In the realm of contemporary optics, the rapid advancement of metalenses has emerged as a revolutionary force, fundamentally redefining the boundaries of light manipulation at the nanoscale. The recent review article titled “Progress in Metalenses: From Single to Array,” authored by the research group of Professor Din Ping Tsai at City University of Hong Kong and published in the inaugural issue of Opto-Electronic Technology in 2025, offers an illuminating assessment of this transformative field. It chronicles the evolution of metalenses from basic single-element designs toward highly sophisticated multi-element arrays, underscoring developments that promise to drastically enhance optical system capabilities.
Metalenses represent a class of flat optical components engineered by precisely arranging metasurfaces—ultra-thin, nanostructured layers that tailor phase, amplitude, and polarization of incident light waves. Unlike traditional bulky lenses relying on optical refraction, metalenses achieve focusing and beam shaping with nanoscopic structures, enabling unprecedented miniaturization. Still, despite their attractive attributes, significant challenges impede broad real-world adoption. Chief among these are expanding achromatic bandwidths to eliminate color dispersions and scaling up aperture sizes to improve resolution without sacrificing compactness.
To address these hurdles, the review presents a comprehensive overview of recent breakthroughs that leverage innovative design paradigms and materials engineering. One pivotal advancement involves the optimization of nanoscale resonator arrangements to minimize chromatic aberrations, enabling broadband achromatic focusing across visible spectra. Furthermore, the integration of nonlinear optical materials into metalens architectures extends functional operation beyond the visible domain into infrared and ultraviolet regions, opening fresh opportunities for multispectral imaging and sensing. This broadening of operational regimes directly confronts longstanding spectrally restrictive challenges and elevates metalenses to new technological heights.
Beyond conventional single-device studies, the team’s article emphasizes the emergence of dual-metalens configurations, accentuating their unique capacity for sophisticated aberration correction and tunability. Vertically stacked metalens systems exploit the axial spatial domain, whereby one metasurface is positioned atop another, allowing for intricate phase compensations unattainable by single layers. These vertically integrated structures pave the way for varifocal lenses capable of dynamically adjusting focal lengths—a major leap for adaptive optics applications.
In contrast, laterally aligned dual-metalens designs incorporate horizontally offset pairs that mimic binocular human vision, facilitating depth perception and 3D spatial awareness. This biomimicry not only enhances imaging fidelity but also stimulates progress toward intelligent visual sensing, critical for autonomous navigation, robotics, and augmented reality. Such systems exhibit promising correlation with neural processing mechanisms, signifying a profound intersection between metamaterial optics and biological inspiration.
The complexity reaches further dimensions with the exploration of metalens arrays, which arrange multiple metasurfaces in dense configurations to harness high-dimensional light-field modulation. Through collective operation, these arrays enable parallelized imaging protocols and volumetric data acquisition—capabilities essential for next-generation optical computing and information processing. The article highlights three revolutionary applications emerging from array systems: integral imaging that reconstructs three-dimensional scenes with remarkable resolution; light-field imaging methods that perform precise metrology and environmental mapping; and quantum light sources engineered to generate complex multi-photon entangled states for quantum information science.
Integral imaging, enabled by metalens arrays, circumvents traditional depth-of-field constraints by capturing light rays from multiple perspectives and computationally reconstructing three-dimensional volumes. This development promises impact from biomedical visualization to virtual reality interfaces. Simultaneously, light-field imaging schemes leverage spatially multiplexed phase modulation to measure subtle displacements, refractive index variations, and surface contours with extraordinary precision, transforming industrial inspection and scientific instrumentation.
Moreover, the interfacing of metalenses with quantum optics paves paths toward scalable quantum networks. Multi-element metalens arrays facilitate coherent control over photon emission sources, improving entanglement purity and photon indistinguishability. Such advancements underpin emerging quantum computing architectures and quantum communication protocols, signaling the intersection of nanophotonics and the quantum frontier.
In addition to capturing the scientific progress, the article thoughtfully forecasts the trajectory of metalens research. Anticipated future developments include the adoption of novel modulation mechanisms that transcend purely geometric phase control, harnessing multilevel amplitude and polarization manipulations. Artificial intelligence and machine learning-based design strategies are expected to optimize metasurface patterns far beyond human intuition, exponentially accelerating development cycles and performance benchmarks.
Another promising prospect lies in the diversification of array architectures. Future innovations may include dynamically reconfigurable arrays capable of real-time adaptation to environmental inputs, tunable focal lengths, and multi-modal operational modes. Such architectures envision applications spanning ultra-compact optical sensors, wearable imaging devices, and high-throughput quantum photonic platforms.
Beyond technological implications, the review highlights the multidisciplinary expertise behind these achievements. It introduces key contributors, including Chang Peng, a Ph.D. student focusing on multifunctional metasurfaces for optical computing, and Prof. Jin Yao, recognized for pioneering research on nonlocal metasurface devices and light-field manipulation. Most notably, Prof. Din Ping Tsai’s prolific career encompasses nanophotonics, quantum optical computing, and extensive global leadership in metamaterials science, lending authoritative insight to the synthesis presented.
Prof. Tsai’s distinguished accolades—including multiple prestigious awards and fellowships across major international scientific societies—reflect his pivotal role in advancing metasurface science from fundamental physics to pragmatic quantum optical chips. His prolific scholarly output, encompassing hundreds of journal articles, patents, and editorial leadership, underscores the dynamism and depth of expertise that propel this field forward.
The comprehensive nature of the review situates itself not merely as a catalog of incremental progress but as a visionary roadmap guiding the evolution of metalenses into versatile components essential for the imminent era of intelligent optics. By coherently linking single metalenses, dual-element systems, and complex arrays, the article elucidates how modular complexity drives functional enhancement, system integration, and new application domains.
As optics continues to merge with information technology, the significance of such metasurface-enabled devices will only magnify. Metalenses, once theoretical curiosities, are transforming into cornerstones of miniaturized, efficient, and programmable photonic systems that will redefine imaging, sensing, quantum computing, and beyond. The City University of Hong Kong’s research collective stands at this exciting frontier, charting paths for breakthroughs that promise to reshape the landscape of optical science and technology for decades to come.
Subject of Research: Metalenses and metasurface optical systems evolution from single devices to integrated arrays.
Article Title: Metalens Evolution: From Individual Devices to Integrated Arrays
News Publication Date: 17-Jul-2025
Web References: https://doi.org/10.29026/oet.2025.250004
Image Credits: Chang Peng, Jin Yao, Din Ping Tsai
