Plasmonic Structures and Devices: Patent Analysis Highlights Nanoscale Electromagnetic Energy Manipulation

The manipulation of light at the nanoscale is driving innovation across numerous fields, and a new analysis of patent disclosures reveals the rapidly expanding landscape of plasmonic technologies. Mahdi Javidnasab and Sajjad Hosseinzade, both from the Department of Condensed Matter Physics at the University of Tabriz, lead a comprehensive review of how researchers are harnessing plasmonic structures for diverse applications. The study demonstrates a clear trend towards utilising highly conductive materials, such as gold and silver, alongside emerging alternatives, to confine and control electromagnetic energy at extremely small scales. This capability underpins advances in areas ranging from highly sensitive detection methods to the development of efficient optical devices, and the patent analysis highlights the growing commercial potential of these innovative technologies.

Conductive noble metals, such as gold and silver, alongside innovative alternatives like transparent conducting oxides and two-dimensional materials, form the basis of this research. These materials are engineered into diverse nanostructures that exploit surface plasmon resonance and localized surface plasmon resonance, generating intense electromagnetic “hot spots” necessary for signal amplification and providing extreme refractive index sensitivity for label-free detection. Key device elements include subwavelength plasmonic waveguides for optical signal routing, with dynamic control achieved through active tuning mechanisms utilizing electrical gating of charge carrier density.

Plasmonics for Data Storage and Biomedicine

Recent research systematically analyzes patent disclosures concerning plasmonic structures, devices, and integrated applications, demonstrating the technology’s capacity to confine and manipulate electromagnetic energy at the nanoscale. A significant portion of the research focuses on improving data storage technology, particularly heat-assisted magnetic recording, with innovations in optical coupling layers and thermally stable alloys. Plasmonics are also explored for various medical uses, including stimulating cells, developing nanobubbles for tumor treatment, creating stimuli-responsive nanocarriers, and amplifying nucleic acids using LED-driven plasmonic heating. Further research explores optical enhancement and collection, utilizing plasmonic light collectors and developing optical elements including light sources and waveguides. Investigations also extend to communications, specifically ultra-massive MIMO communication in the terahertz band, and terahertz technology, including low-duty-cycle continuous-wave terahertz imaging and photoconductive terahertz imaging and spectroscopy systems. This broad range of applications highlights the versatility of plasmonic technologies.

Nanoscale Light Confinement via Plasmonic Structures

Recent research systematically analyzes patent disclosures concerning plasmonic structures, devices, and integrated applications, demonstrating the technology’s capacity to confine and manipulate electromagnetic energy at the nanoscale. Localized surface plasmon resonance occurs within nanometer-sized structures, exhibiting spatial confinement when lateral dimensions are less than half the wavelength of incident electromagnetic radiation. This confinement generates a resonant response, resulting in strong ultraviolet-visible absorption bands and greatly enhanced electric fields in nanoscale locations known as “hot spots”. Crucially, the resonance wavelength of these nanostructures is tunable based on design parameters like size, shape, and architecture, as well as the surrounding refractive index, with gold and silver nanorods exhibiting tunable peaks from the visible through the near infrared based on their aspect ratio.

Beyond localized resonance, long-range surface plasmon resonance, specific to thin metal films or strips, propagates along surfaces for distances up to a few millimeters in the visible spectrum, and even centimeters in the infrared, offering potential for active photonic components and highly sensitive sensors. Specialized resonance types, including toroidal resonances, spoof plasmonics, and exciton-plasmon coupling, further expand the capabilities of plasmonic systems. Exciton-plasmon coupling, in the strong coupling regime, leads to the formation of new quasiparticles exhibiting unusual properties, such as Rabi splitting, while epsilon-near-zero modes enable complete absorption of deeply sub-wavelength films and substantial increases in nonlinear optical processes. Regardless of the specific resonance type, plasmonic systems concentrate and confine electromagnetic waves in regions considerably smaller than their wavelength, enabling sub-wavelength confinement of light and precise control of optical fields.

Plasmonic Innovation, Nanoscale Light Control Demonstrated

This systematic analysis reveals the breadth of innovation in plasmonic components, demonstrating a rapidly evolving field focused on manipulating light at the nanoscale. Researchers are increasingly utilizing highly conductive metals, such as gold and silver, to create nanostructures that support surface plasmon resonance and localized surface plasmon resonance. These resonances enable intense light confinement and amplification, with applications spanning sensing, waveguiding, and energy manipulation. The study highlights the importance of precise dimensional control, with functional elements ranging from a few nanometers to several hundred nanometers depending on the desired application, and demonstrates a diversity of geometries including nanoparticles, nanowires, and plasmonic cavities.

Beyond traditional metallic materials, the work demonstrates a growing interest in alternative materials like transparent conducting oxides and two-dimensional semiconductors. These materials offer potential advantages in tunability and integration into complex circuits, and researchers are actively exploring methods for dynamic control through electrical gating and phase-change materials. While the analysis confirms the versatility of plasmonic components across various substrates, including glass, semiconductors, and even paper, challenges remain in achieving scalable fabrication and consistent performance.