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1

Volume holographic wavelet correlation processor  

Microsoft Academic Search

A volume holographic wavelet correlation processor is proposed and constructed for correlation identification. It is based on the theory of wavelet transforms and the mechanism of angle-multiplexing volume holographic associative storage in a photorefractive crystal. High parallelism and discrimination are achieved with the system. Our research shows that cross-talk noise is significantly reduced with wavelet filtering preprocessing. Correlation outputs can

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

2000-01-01

2

Multiplexing of volume holographic wavelet correlation processor  

Microsoft Academic Search

Volume holographic associative memory in a photorefractive crystal provides an inherent mechanism to develop a multi-channel correlation identification system with high parallelism. Wavelet transform is introduced to improve discrimination of the system. We first investigate parameters of the system for parallelism enhancement, and then study multiplexing of the system on input objects and wavelet filters. A general volume holographic wavelet

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

2000-01-01

3

High accurate volume holographic correlator with 4000 parallel correlation channels  

Microsoft Academic Search

Volume holographic correlator allows simultaneously calculate the two-dimensional inner product between the input image and each stored image. We have recently experimentally implemented in VHC 4000 parallel correlation channels with better than 98% output accuracy in a single location in a crystal. The speckle modulation is used to suppress the sidelobes of the correlation patterns, allowing more correlation spots to

Kai Ni; Zongyao Qu; Liangcai Cao; Ping Su; Qingsheng He; Guofan Jin

2008-01-01

4

Neural network designed volume holographic wavelet correlator for pattern recognition  

Microsoft Academic Search

Neural network (NN) techniques have been introduced to design wavelet filters and wavelet transform systems for pattern recognition. Based on the theory of wavelet matched filtering and the associative characteristic of volume holographic storage in a photo refractive crystal, a novel volume holographic wavelet correlator is constructed. A neural network is proposed to optimize parameters of the wavelet filters to

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

1999-01-01

5

Invariant performance of a volume holographic wavelet correlation processor  

Microsoft Academic Search

A multichannel optical correlation processor based on volume holographic associative memory in a photorefractive crystal and wavelet transform is proposed for human face recognition. Distortions due to shift, rotation, scale, and partial hiding are studied to understand invariant performance of the processor. Our results show that shift-invariance and rotation-invariance are key problems for practical applications of the processor to human

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

2000-01-01

6

Multiple spectrum filtering and thermal fixing for volume holographic correlator  

Microsoft Academic Search

A volume holographic correlator, including off-line thermal fixing, is demonstrated by storing 1020 images in a Fe-doped LiNbO3 crystal through two-dimensional angular-multiplexing. A multiple spectrum filtering is proposed to suppress output noise

Dayong Wang; Shiquan Tao; Zhuqing Jiang; Sunzheng Chen; Wei Yuan

2004-01-01

7

High accurate volume holographic correlator with 4000 parallel correlation channels  

NASA Astrophysics Data System (ADS)

Volume holographic correlator allows simultaneously calculate the two-dimensional inner product between the input image and each stored image. We have recently experimentally implemented in VHC 4000 parallel correlation channels with better than 98% output accuracy in a single location in a crystal. The speckle modulation is used to suppress the sidelobes of the correlation patterns, allowing more correlation spots to be contained in the output plane. A modified exposure schedule is designed to ensure the hologram in each channel with unity diffraction efficiency. In this schedule, a restricted coefficient was introduced into the original exposure schedule to solve the problem that the sensitivity and time constant of the crystal will change as a time function when in high-capacity storage. An interleaving method is proposed to improve the output accuracy. By unifying the distribution of the input and stored image patterns without changing the inner products between them, this method could eliminate the impact of correlation pattern variety on calculated inner product values. Moreover, by using this method, the maximum correlation spot size is reduced, which decreases the required minimum safe clearance between neighboring spots in the output plane, allowing more spots to be parallely detected without crosstalk. The experimental results are given and analyzed.

Ni, Kai; Qu, Zongyao; Cao, Liangcai; Su, Ping; He, Qingsheng; Jin, Guofan

2008-03-01

8

Read-only high accuracy volume holographic optical correlator  

NASA Astrophysics Data System (ADS)

A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2011-09-01

9

Wavelet transform to improve recognition accuracy of a volume holographic correlator  

Microsoft Academic Search

Volume holographic associative storage in a photorefractive crystal provides an inherent mechanism to develop a multichannel correlation system with high parallelism. Wavelet transform is introduced to improve recognition accuracy of the system. A novel volume holographic correlator is proposed and constructed. Its application in human face recognition is studied, and experimental results are given.

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

1999-01-01

10

Fingerprint identification by use of a volume holographic optical correlator  

Microsoft Academic Search

We propose an optical correlator system using volume hologram for database of matched filter. Optical correlator has high speed and parallel processing characteristics of optics. Matched filters are recorded into a volume hologram that can store data with high density, transfer them with high speed, and select a randomly chosen data element. The multiple reference images of database are prerecorded

Seung-Hyun Lee; Sang-Yi Yi; Eun-Soo Kim

1999-01-01

11

Wavelet invariant pattern recognition system based on the volume holographic correlator  

Microsoft Academic Search

In this paper, based on the volume holographic storage in a photorefractive crystal, a new rotation-, shift-invariant pattern recognition system, with the wavelet transform, has been set up. Parameters of rotated input pattern are first estimated and normalized. Rotation-, shift-invariant pattern recognition is then achieved by correlating the normalized input pattern with the undistorted reference, using the system. Simulation result

Qingzeng Xue; Wenzhao Tan; Yingbai Yan; Qingshong He

2002-01-01

12

Multi-sample parallel estimation in volume holographic correlator for remote sensing image recognition.  

