With traditional prism optics, light is transmitted through the substrate, creating problems due to absorption, inclusions and material defects. PLX technology addresses these defects by offering front surface reflection systems which can accommodate any wavelength. In addition, because the patented structures are made from materials with the same C.T.E.s, they have proven long term stability. And, utilizing the proprietary manufacturing processes, critically-accurate structures, which exhibit interferometer-quality exiting wavefronts, are created.