Nonvolatile, Full-Color, Grayscale Tunable Narrowband Filters and Holographic Encoding

Tunable optical filters are essential for dynamic holography, spectral imaging, optical storage and reconfigurable displays. Yet achieving full-color coverage with continuous grayscale control remains an exceptional challenge. Phase-change materials introduce the prospect of nonvolatile optical modulation, pushing these systems beyond conventional limits. Here we present a Fabry–Pérot bandpass filter integrating dual distributed Bragg reflectors with phase change material. Electrical and laser-driven modulation of the optical constants enables narrowband filtering with high spectral selectivity, spanning the visible-to-NIR range. Structural optimization of the cavity thickness enables wide-gamut spectral coverage by design, while active phase-change control enables continuous multilevel grayscale intensity modulation. Materials screening and structural optimization enable wide-gamut color tuning and multilevel grayscale modulation. This lithography-free multilayer structure supports scalable pixel-level programming, with gradual crystallization of the phase change layers enabling multilevel encoding. We implement pixelated full-color and grayscale holography, exploiting both wavelength- and intensity-dependent responses. This compact and energy-efficient reconfigurable photonic platform provides a scalable route to dynamic photonic devices, holographic displays, optical information processing, and adaptive metasurfaces.