PubMed

Based on volume holographic correlator, a multi-sample parallel estimation method is proposed to implement remote sensing image recognition with high accuracy. The essential steps of the method including image preprocessing, estimation curves fitting, template images preparation and estimation equation establishing are discussed in detail. The experimental results show the validity of the multi-sample parallel estimation method, and the recognition accuracy is improved by increasing the sample numbers. PMID:19997416

Wang, Shunli; Tan, Qiaofeng; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2009-11-23

13

Scale-invariant pattern recognition system based on volume holographic wavelet correlator  

Microsoft Academic Search

In this paper, based on the volume holographic storage in a photorefractive crystal, a new scale-invariant pattern recognition system, with the wavelet transform, has been set up. The wavelet filter can increase the discrimination capability of the correlator. However the wavelet-filtered image is edge-enhanced, the phase-only logarithmic radial harmonic (LRH) filter is not suitable for such image when regarding the

Qingzeng Xue; Yingbai Yan; Qingshong He

2001-01-01

14

Volume Holographic Hyperspectral Imaging  

Microsoft Academic Search

A volume hologram has two degenerate Bragg-phase-matching dimensions and provides the capability of volume holographic imaging. We demonstrate two volume holographic imaging architectures and investigate their imaging resolution, aberration, and sensitivity. The first architecture uses the hologram directly as an objective imaging element where strong aberration is observed and confirmed by simulation. The second architecture uses an imaging lens and

Wenhai Liu; George Barbastathis; Demetri Psaltis

2004-01-01

15

Large range rotation distortion measurement for remote sensing images based on volume holographic optical correlator  

NASA Astrophysics Data System (ADS)

Volume holographic optical correlator can compute the correlation results between images at a super-high speed. In the application of remote imaging processing such as scene matching, 6,000 template images have been angularly multiplexed in the photorefractive crystal and the 6,000 parallel processing channels are achieved. In order to detect the correlation pattern of images precisely and distinguishingly, an on-off pixel inverted technology of images is proposed. It can fully use the CCD's linear range for detection and expand the normalized correlation value differences as the target image rotates. Due to the natural characteristics of the remote sensing images, the statistical formulas between the rotation distortions and the correlation results can be estimated. The rotation distortion components can be estimated by curve fitting method with the data of correlation results. The intensities of the correlation spots are related to the distortion between the two images. The rotation distortion could be derived from the intensities in the post processing procedure. With 18 rotations of the input image and sending them into the volume holographic system, the detection of the rotation variation in the range of 180° can be fulfilled. So the large range rotation distortion detection is firstly realized. It offers a fast, large range rotation measurement method for image distortions.

Zheng, Tianxiang; Cao, Liangcai; Zhao, Tian; He, Qingsheng; Jin, Guofan

2012-10-01

16

Scale-invariant pattern recognition system based on volume holographic wavelet correlator  

NASA Astrophysics Data System (ADS)

In this paper, based on the volume holographic storage in a photorefractive crystal, a new scale-invariant pattern recognition system, with the wavelet transform, has been set up. The wavelet filter can increase the discrimination capability of the correlator. However the wavelet-filtered image is edge-enhanced, the phase-only logarithmic radial harmonic (LRH) filter is not suitable for such image when regarding the scale invariance. The LRH filter is modified to achieve scale invariant pattern recognition. Simulation result validates the theory.

Xue, Qingzeng; Yan, Yingbai; He, Qingshong

2001-09-01

17

Volume holographic hyperspectral imaging.  

PubMed

A volume hologram has two degenerate Bragg-phase-matching dimensions and provides the capability of volume holographic imaging. We demonstrate two volume holographic imaging architectures and investigate their imaging resolution, aberration, and sensitivity. The first architecture uses the hologram directly as an objective imaging element where strong aberration is observed and confirmed by simulation. The second architecture uses an imaging lens and a transmission geometry hologram to achieve linear two-dimensional optical sectioning and imaging of a four-dimensional (spatial plus spectral dimensions) object hyperspace. Multiplexed holograms can achieve simultaneously three-dimensional imaging of an object without a scanning mechanism. PMID:15218597

Liu, Wenhai; Barbastathis, George; Psaltis, Demetri

2004-06-20

18

Volume Holographic Hyperspectral Imaging  

NASA Astrophysics Data System (ADS)

A volume hologram has two degenerate Bragg-phase-matching dimensions and provides the capability of volume holographic imaging. We demonstrate two volume holographic imaging architectures and investigate their imaging resolution, aberration, and sensitivity. The first architecture uses the hologram directly as an objective imaging element where strong aberration is observed and confirmed by simulation. The second architecture uses an imaging lens and a transmission geometry hologram to achieve linear two-dimensional optical sectioning and imaging of a four-dimensional (spatial plus spectral dimensions) object hyperspace. Multiplexed holograms can achieve simultaneously three-dimensional imaging of an object without a scanning mechanism.

Liu, Wenhai; Barbastathis, George; Psaltis, Demetri

2004-06-01

19

Performance analysis of a volume holographic correlator based opto-electronic hybrid system for scene matching  

NASA Astrophysics Data System (ADS)

A volume holographic correlator (VHC) can function as an optical processing unit (OPU). With its multi-channel processing ability, the VHC is capable to extract inner products between the target image and all the stored remote sensing images with high speed and high parallelism. An opto-electronic hybrid system based on the VHC for scene matching is proposed. The innovative hybrid processing mode of the system combines the advantages of the high parallelism in VHC with the high flexibility and accuracy of digital processing, improving the overall system performances. The influences of the VHC's unique multi-channel parallel processing ability on the system speed and accuracy are theoretically studied in the context of different VHC working modes. The improvements of the system adaptability for different situations, such as illumination conditions and noise, are also analyzed by numerical simulation. Finally, experimental results are discussed to evaluate the system feasibility.

Zhao, Tian; Cao, Liangcai; Zheng, Tianxiang; Wang, Shunli; He, Qingsheng; Jin, Guofan

2012-10-01

20

Influence of readout optical field variations on inner product calculation in volume holographic correlator  

NASA Astrophysics Data System (ADS)

The volume holographic correlator (VHC) can be employed as a multichannel inner product calculator and has the potential in parallel and massive computing applications. The inner product calculation accuracy of the VHC varies with the optical illumination field in the plane of the spatial light modulator during readout. A theoretical model of the VHC is presented to study the influence of the optical field variations. The simulation results are shown to examine the cases of illumination angle deviation and wavelength deviation. The influences of hologram thickness on the calculation are also discussed. Experiments are carried out to investigate illumination angle deviation of the VHC. The presented method is helpful to improve the inner product calculation accuracy in the VHC for parallel optical image processing.

Zhao, Tian; Cao, Liangcai; Qin, Shuang; He, Qingsheng; Jin, Guofan

2013-07-01

21

Review of volume holographic data storage  

Microsoft Academic Search

We present a review of volume holographic memory technology highlighting the most important issues for the development of commercially viable mass data storage systems. To record data using volume holographic storage, data is encoded on a laser beam with a spatial light modulator (SLM). The object beam is directed into an optically sensitive material, typically a photorefractive crystal, and superimposed

William P. Hinkle

1997-01-01

22

Information quality of volume holographic memory devices  

NASA Astrophysics Data System (ADS)

The estimation of information quality -- value which takes into consideration both system information capacity and rate of data arbitrary access -- has been performed for the volume holographic memories. It has been shown that if the technical possibilities are limited, the super high information capacity of the volume holographic memories exceeds those of the other kinds of memory.

Gurevich, Simon B.; Gurevich, Boris S.; Zhumaliev, Kubanychbek M.; Peckus, Alfonsas M.; Akkoziev, Imil A.; Alymkulov, Salmor A.

