Optical zoom lenses are typically composed of a series of intricately designed lens combinations, requiring precise and complex mechanical structures to adjust the system. Additionally, the bulky size of the lens group increases with the zoom range, making it difficult for traditional lenses to meet the development needs of modern optical systems in terms of miniaturization and lightweight design in certain scenarios. Metasurfaces, composed of periodic subwavelength microstructure units, form a two-dimensional artificial structure capable of flexibly controlling the phase, amplitude, and polarization state of electromagnetic waves. To meet the practical and integrated demands of rapidly advancing terahertz imaging technology, we designed and fabricated a geometric phase-based metasurface zoom lens based on the Moiré effect. Experiments demonstrated its ultra-wide bandwidth of over 60% centered wavelength and 5x zoom range. Additionally, by intelligently introducing bias phase in the design, we optimized the shortcomings of traditional Moiré lenses such as discontinuous zooming and robustness issues. This multifunctional terahertz imaging metasurface lens, capable of wideband focusing, zooming, and fixed focusing, offers significant advantages including robust stability, lightweight structure, simple control, and ease of manufacturing, promising broad applications in the terahertz imaging field.

wideband,terahertz,metalens