Optical devices enabled by vertical dielectric Mie resonators
Dielectric resonators provide a building block for the development of low-loss resonant metamaterials because they replace lossy ohmic currents of metallic resonators with low-loss displacement currents. The spectral locations of electric and magnetic dipole resonances of a dielectric resonator can be tuned by varying the resonator geometry so that desired scattering properties are achieved.
1. An optical device, comprising:
a periodic lattice of unit cells in a low-index substrate, each unit cell comprising a hollow cavity etched into the substrate wherein each cavity comprises one or more non-planar, high-index dielectric resonators deposited on at least one wall of the hollow cavity.
2. The optical device of claim 1 , wherein the one or more non-planar, high-index dielectric resonators has an index of refraction greater than 3.
3. The optical device of claim 1 , wherein the one or more non-planar, high-index dielectric resonator comprises germanium, silicon, chalcogenide, or a chalcogenide alloy.
4. The optical device of claim 1 , wherein the one or more non-planar, high-index dielectric resonators have an elliptical or rectangular geometry.
5. The optical device of claim 4 , wherein the major radius and minor radius of the elliptical or rectangular geometry are selected to provide Huygens' resonators.
6. The optical device of claim 1 , where the one or more non-planar, high-index dielectric resonators comprises two resonators deposited on opposite walls of a unit cell, thereby providing back-to-back vertical resonators in the periodic lattice.
7. The optical device of claim 1 , wherein the one or more non-planar, high-index dielectric resonators comprise two or more vertically stacked resonators.
8. The optical device of claim 1 , wherein the hollow cavities are etched through the low-index substrate, thereby providing a honeycomb structure of through-hole unit cells in a thin membrane.
9. The optical device of claim 1 , further comprising at least one additional periodic lattice of unit cells repeated in a layer-by-layer fashion to provide a three-dimensional volumetric array.
10. The optical device of claim 1 , wherein the low-index substrate has an index of refraction less than 1.5.
11. The optical device of claim 1 , wherein the low-index substrate comprises silicon dioxide, silicon carbide, silicon nitride, aluminum oxide, or aluminum nitride.
12. The optical device of claim 1 , wherein the unit cells are subwavelength to an incident infrared light.