Advances in 3D and 4D multi-photon printing for micro and nano photonics [Invited]

3D printing has revolutionized photonics by enabling the fabrication of intricate, high-precision structures beyond the capabilities of traditional manufacturing. Among various techniques, multi-photon lithography (MPL) stands out for its ability to create micro and nano-scale photonic components with sub-100 nm resolution. MPL’s potential extends to 4D printing, where photonic structures respond dynamically to external stimuli, enabling adaptive optics and reconfigurable optical devices for imaging and communication systems. Recent advancements, including hybrid manufacturing and multi-material 4D printing, further expand its impact on optical components, sensors, and metamaterials. This review examines the role of 3D and 4D printing in micro and nano photonics, focusing on their applications, materials, and future directions.