2001-04-01

23

Image recognition system based on volume holographic memory  

Microsoft Academic Search

In this paper, we describe an image recognition system using a multi-channel optical correlator as the computational element and a volume holographic memory as a template database. By recording the holographic matched filters in the disk-type Ce:Fe:LiNbO3 crystal, the multi-channel optical correlator is constructed. The system performs the multi-category pattern recognition. Experimental results are presented and discussed.

Dayong Wang; Yan Zhou; Shiquan Tao; Baoshen Li; Quan Yuan; Zhuqing Jiang

1998-01-01

24

Rotation-invariant volume holographic correlator by combining the synthetic discriminant function and wavelet filtering  

Microsoft Academic Search

In this paper, it is proposed to record the matched filter in the photorefractive crystal by using the synthetic discriminant function as the input. The synthetic discriminant function is generated by training a set of rotated object images. Multiple matched filters are stored by angle-multiplexing in the same volume. Due to the large difference among the optical throughouts of the

Dayong Wang; Shengtong Feng; Zhuqing Jiang; Shiquan Tao

2006-01-01

25

Wavelet packet compression for volume holographic image recognition  

Microsoft Academic Search

An optical image recognition system based on the mechanism of crystal volume holography and wavelet packet compression method is proposed and constructed. Volume holographic associative storage in a photo-refractive crystal has some special properties, which can provide a suitable mechanism to develop an optical correlation system for image recognition. The method of wavelet packet is introduced in this optical system

Li Ding; Yingbai Yan; Qingzeng Xue; Guofan Jin

2003-01-01

26

Volume holographic image recognition system based on wavelet packet compression  

Microsoft Academic Search

In this paper, a novel optical correlation system on the basis of wavelet packet theory and the mechanism of volume holographic associative storage is proposed for image recognition. Through the wavelet packet transform, a set of best eigen-images, which are regarded as the reference images for recognition in the associative correlation, are extracted from the training images, and then stored

Li Ding; Yingbai Yan; Guofan Jin

2001-01-01

27

Volume holographic imaging with broadband illumination  

NASA Astrophysics Data System (ADS)

In this paper the imaging properties of volume holographic gratings with different illumination sources are investigated. In the experiments, the recording material is a 2-mm-thick LiNbO3: Fe: Cu crystal in which a volume hologram is recorded by two recording beams interfering at the wavelength of 532 nm. The grating recorded at wavelength of 532 nm can be Bragg matched at another wavelength of 640 nm by using a different reconstruction angle. The depth resolution of the volume holographic imaging system at the wavelength 640 nm is obtained experimentally, which is in accordance with the theoretical value. The volume holographic imaging with a white light is also conducted in the experiment. The result shows that more lateral information about the object can be obtained according to the Bragg degeneracy.

Wu, Jiangtao; Jiang, Zhuqing; Song, Lei; Wang, Yujia; Tao, Shiquan

2011-06-01

28

Volume holographic image recognition based on best wavelet packet basis selection  

Microsoft Academic Search

An optical image recognition system based on the mechanism of volume holographic storage and best wavelet packet basis selection is proposed and constructed. Volume holographic associative storage in a photo-refractive crystal has some special properties, which can provide a suitable mechanism to develop an optical correlation system for image recognition. Wavelet packet theory is introduced in this optical system to

Yingbai Yan; Li Ding

2003-01-01

29

Parallelism and discrimination enhancement of volume-holographic image processing system  

Microsoft Academic Search

A multichannel wavelet correlator is proposed and constructed in this paper, which is based on wavelet transform and mechanism of angle multiplexed volume holographic associative storage in a photorefractive crystal. Problems to enhance parallelism and discrimination of the volume holographic image processing system are studied. The cross-talk noise of the system is analyzed by simulation. Our results show that the

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

1999-01-01

30

Optical properties of nonlinear volume holographic elements  

Microsoft Academic Search

In this talk we will discuss the optical properties of volume holographic elements whose index of refraction is intensity dependent. For the elements that we have investigated the index modulation is intensity dependent and hence the diffraction efficiency can be optically controlled. Polaroid Corporation's DMP-128 photopolymer was used to form the host gratings. These gratings were filled with the nematic

M. S. Malcuit; C. Heid; T. W. Stone

1995-01-01

31

Volume holographic narrow-band optical filter.  

PubMed

An 0.0125-nm (FWHM) bandwidth optical filter with >10% throughput, clean sidebands, f/12 speed, and a response roll-off of -40 dB/decade has been developed by using volume holography in photorefractive materials. The performance of the Accuwave holographic filter is characterized and compared with that of a Lyot filter, which is the standard for solar astronomy today. Moreover, this device represents the first commercial application of volume holography in photorefractive crystals. PMID:19802168

Rakuljic, G A; Leyva, V

1993-03-15

32

Volume holographic imaging with broadband illumination  

Microsoft Academic Search

In this paper the imaging properties of volume holographic gratings with different illumination sources are investigated. In the experiments, the recording material is a 2-mm-thick LiNbO3: Fe: Cu crystal in which a volume hologram is recorded by two recording beams interfering at the wavelength of 532 nm. The grating recorded at wavelength of 532 nm can be Bragg matched at

Jiangtao Wu; Zhuqing Jiang; Lei Song; Yujia Wang; Shiquan Tao

2011-01-01

33

Sensitivity of volume holographic optical computing  

NASA Astrophysics Data System (ADS)

Volume holographic correlator (VHC) calculates the inner product between two data pages through parallel optical correlation. It has great potential in the field of information processing and real-time identification because of its high storage density, integration of storing and computing, and multi-channel parallel processing ability. Current studies on the improvements of VHC mainly focus on the processing speed and channel uniformity. However, the accuracy of the VHC is mainly related to the minimum output intensity varying with the spatial light modulator (SLM) pixel intensity, which is the sensitivity of the VHC. In this work, the Minimum Pixel Block Size (MPBS) is proposed to characterize the sensitivity of the VHC. The Effective Number of Pixels (ENP) is employed to evaluate the optical computing ability, which is more accurate compared with traditional calculating method based on the pixel number of the SLM. The theoretical and experimental results are instructive in the system design. Desired system performance can be achieved by optimizing the system parameters.

