SLM Simulation and MonteCarlo Path Tracing for Computer-Generated Holograms

Author(s):

Magallón, Juan; Blesa, Alfonso & Serón, Francisco

Abstract:

“Computer holography is a growing research field that must pay attention to two main issues concerning computing effort: the visualization of a 3D virtual scene with photo-realistic quality and the bottleneck related to hologram digitizalition and visualization limits. This work shows a computational approach based on a Monte Carlo path-tracing algorithm, which accounts for both geometrical and physical phenomena involved in hologram generation, and, therefore, makes a feasible estimation of computing time costs. As these holograms also require yet unavailable visualization devices, their behavior needs to be simulated by computer techniques.”

Link to Publications Page

Publication: SN Computer Science
Issue/Year: SN Computer Science, Volume 2; Number 3; 2021
DOI: 10.1007/s42979-021-00632-6

Twin curvilinear vortex beams

Author(s):

Wang, Zhuang; Yuan, Zheng; Gao, Yuan; Yan, Wenxiang; Liang, Chunjuan; Ren, Zhi-Cheng; Wang, Xi-Lin; Ding, Jianping & Wang, Hui-Tian

Abstract:

“We report on a novel curvilinear optical vortex beam named twin curvilinear vortex beams (TCVBs) with intensity and phase distribution along a pair of two- or three-dimensional curves, both of which share the same shape and the same topological charge. The TCVBs also possess the character of perfect optical vortex, namely having a size independent of topological charge. We theoretically demonstrate that a TCVB rather than a single-curve vortex beam can be created by the Fourier transform of a cylindrically polarized beam. The behavior of TCVBs generated through our method is investigated by simulation and experiment, including interference experiments for identifying the vortex property of the TCVBs. The TCVBs may find applications in optical tweezers, such as trapping low refractive index particles in the dark region between two curves and driving them moving along the curvilinear trajectory.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 9; Pages 14112; 2021
DOI: 10.1364/oe.423803

Holographic contact lens display that provides focusable images for eyes

Author(s):

Sano, Junpei & Takaki, Yasuhiro

Abstract:

“In this paper, we propose a holographic image generation technique for contact lens displays. The proposed technique employs a phase-only spatial light modulator (SLM), a holographic optical element (HOE) backlight, and a polarizer. The proposed holographic technique can generate 3D images apart from the contact lens displays. Therefore, the eyes can focus on the 3D images while simultaneously observing the real scene through the phase-only SLM and the HOE backlight, which provides see-through capability. A bench-top experimental system was constructed to verify the far-distance image generation capability and see-through function.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Volume 29; Number 7; Pages 10568; 2021
DOI: 10.1364/oe.419604

GAN-Holo: Generative Adversarial Networks-Based Generated Holography Using Deep Learning

Author(s):

Khan, Aamir; Zhijiang, Zhang; Yu, Yingjie; Khan, Muhammad Amir; Yan, Ketao & Aziz, Khizar

Abstract:

“Current development in a deep neural network (DNN) has given an opportunity to a novel framework for the reconstruction of a holographic image and a phase recovery method with real-time performance. There are many deep learning-based techniques that have been proposed for the holographic image reconstruction, but these deep learning-based methods can still lack in performance, time complexity, accuracy, and real-time performance. Due to iterative calculation, the generation of a CGH requires a long computation time. A novel deep generative adversarial network holography (GAN-Holo) framework is proposed for hologram reconstruction. This novel framework consists of two phases. In phase one, we used the Fresnel-based method to make the dataset. In the second phase, we trained the raw input image and holographic label image data from phase one acquired images. Our method has the capability of the noniterative process of computer-generated holograms (CGHs). The experimental results have demonstrated that the proposed method outperforms the existing methods.”

Link to Publications Page

Publication: Complexity
Issue/Year: Complexity, Volume 2021; Pages 1-7; 2021
DOI: 10.1155/2021/6662161

An interactive holographic projection system that uses a hand-drawn interface with a consumer CPU

Author(s):

Nishitsuji, Takashi; Kakue, Takashi; Blinder, David; Shimobaba, Tomoyoshi & Ito, Tomoyoshi

Abstract:

“Holography is a promising technology for photo-realistic three-dimensional (3D) displays because of its ability to replay the light reflected from an object using a spatial light modulator (SLM). However, the enormous computational requirements for calculating computer-generated holograms (CGHs)—which are displayed on an SLM as a diffraction pattern—are a significant problem for practical uses (e.g., for interactive 3D displays for remote navigation systems). Here, we demonstrate an interactive 3D display system using electro-holography that can operate with a consumer’s CPU. The proposed system integrates an efficient and fast CGH computation algorithm for line-drawn 3D objects with inter-frame differencing, so that the trajectory of a line-drawn object that is handwritten on a drawing tablet can be played back interactively using only the CPU. In this system, we used an SLM with 1,920 × 1,080 pixels and a pixel pitch of 8 μm × 8 μm, a drawing tablet as an interface, and an Intel Core i9–9900K 3.60 GHz CPU. Numerical and optical experiments using a dataset of handwritten inputs show that the proposed system is capable of reproducing handwritten 3D images in real time with sufficient interactivity and image quality.”

Link to Publications Page

Publication: Scientific Reports
Issue/Year: Scientific Reports, Volume 11; Number 1; 2021
DOI: 10.1038/s41598-020-78902-1

Hologram generation via Hilbert transform

Author(s):

Tomoyoshi Shimobaba, Takashi Kakue, Yota Yamamoto, Ikuo Hoshi, Harutaka Shiomi, Takashi Nishitsuji, Naoki Takada, and Tomoyoshi Ito

Abstract:

“We propose an indirect method for generating a complex hologram and phase-only hologram from an amplitude hologram using the Hilbert transform. The Hilbert transform generates an imaginary part of complex amplitude from only an amplitude hologram, resulting in the reduction of the total computational complexity of complex and phase-only holograms. More importantly, the proposed method can reduce the hardware resources of dedicated hologram processors.”

