Metamaterial has been captivated a popular notion, offering photonic functionalities beyond the capabilities of natural materials. Its desirable functionality primarily relies on well-controlled conditions such as structural resonance, dispersion, geometry, filling fraction, external actuation, etc. However, its fundamental building blocks—meta-atoms—still rely on naturally occurring substances. Here, we propose and validate the concept of gradient and reversible atomic-engineered metamaterials (GRAM), which represents a platform for continuously tunable solid metaphotonics by atomic manipulation. GRAM consists of an atomic heterogenous interface of amorphous host and noble metals at the bottom, and the top interface was designed to facilitate the reversible movement of foreign atoms. Continuous and reversible changes in GRAM’s refractive index and atomic structures are observed in the presence of a thermal field. We achieve multiple optical states of GRAM at varying temperature and time and demonstrate GRAM-based tunable nanophotonic devices in the visible spectrum. Further, high-efficiency and programmable laser raster-scanning patterns can be locally controlled by adjusting power and speed, without any mask-assisted or complex nanofabrication. Our approach casts a distinct, multilevel, and reversible postfabrication recipe to modify a solid material’s properties at the atomic scale, opening avenues for optical materials engineering, information storage, display, and encryption, as well as advanced thermal optics and photonics. Metaphotonics, a captivating field, promises photonic functionalities that can engineer electromagnetic waves in metamaterials to produce unusual physical phenomena ( 1– 3). It holds potential applications in various fields such as display, sensor, information communication, robotics, encryption, and stealth technologies ( 4, 5). However, most metamaterials are passive, with properties fixed once fabricated, limiting the exotic advantages of passive metaphotonics over its natural counterparts ( 6– 8). Active metamaterials introduce a new dimension to the field with promising applications in display, imaging, computing, light detection, and range, optical camouflage, nonreciprocal-photonics and more ( 9– 12). Current tunable metaphotonics rely on either soft materials or active solid materials. While soft-based tunable metaphotonics have been achieved through mechanical stimulus ( 13– 17), integrating them with the top-down nanofabrication process for current semiconductors remains a challenge. Solid-state metadevices have garnered significant attention due to their compatibility with existing semiconductor processes. To create active metamaterials that can dynamically change their properties or structures, one of the main approaches is to use materials that can alter their refractive index in response to external stimuli, such as phase change materials ( 18– 21) and chemical reactions ( 22, 23). These materials’ index can be switched between two different and reversible states, enabling tunable functionalities between two boundary states. However, these mechanisms typically allow only two distinct states of tunability (as illustrated in Fig. 1A). Challenges remain in achieving multilevel programmability at the subnanoscale and integrating with existing solid-state foundry processes ( 7). Therefore, there is a need for new methods to manipulate solid materials at the atomic scale, which would enhance the development of functional nanoscale and subnanoscale devices and high-density chip design.