From non-resonant to resonant meta-devices: imaging, color routing, displaying, and beyond

The rapid evolution of meta-optics has been largely driven by non-resonant phase-control mechanisms, chiefly geometric and propagation phases, enabling high-efficiency, broadband devices such as achromatic metalenses and structural-color displays. Recently, however, resonant physics, especially bound states in the continuum (BICs) and local to nonlocal transition (LNT), has introduced a fundamentally new paradigm. This review highlights how the shift from non-resonant to resonant meta-devices is reshaping imaging and display technologies. Resonant architectures unlock unprecedented functionalities that were previously inaccessible with conventional phase-only designs, including ultra-narrowband wavefront control, spectrally decoupled multiplexing, and pixel-level color routing with high spectral purity. We systematically compare the underlying physics, illustrate key advances in resonant imaging, color manipulation, and structural-color displays, and discuss emerging applications in augmented/virtual reality (AR/VR) and sensing. Ultimately, we outline how resonant meta-optics is expanding the design landscape, offering new avenues toward dynamic, multifunctional, and wavelength-selective photonic systems.