In a groundbreaking advancement that may redefine the landscape of fiber optics and photonic applications, researchers have unveiled a novel class of “tunable metafibers” capable of remote spatial focus control. This innovation hinges on the integration of intricately designed three-dimensional nanoprinted holograms onto dual-core optical fibers, offering unprecedented manipulation of light fields along fiber lengths. The development, recently detailed in Light: Science & Applications, introduces a versatile platform that blends fiber optics with metasurface engineering, profoundly expanding the functional capabilities of conventional optical fibers.
At the heart of this research lies the fusion of two technological powerhouses: dual-core optical fibers and 3D nanoprinted holographic metasurfaces. Dual-core fibers inherently support the propagation of light across two distinct cores, which can facilitate complex mode interactions. By precisely patterning holographic elements with nanoscale features directly onto the fiber facets through advanced 3D nanoprinting techniques, the team has crafted “metafibers” – fibers that no longer merely guide light but actively reshape and control its spatial distribution with high fidelity and remote tunability.
The implications of these metafibers are far-reaching. Traditional optical fibers transmit light with fixed spatial modes defined by their core geometry and refractive index profile; focusing or steering light typically demands bulky, distal optics or external modulators. This new approach effectively embeds the control apparatus within the fiber itself, allowing dynamic adjustment of the focal spots remotely by manipulating the phase relationship between fiber cores. This intrinsic capability to modulate spatial light distribution along the fiber direction introduces a compact, integrable, and highly responsive alternative for beam shaping and focus control.
Technically, the metamaterial holograms are fabricated at the output ends of dual-core fibers using a state-of-the-art 3D nanoscale printing process. This method provides remarkable spatial resolution and feature complexity, enabling the creation of phase patterns tailored to shape the interference patterns emerging from the two cores. By adjusting the relative input signals injected into each core, the researchers demonstrate continuous tuning of the output beam’s focus position and intensity distribution without any mechanical movement or external optical components.
Beyond the fabrication intricacies, the study delves into the optical physics governing the interaction between the dual-core fiber modes and the holographic phase profiles. The interplay yields sophisticated spatial interference patterns that can be computationally modeled and experimentally verified. This level of predictive control underpins potential applications in adaptive optics, where real-time beam shaping is crucial, as well as in optical communication systems seeking to multiplex data via spatial mode encoding within fibers.
Furthermore, tunable metafibers could revolutionize medical endoscopy and micromanipulation technologies. The compactness and remote control capabilities mean that tightly focused spots can be dynamically positioned at the fiber’s distal tip, improving precision in laser surgery or targeted phototherapy. By integrating the holograms directly on fiber surfaces, the device sidesteps conventional limitations associated with lens alignment and external focusing optics, enabling more reliable and scalable deployment in clinical environments.
The research also highlights the robustness of the fabricated metafibers under various operational conditions. The 3D nanoprinted structures demonstrate excellent adhesion and durability on the curved fiber facets, essential for practical applications. Their nanoscale precision allows the encoding of complex holographic functions that can be reconfigured electrically by modulating the input signals, imparting the metafiber with unique reprogramming potential without physical replacement.
One of the compelling aspects revealed in the study is the potential for multiplexed control. By extending the principle beyond two cores, future iterations could employ multi-core fibers combined with metasurfaces encoding multiplexed holograms, vastly increasing the degrees of freedom for spatial light manipulation within a single fiber. This capability could transform fiber-based sensing, imaging, and data transmission, delivering spatially diverse beam profiles on demand and over long distances.
The researchers leveraged advanced computational design algorithms to optimize the hologram phase patterns, enhancing the interference contrast and focusing efficiency. Experimental validations confirm near-diffraction-limited spot control, a critical benchmark for high-resolution applications. The tunable metastate is also shown to be resilient to minor misalignments and manufacturing variances, underscoring its feasibility for mass production and integration into existing photonic systems.
Complementing the core experimental work, theoretical modeling provides insight into modal coupling dynamics under holographic phase modulation. These analyses unravel how subtle phase shifts introduced by the holographic structures manipulate the amplitude and phase of guided modes. The understanding informs strategies to precisely tailor output beam shapes, promising a flexible design space to target user-specific optical functionalities.
Given the increasing demand for compact and multifunctional photonic devices, tunable metafibers represent a timely innovation. Their capacity to merge metasurface optics with the fiber waveguide platform paves the way for next-generation optical components that are smaller, smarter, and more adaptable. This synergy sparks opportunities across telecommunications, biomedical optics, remote sensing, and beyond.
In summary, the work presented by Sun, Huang, Lorenz, and colleagues introduces a versatile platform that seamlessly integrates 3D nanoprinting and dual-core fiber technologies, crafting metafibers with remotely controllable spatial focus capabilities. This advancement heralds a transformative shift in how light is manipulated within optical fibers, bridging the gap between bulk optics and miniature integrated systems. As this technology matures, it is poised to redefine the boundaries of fiber optics and nonlinear photonics, inspiring novel devices and applications that harness the full potential of light.
Subject of Research: Tunable metafibers with remote spatial focus control using 3D nanoprinted holograms on dual-core fibers.
Article Title: Tunable metafibers: remote spatial focus control using 3D nanoprinted holograms on dual-core fibers.
Article References:
Sun, J., Huang, W., Lorenz, A. et al. Tunable metafibers: remote spatial focus control using 3D nanoprinted holograms on dual-core fibers. Light Sci Appl 14, 237 (2025). https://doi.org/10.1038/s41377-025-01903-0
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