A first aspect of the invention relates to a luminescent object comprising: a. a luminescent layer or core containing a photoluminescent material; and b. a wavelength-selective mirror; wherein the luminescent layer or luminescent core is optically coupled to the wavelength-selective mirror, said wavelength-selective mirror being at least 50% transparent to light absorbed by the photoluminescent material and at least 50% reflective to radiation that is emitted by the photoluminescent material. The luminescent object according to the present invention may advantageously be employed in luminescent solar concentrator systems as it enables highly efficient transportation of radiation emitted by the photoluminescent material following exposure to incident solar light. Another aspect of the invention concerns a photovoltaic device comprising an electromagnetic radiation collection medium containing the aforementioned luminescent object and a photovoltaic cell capable of converting optical radiation to electrical energy which is optically coupled to the luminescent object. Further aspects of the invention include a fluorescent light activated display and a room lighting system comprising the aforementioned luminescent object.