Fig. 1. (a) Schematic representation of a single LiNbO₃ nanoparticle used in this work. (b) Side profile of the nanoparticle with a height of h, a length and width of d, and a side-wall angle of θ. The x, y, and z axis orientations represent the LiNbO₃ crystalline axes.

Fig. 2. (a) Simulated scattering cross section and electric field enhancement of an on-chip LiNbO₃ nanoparticle (d = 800 nm, h = 960 nm, θ = 5°) with a SiO₂ substrate and air superstrate. The spatial distributions of the normalized (b), (d) electric field intensity and (c), (e) magnetic field intensity for the (b), (c) ED and the (d), (e) MD resonances. The color scales represent the field intensity, and the black arrows represent the real part of the vectorial (c) magnetic and (d) electric field projected in the (c) yz and (d) xz plane, respectively.

Fig. 3. COMSOL simulations of (a) scattering cross section and (b) electric field enhancement of arrayed LiNbO₃ nanoantennas with lattice period from 900 nm to 1600 nm. The maximum electric field enhancement positions for ED and MD modes are marked in the figures, labeled as ED-SLR and MD-SLR, respectively.

Fig. 4. COMSOL simulations of RA-engineered MD and ED modes at their maximum electric field enhancement positions (with lattice periods of 1425 nm and 925 nm). (a) Simulated scattering cross section and electric field enhancement of MD-SLR resonance and the spatial distributions of the normalized (b) electric field intensity and (c) magnetic field intensity at the maximum field enhancement position. (d) Simulated scattering cross section and electric field enhancement of ED-SLR resonance and the spatial distributions of the normalized (e) electric field intensity and (f) magnetic field intensity at the maximum field enhancement position. The color scale represents the magnetic and electric field intensity enhancements. The black arrows are the real components of the vectorial electric and magnetic fields.

Fig. 5. COMSOL simulations of electric field enhancements of (a) MD-SLR and (b) ED-SLR in arrayed LiNbO₃ nanoantennas with side-wall angles tuning from 0° to 16°.