Abstract: A cooling device for protecting a light absorbing optical element is provided. The cooling device includes an optical unit which comprises a transparent, thermally-conductive material disposed in heat conductive relation to the optical element. A mounting body supports the optical unit and receives heat energy therefrom. A heat pipe is mounted in the mounting body. Thus, heat energy is removed from the optical element and transferred to ambient through the thermally-conductive material, the mounting body and the heat pipe.