Collective lattice resonances in arrays of dielectric nanoparticles: a matter of size

Collective Lattice Resonances in All-Dielectric Nanostructures under Oblique Incidence

“…As it might be expected from Ref. [37], the extinction efficiency at the CLR regime grows with N tot ; thus, the CLRs that have emerged from the interaction with high-order WRAs are more pronounced for larger arrays, which can be clearly seen by the following Figure 1b On the contrary, by changing θ y and keeping θ x = 0 constant, one can control the spectral position of MD CLRs, as clearly shown in Figure 2. In this case, however, ED CLR does not vanish so rapidly for 0 < θ y < 5 • (as it does MD CLR from Figure 1 for the opposite case of 0 • < θ x < 5 • ).…”

“…We consider regular arrays from Si NPs with R = 65 nm, arranged in a 2D rectangular lattice with h y = 480 nm and h x = 580 nm. A direct comparison with full-field simulations ([31] Figure 1) ( [38] Figure 3) has confirmed a reliability of the coupled dipole approximation (1) for arrays with similar pitches and the same R. Under a normal incidence with E 0 = (E 0x , 0, 0) and H 0 = 0, H 0y , 0 , arrays with these geometrical parameters exhibit ED and MD CLRs ( [37] Figure 2b) at λ ≈ 490 nm and λ ≈ 586 nm, respectively, which is the result of a hybridization between ED (λ ≈ 450 nm) and MD (λ Figure 2), it is insightful to consider an incidence with only one θ x,y varied keeping the other θ y,x = 0. Following this approach, it is possible to study separately ED and MD CLRs, while, for any other oblique incidence with θ x = 0 and θ y = 0, one can expect the optical response to be a superposition of the studied examples.…”

“…x + k 2 y = (2π/λ) 2 , which along with Equation (4) provide the quadratic equation in λ: [32,36,37,57]. For a special case of normal incidence (θ x = θ y = 0), these WRAs are simply λ ±1,0 = h x and λ 0,±1 = h y .…”

“…Well-developed state-of-the-art methods for synthesis of different all-dielectric materials [2] enable their successful implementation in color printing [3][4][5][6][7], biosensing [8][9][10], lasing [11,12], waveguiding [13][14][15], optical filtering [16][17][18], and nonlinear [19][20][21][22][23] optics. Among a rich variety of electromagnetic phenomena arising in all-dielectric nanostructures, collective effects in regular arrays of nanoparticles (NPs) have attracted a lot of attention recently [24][25][26][27][28][29][30][31][32][33][34][35][36][37], which is justified by the appearance of non-trivial lattice-mediated phenomena-for example, suppression of the back-scattering (Kerker effect) [38][39][40][41].…”

“…In contrast to plasmonic NPs (in most of the cases characterized by weak magnetic and strong electric responses), all-dielectric NPs with pronounced electric and magnetic optical resonances [58] give rise to a rich variety of tunable CLRs that emerge even in regular rectangular-shaped arrays [32]. Moreover, 2D structures from all-dielectric NPs with two distinct electric dipole (ED) and magnetic dipole (MD) resonances exhibit inherently more sophisticated and intriguing behavior compared to the respective situations in purely ED-responsive plasmonic arrays, for example, in disordered [36,59] and finite-size [37,38,[60][61][62] lattices.…”