TY - JOUR

T1 - Toroidic and antitoroidic orders in hexagonal arrays of dielectric trimers

T2 - Magnetic group approach

AU - Dmitriev, Victor

AU - Santos, Silvio Domingos Silva

AU - Evlyukhin, Andrey B.

AU - Kupriianov, Anton S.

AU - Tuz, Vladimir R.

N1 - Funding Information: V.D. thanks the Brazilian Agency National Council of Technological and Scientific Development (CNPq) for financial support. S.D.S.S. acknowledges support from CNPq (Grant No. 160344/2019-0). A.S.K. and V.R.T. acknowledge financial support from the National Key R&D Program of China (Project No. 2018YFE0119900). A.B.E. thanks funding support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453).

PY - 2021/4/5

Y1 - 2021/4/5

N2 - Herein, we investigate symmetry-protected toroidal dipole resonances and conditions of their excitation in a new type of electromagnetic metamaterials. These metamaterials are all-dielectric planar periodic arrays of dielectric disks disposed on a dielectric substrate. The elementary building blocks of the array are trimers which are distributed in hexagonal unit supercells. The highest geometrical symmetry of the unit supercell is C6v. The analysis is fulfilled by using the representation theory of groups with application of the magnetic group theory, which is a new approach in solving such problems. We have shown that to get access to the toroidal supermodes of the array, the symmetry of the unit supercell must be broken twice: firstly, the C3v symmetry of the trimer, and secondly, the C6v symmetry of the unit supercell needs to be reduced. Selection rules for the symmetric and antisymmetric orders of the toroidal dipole moments in the arrays are defined. In particular, we have shown that with the reduction of the unit supercell symmetry to the C2v group, the array exhibits the toroidal dipole resonance with antitoroidic order. The arrays with the lower Cs symmetry can provide resonances with both toroidic and antitoroidic orders. It is also shown that these arrays are always polarization sensitive. Full-wave simulations and experiments confirm the theoretical predictions. The suggested metamaterials can provide an enhanced light-matter interaction due to the spatially and temporally confined light in resonant systems with very high quality factors.

AB - Herein, we investigate symmetry-protected toroidal dipole resonances and conditions of their excitation in a new type of electromagnetic metamaterials. These metamaterials are all-dielectric planar periodic arrays of dielectric disks disposed on a dielectric substrate. The elementary building blocks of the array are trimers which are distributed in hexagonal unit supercells. The highest geometrical symmetry of the unit supercell is C6v. The analysis is fulfilled by using the representation theory of groups with application of the magnetic group theory, which is a new approach in solving such problems. We have shown that to get access to the toroidal supermodes of the array, the symmetry of the unit supercell must be broken twice: firstly, the C3v symmetry of the trimer, and secondly, the C6v symmetry of the unit supercell needs to be reduced. Selection rules for the symmetric and antisymmetric orders of the toroidal dipole moments in the arrays are defined. In particular, we have shown that with the reduction of the unit supercell symmetry to the C2v group, the array exhibits the toroidal dipole resonance with antitoroidic order. The arrays with the lower Cs symmetry can provide resonances with both toroidic and antitoroidic orders. It is also shown that these arrays are always polarization sensitive. Full-wave simulations and experiments confirm the theoretical predictions. The suggested metamaterials can provide an enhanced light-matter interaction due to the spatially and temporally confined light in resonant systems with very high quality factors.

UR - http://www.scopus.com/inward/record.url?scp=85104417675&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.103.165402

DO - 10.1103/PhysRevB.103.165402

M3 - Article

AN - SCOPUS:85104417675

VL - 103

JO - Physical Review B

JF - Physical Review B

SN - 2469-9950

IS - 16

M1 - 165402

ER -