(EN) Optical elements, concentrating photovoltaic devices and methods of forming optical elements are provided. An optical element includes a transparent material including a first surface and a second surface opposite the first surface. The first surface has a Fresnel lens and the second surface has a plurality of microlenses corresponding to the Fresnel lens. One of the first surface and the second surface is configured to receive light. The optical element is configured so that light passing through the optical element is separated into a plurality of beamlets via the plurality of microlenses. The Fresnel lens has a height where, at the height of the Fresnel lens, a diffraction efficiency of at least two different wavelengths of the light passing through the optical element is maximized.
(FR) L'invention porte sur des éléments optiques, sur des dispositifs photovoltaïques à concentration et sur des procédés de formation d'éléments optiques. Un élément optique comprend un matériau transparent comprenant une première surface et une seconde surface opposée à la première surface. La première surface a une lentille de Fresnel, et la seconde surface a une pluralité de microlentilles correspondant à la lentille de Fresnel. L'une de la première surface et de la seconde surface est configurée de façon à recevoir de la lumière. L'élément optique est configuré de sorte qu'une lumière traversant l'élément optique soit séparée en une pluralité de petits faisceaux par l'intermédiaire de la pluralité de microlentilles. La lentille de Fresnel a une hauteur où, à la hauteur de la lentille de Fresnel, un rendement de diffraction d'au moins deux longueurs d'onde différentes de la lumière traversant l'élément optique est maximisé.
(JA) Optical elements, concentrating photovoltaic devices and methods of forming optical elements are provided. An optical element includes a transparent material including a first surface and a second surface opposite the first surface. The first surface has a Fresnel lens and the second surface has a plurality of microlenses corresponding to the Fresnel lens. One of the first surface and the second surface is configured to receive light. The optical element is configured so that light passing through the optical element is separated into a plurality of beamlets via the plurality of microlenses. The Fresnel lens has a height where, at the height of the Fresnel lens, a diffraction efficiency of at least two different wavelengths of the light passing through the optical element is maximized.