Dynamic 2D implementation of 3D diffractive optics

Author(s):

Haiyan Wang and Rafael Piestun

Abstract:

“Volumetric computer-generated diffractive optics offer advantages over planar 2D implementations, including the generation of space-variant functions and the multiplexing of information in space or frequency domains. Unfortunately, despite remarkable progress, fabrication of high volumetric space-bandwidth micro- and nanostructures
is still in its infancy. Furthermore, existing 3D diffractive optics implementations are static while programmable volumetric spatial light modulators (SLMs) are still years or decades away. In order to address these shortcomings, we propose the implementation of volumetric diffractive optics equivalent functionality via cascaded
planar elements. To illustrate the principle, we design 3D diffractive optics and implement a two-layer continuous phase-only design on a single SLM with a folded setup. The system provides dynamic and efficient multiplexing capability. Numerical and experimental results show this approach improves system performance such as diffraction
efficiency, spatial/spectral selectivity, and number of multiplexing functions relative to 2D devices while providing dynamic large space-bandwidth relative to current static volume diffractive optics. The limitations and capabilities of dynamic 3D diffractive optics are discussed.”

Link to Publications Page

Publication: Optica

Issue/Year/DOI: Optica Volume 5, Issues 10
DOI: doi.org/10.1364/OPTICA.5.001220

Compact design for optical-see-through holographic displays employing holographic optical elements

Author(s):

Pengcheng Zhou and Yan Li and Shuxin Liu and Yikai Su

Abstract:

“Holographic AR display is a promising technology for head-mounted display
devices. However, it usually has a complicated optical system and a large form factor, preventing it from widespread applications. In this work, we propose a flat-panel design to produce a compact holographic AR display, wh
ere traditional optical elements are replaced by two holographic optical elements (HOEs). Here, these two thin HOEs together perform the optical functions of a beam expander, an ocular lens, and an optical combiner. Without any bulky traditional optics, our design could achieve a compact form factor that is similar to a
pair of glasses. We also implemented a proof-of-concept prototype to verify its feasibility. Being compact, lightweight and free from accommodation-conve
rgence discrepancy, our design is promising for fatigue-free AR displays.”

Link to Publications Page

Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 26, Issue 18
DOI: 10.1364/OE.26.022866

Three-dimensional vectorial multifocal arrays created by pseudo-period encoding

Author(s):

Tingting Zeng and Chenliang Chang and Zhaozhong Chen and Hui-Tian Wang and Jianping Ding

Abstract:

“Multifocal arrays have been attracting considerable attention recently owing to their potential
applications in parallel optical tweezers, parallel single-molecule orientation determination,
parallel recording and multifocal multiphoton microscopy. However, the generation of vectorial
multifocal arrays with a tailorable structure and polarization state remains a great challenge, and
reports on multifocal arrays have hitherto been restricted either to scalar focal spots without
polarization versatility or to regular arrays with fixed spacing. In this work, we propose a specific
pseudo-period encoding technique to create three-dimensional (3D) vectorial multifocal arrays
with the ability to manipulate the position, polarization state and intensity of each focal spot. We
experimentally validated the flexibility of our approach in the generation of 3D vectorial multiple
spots with polarization multiplicity and position tunability.”

Link to Publications Page

Publication: Journal of Optics

Issue/Year/DOI: Journal of Optics, Volume 20, Number 6
DOI: 10.1088/2040-8986/aac1de

Generation of optical vortex array along arbitrary curvilinear arrangement

Author(s):

Lin Li and Chenliang Chang and Xiangzheng Yuan and Caojin Yuan and Shaotong Feng and Shouping Nie and Jianping Ding

Abstract:

“We propose an approach for creating optical vortex array (OVA) arranged along arbitrary curvilinear path, based on the coaxial interference of two width-controllable component curves calculated by modified holographic beam shaping technique. The two component curve beams have different radial dimensions as well as phase gradients along each beam such that the number of phase singularity in the curvilinear arranged optical vortex array (CA-OVA) is freely tunable on demand. Hybrid CA-OVA that comprises of multiple OVA structures along different respective curves is also discussed and demonstrated. Furthermore, we study the conversion of CA-OVA into vector mode that comprises of polarization vortex array with varied polarization state distribution. Both simulation and experimental results prove the performance of the proposed method of generating a complex structured vortex array, which is of significance for potential applications including multiple trapping of micro-sized particles.”

