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.”

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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.”

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Publication: Scientific Reports

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

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.”

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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.”

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Publication: Optics Letters

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

DOI: 10.1364/OL.42.003992

 

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.”

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Publication: Optica

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

Interferenceless coded aperture correlation holography–a new technique for recording incoherent digital holograms without two-wave interference

Author(s):

A. Vijayakumar and Joseph Rosen

Abstract:

“Recording digital holograms without wave interference simplifies the optical systems, increases their power efficiency and avoids complicated aligning procedures. We propose and demonstrate a new technique of digital hologram acquisition without two-wave interference. Incoherent light emitted from an object propagates through a random-like coded phase mask and recorded directly without interference by a digital camera. In the training stage of the system, a point spread hologram (PSH) is first recorded by modulating the light diffracted from a point object by the coded phase masks. At least two different masks should be used to record two different intensity distributions at all possible axial locations. The various recorded patterns at every axial location are superposed in the computer to obtain a complex valued PSH library cataloged to its axial location. Following the training stage, an object is placed within the axial boundaries of the PSH library and the light diffracted from the object is once again modulated by the same phase masks. The intensity patterns are recorded and superposed exactly as the PSH to yield a complex hologram of the object. The object information at any particular plane is reconstructed by a cross-correlation between the complex valued hologram and the appropriate element of the PSH library. The characteristics and the performance of the proposed system were compared with an equivalent regular imaging system.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Vol. 25, Issue 12, pp. 13883-13896 (2017)

DOI: 10.1364/OE.25.013883

 

Spectrum and space resolved 4D imaging by coded aperture correlation holography (COACH) with diffractive objective lens

Author(s):

A. Vijayakumar and Joseph Rosen

Abstract:

“In this Letter, we present an advanced optical configuration of coded aperture correlation holography (COACH) with a diffractive objective lens. Four-dimensional imaging of objects at the three spatial dimensions and with an additional spectral dimension is demonstrated. A hologram of three-dimensional objects illuminated by different wavelengths was recorded by the interference of light diffracted from the objects with the light diffracted from the same objects, but through a random-like coded phase mask (CPM). A library of holograms denoted point spread function (PSF) holograms were prerecorded with the same CPM, and under identical conditions, using point objects along different axial locations and for the different illuminating wavelengths. The correlation of the object hologram with the PSF hologram recorded using a particular wavelength, and at a particular axial location, reconstructs only the object corresponding to the particular axial plane and to the specific wavelength. The reconstruction results are compared with regular imaging and with another well-established holographic technique called Fresnel incoherent correlation holography.”

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Publication:  Optics Letters

Issue/Year/DOI: Optics Letters Vol.42, Issue 5, pp. 947-950 (2017)
DOI: 10.1364/OL.42.000947

Methods of Single-Channel Digital Holography for Three-Dimensional Imaging

Author(s):

R. Kelner and J. Rosen

Abstract:

“Digital holography is an effective tool for imaging three-dimensional (3-D) scenes or objects. In this paper, recently developed methods of single channel digital holography are reviewed: the joint object reference digital interferometer (JORDI), Fresnel incoherent correlation holography (FINCH), and Fourier incoherent single channel holography (FISCH).”

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Publication: IEEE Transactions on Industrial Informatics

Issue/Year/DOI: IEEE Transactions on Industrial Informatics ( Volume: 12, Issue: 1, Feb. 2016 )
DOI: 10.1109/TII.2015.2475247