Optical performance of holographic kinoforms

Abstract

The optical properties of holographic kinoforms are described. It is shown that paraxial designs are not adequate for f/Nos. less than F/10. A nonparaxial design is introduced that retains the high diffraction efficiency of the paraxial designs, yet also produces an unaberrated diffracted wavefront for the design wavelength. Aberration calculations and computer calculations, based on the Huygens-Fresnel principle, of the point spread functions for these elements show the necessity of using the nonparaxial design. Specifications for a surface profile that takes account of the finite thickness of the diffracting surface are given. A model for kinoforms which can be used in optical design programs is proposed.

Diffractive-refractive hybrid doublet to achromatize the human eye

“…Thus, multiple diffraction orders decrease the resolution, and non-unity diffraction efficiency can arise from manufacturing errors [35,36]. The effect of the unwanted diffractive light may be offset by the human visual system, because of the diffraction efficiency of our kinoform lens and the spectral sensitivity of the eye [21,22,35,36], validating our design.…”

Dual focus diffractive optical element with extended depth of focus

“…For simplicity, the phase function that we considered in the simulation has a continuous phase level modulo 2 and has no wavelength mismatch, which leads to a diffraction efficiency of 100% for the designed wavelength. 7,8) The results of axial intensity profiles and lateral intensity profiles (diffraction patterns) are also shown in this section. Some concluding remarks are provided in Sect.…”

Diffractive optical elements with modulated zone sizes

“…The zone boundary locations »p of a conventional Mth order diå ractive lens with N zones and a focal length f are determined by [6,13] …”

“…the new phase delay function for the pth zone can be calculated using equation (13) and the requirement of M2 p phase steps between neighbouring zones is kept. The factor Dp limiting the displacement of the boundary between zones p and p ‡ 1 to a certain percentage of the size of zone p ‡ 1 should be chosen such that the conditions for the validity of scalar diå raction theory are ful® lled.…”

“…Thereby, the energy in a focal point f k corresponds to the energy diå racted into the kth diå raction order [13,17]. It is also known that the eae ciency of the kth diå raction order ²k is given by the same relation that holds for a regular blazed grating (see equation (6)).…”