Image Plane Hologram Research Articles

Volume reflection holographic confocal imaging

The Denisyuk volume reflection hologram is produced with spatially incoherent light to form an image-plane hologram. The image formed in readout combines the properties of volume holography and confocal image formation.

3D displacement measurements of vibrating objects with multi-pulse digital holography

An optoelectronic system based on multi-pulse digital holography is used to measure three different displacement-vector components of a vibrating cylindrical object. Four pulses from a Q-switched ruby laser are used to record image plane holograms which are later digitally reconstructed on three CCD cameras. Three different illumination directions are used to obtain the resultant three-dimensional (3D) object deformation from the vectorial addition of three sensitivity displacement vectors. In order to complete the 3D integral study of the object deformation its cylindrical shape is calculated. The shape and 3D vectorial are combined and graphically presented. Thus, this paper describes the integration of a novel methodology for 3D deformation evaluation of vibrating objects.

Digital double pulse-TV-holography

A digitial double-pulsed holographic system will be described. Two separate holograms of an object under test are recorded within a few microseconds using a CCD-camera and stored in a frame grabber. Different recording arrangements for Fresnel hologram, quasi-Fourierand image-plane hologram are discussed and compared. The holograms are reconstructed digitally using a computer. The phases of the two reconstructed wave fields are calculated from the complex amplitudes. The deformation information is obtained from the phase difference. In the case of the image-plane hologram the deformation can be obtained by using a sinusoid-fitting method without reconstruction of the wavefront. Experimental results are presented.

Absorption effects in photorefractive volume-holographic memory systems II Material heating

We consider how absorption-induced material heating alters the phase profile, the scale, the orientation, and the Bragg matching of volume holograms. We derive theoretical equations that consider the prisming, the lensing, and the Bragg mismatching that occur during material heating and compare these with experimental observations. From our Bragg-mismatching considerations we show how both read beam angle and wavelength need to be dithered for proper compensation of volume holograms for material-heating effects. Our results indicate that material heating in volume-holographic memory systems poses a severe threat to system performance. This threat is shown to be very significant in Fourier plane holograms but only moderately significant in image plane holograms.

Digital Double-Pulse Holographic Interferometry for Vibration Analysis

Different arrangements for double-pulsed holographic and speckle interferometry for vibration analysis will be described. Experimental results obtained with films (classical holographic interferometry) and CCD cameras (digital holographic interferometry) as storage materials are presented. In digital holography, two separate holograms of an object under test are recorded within a few microseconds using a CCD camera and are stored in a frame grabber. The phases of the two reconstructed wave fields are calculated from the complex amplitudes. The deformation is obtained from the phase difference. In the case of electronic speckle pattern interferometry (or image plane hologram), the phase can be calculated by using the sinusoid-fitting method. In the case of digital holographic interferometry, the phase is obtained by digital reconstruction of the complex amplitudes of the wave fronts. Using three directions of illumination and one direction of observation, all the information necessary for the reconstruction of the 3-dimensional deformation vector can be recorded at the same time. Applications of the method for measuring rotating objects are discussed where a derotator needs to be used.

Digital Double-Pulse Holographic Interferometry for Vibration Analysis

Different arrangements for double-pulsed holographic and speckle interferometry for vibration analysis will be described. Experimental results obtained with films (classical holographic interferometry) and CCD cameras (digital holographic interferometry) as storage materials are presented. In digital holography, two separate holograms of an object under test are recorded within a few microseconds using a CCD camera and are stored in a frame grabber. The phases of the two reconstructed wave fields are calculated from the complex amplitudes. The deformation is obtained from the phase difference. In the case of electronic speckle pattern interferometry (or image plane hologram), the phase can be calculated by using the sinusoid-fitting method. In the case of digital holographic interferometry, the phase is obtained by digital reconstruction of the complex amplitudes of the wave fronts. Using three directions of illumination and one direction of observation, all the information necessary for the reconstruction of the 3-dimensional deformation vector can be recorded at the same time. Applications of the method for measuring rotating objects are discussed where a derotator needs to be used.

Digital double-pulse holographic interferometry using Fresnel and image plane holograms

Different arrangements for digital double-pulse holographic and speckle interferometry for vibration analysis are described. In the case of digital double-pulse holographic interferometry, two separate holograms of an object under test are recorded within a few microseconds using a CCD camera and stored in a frame grabber. The phases of the two reconstructed wave fields are calculated from the complex amplitudes which are obtained by digital reconstruction of the wavefront produced by the hologram. The deformation is obtained from the phase difference. In the case of ESPI (or image plane hologram) the phase can be calculated by using the sinusoid-fitting method or the Fourier method. Using three directions of illumination and one direction of observation, all the information necessary for the reconstruction of the three-dimensional deformation vector can be recorded at the same time. Applications of the method for measuring rotating objects are discussed, together with the derotator needed.

