Dual-wavelength operation diffractive phase elements for pattern formation

Abstract

We report on the design and fabrication of novel diffractive phase elements that reconstruct distinct intensity patterns in the far-field on illumination with two specific wavelengths. The elements contain deep surface-relief structures that represent phase-delays of greater than 2p radians. The design process incorporates a modified version of the iterative Fourier transform algorithm. A 16 phase-level element for dual wavelength (blue and red) operation, with high diffraction efficiency, is demonstrated experimentally.

Spatial and Spectral Light Shaping with Metamaterials

“…Hence, current CGH technology does not possess sufficient and controllable dispersion to create CGHs with meaningful spectral control, for example for producing multiple diffraction patterns at different wavelengths. It should be mentioned, though, that a limited degree of multiplexed information has been encoded by using orthogonal polarization states,16 2π phase ambiguities,17 or involved, staged arrangements of wavelength‐selective mirrors 18. Considering the state‐of‐the‐art of CGH technology, it remains a highly desirable goal to realize CGHs with full spectral control that is based on the highly dispersive manipulation of light in amplitude and phase implemented in only a single nanostructured layer.…”

Design of hybrid free-space wavelength-division multiplexers for integration

“…This distance parameter is kept minimum in good practices, for example, by using a waveguide concentrator for grating-based MUX's [7]. However, the required mechanical tolerance for environment stability (vibration, temperature, humidity, etc.)…”

“…In addition, wavelength-sensitive or selective components prove very benefitial to significient improvements of overall performance of subsystems or systems, for example, wavelength-division multiplexing used in long-haul optical communications [1,2]. Diffractive optics exhibits particularly versatile characteristics in designing multifunctional devices [3][4][5][6][7][8]. In Ref.…”

Diffraction properties of double-layer rectangular phase gratings

“…It is well known that di raction optical elements, or kinof orms designed specially, have the ability of splitting an incident beam into a set of output beam numbers by tuning the incident angles and/or the wavelengths of the readout beam [7,8]. Kinoforms generally su er from complicated design schemes and expensive equipment.…”