Yi, Yao; Cao, Liang-cai; Zheng, Tian-xiang; Guo, Wei; He, Qing-sheng; Jin, Guo-fan

2013-08-01

34

Volume holographic narrow-band optical filter  

Microsoft Academic Search

An 0.0125-nm (FWHM) bandwidth optical filter with greater than 10 percent throughput, clean sidebands, f\\/12 speed, and a response roll-off of -40 dB\\/decade has been developed by using volume holography in photorefractive materials. The performance of the Accuwave holographic filter is characterized and compared with that of a Lyot filter, which is the standard for solar astronomy today. Moreover, this

George A. Rakuljic; Victor Leyva

1993-01-01

35

Laser threat discrimination based on volume holographic memory  

Microsoft Academic Search

Volume holographic memory offers a compact means of information storage through angle and wavelength multiplexing in three dimensions. As laser warning systems often use both angle-of-arrival and wavelength information in order to identify and\\/or discriminate among laser threats, volume holographic memory structures are ideally suited for consideration as laser warning receiver sensors. Holographic imaging in volume phase media is examined

Mark L. DeLong; Bradley D. Duncan

1995-01-01

36

Applications of Volume Holographic Optical Elements  

NASA Astrophysics Data System (ADS)

Volume holographic optical elements (VHOEs) can be used to perform most functions of classical optical elements and have a number of advantages over classical optics. In this dissertation, characteristics of dichromated gelatin (DCG) for VHOEs, and their applications in magneto -optic (MO) head systems, phase retardation elements, and computer backplane optical interconnects will be presented. One of the most important volume holographic recording materials is DCG. The fabrication technique, hologram formation mechanism and environmental stability of DCG film are presented. The important parameters in designing VHOEs are the bias refractive index, the refractive index modulation, and the emulsion shrinkage or swelling factor; characteristics of these parameters are discussed. A holographic leaky beam splitter and polarization beam splitter are designed and fabricated using DCG to replace the bulk optical elements in MO head systems. The form birefringence properties of the 0th order diffracted beam through subwavelength period gratings are investigated using effective medium theory and rigorous coupled wave analysis. A quarterwave phase retardation element formed in a DCG emulsion is demonstrated. Multiplexed gratings are analyzed and implemented in a 1 x 3 fan-out element for an optical connection cube. A four-port interconnect system has been built using this connection cube and tested at 500 MHz. Alignment tolerances and packaging issues for this connection scheme are also discussed.

Kim, Tae Jin

1995-01-01

37

Holographic 3-D disks and optical correlators using photopolymer materials  

NASA Astrophysics Data System (ADS)

This thesis presents an experimentalist's approach to data storage and information processing using volume holography. In Chapter 1, a short introduction in volume holography and some commonly used recording materials are presented. Chapter 2 discusses in detail a specific recording material, the DuPont photopolymer. The recording behavior of the DuPont photopolymer was fully characterized by using a new multiplexing method called peristrophic multiplexing. From its recording behavior, we were able to derive an exposure schedule to multiplex equal strength holograms in the same volume. This method of determining the exposure schedule was put to the test by multiplexing 1,000 holograms in a piece of photopolymer that is only 100 microns thick. One of the goals of this thesis is to demonstrate that information can be stored much more densely using holography. In Chapter 3, results from several different high density holographic data storage experiments are presented. In one experiment, a surface density of 100 bits//mu m2 was achieved. That is approximately two orders of magnitude higher than the compact discs we use today. Holography can also be used to process a vast amount of information very quickly through the parallel nature of optics. Chapter 4 shows how optical correlator systems, using a holographic database, can be trained to perform complex tasks. By programming the holographic database appropriately, we have used optical correlator systems to navigate an autonomous vehicle, to recognize/track a target, and to identify users through sequential fingerprint inputs.

Pu, Allen

38

Improved multiplexing density in volume holographic memories through beam apodization  

Microsoft Academic Search

Volume holographic memories (VHM) achieve large storage capacities by multiplexing many holographic data pages in a small volume. On retrieval, a reference beam addresses the optical memory reconstructing the desired hologram with a large diffraction efficiency. In addition, all the other multiplexed holograms also reconstruct at a very low diffraction efficiency as determined by the Bragg selectivity function (BSF) of

Brian M. King; Mark A. Neifeld; Xuewen Chen

2000-01-01

39

Correlation functions in the holographic replica method  

NASA Astrophysics Data System (ADS)

Disorder has long been a difficult subject in condensed matter systems and the The replica method is a well-known tool in this field. Implementing the replica method the AdS/CFT correspondence has been proposed and discussed in literatures. We point out, for any CFT that has a holographic dual and to the leading order of the large- N expansion, the corrections due to the presence of random disorder to any connected correlation functions vanish identically, provided that the disorder strength is normalized as discussed in literatures and that the symmetry among replicas is unbroken. Same must hold true to any observables that are determined by the connected correlation functions through a linear relation. This behavior resembles strongly that of a free theory where disorder is coupled to the fundamental field. We demonstrate this by both the means of holographic principle and field theory analysis in a toy model. We also propose ways of evaluating the non-zero sub-leading effects perturbatively in terms of the disorder strength and discuss a novel possibility of defining a new holographic dual if we adopt a different normalization for the disorder strength.

Shang, Yanwen

2012-12-01

40

Volume holographic quarter-wave plate  

NASA Astrophysics Data System (ADS)

It is well known that gratings with high spatial frequency (spacings volume holographic quarterwave plate formed in DCG operating at 632.8 nm. To our knowledge this is the first demonstration of a retardation plate exhibiting this magnitude of phase delay in a volume material. The fabrication techniques required to realize this element are also presented.

Kim, Tae-Jin; Campbell, Eugene W.; Kostuk, Raymond K.

1995-09-01

41

Volume holographic storage using polarization multiplexing  

Microsoft Academic Search

We propose a new holographic multiplexing technique in LiNbO3 with 90° geometry. The advanced concept of polarization-multiplexed holographic memory is based on photorefractive effect and photovoltaic effect. The holographic gratings are constructed in the crystal using two writing beams with isotropic and anisotropic polarizaiton recording. Even mutually orthogonal polarized waves can be used in holographic storage. The polarization multiplexing technique

Wei-Chia Su; Shih-Hsin Ma; Ching-Cherng Sun; Arthur E. T. Chiou; Nicholai V. Kukhtarev

2003-01-01

42

Performance of a volume holographic wavelet packet compression image recognition system  

Microsoft Academic Search

Volume holographic associative storage in a photorefractive crystal has some special properties such as multichannal operation, parallel processing, and real-time response. It can provide a suitable mechanism to develop an optical correlation system for image recognition. In this paper, a practical image recognition system based on such mechanism is proposed and constructed. Wavelet packet theory is introduced in this system

Li Ding; Yingbai Yan; Guofan Jin

2001-01-01

43

Filter characteristics of a chirped volume holographic grating  

Microsoft Academic Search

We compare and analyze the filter properties of transmission-type volume holographic gratings, especially the dispersion characteristics for uniform and chirped gratings. It is theoretically and experimentally shown that the dispersion characteristics can be controlled by introducing one-dimensional chirping to the volume grating in a photorefractive crystal. The filter response including output power and dispersion comes from a combined effect of

