An optical apparatus (100), an optical system (200) and a method (300) of light amplification by stimulated emission employ an endohedral metallofullerene (120, 220) as an active material coupled to an optical waveguide (110, 210). The endohedral metallofullerene (120, 220) is optically coupled to an optical field of the optical waveguide (110, 210). The coupled optical field produces a stimulated emission in the endohedral metallofullerene (120, 220). The optical system (200) further includes an optical source (230) that generates optical power (232) to pump a stimulated emission. The method (300) further includes optically pumping (330) the coupled endohedral metallofullerene by introducing an optical pump into the optical waveguide.