Link to Publications Page

Publication: OSA Continuum
Issue/Year: Vol. 3, Issue 6, pp. 1498-1503 (2020)
DOI: 10.1364/OSAC.395003

Fabrication of oil–water separation copper filter by spatial light modulated femtosecond laser

Author(s):

Xiaoyan Sun, Zhuolin Dong, Kaifan Cheng, Dongkai Chu, Dejian Kong, Youwang Hu and Ji’an Duan

Abstract:

“Surface with oil–water separation performance has attracted more and more attention in the application of oil-containing wastewater purification. Much related work has been done by many researchers. However, there are still many difficulties in rapid manufacturing of filter membranes with special wettability. In this paper, an efficient, flexible method to fabricate microporous arrays by using a femtosecond (fs) laser combined with a spatial light modulator is proposed. The laser treated copper sheet surface shows hydrophobic and superoleophilic properties due to the microstructure. Meanwhile, the array of micro-through-holes on the surface can allow oil to penetrate through holes and prevent water from penetrating. The manufacturing process is not only extremely efficient, with a 10 × 10 focus array used in the ablation, but also it is without chemical method and the filter presents a long-term stable hydrophobic and superoleophilic performance.”

Link to Publications Page

Publication: Journal of Micromechanics and Microengineering
Issue/Year: Volume 30, Number 6
DOI: 10.1088/1361-6439/ab870d

Fast calculation of computer-generated hologram of line-drawn objects without FFT

Author(s):

Nishitsuji, Takashi; Shimobaba, Tomoyoshi; Kakue, Takashi & Ito, Tomoyoshi

Abstract:

“Although holographic display technology is one of the most promising three-dimensional (3D) display technologies for virtual and augmented reality, the enormous computational effort required to produce computer-generated holograms (CGHs) to digitally record and display 3D images presents a significant roadblock to the implementation of this technology. One of the most effective methods to implement fast CGH calculations is a diffraction calculation (e.g., angular spectrum diffraction) based on the fast-Fourier transform (FFT). Unfortunately, the computational complexity increases with increasing CGH resolution, which is what determines the size of a 3D image. Therefore, enormous calculations are still required to display a reasonably sized 3D image, even for a simple 3D image. To address this issue, we propose herein a fast CGH algorithm for 3D objects comprised of line-drawn objects at layers of different depths. An aperture formed from a continuous line at a single depth can be regarded as a series of aligned point sources of light, and the wavefront converges for a sufficiently long line. Thus, a CGH of a line-drawn object can be calculated by synthesizing converged wavefronts along the line. Numerical experiments indicate that, compared with the FFT-based method, the proposed method offers a factor-56 gain in speed for calculating 16-k-resolution CGHs from 3D objects composed of twelve line-drawn objects at different depths.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Volume 28; Number 11; Pages 15907; 2020
DOI: 10.1364/oe.389778

Rapid tilted-plane Gerchberg-Saxton algorithm for holographic optical tweezers

Author(s):

Yanan Cai, Shaohui Yan, Zhaojun Wang, Runze Li, Yansheng Liang, Yuan Zhou, Xing Li, Xianghua Yu, Ming Lei and Baoli Yao

Abstract:

“Benefitting from the development of commercial spatial light modulator (SLM), holographic optical tweezers (HOT) have emerged as a powerful tool for life science, material science and particle physics. The calculation of computer-generated holograms (CGH) for generating multi-focus arrays plays a key role in HOT for trapping of a bunch of particles in parallel. To realize dynamic 3D manipulation, we propose a new tilted-plane GS algorithm for fast generation of multiple foci. The multi-focal spots with a uniformity of 99% can be generated in a tilted plane. The computation time for a CGH with 512512 pixels is less than 0.1 second.
We demonstrated the power of the algorithm by simultaneously trapping and rotating silica beads with a 77 spots array in three dimensions. The presented algorithm is expected as a powerful kernel of HOT.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Vol. 28, Issue 9, pp. 12729-12739
DOI: 10.1364/OE.389897

Wirtinger holography for near-eye displays

Author(s):

Chakravarthula, Praneeth; Peng, Yifan; Kollin, Joel; Fuchs, Henry & Heide, Felix

Abstract:

“Near-eye displays using holographic projection are emerging as an exciting display approach for virtual and augmented reality at high-resolution without complex optical setups — shifting optical complexity to computation. While precise phase modulation hardware is becoming available, phase retrieval algorithms are still in their infancy, and holographic display approaches resort to heuristic encoding methods or iterative methods relying on various relaxations.
In this work, we depart from such existing approximations and solve the phase retrieval problem for a hologram of a scene at a single depth at a given time by revisiting complex Wirtinger derivatives, also extending our framework to render 3D volumetric scenes. Using Wirtinger derivatives allows us to pose the phase retrieval problem as a quadratic problem which can be minimized with first-order optimization methods. The proposed Wirtinger Holography is flexible and facilitates the use of different loss functions, including learned perceptual losses parametrized by deep neural networks, as well as stochastic optimization methods. We validate this framework by demonstrating holographic reconstructions with an order of magnitude lower error, both in simulation and on an experimental hardware prototype.”

Link to Publications Page

Publication: ACM Transactions on Graphics (TOG)
Issue/Year: ACM Transactions on Graphics (TOG), Volume 38; Number 6; Pages 213; 2019
DOI: 10.1145/3355089.3356539