Abstract: A photovoltaic generator including at least one photovoltaic cell, and a transparent matrix placed with at least one optically active material with an absorption wavelength &lgr;a and a reemission wavelength &lgr;r, the optically active material selected such that &lgr;a corresponds to a range of the photovoltaic cell with a lower sensitivity than &lgr;r, the matrix having an input surface and an opposite surface and comprises a reflecting coating an a dichroic filter on the input surface that substantially reflects wavelengths longer than about 950 nm and is substantially transparent for wavelengths less than about 950 nm, and on the opposite surface the matrix has a reflecting coating that reflects wavelengths greater than about 400 nm, and wherein the photovoltaic cell is included in the matrix.