Seunghoon Han; Bong-Ahn Yu; Seunghwan Chung; Hwi Kim; Jungwook Paek; Byoungho Lee

2004-01-01

44

Volume Holographic Storage Using the 90DEGREE Geometry  

Microsoft Academic Search

Volume holographic data storage involves the superposition and independent recall of multiple pages of data within the same volume of a storage medium. These pages, stored as separate holograms, can be accessed by changing the angle of the reference laser beam used to store and retrieve them. Because data is read out in parallel, the output data rate can be

Geoffrey W. Burr

1996-01-01

45

Vertical angular selectivity and grating degeneracy of volume holographic gratings  

Microsoft Academic Search

The vertical angular selectivity of volume holographic gratings in photorefractive crystals is investigated both theoretically and experimentally. The vertical selective angle and the shape of the grating degeneracy lines are derived by using a simplified geometrical model relating the k-vector sphere to the reference point plane. The study shows that volume gratings have finite selectivity in vertical direction, so that

Quan Yuan; Shiquan Tao; Zuqing Jiang; Xinchang Yang

1996-01-01

46

All-optical nonlinear holographic correlation using bacteriorhodopsin films  

Microsoft Academic Search

Films made of the halobacterial photochrome bacteriorhodopsin (BR) can be used in a number of holographic real-time applications. Their application as active material in a dual-axis joint- Fourier-transform (DAJFT) real-time correlator was shown recently. The BR films have a strong nonlinear intensity dependence on the light-induced absorption and refractive-index changes. Therefore the holographic diffraction efficiency also shows a nonlinear dependence

Ralph Thoma; Michael Dratz; Norbert Hampp

1995-01-01

47

Stereoscopic Display Based on a Volume Holographic Storage  

NASA Astrophysics Data System (ADS)

We present a stereoscopic display system using a volume hologram. The stereoscopic image pairs are recorded into a volume holographic memory with a reference beam. Multiple stereoscopic image pair holograms within common volume is possible using angular multiplexing. The reference beam with Bragg matching condition is scattered by the index grating and the diffracted beams are propagating along the directions of the stereoscopic image pairs. The images are to be suitably projected on the left and right display plane for stereoscopic viewing.

Lee, Seung-Hyun; Kim, Eun-Soo

1998-10-01

48

Pulse shaping properties of volume holographic gratings in anisotropic media  

Microsoft Academic Search

Based on a modified coupled wave theory, the pulse shaping properties of volume holographic gratings (VHGs) in anisotropic media VHGs are studied systematically. Taking photorefractive LiNbO3 crystals as an example, the combined effect that the grating parameters, the dispersion and optical anisotropy of the crystal, the pulse width, and the polarization state of the input ultrashort pulsed beam (UPB) have

Chunhua Wang; Liren Liu; Aimin Yan; Dean Liu; Dashan Li; Weijuan Qu

2006-01-01

49

Angle amplifier based on multiplexed volume holographic gratings  

Microsoft Academic Search

Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of

Liangcai Cao; Yifei Zhao; Qingsheng He; Guofan Jin

2008-01-01

50

Volume holographic storage demonstrator based on phase-coded multiplexing  

Microsoft Academic Search

We present the design and realization of a compact volume holographic memory based on phase-coded multiplexing. Due to the use of nonmechanical reference beam changes in this multiplexing technique, rapid access of the stored data pages is achieved. Our system can reach a maximum storage capacity up to 480 data pages with a resolution of 640×480 pixels in a single

Cornelia Denz; K.-O. Muller; T. Heimann; T. Tschudi

1998-01-01

51

Improved associative recall of binary data in volume holographic memories  

Microsoft Academic Search

A new technique is presented that improves the results of associative recall in a volume holographic memory system. A background is added to the normal search argument to increase the amount of optical power that is used to reconstruct the reference beams in the crystal. This is combined with post-processing of the captured image of the reference beams. The use

Alexandre Laisné; Pericles A. Mitkas

1999-01-01

52

Irregular Repeat-Accumulate Codes for Volume Holographic Memory Systems  

NASA Astrophysics Data System (ADS)

We investigate the application of irregular repeat-accumulate (IRA) codes in volume holographic memory (VHM) systems. We introduce methodologies to design efficient IRA codes. We show that a judiciously designed IRA code for a typical VHM can be as good as the optimized irregular low-density-parity-check codes while having the additional advantage of lower encoding complexity. Moreover, we present a method to reduce the error-floor effect of the IRA codes in the VHM systems. This method explores the structure of the noise pattern in holographic memories. Finally, we explain why IRA codes are good candidates for the VHM systems.

Pishro-Nik, Hossein; Fekri, Faramarz

2004-09-01

53

Invariant correlation filter with linear phase coefficient holographic realization in 4-F correlator  

NASA Astrophysics Data System (ADS)

Realization of distortion invariant correlation filters in optical image correlators open possibilities for object identification with remarkably high computational capabilities. Application of the linear phase coefficient composite filter (LPCCF) is attractive for recognition of binary edged images. We use methods of digital holographic synthesis to realize LPCCF in a coherent 4-F correlator as a computer-generated amplitude holographic filter. A high resolution spatial light modulator (SLM) has to be implemented for such a filter representation. Transparency limitations of high frame rate and high resolution SLM's and its effect on recognition performance of holographic filter in the 4-F correlator are discussed in the given paper.

Evtikhiev, Nickolay N.; Starikov, Sergey N.; Shaulskiy, Dmitriy V.; Starikov, Rostislav S.; Zlokazov, Evgeny Yu.

2011-06-01

54

Translation-invariant object recognition system using an optical correlator and a super-parallel holographic random access memory  

NASA Astrophysics Data System (ADS)

We demonstrate a translation-invariant VanderLugt correlator (VLC) for a set of images stored via holographic angle multiplexing of volume gratings in a polymeric substrate. The images read out from the volume gratings are optically correlated in a translation-invariant manner with a dc-suppressed holographic filter. The quality and efficiency of this correlator are observed to be nearly as good as that of another VLC with images directly from a spatial light modulator used as inputs. This experiment is the first step toward realizing a novel optical image recognition system capable of identifying a query image through an exhaustive search in a large database of filter images stored in an ultrahigh capacity superparallel holographic random access memory (SPHRAM). In this system, the identification of the query image is to be performed with a translation invariant, real-time VLC or a joint transform correlator (JTC).

Heifetz, Alexander; Shen, John T.; Lee, Jong-Kwon; Tripathi, Renu; Shahriar, M. S.

