in various embodiments of the invention , a unique construction for light emitting diodes with at least one luminescent rod and extracting optical elements used to generate a variety of high brightness light sources with different emission spectra . in an embodiment of the invention , forced air cooling is used to cool the luminescent rod . in an embodiment of the invention , totally internal reflected light can be redirected outward and refocused . in another embodiment of the invention , light emitted by the luminescent rod is out - coupled for use in a variety of applications .