Comparison of two reflecting surfaces by using digital holographic interferometry

In this paper we describe a digital holographic system for the comparison of two reflecting surfaces (e.g. spherical mirrors). Two holograms of the two objects to be compared are recorded using a CCD-camera and stored in a frame grabber. Two methods are presented. In the first method we record image plane holograms and the sinusoid fitting is used in order to determine the phases of the two wavefields. In the second we record Fresnel holograms and reconstruct the wavefields by simulating the Fresnel diffraction of the holograms illuminated by the reference wave. The phases of the two wavefields are calculated from the complex amplitudes. The surface shapes are compared by phase difference. Experimental results are presented.

Statistical analysis of cross-talk noise and storage capacity in volume holographic memory: image plane holograms

We investigate the cross-talk noise in optical storage based on angle-multiplexed image plane volume holograms. Simple expressions for the signal-to-noise ratio and the storage density are obtained. The cross-talk noise is found to limit the size of the pixels and the number of recorded holograms. The cross-talk-limited storage density of image plane holographic storage is found to be close to that of Fourier plane holographic storage.

Cross talk for angle- and wavelength-multiplexed image plane holograms

The cross talk for image plane holograms is calculated and compared with previously derived results for Fourier plane holograms. Image plane storage is found to have significantly smaller cross talk.

Forms of Light: A Personal History in Holography

O n a sunny Sunday afternoon in early autumn of 1972, I visited the annual San Francisco Art Festival. A jazz band was playing improvised music that carried on the breeze. I entered a dark tent that was filled with moving and scintillating dots of red laser light, diffracted by a primitive holographic diffraction grating. Outside again, blinking in the bright sunshine, I found that the random event of visiting an art festival had become a vehicle for a conscious choice. I knew that if I re-entered the tent, it would change the direction of my life. I discovered two strong aesthetic motivations that day: laser light and holography. The festival's background jazz music formed a third motivation. With the addition of my interest in glass, these elements were to become my primary artistic preoccupations for the next 20 years. Their exploration led in a straight, if somewhat complicated, line to the development of my holographic compositions, which include reflection-hologram composites and transmission-hologram sculptures. Reflection-hologram composites are arranged compositions of multiple reflection holograms on glass plates. I usually originate the holograms by creating laser-viewable holographic masters, often derived from original sculpture and artwork. After mastering, I transfer the holographic images as image-plane reflection holograms, which are viewable in white light. Occasionally, I include Denisyuk and off-axis reflection holograms for the special effects these types of holograms provide to the overall composition. The reflection holograms are designed, arranged and mounted together to compose the completed art pieces. The finished reflection-hologram composites are designed to present an integrated picture that tells a story. The flow of three-dimensional (3D) imagery from hologram to hologram is created for maximum interplay between images, varying dimensions, parallax and deep space. Through the use of exotic color arrangement, juxtaposition and repetition of imagery, I attempt to create visual rhythm patterns, textures and lines that are akin to those found in musical composition. On paper, it is easy to make a 20-year leap from my introduction to the early holographic media to their current applications in my artwork; however, the actual journey from fragments of ideas to completed holograms was a long process, filled with almost as many disappointments and setbacks as realized artworks. The process of developing as an artist who counts holography as a medium was filled with many aesthetic divergences, public 'services' and 'subroutines'. I will enumerate some of these events in my life, as

Pseudocolor transmission holographic stereograms with point white light source illumination

This paper presents a set of design rules to implement dispersion correction for pseudocolor transmission holographic stereograms illuminated by a point white light source. The axial and vertical correction involves tilting of the master hologram relative to the image plane hologram and the lateral compensation is done by a 1-D magnification along the lateral axis for different color contributions in the white light reconstruction. Experimental data verify the basic analysis and modeling of the dispersion correction demonstrates its effectiveness.

Pinhole hologram and its applications

We propose the use of a pinhole-camera approach to make holograms. On recording the object beam passes through a pinhole, forming an image plane hologram, but on reconstruction the pinhole can be taken away. The reconstructed image can be programmed and processed by using optical information-processing elements placed in the position of the reconstructed pinhole or pinholes. Pinhole holography can also suppress intermodulation effects. We present brief theoretical considerations and experimental results for pinhole holograms produced for programmable holographic optical interconnects.

