A light concentrator comprising: at least one lighting element configured to emit light; an optical filter arranged so as to receive light having a wavelength within a selected wavelength emission band via a light in-coupling surface and configured to selectively transmit light incident on the light in-coupling surface through the optical filter and output the light via a light out-coupling surface, on a condition that the light incident on the light in-coupling surface has a wavelength within a selected wavelength transmission band; a light-redirection element having a light-redirection surface arranged substantially parallel in relation to the light out-coupling surface of the optical filter so as to receive at least some of the light out-coupled via the light out-coupling surface, and configured to redirect light impinging on the light-redirection surface; and a light-guiding region, which is delimited at least by the light-redirection surface and the light out-coupling surface of the optical filter, for guiding light out-coupled via the light out-coupling surface towards at least one light-exiting region arranged substantially perpendicular to the light out-coupling surface and via which light may leave the light concentrator; a wavelength-selective element arranged so as to receive at least a portion of light having been emitted by the at least one lighting element and configured to, responsive thereto, output light having a wavelength within the selected wavelength emission band, wherein the optical filter is arranged so as to receive at least a portion of light having been output by the wavelength-selective element, and wherein the wavelength-selective element comprises luminescent material, wherein the wavelength-selective element is configured such that light output by the wavelength-selective element has a full width at half maximum of less than about 30 nm, wherein the optical filter is configured such that characteristics of the wavelength transmission band depend at least in part on the angle of incidence of light incident on the light in-coupling surface, and wherein the optical filter is configured such that the wavelength transmission band for a selected angle or angles of incidence of light incident on the light in-coupling surface at least in part overlaps with the selected wavelength emission band, whereby light incident on the light in-coupling surface with an angle of incidence equal to or within the selected angle or angles of incidence of light is transmitted through the optical filter. at least one lighting element configured to emit light; an optical filter arranged so as to receive light having a wavelength within a selected wavelength emission band via a light in-coupling surface and configured to selectively transmit light incident on the light in-coupling surface through the optical filter and output the light via a light out-coupling surface, on a condition that the light incident on the light in-coupling surface has a wavelength within a selected wavelength transmission band; a light-redirection element having a light-redirection surface arranged substantially parallel in relation to the light out-coupling surface of the optical filter so as to receive at least some of the light out-coupled via the light out-coupling surface, and configured to redirect light impinging on the light-redirection surface; and a light-guiding region, which is delimited at least by the light-redirection surface and the light out-coupling surface of the optical filter, for guiding light out-coupled via the light out-coupling surface towards at least one light-exiting region arranged substantially perpendicular to the light out-coupling surface and via which light may leave the light concentrator; a wavelength-selective element arranged so as to receive at least a portion of light having been emitted by the at least one lighting element and configured to, responsive thereto, output light having a wavelength within the selected wavelength emission band, wherein the optical filter is arranged so as to receive at least a portion of light having been output by the wavelength-selective element, and wherein the wavelength-selective element comprises luminescent material, wherein the wavelength-selective element is configured such that light output by the wavelength-selective element has a full width at half maximum of less than about 30 nm, wherein the optical filter is configured such that characteristics of the wavelength transmission band depend at least in part on the angle of incidence of light incident on the light in-coupling surface, and wherein the optical filter is configured such that the wavelength transmission band for a selected angle or angles of incidence of light incident on the light in-coupling surface at least in part overlaps with the selected wavelength emission band, whereby light incident on the light in-coupling surface with an angle of incidence equal to or within the selected angle or angles of incidence of light is transmitted through the optical filter.