Search results for "holography"

In-Situ Measurements of the Cloud Microphysical Structure Using Holography

2007

Advances in three-dimensional integral imaging: sensing, display, and applications [Invited]

2013

Three-dimensional (3D) sensing and imaging technologies have been extensively researched for many applications in the fields of entertainment, medicine, robotics, manufacturing, industrial inspection, security, surveillance, and defense due to their diverse and significant benefits. Integral imaging is a passive multiperspective imaging technique, which records multiple two-dimensional images of a scene from different perspectives. Unlike holography, it can capture a scene such as outdoor events with incoherent or ambient light. Integral imaging can display a true 3D color image with full parallax and continuous viewing angles by incoherent light; thus it does not suffer from speckle degrad…

Microscopic and macroscopic 3D imaging and display by integral imaging

2011

Integral imaging is a rising 3D imaging technique that can be considered the incoherent version of holography. In integral imaging the multiperspective information of 3D scenes is stored in a 2D picture. Such picture, composed by a set of elemental images, is obtained through a 2D array of microlenses. The elemental-images set can be used for many purposes. One is the display of 3D color scenes to audiences or much more than one person. Other is the 3D display, with full parallax, in personal monitors, like the screen of a smartphone, a tablet, or the monitor used by a surgeon in an endoscopic operation. Other important types of applications are connected with the topographic reconstruction…

Three Dimensional Sensing, Visualization, and Display

2008

This keynote address will present an overview of recent advances in Three-dimensional (3D) sensing, imaging and display. We shall discuss both passive sensing integral imaging and active sensing computational holographic imaging for 3D visualization, display, and image recognition. Mathematical analysis, computer simulations, and optical experimental results will be presented. There are numerous applications of these technologies including medical 3D imaging, 3D visualization, 3D identification and inspection, 3D television, 3D video, 3D multimedia, interactive communication, education, entertainment, and commerce.

Characterization of impervious layers using scale models and an inverse method

2009

We describe a novel procedure that uses an inverse method to determine unknown parameters for impervious layers used in multilayer structures. The proposed model of the multilayer structure is limited to an ideal double plate separated by an unbonded, fibrous, sound-absorbing material. Experimental data were obtained by nearfield acoustic holography for the calculation of the transmission loss of various multilayer structures mounted in a window in a wooden box designed specifically for this purpose. We used the Trochidis and Kalaroutis forecast model of acoustic insulation for multilayer structures, which is based on a spatial Fourier transform. The experimental pressure and velocity data …

Spatially multiplexed interferometric microscopy with partially coherent illumination

2016

We have recently reported on a simple, low cost, and highly stable way to convert a standard microscope into a holographic one [Opt. Express 22, 14929 (2014)]. The method, named spatially multiplexed interferometric microscopy (SMIM), proposes an off-axis holographic architecture implemented onto a regular (nonholographic) microscope with minimum modifications: the use of coherent illumination and a properly placed and selected one-dimensional diffraction grating. In this contribution, we report on the implementation of partially (temporally reduced) coherent illumination in SMIM as a way to improve quantitative phase imaging. The use of low coherence sources forces the application of phase…

Optical field-induced surface-relief micropatterning of amorphous chalcogenide thin films

2015

The study of direct recording of the surface relief gratings on amorphous chalcogenide thin (2.5 to 5  μm films is presented by three different recording setups. Recording was performed on As2S3 by 532-nm wavelength laser light. Additionally, the evolution of a surface relief in dependence from the recording time and polarization has been investigated in detail and for the first time, the mass transfer process has been explained from the point of view of the photoinduced birefringence. The role of photoinduced plasticity in the formation of surface relief in amorphous chalcogenides during holographic recording has been discussed.

Programmable color tuning of a multiline laser by means of a twisted nematic liquid crystal display.

2012

An optical system useful to tune in a controlled way the color of a triline argon krypton (Ar–Kr) laser by means of a twisted nematic liquid crystal display (TNLCD) is presented. The optical setup employs a 4f system and two blazed gratings to first separate and then recombine the spectrum of the light beam. The TNLCD is included in the intermediate focal plane operating in the amplitude modulation mode to control the relative transmission of each spectral line. The resulting color is accurately predicted by using a previously developed physical model of the spectral and voltage dependence of the TNLCD birefringence. By simply changing the gray level image addressed to the display, the Ar–K…

Application of amorphous chalcogenide thin films in optical recording technologies

2005

A solid immersion holographic method for the recording of refractive-index and surface-relief modulated gratings with a period of 0.2 µm–1 µm in amorphous films of chalcogenide semiconductors As2S3 and As-S-Se has been developed and studied. The angular selectivity of holographic recording in amorphous chalcogenide thin films can be improved significantly by a decrease of grating period. The possibility to use the amorphous chalcogenide films as a media for holographic recording and storage of information with high density is discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

<title>Holographic recording of subwavelength structures in amorphous chalcogenide thin films</title>

2005

Holographic recording of surface-relief and refiactive-index-modulated gratings with a period ranging from 0.15 to 1 μm in thin amorphous chalcogenide films of As-S-Se and As2S3 is studied. The profile of the surface-relief gratings is measured by atomic force microscopy. By structuring the As-S-Se films with the subwavelength-period surface-relief gratings their reflectivity is decreased from 25-30% to less than 2%. In the refractive-index-modulated As2S3 films polarization effects are revealed. It is shown that the angular selectivity of the holographic recording in amorphous chalcogenide thin films can be substantially improved by decreasing the grating period.© (2005) COPYRIGHT SPIE--Th…