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We consider a design approach to reduce unwanted zero-order intensity due to profile depth error in diffractive elements. Our method is based on addition of local bias phase to a binary element phase, leading to the introduction of a third phase level. We show theoretically and experimentally that gratings obtained with such modifications are more tolerant to profile depth error than conventionally designed binary or multilevel elements, thus reducing the appearance of unwanted zero order.

Design and simulation of two-dimensional diffractive optical elements are often limited by the amount of data required to represent the element in the computer's memory. We present a technique based on a geometrical description of the element, which requires fewer data than the traditional pixel description. Moreover, the element is being described more accurately and consequently the pixel-related artefacts are suppressed. This technique can be used for both periodic and non-periodic structures of large dimensions under Fraunhofer or Fresnel approximations. We apply the method to analysis of far-field beam-shaping elements and discuss possible extensions and refinements of the technique.

We present a comparison of some of the most used iterative Fourier transform algorithms (IFTA) for the design of continuous and multilevel diffractive optical elements (DOE). Our aim is to provide optical engineers with advice for choosing the most suited algorithm with respect to the task. We tackle mainly the beam-shaping and the beam-splitting problems, where the desired light distributions are almost binary. We compare four recent algorithms, together with the historical error-reduction and input-output methods. We conclude that three of these algorithms are interesting for continuous-phase kinoforms, and two, namely the three-step method proposed by Wyrowski and the over-compensation of Prongué, still perform well with multilevel- and binary-phase DOE.

Design and simulation of two-dimensional diffractive optical elements are often limited by the amount of data required to represent the element in the computer's memory. We present a technique based on a geometrical description of the element, which requires fewer data than the traditional pixel description. Moreover, the element is being described more accurately and consequently the pixel-related artefacts are suppressed. This technique can be used for both periodic and non-periodic structures of large dimensions under Fraunhofer or Fresnel approximations. We apply the method to analysis of far-field beam-shaping elements and discuss possible extensions and refinements of the technique.

We consider a design approach to reduce unwanted zero-order intensity due to profile depth error in diffractive elements. Our method is based on addition of local bias phase to a binary element phase, leading to the introduction of a third phase level. We show theoretically and experimentally that gratings obtained with such modifications are more tolerant to profile depth error than conventionally designed binary or multilevel elements, thus reducing the appearance of unwanted zero order.

We present a comparison of some of the most used iterative Fourier transform algorithms (IFTA) for the design of continuous and multilevel diffractive optical elements (DOE). Our aim is to provide optical engineers with advice for choosing the most suited algorithm with respect to the task. We tackle mainly the beam-shaping and the beam-splitting problems, where the desired light distributions are almost binary. We compare four recent algorithms, together with the historical error-reduction and input-output methods. We conclude that three of these algorithms are interesting for continuous-phase kinoforms, and two, namely the three-step method proposed by Wyrowski and the over-compensation of Prongué, still perform well with multilevel- and binary-phase DOE.