Link to Publications Page

Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol.26, Issue 8, pp. 9798- 9812 (2018)
DOI: 10.1364/OE.26.009798

Real-time colour hologram generation based on ray-sampling plane with multi-GPU acceleration.

Author(s):

Sato, Hirochika and Kakue, Takashi and Ichihashi, Yasuyuki and Endo, Yutaka and Wakunami, Koki and Oi, Ryutaro and Yamamoto, Kenji and Nakayama, Hirotaka and Shimobaba, Tomoyoshi and Ito, Tomoyoshi

Abstract:

“Although electro-holography can reconstruct three-dimensional (3D) motion pictures, its computational cost is too heavy to allow for real-time reconstruction of 3D motion pictures. This study explores accelerating colour hologram generation using light-ray information on a ray-sampling (RS) plane with a graphics processing unit (GPU) to realise a real-time holographic display system. We refer to an image corresponding to light-ray information as an RS image. Colour holograms were generated from three RS images with resolutions of 2,048 × 2,048; 3,072 × 3,072 and 4,096 × 4,096 pixels. The computational results indicate that the generation of the colour holograms using multiple GPUs (NVIDIA Geforce GTX 1080) was approximately 300-500 times faster than those generated using a central processing unit. In addition, the results demonstrate that 3D motion pictures were successfully reconstructed from RS images of 3,072 × 3,072 pixels at approximately 15 frames per second using an electro-holographic reconstruction system in which colour holograms were generated from RS images in real time.”

Link to Publications Page

Publication: Scientific Reports

Issue/Year/DOI:  Scientific Reports Volume 8, Article number: 1500 (2018)
DOI: 10.1038/s41598-018-19361-7

Time multiplexing technique of holographic view and Maxwellian view using a liquid lens in the optical see-through head mounted display

Author(s):

Jin Su Lee and Yoo Kwang Kim and Yong Hyub Won

Abstract:

“We report a liquid lens based optical see-through head mounted display that can simultaneously display both a maxwellian view and a hologram. Holograms are reconstructed by an angular spectrum layer based synthesis method. A hologram and Maxwellian view are simultaneously displayed by focusing the liquid lens from 0 D to 20 D with 60 Hz. The hologram is reconstructed at a position 1.5 m from the eye, and it is confirmed that the Maxwellian view is clear, even if the focus of the eye changes from 50 cm to 1.7 m. In the proposed system, the liquid lens acts as a low-pass filter. Since the PSNR is about 23 dB in the currently used 10 mm diameter liquid lens, the image quality is not adequate. However, we successfully verify the feasibility of our proposed system. In addition, if a large diameter liquid lens of 30 mm or more is applied, excellent image quality of 30 dB or more can be realized.”

Link to Publications Page

Publication: Opt. Express

Issue/Year/DOI: Opt. Express, Vol. 26, Issue 2, pp. 2149-2159 (2018)
DOI: 10.1364/OE.26.002149

Near-eye light field holographic rendering with spherical waves for wide field of view interactive 3D computer graphics

Author(s):

Liang Shi and Fu-Chung Huang and Ward Lopes and Wojciech Matusik and David Luebke

Abstract:

“Holograms display a 3D image in high resolution and allow viewers to focus freely as if looking through a virtual window, yet computer generated holography (CGH) hasn’t delivered the same visual quality under plane wave illumination and due to heavy computational cost. Light field displays have been popular due to their capability to provide continuous focus cues. However, light field displays must trade off between spatial and angular resolution, and do not model diffraction.

We present a light field-based CGH rendering pipeline allowing for reproduction of high-definition 3D scenes with continuous depth and support of intra-pupil view-dependent occlusion. Our rendering accurately accounts for diffraction and supports various types of reference illuminations for hologram. We avoid under- and over-sampling and geometric clipping effects seen in previous work. We also demonstrate an implementation of light field rendering plus the Fresnel diffraction integral based CGH calculation which is orders of magnitude faster than the state of the art [Zhang et al. 2015], achieving interactive volumetric 3D graphics.