2006-02-01

55

Volume Holographic Storage of Digital Data Implemented in Photorefractive Media  

NASA Astrophysics Data System (ADS)

A holographic data storage system is fundamentally different from conventional storage devices. Information is recorded in a volume, rather than on a two-dimensional surface. Data is transferred in parallel, on a page-by -page basis, rather than serially. These properties, combined with a limited need for mechanical motion, lead to the potential for a storage system with high capacity, fast transfer rate, and short access time. The majority of previous volume holographic storage experiments have involved direct storage and retrieval of pictorial information. Success in the development of a practical holographic storage device requires an understanding of the performance capabilities of a digital system. This thesis presents a number of contributions toward this goal. A description of light diffraction from volume gratings is given. The results are used as the basis for a theoretical and numerical analysis of interpage crosstalk in both angular and wavelength multiplexed holographic storage. An analysis of photorefractive grating formation in photovoltaic media such as lithium niobate is presented along with steady-state expressions for the space-charge field in thermal fixing. Thermal fixing by room temperature recording followed by ion compensation at elevated temperatures is compared to simultaneous recording and compensation at high temperature. In particular, the tradeoff between diffraction efficiency and incomplete Bragg matching is evaluated. An experimental investigation of orthogonal phase code multiplexing is described. Two unique capabilities, the ability to perform arithmetic operations on stored data pages optically, rather than electronically, and encrypted data storage, are demonstrated. A comparison of digital signal representations, or channel codes, is carried out. The codes are compared in terms of bit-error rate performance at constant capacity. A well-known one-dimensional digital detection technique, maximum likelihood sequence estimation, is extended for use in a two-dimensional page format memory. The effectiveness of the technique in a system corrupted by intersymbol interference is investigated both experimentally and through numerical simulations. The experimental implementation of a fully-automated multiple page digital holographic storage system is described. Finally, projections of the performance limits of holographic data storage are made taking into account typical noise sources.

Heanue, John Frederick

56

Stereoscopic viewer using a volume holographic memory  

Microsoft Academic Search

We present a stereoscopic vision system that the stereoscopic images pairs are recorded into a volume hologram. If the two stereoscopic image pairs and a reference beam are of the same wavelength, a stationary interference pattern in s formed in a volume hologram. When the reference beam are of the same wavelength, a stationary interference pattern is formed in a

Seung-Hyun Lee; Eun-Soo Kim

1999-01-01

57

Space-Charge Fields in Photorefractive Crystals for Volume Holographic Interconnections  

Microsoft Academic Search

In this dissertation, the space-charge fields in photorefractive crystals due to the illumination of light interference patterns have been analyzed for volume holographic interconnections. Volume holograms stored in a three-dimensional medium such as a photorefractive crystal is considered as a promising candidate for the implementation of neural network. This volume holographic interconnection scheme has a potential for a dramatic increase

Woon Sik Baek

1991-01-01

58

Simulation and optimization of volume holographic imaging systems in Zemax.  

PubMed

We present a new methodology for ray-tracing analysis of volume holographic imaging (VHI) systems. Using the k-sphere formulation, we apply geometrical relationships to describe the volumetric diffraction effects imposed on rays passing through a volume hologram. We explain the k-sphere formulation in conjunction with ray tracing process and describe its implementation in a Zemax UDS (User Defined Surface). We conclude with examples of simulation and optimization results and show proof of consistency and usefulness of the proposed model. PMID:18545457

Wissmann, Patrick; Oh, Se Baek; Barbastathis, George

2008-05-12

59

Stereoscopic viewer using a volume holographic memory  

NASA Astrophysics Data System (ADS)

We present a stereoscopic vision system that the stereoscopic images pairs are recorded into a volume hologram. If the two stereoscopic image pairs and a reference beam are of the same wavelength, a stationary interference pattern in s formed in a volume hologram. When the reference beam are of the same wavelength, a stationary interference pattern is formed in a volume hologram. When the reference beam with Bragg matching condition is illuminated for reconstruction, stereoscopic images are suitably projected on the left and right display p;lane for stereoscopic viewing. We present experimental results of stereoscopic pairs recording and reading with a 45 degree cut Fe: LiNbO3 crystal.

Lee, Seung-Hyun; Kim, Eun-Soo

1999-05-01

60

Volume photorefractive optical interconnect elements for wavelength division multiplexing and volume holographic storage applications  

Microsoft Academic Search

Volume photorefractive optical interconnect elements (V- POIEs) which operate at approximately 850 nm are being designed for integration into a low power, optoelectronic integrated circuit architecture. When a tunable laser is integrated with the V-POIE crystal, a photonic random optical memory access system may be developed for wavelength division multiplexing and volume holographic storage applications. The insertion of V-POIE technology

Peter S. Guilfoyle; John M. Hessenbruch

1998-01-01

61

Volume holographic interconnection using random phase encoding  

Microsoft Academic Search

Optical interconnections based on random phase encoding using a ground glass in a volume hologram have been presented. In the system, a crystal plays the role of interconnector, which translates Chinese words into English words. The stimulation results and experimental results of the translation system are demonstrated.

Wei-Chia Su; Ching-Cherng Sun

2002-01-01

62

Effective dynamic range metric of photorefractive crystal for the speckle volume holographic memory  

Microsoft Academic Search

The volume holographic memory in the photorefractive crystal is considered to be an efficient approach for high throughput data storage and retrieval. Among different techniques for data multiplexing, the hologram with speckle reference beam is a potential approach for high-density holographic information storage. However the existing research are mainly focused on the selective properties of volume holograms with speckle reference

Peikun Zhang; Guofan Jin; Qingsheng He; Minxian Wu; Yingbai Yan; Fengtao Wang

2000-01-01

63

Volume holographic recording utilizing photo-initiated polymerization for nonvolatile digital data storage  

Microsoft Academic Search

Volume holographic recording offers an attractive solution for next generation digital storage with high density (>=10 Gb\\/cm 2) and transfer rate (Gb\\/sec). In holographic storage, data is recorded as volume phase gratings (refractive index modulation) in an optical medium. The system performance is practically determined by the physical characteristics of the recording medium. Photorefractive crystals, the most extensively investigated volumetric

Loukas Paraschis

2000-01-01

64

Improved associative recall of binary data in volume holographic memories  

NASA Astrophysics Data System (ADS)

A new technique is presented that improves the results of associative recall in a volume holographic memory system. A background is added to the normal search argument to increase the amount of optical power that is used to reconstruct the reference beams in the crystal. This is combined with post-processing of the captured image of the reference beams. The use of both the background and post-processing greatly improves the results by allowing associative recall using small arguments. In addition, the number of false hits is reduced and misses are virtually eliminated.

