Abstract: A metamaterial flat lens having one or more dielectric layers and one or more metal layers. Each of the one or more metal layers is disposed on one of the one or more dielectric layers or between two of the one or more dielectric layers. Each of the one or more metal layers has a regularly spaced pattern of metal features. The metal features differ in size, and each metal feature in each of the one or more metal layers is aligned with corresponding metal features in the other one or more metal layers if present to define a pixel having a thickness of the lens. The lens comprises a multiplicity of pixels, with each pixel of the multiplicity of pixels having a side length in the plane of the lens based on the free-space wavelength of the light to be focused. The light to be focused has a frequency of at least 480 GHz.

Abstract: The invention relates to calcium hydroxyapatite particles having been sintered at a certain temperature range and which are not treated at a temperature above this range. Furthermore, the present invention relates to an injectable composition comprising such particles and to uses thereof. Surprisingly, it was found that the particles of the invention are superior over calcium hydroxyapatite particles known in the art with respect to bio-stimulation.