Artificial dielectric optical structures: A challenge for nanofabrication

Diffractive optical components can be made using multiple level kinoforms o r single level artificial dielectric structures. The latter require the fab rication of pillars of equal depth but differing width and spacing. As a de monstration device, the diffractive optic equivalent of a wedge has been ma de in GaAs for use at 1.15 mu m. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. (C) 1998 Ameri can Vacuum Society. [S0734-211X(98)03706-8].