidden by quantum-mechanical selection rules, which makes absorption weak, and the stepwise energy transfer process competes with numerous decay pathways. This is where the metasurface enters. A metasurface is a two-dimensional array of engineered nanostructures, often metallic or dielectric pillars and antennas, patterned at a scale smaller than the wavelength of light. By adjusting the geometry, spacing, and material composition of these building blocks, researchers can sculpt how light behaves at the surface: concentrating it into tiny volumes, redirecting it, filtering specific wavelengths, or imposing precise phase shifts across a wavefront. Metasurfaces have already revolutionized flat optics, enabling ultrathin lenses and holograms, and the new work harnesses that same design freedom to supercharge upconversion.

The hybrid screens described in the study integrate the two components so that the metasurface acts as an optical antenna system for the nanoparticles. Resonant modes supported by the metasurface trap incoming infrared light near the surface, dramatically increasing the local electromagnetic field intensity exactly where the nanoparticles sit. Because upconversion is a nonlinear process, in which the emission rate scales steeply with excitation intensity, even a modest field enhancement translates into a large boost in output. The metasurface can also be tuned to match the absorption bands of the sensitizer ions and to extract the emitted visible light efficiently, reducing the losses that would otherwise trap the upconverted photons inside the structure. The researchers report that this combined electromagnetic and photonic engineering yields imaging screens with substantially enhanced brightness and sensitivity compared with films of nanoparticles alone.

What elevates the work from a materials demonstration to an imaging technology is the spatial dimension. Because metasurfaces are patterned with lithographic precision, the hybrid screens can be designed to do more than simply brighten an image. The authors show that the screens can impose controlled phase and amplitude modifications on the upconverted visible light, effectively performing optical processing at the moment of conversion. In one configuration, the screen functions as a direct infrared imager: infrared light from a scene strikes the screen, is converted locally into visible emission, and the resulting visible image can be captured with an ordinary camera or viewed directly. In another configuration, the metasurface patterning enables edge enhancement, a computational imaging operation in which the outlines and boundaries of objects are emphasized, all performed passively in optics without any digital processing.

This ability to merge light conversion with analog optical computation in a single thin film points toward a compelling vision of the future of imaging. Conventional infrared cameras chain together optics, detectors, amplifiers, and processors, each stage adding cost, weight, latency, and power consumption. A hybrid upconversion screen collapses much of that chain into a passive optical element. The infrared image is converted, enhanced, and even pre-processed before a single electron is moved. Such screens could be produced as coatings on standard camera lenses, integrated into smartphone modules, or deployed as large-area viewing panels that make invisible laser beams, thermal signatures, or biomedical fluorescence directly visible to the eye.

The potential applications span an unusually wide range. In night vision, low-cost, uncooled upconversion screens could complement or replace bulky image intensifier tubes, offering a lighter and potentially cheaper alternative for both military and civilian use. In medicine, near-infrared light penetrates tissue more deeply than visible light and scatters less, and upconversion nanoparticles are already explored as imaging probes and as agents for light-triggered therapies; screens that convert scattered near-infrared light into visible images could improve surgical guidance and diagnostics. In telecommunications, silicon photonic circuits and optical fibers operate in the near-infrared, and efficient, fast upconversion could allow infrared signals to be inspected visually or routed with visible-light components. In industrial settings, the screens could reveal hot spots, gas absorption features, or defects that are invisible under ordinary illumination, while in fundamental research they could serve as diagnostic foils for characterizing infrared laser beams and photonic devices.

The authors are candid about the challenges that remain before such devices become routine. Upconversion efficiency, even with metasurface enhancement, still falls short of what high-speed, low-light imaging would demand, and the nonlinear nature of the process means performance degrades at low illumination levels, precisely where night-vision applications matter most. The spectral bandwidth of lanthanide-based conversion is inherently narrow, tied to the discrete energy levels of the ions, so covering the broader infrared spectrum, including the mid-infrared region where thermal imaging lives, will require different material combinations or multi-resonant metasurface designs. Response time is another consideration: the excited-state lifetimes that make lanthanides stable emitters also limit how quickly the screens can follow rapidly changing scenes. Scaling the nanofabrication from centimeter-scale laboratory samples to large, uniform, low-cost panels is an engineering task in its own right.

Nevertheless, the demonstration marks a meaningful step in the convergence of two of nanophotonics’ most productive threads: flat metasurface optics and lanthanide luminescence. By treating the upconversion screen not as a passive phosphor but as an actively engineered optical element, the researchers have shown that the conversion of invisible light into visible images can be made brighter, more controllable, and more functional than previously imagined. If the efficiency and bandwidth gaps can be closed through continued materials and design refinement, hybrid metasurface-nanoparticle screens could reshape how we see the invisible half of the electromagnetic spectrum, turning infrared imaging from a specialized electronic undertaking into something as simple and ubiquitous as a sheet of smart glass.