To verify our computational results, we build a see-through, near-eye, color CGH display prototype which enables co-modulation of both amplitude and phase. We show that our rendering accurately models the spherical illumination introduced by the eye piece and produces the desired 3D imagery at the designated depth. We also analyze aliasing, theoretical resolution limits, depth of field, and other design trade-offs for near-eye CGH.”

Link to Publications Page

Publication: {ACM} Transactions on Graphics

Issue/Year/DOI: ACM Transactions on Graphics, Vol. 36, No. 6, Article 236. (November 2017)
DOI: 10.1145/3130800.3130832

Single camera shot interferenceless coded aperture correlation holography

Author(s):

Mani Ratnam Rai and A. Vijayakumar and Joseph Rosen

Abstract:

“We propose a new scheme for recording an incoherent digital hologram by a single camera shot. The method is based on a motionless, interferenceless, coded aperture correlation holography for 3D imaging. Two random-like coded phase masks (CPMs) are synthesized using the Gerchberg–Saxton algorithm with two different initial random phase profiles. The two CPMs are displayed side by side and used as the system aperture. Light from a pinhole is introduced into the system, and two impulse responses are recorded corresponding to the two CPMs. The two impulse responses are subtracted, and the resulting intensity profile is used as a reconstructing hologram. A library of reconstructing holograms is created corresponding to all possible axial locations. Following the above training stage, an object is placed within the axial limits of the library, and the intensity patterns of a single shot, corresponding to the same two CPMs, are recorded under identical conditions to generate the object hologram. The image of the object at any plane is reconstructed by a cross-correlation between the object hologram and the corresponding reconstructing hologram from the library.”

Link to Publications Page

Publication: Optics Letters

Issue/Year/DOI: Optics Letters Vol. 42, Issue 19, pp. 3992-3995 (2017)

DOI: 10.1364/OL.42.003992

 

Shaping of optical vector beams in three dimensions

Author(s):

Chenliang Chang and Yuan Gao and Jianpei Xia and Shouping Nie and Jianping Ding

Abstract:

“We present a method of shaping three-dimensional (3D) vector beams with prescribed intensity distribution and controllable polarization state variation along arbitrary curves in three dimensions. By employing a non-iterative 3D beam-shaping method developed for the scalar field,
we use two curved laser beams with mutually orthogonal polarization serving as base vector components with a high-intensity gradient and controllable phase variation,
so that they are collinearly superposed to produce a 3D vector beam. We experimentally demonstrate the generation of 3D vector beams that have a polarization gradient (spatially continuous variant polarization state) along 3D curves, which may find applications in polarizationmediated
processes, such as to drive the motion of micro-particles.”

Link to Publications Page

Publication: Optics Letters

Issue/Year/DOI: Optics Letters Volume 42, Issue 19 pp. 3884-3887 (2017)
DOI: 10.1364/OL.42.003884

Resolving images by blurring: superresolution method with a scattering mask between the observed objects and the hologram recorder

Author(s):

Yuval Kashter and A. Vijayakumar and Joseph Rosen

Abstract:

“An important quest in optical imaging has been, and still is, extending the resolution of imaging systems beyond the diffraction limit. We propose a superresolution technique in which the image is first blurred by a scattering mask, and then recovered from the blurry data with improved resolution. We introduced a scattering mask into the space between the observed objects and the objective lens of a Fresnel incoherent correlation holography (FINCH) system to demonstrate the method. Optical waves, containing high spatial frequencies of the object, which are usually filtered out by the limited system aperture, were introduced into the system due to the scattering nature of the scattering mask. As a consequence, both the effective numerical aperture and the spatial bandwidth of the system were enlarged. The image resolution could therefore be improved far beyond the resolution limit dictated by the limited numerical aperture of the system. We demonstrated the technique using a modified FINCH system and the results were compared with other systems, all having the same aperture dimensions. We showed a resolution enhancement in comparison to conventional FINCH and regular imaging systems, with the same numerical apertures. The theoretical and experimental data presented here establishes the proposed method as an attractive platform for an advanced superresolution system that can resolve better than conventional imaging systems.”

Link to Publications Page

Publication: Optica

Issue/Year/DOI: Optica, Vol. 4, Issue 8, (2017)
DOI: 10.1364/OPTICA.4.000932

1 2 3 11