Image plane holography for holographic presentation of a three-dimensional data base

Holographic presentation of three-dimensional data from CT, NMR, PET or ultrasonic scan should greatly aid in diagnostic and therapeutic procedures. Originally a multiplex white light hologram was formed from many X-rays of a cadaver's hand. Many methods of computer generating a hologram have been explored. In this paper we examine a method of calculating an Image Plane Hologram by computer and show the white light characteristics of the Image Plane Hologram.

Computer generated holograms using personal computers

Holography or the method of wave-front reconstruction to produce an image was introduced by D. Gabor in 1948. Normally a laser is necessary to produce holograms in the laboratory. This paper introduces the usage of the high resolution display of the IBM-PC and a graphics printer to generate holograms. The advantages of using this method are that holograms of real or fictitious objects can be made, since all objects can be represented by a collection of points and one does not need an elaborate set up to make the holograms. This method is also useful for making Fourier transform holograms, image plane holograms, spatial filters, optical elements, etc. 1,2

An alternative technique for extraction of in-plane displacement from an image plane hologram

The combination of image plane holography and speckle photography for measurement of 3-D displacements has been reported earlier. It has been observed that when we interrogate such a hologram by an unexpanded laser beam, in addition to the formation of Young's fringes in the direct diffracted beam, very bright side lobes are also generated. If the specimen has undergone any in-plane displacement, high contrast fringes appear in the side lobes. We have demonstrated that these fringes can be used to obtain a precise quantitative in-plane displacement of the object.

NOE: A Hybrid Method for Multiplexed Holography for Display Purposes

In this paper, we propose a new hybrid processing method for generation of multiplexed holograms for display purposes. This method—named the NOE method—is very simple, and combines the rapidity of optical restitution, the flexibility of numerical computation and the simplicity of electrical control, in order to allow a large number of objects to be stored. The computer generates a multiplexed grating profile, leaving the Fourier transform to the optical restitution step. Image plane holograms are generated, for white light reconstruction, by a set of independent white light sources.

Comparison of Measured and Predicted Transonic Flow Around an Airfoil

ATWO-DIMENSIONAL numerical solution using an inviscid time marching method has been compared with interferometric data obtained from image plane holograms. This has been done over the whole blade profile including the trailing edge shock region, but a particularly detailed analysis has been made of the leading edge. The data obtained show isodensity/iso-Mach contours (AM=0.03), with a spacing of typically 50 /mi between them. It was found that a highly refined grid size of similar resolution was required to compute an accurate solution. Contents Description of Flow The two-dimensional airfoil section which was based upon a NACA 0010-34 profile1 was mounted at zero incidence in the center of the tunnel on two supports from below. These were located within the tunnel flow, causing a 12% blockage of the throat area beneath the blade. It may be thought that such a large blockage would generate three-dimensional effects; previous oil flow and pressure measurements show this not to be the case.1 They also show that despite a 5-mmthick sidewall boundary layer the flow on the upper surface of the blade is two-dimensional for 90% of its span. As a result of the partial blockage of the blade at the leading edge, the stagnation point has moved toward the pressure surface. The flow is seen to accelerate around the leading edge up to a maximum speed of M=1.25 (Fig. 1). This can be compared with the computed flow solutions shown in Figs. 2-4. The flow remains attached around the leading edge and subsequently decelerated to a minimum Mach number of 1.06 at 10% of the blade chord. The suction surface of the blade then behaves in a more conventional manner, the supersonic flow being accelerated by the convex surface of the blade profile up to M= 1.26. It is also noted that the boundary-layer thickness at the trailing edge is 2 mm. This thickness has not been taken into account in the inviscid calculations. Optical System The optical system used in this experiment was similar to that applied previously2 to turbine cascade, image plane holography. The interferometric fringes formed in the

Spatial frequency response and resolution in holography

Measurements were taken in order to compare “spatial frequency response” (SFR) and resolution properties of several types of holographic methods. The best SFR was obtained for the “Fourier holographic method”; good resolution and SFR were also found for the “image plane hologram” (IPH) reconstructed with a laser light.

Multiple-aperture three-dimensional image construction utilizing fringe-modulated speckle patterns

A technique is described for recording and reconstructing two- and three-dimensional color images utilizing a fringe-modulated speckle pattern. A multiple-aperture imaging system generates the modulated speckles and produces an image plane hologram in which the various complex waveforms, passing through the individual apertures, operate simultaneously as object and reference beams. This holographic recording system is considerably less sensitive to external vibration than conventional off-axis holography and requires much less stringent temporal- and spatial-coherence specifications for its light source.