Total space focus adjustable super-structure lens and design method thereof

Abstract

The invention discloses a total-space focus-adjustable super-structure lens and a design method thereof, the total-space focus-adjustable super-structure lens comprises a first super-structure surface, a second super-structure surface and a third super-structure surface, and emergent wave phases corresponding to nano antennas of the first super-structure surface meet a formula: P1 =-a ((x1 + d) 2 + y12), the emergent wave phase corresponding to each nano antenna on the second metasurface meets the formula: P2 = a ((x2 + d) 2 + y22) (a (x22 + y22)) phi 1, the emergent wave phase corresponding to each nano antenna on the third metasurface meets the formula: P3 =-(a (x32 + y32)) phi 2, a and d are constants, x1 and y1 are first plane coordinates corresponding to each nano antenna on the first metasurface, x2 and y 2 are second plane coordinates corresponding to the nano antennas on the second metasurface, x3 and y3 are third plane coordinates corresponding to the nano antennas on the third metasurface, phi < 1 > and phi < 2 > are angles under a cylindrical coordinate system, phi < 1 > = tan-1 (y2/x2), and phi < 2 > = tan-1 (y3/x3). The planar structure of the super-structure lens avoids spherical aberration and chromatic aberration, the numerical aperture is increased, the super-structure lens is small in size and beneficial to integration, and free adjustment of the full-space focus can be achieved. 本发明公开了一种全空间焦点可调超构透镜及其设计方法，包括：第一超构表面、第二超构表面以及第三超构表面，第一超构表面的各个纳米天线对应的出射波相位满足公式：P1＝‑a((x1+d)2+y12)，第二超构表面的各个纳米天线对应的出射波相位满足公式：P2＝a((x2+d)2+y22)(a(x22+y22))φ1，第三超构表面的各个纳米天线对应的出射波相位满足公式：P3＝‑(a(x32+y32))φ2，其中，a和d为常数，x1和y1为第一超构表面的各个纳米天线对应的第一平面坐标，x2和y2为第二超构表面的各个纳米天线对应的第二平面坐标，x3和y3为第三超构表面的各个纳米天线对应的第三平面坐标，φ1和φ2为柱坐标系下的角度，φ1＝tan‑1(y2/x2)，φ2＝tan‑1(y3/x3)。本发明的超构透镜的平面化结构避免了球差、色差的产生，增加了数值孔径，超构透镜体积小，利于集成，可实现全空间焦点自由可调。