Subject of Research: Hybrid metasurface–lanthanide nanoparticle screens for enhanced infrared-to-visible upconversion imaging

Article Title: Enhanced infrared-to-visible upconversion imaging via metasurface–lanthanide nanoparticle hybrid screens

Article References: Sefidmooye Azar, N., Parry, M., Qi, X., Lee, C., Lee, W. S. L., Russell, B., Luo, W., de Gille, R. W., Nelson, D., Balendhran, S., Meng, J., Tan, H., Bonin, G. O., Choi, D.-Y., Schuck, P. J., Chan, E. M., Cohen, B. E., Neshev, D. N., & Crozier, K. B. (2026). Enhanced infrared-to-visible upconversion imaging via metasurface–lanthanide nanoparticle hybrid screens. Light: Science & Applications, 15(1), Article 377. https://doi.org/10.1038/s41377-026-02449-5

Image Credits: AI Generated

DOI: 10.1038/s41377-026-02449-5

Keywords: upconversion, metasurfaces, lanthanide nanoparticles, infrared imaging, nanophotonics, night vision, optical computing, core-shell nanoparticles, photoluminescence, flat optics, biomedical imaging, light conversion

Core-shell nanoparticles are engineered structures with two distinct layers: a core that encapsulates drugs and a shell that serves various functional purposes, including protecting drugs from degradation. This intricate design is pivotal for ensuring that therapeutics remain stable until they reach their desired target. By leveraging the unique properties of materials—ranging from polymers and lipids to inorganic compounds—researchers can tailor these nanoparticles for optimal drug loading and distribution, addressing the specific needs of diverse therapeutic interventions.

One of the paramount benefits of core-shell nanoparticles lies in their capability for controlled drug release. This mechanism not only enhances the efficacy of the treatment but also significantly minimizes adverse effects, rendering it an attractive alternative to traditional drug delivery methods. Enhanced bioavailability and targeted action are essential components of personalized medicine, where treatments are customized based on individual patient profiles. This targeted approach embodies the future of medicine, complementing advancements in genomics and biotechnology that aim to provide precision healthcare solutions.

The study conducted by Suren A. Ramadhan and Diyar S. Ali representatives from Knowledge University and Salahaddin University in Iraq sheds light on several avenues through which core-shell nanoparticles can be utilized effectively. For instance, the ability of these nanoparticles to encapsulate a wide range of therapeutic agents—including chemotherapeutics, biologics, and vaccines—opens up possibilities for developing multifaceted treatment regimens. Moreover, as the healthcare community strives to improve patient outcomes, the role of customized drug delivery systems becomes undeniably significant.

Equipped with the capacity to shield drugs from premature degradation, core-shell nanoparticles foster controlled drug release, enabling the sustained delivery of therapeutics over extended periods. This sustained mechanism is especially crucial for conditions that require chronic treatment, allowing for consistent therapeutic levels while mitigating fluctuations in drug concentration that are common with conventional delivery methods. As such, patients can experience improved treatment outcomes, ultimately leading to a better quality of life.

Current research highlights diverse applications of core-shell nanoparticles in oncology, where they have shown promise in enhancing the effectiveness of chemotherapeutic agents while concurrently reducing their toxic side effects. By utilizing these advanced nanocarriers, clinicians can potentially increase drug efficacy while sparing healthy tissues, a significant advancement in cancer treatment paradigms. This integration of nanotechnology within oncology also points to a future where combination therapies, conducted simultaneously, can be more efficient and targeted.

The development of core-shell nanoparticles also raises questions related to material safety, biocompatibility, and potential toxicity. Researchers are dedicated to addressing these concerns to improve the overall efficacy and safety profile of these nanoparticle systems. This comprehensive investigation enables teams to devise innovative materials that not only deliver drugs effectively but also conform to stringent safety standards. Businesses and research institutions are actively collaborating to generate comparative studies assessing the performance of various core-shell configurations, thereby refining the design process.

As scientists and researchers delve deeper into the potential of nanoparticles, advancements in synthesis techniques promise to yield more sophisticated structures with improved functionalities. Novel approaches, including the use of smart materials responsive to specific triggers—such as pH changes or specific enzymes—can facilitate the design of more intelligent drug delivery systems. This capability could potentially diminish the risk of systemic toxicity while enhancing the therapeutic outcomes for patients who require complex drug regimens.

In conclusion, the meticulous exploration of core-shell nanoparticles is set to redefine therapeutic paradigms in personalized and precision medicine. Their ability to provide targeted, controlled, and sustained drug release represents a paradigm shift that holds the possibility of revolutionizing the way we approach various medical conditions. Such innovations highlight the confluence of nanotechnology and medicine, illustrating a promising trajectory toward more refined healthcare solutions that prioritize patient outcomes. The research community’s dedication to unraveling the complexities of these systems paves the way for groundbreaking advancements that could enhance treatment accessibility, efficacy, and safety.

As we venture forward, the publication of pivotal studies in respected journals is essential to communicate these findings and foster collaborative efforts across the scientific community. The journey of core-shell nanoparticle research exemplifies the innovative spirit that drives science toward a future where healthcare is more personalized, effective, and holistic than ever before.

Subject of Research: Not applicable
Article Title: Innovations in Core–Shell Nanoparticles: Advancing Drug Delivery Solutions and Precision Medicine
News Publication Date: Not applicable
Web References: Not applicable
References: Not applicable
Image Credits: Mary Ann Liebert, Inc.