TY - JOUR

T1 - Ultrathin and high-efficiency Pancharatnam-Berry phase metalens for millimeter waves

AU - Moreno-Peñarrubia, Alexia

AU - Teniente, Jorge

AU - Kuznetsov, Sergei

AU - Orazbayev, Bakhtiyar

AU - Beruete, Miguel

N1 - Funding Information: This research was funded by Spanish Ministerio de Ciencia, Innovación y Universidades, Project No. RTI2018-094475-B-I00 (MCIU/AEI/FEDER,UE). Sergei Kuznetsov acknowledges support from the Ministry of Science and Higher Education of the Russian Federation, Project No. 075-15-2020-797. Bakhtiyar Orazbayev acknowledges support from the Nazarbayev University under the Social Policy Grant program. Publisher Copyright: © 2021 Author(s).

PY - 2021/5/31

Y1 - 2021/5/31

N2 - Applying the Pancharatnam-Berry (PB) principle to half-wave plate (HWP) metasurfaces allows the manipulation of wavefronts along with the conversion of the handedness of circularly polarized incident waves by simply rotating the meta-atoms that compose the metasurface. PB metasurfaces (PBM) working in transmission mode with four or more layers have been demonstrated to reach levels of transmission efficiency near 100% but also have resulted in bulky structures. On the other hand, compact tri-layer ultrathin (λ/8) designs have reached levels near 90% but are more challenging than single- or bi-layer structures from a manufacturing viewpoint. Here, we propose a compact ultrathin (<λ/13) transmissive PBM with only two layers (which significantly simplifies the fabrication process) achieving a transmission efficiency level of around 90%, focusing the wavefront of a circularly polarized incident wave and converting its handedness. The metasurface is composed of identical bi-layered H-shaped unit cells (meta-atoms) whose transmission phases are chosen by introducing different rotation angles to each unit cell according to a lens spatial phase profile. The structure is analytically and numerically studied and experimentally measured, verifying an excellent behavior as an HWP PB metalens at 87 GHz.

AB - Applying the Pancharatnam-Berry (PB) principle to half-wave plate (HWP) metasurfaces allows the manipulation of wavefronts along with the conversion of the handedness of circularly polarized incident waves by simply rotating the meta-atoms that compose the metasurface. PB metasurfaces (PBM) working in transmission mode with four or more layers have been demonstrated to reach levels of transmission efficiency near 100% but also have resulted in bulky structures. On the other hand, compact tri-layer ultrathin (λ/8) designs have reached levels near 90% but are more challenging than single- or bi-layer structures from a manufacturing viewpoint. Here, we propose a compact ultrathin (<λ/13) transmissive PBM with only two layers (which significantly simplifies the fabrication process) achieving a transmission efficiency level of around 90%, focusing the wavefront of a circularly polarized incident wave and converting its handedness. The metasurface is composed of identical bi-layered H-shaped unit cells (meta-atoms) whose transmission phases are chosen by introducing different rotation angles to each unit cell according to a lens spatial phase profile. The structure is analytically and numerically studied and experimentally measured, verifying an excellent behavior as an HWP PB metalens at 87 GHz.

UR - http://www.scopus.com/inward/record.url?scp=85107361620&partnerID=8YFLogxK

U2 - 10.1063/5.0048907

DO - 10.1063/5.0048907

M3 - Article

AN - SCOPUS:85107361620

VL - 118

JO - Applied Physics Letters

JF - Applied Physics Letters

SN - 0003-6951

IS - 22

M1 - 221105

ER -