Full-color, large area, transmissive holograms enabled by multi-level diffractive optics

Mohammad, Nabil; Meem, Monjurul; Wan, Xiaowen; Menon, Rajesh

doi:10.1038/s41598-017-06229-5

Cited by 34 publications

(21 citation statements)

References 25 publications

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“…To solve this nonlinear search problem, a variation of the DBS algorithm 16–20,22,23 has been studied and implemented. The optimization based search algorithm operates on the assumption that the solution for the specified design problem statement already exists i.e.…”

Section: Resultsmentioning

confidence: 99%

“…Various optimal search strategies like direct search methods (which includes the most commonly used variant i.e. Gerchberg–Saxton algorithm) 16–20,22,23,27,33 , iterative fourier transform algorithms (IFTA) 21,24,25 , genetic algorithms 25,26,36 and Monte Carlo optimization 34,35 have already been implemented. In addition, lesser-known simulation strategies like angular spectrum method 28 or even the point-to-point method 29 have also been employed.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, our primary objective is to introduce a systematic design framework to design a myriad of arbitrary THz optical elements by adopting and modifying one of the most widely used algorithms i.e. the Direct Binary Search (DBS) algorithm; 16–20,22,23 thereby employing a Gradient Descent Assisted Binary Search (GDABS) technique. We demonstrate our approach with the help of three different design examples of varying design complexity.…”

Section: Introductionmentioning

confidence: 99%

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A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

Banerji

Sensale‐Rodriguez

2019

Sci Rep

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We demonstrate ultra-thin (1.5-3λ 0 ), fabrication-error tolerant efficient diffractive terahertz (THz) optical elements designed using a computer-aided optimization-based search algorithm. The basic operation of these components is modeled using scalar diffraction of electromagnetic waves through a pixelated multi-level 3D-printed polymer structure. Through the proposed design framework, we demonstrate the design of various ultrathin planar THz optical elements, namely ( i ) a high Numerical Aperture (N.A.), broadband aberration rectified spherical lens (0.1 THz–0.3 THz), ( ii ) a spectral splitter (0.3 THz–0.6 THz) and ( iii ) an on-axis broadband transmissive hologram (0.3 THz–0.5 THz). Such an all-dielectric computational design-based approach is advantageous against metallic or dielectric metasurfaces from the perspective that it incorporates all the inherent structural advantages associated with a scalar diffraction based approach, such as ( i ) ease of modeling, ( ii ) substrate-less facile manufacturing, ( iii ) planar geometry, ( iv ) high efficiency along with (v) broadband operation, ( vi ) area scalability and ( vii ) fabrication error-tolerance. With scalability and error tolerance being two major bottlenecks of previous design strategies. This work is therefore, a significant step towards the design of THz optical elements by bridging the gap between structural and computational design i.e. through a hybrid design-based approach enabling considerably less computational resources than the previous state of the art. Furthermore, the approach used herein can be expanded to a myriad of optical elements at any wavelength regime.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

Banerji

Sensale‐Rodriguez

2019

Sci Rep

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“…These holograms do not need to be recorded separately, and can be multiplexed inside the same material, provided that the material is sensitive to these wavelengths. For this display effort, we will be able to take advantage of full-color holographic display systems [22,23] for injecting the source image into our waveguide system.…”

Section: Possible Future Work: Full-color Hud Systemmentioning

confidence: 99%

Holographic waveguide heads-up display for longitudinal image magnification and pupil expansion

2018

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The field of view of traditional heads-up display systems is limited by the size of the projection optics. Our research is focused on overcoming this limitation by coupling image-bearing light into a waveguide using holographic elements, propagating the light through that waveguide, and extracting the light several times with additional holographic optical elements. With this configuration, we demonstrated both longitudinal magnification and pupil expansion of the heads-up display. We created a ray-trace model of the optical system to optimize the component parameters and implemented the solution in a prototype that demonstrates the merit of our approach. Longitudinal magnification is achieved by encoding optical power into the hologram injecting the light into the waveguide, while pupil expansion is obtained by expanding the size of the hologram extracting the light from the waveguide element. To ensure uniform intensity of the image, the diffraction efficiency of the extracting hologram is modulated according to the position. Our design has a 12°×8° field of view at a viewing distance of 10 in. (250 mm), with infinite longitudinal magnification and a 1.7× lateral pupil expansion.

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“…High transmission efficiency multiplexed holograms that project up to three different images depending on the incident wavelength have previously been demonstrated using a variety of techniques including phase modulation [14][15][16] and depth division 17 . Recently, white-light transmission colour holograms 18 operating in the Fresnel limit have also been developed.…”

mentioning

confidence: 99%

Holographic colour prints for enhanced optical security by combined phase and amplitude control

et al. 2019

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Conventional optical security devices provide authentication by manipulating a specific property of light to produce a distinctive optical signature. For instance, microscopic colour prints modulate the amplitude, whereas holograms typically modulate the phase of light. However, their relatively simple structure and behaviour is easily imitated. We designed a pixel that overlays a structural colour element onto a phase plate to control both the phase and amplitude of light, and arrayed these pixels into monolithic prints that exhibit complex behaviour. Our fabricated prints appear as colour images under white light, while projecting up to three different holograms under red, green, or blue laser illumination. These holographic colour prints are readily verified but challenging to emulate, and can provide enhanced security in anti-counterfeiting applications. As the prints encode information only in the surface relief of a single polymeric material, nanoscale 3D printing of customised masters may enable their mass-manufacture by nanoimprint lithography.

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Full-color, large area, transmissive holograms enabled by multi-level diffractive optics

Cited by 34 publications

References 25 publications

A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

A Computational Design Framework for Efficient, Fabrication Error-Tolerant, Planar THz Diffractive Optical Elements

Holographic waveguide heads-up display for longitudinal image magnification and pupil expansion

Holographic colour prints for enhanced optical security by combined phase and amplitude control

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