Reconfigurable continuous-zoom metalens in visible band

Abstract

Design of a conventional zoom lens is always challengeable because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for lens adjustment. In this paper, we propose a continuous zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces along its optical axis without changing any other conditions. More importantly, because of the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varyingfocal lengths ranging from − to + in principle. On account of its advantages of compactness, flexibility and easiness in design, the proposed zoom metalens can provide new perspectives for the development of continuous-zoom optical system and it can find applications in fields which require ultracompact and continuous-zoom imaging and reconfigurable beam wavefront steering.

Principles, Functions, and Applications of Optical Meta‐Lens

“…[147,148] A derivative of the Alvarez system is also presented where the two lenses are coaxially rotated rather than being parallelly moved, which is inspired by the Moiré lens. [149][150][151][152][153] Cui et al [151] proposed a rotationally tunable polarization-dependent varifocal metasurface, and Yilmaz et al [152] demonstrated a polarizationindependent varifocal metasurface. Subsequently, Guo et al [153] fabricated a 3.5× continuous varifocal meta-lens in the microwave band, with an improved N.A.…”

Advances in exploiting the degrees of freedom in nanostructured metasurface design: from 1 to 3 to more

“…This kind of step-zoom metalens can readily switch between two FOVs and has potential application in target tracking and recognition. In 2019, Cui et al combined the Moire effect with GEMS, and by rotating one of the two GEMS, the focal length changes from −∞ to +∞ theoretically ( Figure 10C) [85]. [79].…”

“…(C) Continuous-zoom metalens conducted with Moire effect[85]. Reprint permission obtained from[83][84][85].above work, Wang et al designed two different nanostructures to manipulate the phase of RCP and LCP light independently (Figure 11H)[93] rather than the opposite phase control of two CP light with different handedness. This kind of CP-selective metasurface can reduce the interference of light with different handedness to the diffraction results.…”

Inverse Design of On-Chip Thermally Tunable Varifocal Metalens Based on Silicon Metalines

“…Tunable focal length, or varifocal lens, is one of the most probable and expected functionalities of metalens. A number of mechanical tuning techniques have been developed such as stretching the metalens on the elastic substrate [21][22][23], MEMs-actuated silicon metasurface lens [24], MEMsactuated axially moving metasurface doublet lens [25], manually-actuated [26][27] or MEMs-actuated [1] laterally moving two cubic phase metasurfaces of an Alvarez lens, and controlling the angular orientation of the metalens doublets [28][29][30]. Furthermore, other forms of tuning such as incorporating tunable materials into metasurfaces for changing focal position have been studied [20,[31][32][33][34][35][36][37][38][39][40][41][42][43].…”