Betzos, G. A.; Laisné, A.; Mitkas, P. A.

1999-11-01

65

Aspects of current correlators in holographic theories with hyperscaling violation  

NASA Astrophysics Data System (ADS)

We study the low-energy and low-momentum behavior of current correlators in a class of holographic zero-temperature, finite-density critical theories which do not respect the hyperscaling relation. The dual holographic description is assumed to be given by probe D-branes embedded in background geometries characterized by a dynamical critical exponent z and a hyperscaling violation exponent ?. We show that a subset of these theories with 1?z<2(1-?/d) exhibit a stable, linearly dispersing mode in their low-energy spectrum of excitations. This mode, which appears as a pole in the retarded correlators of charge density and longitudinal currents, has some characteristics similar to that of the zero sound in Fermi liquids. Given some reasonable assumptions, we argue that the class of theories with ?=d-1 that logarithmically violate the area law in the entanglement entropy in a manner reminiscent of theories with Fermi surfaces does not exhibit a zero-sound-like mode in the low-energy spectrum of the probe sector. Furthermore, utilizing the holographic Wilsonian approach, we explicitly show that such a mode has a natural interpretation as a Goldstone boson arising from the spontaneous breaking of a specific symmetry.

Edalati, Mohammad; Pedraza, Juan F.

2013-10-01

66

The Impact of Volume Phase Holographic Filters and Gratings on the Development of Raman Instrumentation  

ERIC Educational Resources Information Center

|Volume phase holographic (VPH) optical elements have made a major contribution to Raman spectroscopy by providing notch filters, and VPH gratings that provide remarkable performance advantages over previous technologies. Holographic notch filters have eliminated Rayleigh scattered laser light from single monochromators, thereby contributing to…

Owen, Harry

2007-01-01

67

Angle amplifier based on multiplexed volume holographic gratings  

NASA Astrophysics Data System (ADS)

Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of the Bragg compensatory relation between angle and wavelength, this device could be recorded at another wavelength. The design of the angle amplifier recording at the wavelength of 514.2nm for the working wavelength of 632.8nm is described. An optical setup for recording the angle amplifier device is designed and discussed. Experimental results in the photorefractive crystal Fe:LiNbO3 demonstrate the feasibility of the angle amplifier scheme.

Cao, Liangcai; Zhao, Yifei; He, Qingsheng; Jin, Guofan

2008-03-01

68

Pulse shaping properties of volume holographic gratings in anisotropic media  

NASA Astrophysics Data System (ADS)

Based on a modified coupled wave theory, the pulse shaping properties of volume holographic gratings (VHGs) in anisotropic media VHGs are studied systematically. Taking photorefractive LiNbO3 crystals as an example, the combined effect that the grating parameters, the dispersion and optical anisotropy of the crystal, the pulse width, and the polarization state of the input ultrashort pulsed beam (UPB) have on the pulse shaping properties are considered when the input UPB with arbitrary polarization state propagates through the VHG. Under the combined effect, the diffraction bandwidth, pulse profiles of the diffracted and transmitted pulsed beams, and the total diffraction efficiency are shown. The studies indicate that the properties of the shaping of the o and e components of the input UPB in the crystal are greatly different; this difference can be used for pulse shaping applications.

Wang, Chunhua; Liu, Liren; Yan, Aimin; Liu, Dean; Li, Dashan; Qu, Weijuan

2006-12-01

69

Pulse shaping properties of volume holographic gratings in anisotropic media.  

PubMed

Based on a modified coupled wave theory, the pulse shaping properties of volume holographic gratings (VHGs) in anisotropic media VHGs are studied systematically. Taking photorefractive LiNbO(3) crystals as an example, the combined effect that the grating parameters, the dispersion and optical anisotropy of the crystal, the pulse width, and the polarization state of the input ultrashort pulsed beam (UPB) have on the pulse shaping properties are considered when the input UPB with arbitrary polarization state propagates through the VHG. Under the combined effect, the diffraction bandwidth, pulse profiles of the diffracted and transmitted pulsed beams, and the total diffraction efficiency are shown. The studies indicate that the properties of the shaping of the o and e components of the input UPB in the crystal are greatly different; this difference can be used for pulse shaping applications. PMID:17106475

Wang, Chunhua; Liu, Liren; Yan, Aimin; Liu, Dean; Li, Dashan; Qu, Weijuan

2006-12-01

70

Volume Holographic Filter at 1.55 mum in Near-Stoichiometric Lithium Niobate  

Microsoft Academic Search

A volume holographic filter operating in the reflection geometry at communication wavelengths was demonstrated in oxidized Fe-doped near-stoichiometric lithium niobate crystals, and the designed filter showed a narrow bandwidth of less than 0.2 nm and an express loss of more than 20 dB. An array of volume holographic filters was constructed in the same crystal with central wavelength separation of

Youwen Liu; Kenji Kitamura; Shunji Takekawa; Masaru Nakamura; Hideki Hatano

2006-01-01

71

High-density nonvolatile volume holographic disc storage  

Microsoft Academic Search

The batch-thermal fixing scheme was combined into holographic disk storage, for the first time to our knowledge, yielding to a track-division thermal fixing scheme (TDTF), in order to increase the storage density and overcome the volatility of the holographic memories. As a specific batch-thermal fixing scheme, the concept of TDTF scheme was described in this paper. Three principal holographic time-constants

Yuhong Wan; Ye Wang; Zhuqing Jiang; Guoqing Liu; Dayong Wang; Shiquan Tao

2004-01-01

72

Multiquark Correlations in Light Mesons and Baryons from holographic QCD  

SciTech Connect

A hadron's multiquark content reflects itself in the quark composition of the interpolator with which it has maximal overlap. The AdS/CFT dictionary translates the anomalous dimension of this interpolator into a mass correction for the corresponding dual mode. Hence such bulk-mass corrections can carry specific information on multiquark correlations. Two prominent examples are studied by implementing this robust and universal holographic mechanism into AdS/QCD gravity duals. In the baryon sector bulk-mass corrections are used to describe systematic good (i.e. maximally attractive) diquark effects. The baryon sizes are predicted to decrease with increasing good-diquark content, and the masses of all 48 observed light-quark baryon states are reproduced with unprecedented accuracy. Our approach further provides the first holographic description of a dominant tetraquark component in the lowest-lying scalar mesons. The tetraquark ground state emerges naturally as the lightest scalar nonet whereas higher excitations become heavier than their quark--antiquark counterparts and are thus likely to dissolve into the multiparticle continuum.

