High-Momentum 2D Emission Coupled to Surface Resonance

In the ever-evolving landscape of photonics and nanophotonics, a groundbreaking study has emerged that pushes the boundaries of our understanding of light-matter interaction at the nanoscale. Researchers Y. Koo, D.K. Oh, J. Mun, and colleagues have unveiled a novel phenomenon highlighting the high momentum, two-dimensional propagation of photoluminescence emissions intricately coupled with surface lattice resonances (SLRs). Published in Light: Science & Applications in 2025, their discovery charts new territory in the precise control and directional manipulation of light emissions from nanostructured materials, promising a leap forward in photonic device engineering.

Photoluminescence, the process by which a material absorbs photons and subsequently re-emits them, is a cornerstone of various optical technologies, from light-emitting diodes to quantum information systems. Traditionally, the directionality and momentum characteristics of emitted photoluminescence have been constricted by the intrinsic electronic and optical properties of the material. However, by harnessing the complex interactions between periodic nanostructures and the coupled electromagnetic fields they induce, the research team has demonstrated a remarkable ability to influence the momentum distribution of emitted photons, enabling their propagation in two dimensions with unprecedented control.

Central to this achievement is the exploitation of surface lattice resonances, a collective resonance phenomenon that occurs when the diffractive orders of a periodic nanoparticle array coincide spectrally with localized surface plasmon resonances. These SLRs emerge from the hybridization of plasmonic oscillations and photonic diffractive modes sustained by the periodic lattice, producing modes with sharp spectral features and enhanced electromagnetic field intensities. The interplay between photoluminescence and SLRs leverages these intense, coherent fields to modify the angular momentum and propagation characteristics of the emitted light.

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The research team’s experimental platform comprised meticulously engineered arrays of metallic nanoparticles configured to support well-defined surface lattice resonances under visible to near-infrared illumination. By exciting these arrays with ultrafast pulsed lasers, they induced photoluminescence within the plasmonic material lattice. Intriguingly, the emitted light did not simply diffuse isotropically but exhibited high-momentum propagation confined within the two-dimensional plane of the nanoparticle array. This behavior starkly contrasts with conventional photoluminescence, which typically radiates in all directions with broader momentum distributions.

The phenomenon of two-dimensional propagation of photoluminescence arises from the efficient coupling between the emission dipoles and the lattice’s collective plasmonic modes. This coupling effectively transfers momentum from the lattice resonances to the photons, directing their trajectory along the surface plane. Such momentum steering holds profound implications for integrated photonic circuits, where directional control of light emission is paramount for signal routing, information processing, and minimizing losses due to scattering.

To dissect the underlying physics driving their observations, the researchers employed a combination of angle-resolved photoluminescence spectroscopy and rigorous numerical simulations. Spectroscopic measurements revealed narrow angular emission peaks corresponding with the predicted SLR modes, reinforcing the assertion that the emitted photons inherit their momentum characteristics from the surface lattice resonances. Moreover, simulations based on finite-difference time-domain (FDTD) methods elucidated the intricate electromagnetic field distributions surrounding the nanoparticle arrays, confirming the strong field confinement necessary to facilitate momentum transfer.

Beyond their experimental insights, the authors explored the tunability of this high momentum photoluminescence propagation by varying the lattice parameters, such as nanoparticle size, shape, and array periodicity. Adjusting these parameters shifted the spectral positions and angular distributions of the SLR modes, providing a versatile toolkit for tailoring the photoluminescence emission profile. This adaptability introduces a potent degree of control over light-matter interaction, opening avenues for custom-designed photonic devices with on-demand emission directionality.

One of the most striking potential applications of this discovery resides in the realm of nanoscale lasing and coherent light sources. By harnessing the high momentum, directional propagation of photoluminescent emissions, it becomes feasible to engineer ultrathin, planar laser architectures capable of coherent emission with minimal divergence. This could revolutionize optical on-chip communication systems, where compact and directional coherent light sources are critical components.

Furthermore, the enhanced light-matter coupling mediated by surface lattice resonances imparts increased photoluminescence quantum yields and emission intensities. Such enhancements are invaluable for sensing applications, particularly in biochemical environments where detecting minute changes in emission properties can signal the presence of specific molecules or environmental conditions. The confined momentum space of the emissions also facilitates improved spatial resolution in sensing experiments, as the directional light propagation can be harnessed for precise spatial interrogation.

The integration of these findings into practical device architectures does not come without challenges. Fabrication of nanoparticle arrays with the requisite precision and uniformity demands advanced nanolithography techniques and material synthesis methods. Additionally, controlling the dielectric environment surrounding the arrays is necessary to preserve the sharpness and strength of surface lattice resonances. Despite these hurdles, recent advancements in manufacturing techniques make the translation of this research into commercial technologies increasingly attainable.

In the broader context of photonic research, this study represents a paradigm shift by showcasing the role of collective plasmonic phenomena in dictating emitted photon momentum beyond the constraints of conventional spontaneous emission. It underscores the importance of lattice engineering in manipulating photonic phenomena and paves the way for novel light control strategies at the nanoscale, including directional single-photon sources and angle-dependent emission devices.

The implications extend toward the burgeoning fields of quantum information science and ultrafast optics, where controlling the phase and momentum of emitted photons is fundamental. The strong confinement and directionality imparted by surface lattice resonances enhance photon indistinguishability and coherence times, vital metrics for quantum communication protocols and quantum computing architectures relying on photonic qubits.

Importantly, the synergy between plasmonics and photoluminescence explored in this research elucidates new mechanisms where emitted light is not merely a passive product of material excitation but an actively shaped entity by the engineered electromagnetic environment. This insight deepens our fundamental grasp of light emission processes and inspires new conceptual frameworks for future optical technologies.

In conclusion, the work by Koo, Oh, Mun, and collaborators marks a significant leap forward in nanoscale optics. By demonstrating high momentum two-dimensional propagation of emitted photoluminescence coupled with surface lattice resonance, they introduce a powerful approach to tailor light emission properties with precision and flexibility. This advancement promises to impact a diverse array of fields, including integrated photonics, sensing technologies, quantum optics, and beyond, heralding a new era of engineered light manipulation at the smallest scales.

Subject of Research: High momentum propagation of photoluminescence coupled with surface lattice resonance in nanostructured materials.

Article Title: High momentum two-dimensional propagation of emitted photoluminescence coupled with surface lattice resonance.

Article References:
Koo, Y., Oh, D.K., Mun, J. et al. High momentum two-dimensional propagation of emitted photoluminescence coupled with surface lattice resonance. Light Sci Appl 14, 218 (2025). https://doi.org/10.1038/s41377-025-01873-3

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41377-025-01873-3

Tags: advanced optical technologiescontrol of photon momentum distributiondirectional manipulation of light emissionselectromagnetic field interactionshigh-momentum photoluminescencelight-matter interaction at nanoscalenanophotonics innovationsnanostructured material applicationsphotonic device engineering advancementsphotonics research breakthroughssurface lattice resonancestwo-dimensional light propagation