A Broadband Scalar Vortex Coronagraph

Broadband coronagraphy with deep nulling and small inner working angle has the potential of delivering images and spectra of exoplanets and other faint objects. In recent years, many coronagraphic schemes have been proposed, the most promising being the optical vortex phase mask coronagraphs. In this paper, a new scheme of broadband optical scalar vortex coronagraph is proposed and characterized experimentally in the laboratory. Our setup employs a pair of computer generated phase gratings (one of them containing a singularity) to control the chromatic dispersion of phase plates and achieves a constant peak-to-peak attenuation below $1\cdot 10^{-3}$ over a bandwidth of 120 nm centered at 700 nm. An inner working angle of ~\lambda/D is demonstrated along with a raw contrast of 11.5 magnitudes at 2\lambda/D.Comment: Accepted, 6 pages, 6 image

Computer Generated Holograms of 3D Points Cloud

Computer generated holography is a method of using numerical methods to simulate the physical processes underlying a real hologram’s optical recording and reconstruction i.e. the method of digitally generating holographic interference patterns. As such, it represents substantial progress compared to classical holography. A major disadvantage of this approach is the absence of specialized software tools for computer generated holograms and extremely high computer resource consumption, resulting in an excessive computing time. The goal of this paper is to create a physically plausible computer model for generating holograms, with a large potential for calculation optimization and acceleration, as well as the integration of this model into simple hologram creation software. We made software that simulates wave optics using previously known physical model to generate a hologram with the possibility of connection with commercial 3D tools via .obj documents. Considering that there is a problem of high computing resources consumption and time we have incorporated in our software the possibility of a parallel calculation for the purpose of testing, further software development and customization to optimize the computer generation of holograms

One-step volumetric additive manufacturing of complex polymer structures.

Two limitations of additive manufacturing methods that arise from layer-based fabrication are slow speed and geometric constraints (which include poor surface quality). Both limitations are overcome in the work reported here, introducing a new volumetric additive fabrication paradigm that produces photopolymer structures with complex nonperiodic three-dimensional geometries on a time scale of seconds. We implement this approach using holographic patterning of light fields, demonstrate the fabrication of a variety of structures, and study the properties of the light patterns and photosensitive resins required for this fabrication approach. The results indicate that low-absorbing resins containing ~0.1% photoinitiator, illuminated at modest powers (~10 to 100 mW), may be successfully used to build full structures in ~1 to 10 s

Holographic data visualization: using synthetic full-parallax holography to share information

This investigation explores representing information through data visualization using the medium holography. It is an exploration from the perspective of a creative practitioner deploying a transdisciplinary approach. The task of visualizing and making use of data and “big data” has been the focus of a large number of research projects during the opening of this century. As the amount of data that can be gathered has increased in a short time our ability to comprehend and get meaning out of the numbers has been brought into attention. This project is looking at the possibility of employing threedimensional imaging using holography to visualize data and additional information. To explore the viability of the concept, this project has set out to transform the visualization of calculated energy and fluid flow data to a holographic medium. A Computational Fluid Dynamics (CFD) model of flow around a vehicle, and a model of Solar irradiation on a building were chosen to investigate the process. As no pre-existing software is available to directly transform the data into a compatible format the team worked collaboratively and transdisciplinary in order to achieve an accurate conversion from the format of the calculation and visualization tools to a configuration suitable for synthetic holography production. The project also investigates ideas for layout and design suitable for holographic visualization of energy data. Two completed holograms will be presented. Future possibilities for developing the concept of Holographic Data Visualization are briefly deliberated upon. (c) 2017, Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Integral imaging based 3D display of holographic data

Cataloged from PDF version of article.We propose a method and present applications of this method that converts a diffraction pattern into an elemental image set in order to display them on an integral imaging based display setup. We generate elemental images based on diffraction calculations as an alternative to commonly used ray tracing methods. Ray tracing methods do not accommodate the interference and diffraction phenomena. Our proposed method enables us to obtain elemental images from a holographic recording of a 3D object/scene. The diffraction pattern can be either numerically generated data or digitally acquired optical data. The method shows the connection between a hologram (diffraction pattern) and an elemental image set of the same 3D object. We showed three examples, one of which is the digitally captured optical diffraction tomography data of an epithelium cell. We obtained optical reconstructions with our integral imaging display setup where we used a digital lenslet array. We also obtained numerical reconstructions, again by using the diffraction calculations, for comparison. The digital and optical reconstruction results are in good agreement. © 2012 Optical Society of America

Tunable Holographic Components in WDM Optical Networks

This paper describes the applications of a multipurpose holographic device in optical networks with Coarse and Dense Wavelength Division Multiplexing (CWDM/ DWDM) technologies. In its basic structure, it can operate as a tunable wavelength filter, wavelength multiplexer or λ router. By using a more complex structure, the device works as OADM (Optical Add Drop Multiplexer) or OS (Optical Switch). Some simulations of the basic devices, from the optical transmission point of view, are made to match the transmission parameters for the application in optical networks. Performance parameters of the device, like switching time, losses, cross-talk or polarization insensitivity are analyzed and compared with other multiplexing or switching technologies. To complete the review of these components, a study of computer generated holograms (CGH) design is carried out. The results are used in the design of holographic devices to perform different applications: in Metro networks, where a design of a holographic device with wavelength conversion and routing is analyzed, or, in Access Networks like a tunable filter or demultiplexer in Fiber to the Home/Business (FTTH/FTTB) topologies

A high-resolution optically addressed spatial light modulator based on ZnO nanoparticles

AbstractAn optically addressed spatial light modulator (OASLM) can modulate the wavefront of a read light by displaying a phase pattern or a hologram configured by the intensity distribution of a write light. Using ZnO nanoparticles (NPs) as a novel photoconductor, a high-resolution OASLM was fabricated. A ZnO NP suspension was spin-coated on an indium tin oxide (ITO)-coated glass substrate and annealed to form a photosensitive layer. The device was characterized electrically and optically. The device was operated at low driving voltages in the transmission mode. Updatable recording of a diffraction grating up to 825 lp mm−1 with a diffraction efficiency (DE) of 0.05% and binary holograms with pixel sizes from 2 µm down to 0.72 µm were demonstrated using a 405 nm wavelength write laser and a 635 nm wavelength read laser.This work was supported by the EPSRC through the Platform Grant for LC Photonics (EP/F00897X/1).This is the final version. It was first published by NPG at http://www.nature.com/lsa/journal/v4/n3/full/lsa201532a.htm

Adaptive applications of OPTO-VLSI processors in WDM networks

Communication is an inseparable part of human life and its nature continues to evolve and improve. The advent of laser was a herald to the new possibilities in the communication world. In recent years technologies such as Wavelength Division Multiplexing (WDM) and Erbium Doped Fiber Amplifiers (EDFA) have afforded significant boost to the practice of optical communication. At the heart of this brave new world is the need to dynamically/ adaptively steer/route beams of light carrying very large amounts of data. In recent years many techniques have been proposed for this purpose by various researchers. In this study we have elected to utilise the beam-steering capabilities of Opto-VLSI processors to investigate band-pass filtering and channel equalisation as two possible and practical applications in WDM networks

SLM simulation and MonteCarlo path tracing for computer-generated holograms

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