US 11,747,518 B2
Self-biased magneto-optical non-reciprocal metasurface device
Lei Bi, Chengdu (CN); Weihao Yang, Chengdu (CN); Jun Qin, Chengdu (CN); Jiawei Long, Chengdu (CN); and Longjiang Deng, Chengdu (CN)
Assigned to UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA, Chengdu (CN)
Filed by University of Electronic Science and Technology of China, Chengdu (CN)
Filed on Mar. 15, 2021, as Appl. No. 17/200,944.
Claims priority of application No. 202010031484.1 (CN), filed on Jan. 13, 2020.
Prior Publication US 2022/0082730 A1, Mar. 17, 2022
Int. Cl. G02F 1/1335 (2006.01); G02B 1/00 (2006.01); G02F 1/13357 (2006.01)
CPC G02B 1/002 (2013.01) [G02F 1/133606 (2013.01); G02F 1/133504 (2013.01); G02F 1/133541 (2021.01)] 3 Claims
OG exemplary drawing
 
1. A device, comprising:
a substrate layer; and
a sub-wavelength structure layer;
wherein:
the substrate layer is a material layer with a refractive index of 1 to 5 in a microwave frequency band;
the sub-wavelength structure layer comprises a plurality of square columnar elements arranged in a matrix period with equal period in row and column directions;
the square columnar elements comprise a magneto-optical material;
adjustment of phase and amplitude of a circularly polarized electromagnetic wave is achieved by changing the length, width and height of the square columnar elements, and thus the device attains a desired isolation and insertion loss at a center frequency f0;
parameters of the magneto-optical material are:
coercivity Hc≥1000 A/m; remanence Br≥1 kGs; a voigt parameter of a permittivity tensor or permeability tensor in a working frequency band≥0.01;
self-biased work state is achieved by utilizing the remanence, and a magneto-optical effect provides non-reciprocity;
a thickness of the substrate layer is L, the square columnar elements have a height of h, a length of w1 and a width of w2; the square columnar elements are arranged to form a matrix array with equal row and column periods p; the device size is D1×D2; the device responds to circularly polarized incident electromagnetic waves; dimensions of the device satisfy the relationship: w1≤10 mm, w2=0.75 w1−1.25 w1, h=w1−3 w1, p=3 w1−4 w1, L=1/2 w1−2 w1, D1=10λ0−15λ0, D2=10λ0−15λ0, λ0=c/f0, and c is a speed of light in vacuum; and
a thickness of the device is sub-wavelength; the device is magnetized only once; and a remanence direction is parallel to an incident electromagnetic wave direction.