Review maps the shift from non-resonant to resonant metasurfaces

A new review from Professor Din Ping Tsai’s group at City University of Hong Kong lays out how non-resonant and resonant metasurfaces can work together to power better imaging, color routing, and AR/VR displays. The paper argues hybrid meta-devices could combine broadband control with ultra-narrow spectral selectivity for chip-integrated photonics.

Why it matters: - Metasurfaces are moving from single-function optical components toward multifunctional meta-devices. - The review says non-resonant and resonant designs are complementary, not competing, and their fusion could improve imaging, display, and light-field control. - That combination could matter for AR/VR, LiDAR, quantum photonics, and biosensing.

What happened: - Professor Din Ping Tsai’s group at City University of Hong Kong published a review in Opto-Electronic Science titled “From non-resonance to resonant meta-devices: imaging, color routing, displaying, and beyond.” - The review was made available online on June 28, 2026. - The paper examines the physical mechanisms, structures, and applications of non-resonant and resonant metasurfaces. - The DOI is 10.29026/oes.2026.260016.

The details: - Non-resonant meta-devices use geometric and propagation phases, plus group delay and band engineering, to deliver broadband and achromatic functions. - These devices include achromatic metalenses and full-color structural color displays. - Non-resonant designs are efficient, but they do not offer strong spectral selectivity. - Resonant mechanisms such as bound states in the continuum, local–nonlocal transitions, localized surface plasmon resonances, surface lattice resonances, and Mie resonances add ultra-narrowband wavefront control. - The review organizes the field into three layers: principles, structures, and applications. - Typical structures include achromatic metalenses, color-routing metasurfaces, Mie cavities, and resonant metalenses. - The application set includes imaging, displays, wavefront shaping, and AR/VR. - In resonant wavefront control, the review highlights multilayer nonlocal metasurfaces for multifunctional resonant shaping. - Nonlocal Huygens metalenses have reached Q-factors up to 10^4 through the generalized Kerker effect. - Spin-multiplexed devices can support bright-field and edge-enhanced imaging at the same time. - Quasi-BIC metasurfaces have been used for terahertz single-pulse imaging, near-field sensing, and simultaneous spectral-polarization detection from visible to near-infrared wavelengths. - A reported metalaser uses local–nonlocal transitions to excite quasi-BIC resonances. - The metalaser combines a Q-factor of about 3,700 with geometric phase control. - The device can emit narrowband laser beams with arbitrary wavefronts, including focused spots, vortex beams, and speckle-free holograms, without external shaping optics. - In structural color displays, a refractive-index-matching layer narrows the resonance linewidth of high-contrast all-dielectric metasurfaces. - That approach enables wide-gamut, high-saturation structural colors. - Silicon nanoantennas based on quasi-BIC suppress higher-order multipole resonances to produce bright, pure red pixels. - Pixelated plasmonic metasurfaces with shallow nanocavities can independently tune hue, saturation, and brightness. - Those plasmonic devices support full-color nano-paintings and can hide information with polarization encryption. - The review says resonant mechanisms are pushing structural color displays toward higher resolution, wider color gamut, and higher information density.

Between the lines: - The review frames the field’s direction as hybridization rather than replacement. - Broadband non-resonant optics still matter for efficient baseline performance. - Resonant optics add the spectral precision needed for multiplexing, encoding, and finer wavefront control. - The main barrier is no longer only device design. Large-area fabrication, modeling nonlocal effects, and CMOS-compatible integration remain difficult.

What's next: - The review points to hybrid meta-optics that combine broadband achromatic response with high-Q spectral selectivity. - Dynamic tunable materials and deep-learning inverse design are expected to accelerate that shift. - The paper suggests the next generation of devices will be chip-integrated and more programmable across imaging and display tasks. - Remaining work will focus on scaling fabrication, improving models for complex resonant interactions, and integrating with standard semiconductor processes.

The bottom line: - The review argues that the next leap in metasurface technology will come from combining non-resonant efficiency with resonant precision, not choosing one over the other.