A photonic structure for "white" light generation by phosphors under the excitation of a LED. The photonic structure mounts the LED and an optically transparent nanocomposite matrix having dispersed therein phosphors which will emit light under the excitation of the radiation of the LED. The phosphors dispersed in the matrix may be nanocrystalline, or larger sized with the addition of non light emitting, non light scattering nanoparticles dispersed within the matrix material so as to match the index of refraction of the matrix material to that of the phosphors. The nanocomposite matrix material may be readily formed by molding and formed into a variety of shapes including lenses for focusing the emitted light. A large number of the photonic structures may be arranged on a substrate to provide even illumination or other purposes.