A method for geometrically modifying high-index dielectric structures on a support structure, said method comprising: a. Providing a support structure, b. Providing a first plurality of high-index dielectric structures, said first plurality of high-index dielectric structures being supported by the support structure, c. Changing a geometry specifically of high-index dielectric structures within a second plurality of high-index dielectric structures, wherein the second plurality of high-index dielectric structures is a sub-set of the first plurality of high-index dielectric structures, wherein said changing the geometry is carried out by photothermally melting at least a portion of each of the high-index dielectric structures within the second plurality of high-index dielectric structures by irradiating the second plurality of high-index dielectric structures with incident electromagnetic radiation having an incident intensity in a plane of the second plurality of high-index dielectric structures, and thereby exciting resonances associated with each of the high-index dielectric structures within the second plurality of high-index dielectric structures, wherein said support structure comprises a first plurality of topographical features comprising topographical pillars or topographical holes formed on a surface of the support structure, and wherein the first plurality of high-index dielectric structures are given by: - high-index dielectric structures on said topographical pillars or in said topographical holes, and - holes in a high-index dielectric film, wherein said holes correspond to said topographical features, wherein the first plurality of high-index dielectric structures are provided by depositing the high-index dielectric film on the support structure with the topographical features, wherein said incident intensity is less than an incident intensity required to melt a film of a same material and a same thickness as the high-index dielectric structures within the second plurality of high-index dielectric structures, and wherein the relative permittivity at 532 nm of the first plurality of high-index dielectric structures is equal to or larger than 5. a. Providing a support structure, b. Providing a first plurality of high-index dielectric structures, said first plurality of high-index dielectric structures being supported by the support structure, c. Changing a geometry specifically of high-index dielectric structures within a second plurality of high-index dielectric structures, wherein the second plurality of high-index dielectric structures is a sub-set of the first plurality of high-index dielectric structures, wherein said changing the geometry is carried out by photothermally melting at least a portion of each of the high-index dielectric structures within the second plurality of high-index dielectric structures by irradiating the second plurality of high-index dielectric structures with incident electromagnetic radiation having an incident intensity in a plane of the second plurality of high-index dielectric structures, and thereby exciting resonances associated with each of the high-index dielectric structures within the second plurality of high-index dielectric structures, wherein said support structure comprises a first plurality of topographical features comprising topographical pillars or topographical holes formed on a surface of the support structure, and wherein the first plurality of high-index dielectric structures are given by: - high-index dielectric structures on said topographical pillars or in said topographical holes, and - holes in a high-index dielectric film, wherein said holes correspond to said topographical features, - high-index dielectric structures on said topographical pillars or in said topographical holes, and - holes in a high-index dielectric film, wherein said holes correspond to said topographical features, wherein the first plurality of high-index dielectric structures are provided by depositing the high-index dielectric film on the support structure with the topographical features, wherein said incident intensity is less than an incident intensity required to melt a film of a same material and a same thickness as the high-index dielectric structures within the second plurality of high-index dielectric structures, and wherein the relative permittivity at 532 nm of the first plurality of high-index dielectric structures is equal to or larger than 5.