Structured light refers to the ability to tailor and control light in all its degrees of freedom, to enhance functionality in real-world applications, and to probe deeper into fundamental aspects of light. Recent advances in the field are fueled by emerging technologies such as metasurfaces, PiCs, spatial light modulators and digital micro-mirror devices, and have led to new applications in diverse fields, from communication to imaging, sensing to metrology, and microscopy to machining. This feature issue will highlight research spanning all fields influenced by structured light. We encourage papers that are application based, exploring the use of structured light. We will allow a limited number of submissions that are wave based, for structured waves beyond light, e.g., THz waves, water waves, acoustic waves and matter waves.

The flexibly and precisely control of wavefronts of electromagnetic waves has always been a hot issue, and the emergence of metasurfaces has provided a platform to solve this problem, but their design and optimization remain challenging. In this work, the research team combined diffraction metagratings with asymmetric scattering patterns to achieve an angle-suppressed effect, which breaks this symmetry so that the energy is no longer equally distributed into positive and negative diffraction orders. The asymmetric scattering metagrating with different diffraction orders were designed and combined in a periodic circular array to form a metalens, which works to generate bending angles of wavefront manipulation for focusing at different radial positions. Well, in the terahertz band, it is challenging to design a focusing metalens with the sub-wavelength scale focal spot and long DOF, and simultaneously remain high efficiencies.

Structural colors in nature, such as those found on butterfly wings, peacock feathers, and natural opals, are commonly seen in our daily life. These dazzling effects arise from the interaction of light with microscopic, periodic structures in otherwise colorless materials. 3D printing technology based on two-photon polymerization (TPP) offers a high-precision, flexible, and cost-effective solution for fabricating intricate micro-nano structures. In this process, a laser beam acts like a microscopic brush, selectively curing low-refractive-index polymer materials (photoresists) into an array of complex structures. The interaction between light and these artificially created micro-nano structures gives rise to structural colors that not only mimic but often surpass those found in nature. This innovation opens up endless possibilities for micro-nano art and design, blending science and creativity to achieve unprecedented aesthetic and functional outcomes.

Femtosecond laser direct writing (FsLDW) technology has been widely used in high-quality micro–nano fabrication by scanning the ultrafast laser pulses with durations ranging from tens to hundreds of femtoseconds. In these applications, energy depositions induced by ultra-short pulse width occur at a time scale shorter than electron–phonon coupling processes in many materials. This feature can suppress the formation of heat-affected zone, resulting in the laser processing with high precision and resolution. In the FsLDW-based strategies, the subtractive and additive manufacturing are two of the mostly-adopted technologies. As a typical additive manufacturing technology, multi-photon lithography including the two-photon polymerization (2PP) is capable to form true 3D complex multi-element structures with sub-100-nm resolution. As an alternative approach to the conventional photolithographic patterning, the FLA process has also attracted considerable attention because it is a non-photolithographic, non-vacuum, on-demand, and cost-effective metal patterning fabrication route that can be applied to various substrates.