IMPROVEMENTS IN DIFFRACTION EFFICIENCY OF GRATINGS AND MICROLENSES WITH CONTINUOUS RELIEF STRUCTURES

The fabrication of diffractive optical elements by laser-beam writing or gray-tone technology leads to continuous-relief phase elements. The diffraction efficiency of such elements is limited by the resolution of the process. In this paper, we compare the continuous-relief elemen ts with the multilevel elements fabricated by binary technology. In pa rticular, we will show that for similar sampling resolution of the ide al phase function, the continuous profiles have higher efficiencies th an the multilevel profiles if the designed phase modulation is 4 pi an d more.