Forkel, Hilmar [Institut fuer Physik, Humboldt-Universitaet zu Berlin, D-12489 Berlin (Germany)

2011-10-21

73

Ultra-high resolution and compact volume holographic spectrometers  

NASA Astrophysics Data System (ADS)

Compact and efficient spectrometers are of great interest for biological and environmental sensing. In this paper, we describe a new class of spectrometers that work based on diffractive properties of spherical beam volume holograms (SBVHs) and cylindrical beam volume holograms (CBVHs). The hologram in these spectrometers acts as a spectral diversity filter (SDF) that maps different input wavelengths onto different locations in the output plane. The main properties of these holographic SDFs and new techniques for removing the ambiguity between incident wavelength (or the input channel) and incident angle (or the input spatial mode) are discussed. By using CBVHs, we show that the spectral mapping of the input beam can be obtained in one direction and the beam can be independently modified in the perpendicular direction. Using this unique property, we demonstrate a spectral wrapping technique to considerably increase the operation spectral range of spectrometers, without sacrificing their resolution. Finally, it is also shown that by combining CBVHs with a Fabry-Perot interferometer, a true two-dimensional spatial-spectral mapping can be formed, and an ultra-high resolution of 0.2 nm with large spectral bandwidth is demonstrated for this tandem spectrometer.

Adibi, Ali; Hsieh, Chaoray; Momtahan, Omid; Badieirostami, Majid

2008-03-01

74

Volume holographic storage in photorefractives: material peculiarities and memory performances  

Microsoft Academic Search

In this paper we review the currently achievable performances of holographic memories stored in photorefractive crystals. We discuss the dependence of the memory performances on the material peculiarities in three major aspects: storage capacity, data transfer rate,and image fidelity. In the recent years the research at Beijing Polytechnic University on the photorefractive holographic storage has been focused to the optimization

Shiquan Tao

1998-01-01

75

Volume holographic wavelength demultiplexer based on rotation multiplexing in the \\/90° geometry  

Microsoft Academic Search

A novel photorefractive wavelength demultiplexing scheme for optical communications and spectroscopy applications has been proposed and experimentally demonstrated for the first time, by using the narrowband filtering and demultiplexing properties of volume holographic gratings formed in LiNbO3:Fe crystal. The holographic gratings are superimposed in the crystal with rotation multiplexing in the 90\\/° geometry. In this scheme, the center wavelength and

J.-W. An; N. Kim; K.-W. Lee

2001-01-01

76

Volume holographic wavelength demultiplexer based on rotation multiplexing in the 90° geometry  

Microsoft Academic Search

A novel photorefractive wavelength demultiplexing scheme for optical communications and spectroscopy applications has been proposed and experimentally demonstrated for the first time, by using the narrowband filtering and demultiplexing properties of volume holographic gratings formed in LiNbO3:Fe crystal. The holographic gratings are superimposed in the crystal with rotation multiplexing in the 90° geometry. In this scheme, the center wavelength and

J.-W An; N Kim; K.-W Lee

2001-01-01

77

Phase aberration correction by correlation in digital holographic adaptive optics  

PubMed Central

We present a phase aberration correction method based on the correlation between the complex full-field and guide-star holograms in the context of digital holographic adaptive optics (DHAO). Removal of a global quadratic phase term before the correlation operation plays an important role in the correction. Correlation operation can remove the phase aberration at the entrance pupil plane and automatically refocus the corrected optical field. Except for the assumption that most aberrations lie at or close to the entrance pupil, the presented method does not impose any other constraints on the optical systems. Thus, it greatly enhances the flexibility of the optical design for DHAO systems in vision science and microscopy. Theoretical studies show that the previously proposed Fourier transform DHAO (FTDHAO) is just a special case of this general correction method, where the global quadratic phase term and a defocus term disappear. Hence, this correction method realizes the generalization of FTDHAO into arbitrary DHAO systems. The effectiveness and robustness of this method are demonstrated by simulations and experiments.

Liu, Changgeng; Yu, Xiao; Kim, Myung K.

2013-01-01

78

Volume holographic phase conjugation through a sub-wavelength hole  

Microsoft Academic Search

Holographic phase conjugation is used to focus light onto sub-wavelength holes in a gold film directly on top of a photorefractive lithium niobate crystal. This could lead to a high-numerical-aperture-focusing system.

F. Kalkum; S. Broch; K. Buse

2008-01-01

79

SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Optical neural networks based on holographic correlators  

NASA Astrophysics Data System (ADS)

The three most important models of neural networks — a bidirectional associative memory, Hopfield networks, and adaptive resonance networks — are used as examples to show that a holographic correlator has its place in the neural computing paradigm.

Sokolov, V. K.; Shubnikov, E. I.

1995-10-01

80

Hierarchical volume gratings by combining holographic-patterning and block copolymer self-assembly  

NASA Astrophysics Data System (ADS)

A novel hierarchical photonic crystal (HPC) was fabricated by combining top-down and bottom-up nanomanufacturing techniques. The hierarchical structure was fabricated from a volume of material by combining holographic patterning (HP) and block copolymer (BCP) self assembly. The structure of the HPC was investigated as a function of the BCP architecture, BCP concentration and crystallization temperature. Upon heating the photonic crystal a red shift in the reflected wavelength occurs; but, an initial decrease in diffraction efficiency (DE) followed by an increase in DE indicates a non-monotonic change in the structure of the HPC. Upon cooling the reverse occurs reflecting the dynamic change in the hierarchical structure. Transmission electron microscopy, in-situ FTIR and optical spectroscopy were used to correlate the optical property change with BCP/HPC morphology. This approach could open a gateway to fabricating multifunctional hierarchical nanostructures.

Birnkrant, Michael; Marron, Russell; Li, Christopher; Natarajan, Lalgudi; Tondiglia, Vincent; Bunning, Timothy

2009-03-01

81

Characteristics of reflected holographic volume gratings in photosensitive-refractive glass  

Microsoft Academic Search

Holographic volume gratings as diffractive elements have much practical and more potential applications, such as spatial filters, attenuators, modulators, imaging lenses and so on. The reflection volume gratings have more higher wavelength selectivity than transmission gratings and is more suitable for spectral selectors. A type of photosensitive-refractive glass, silicate glass doped with silver, cerium, fluorine, and bromine, was fabricated at

Lin Lin; Yuhong Wan; Guoqing Liu; Maoluan Ding; Shiquan Tao

2010-01-01

82

Beam-width-dependent filtering properties of strong volume holographic gratings  

Microsoft Academic Search

The finite dimension of the incident beam used to read out volume holographic gratings has interesting effects on their filtering properties. As the readout beam gets narrower, there is more deviation from the ideal response predicted for monochromatic plane waves. In this paper we experimentally explore beam-width-dependent phenomena such as wavelength selectivities, angular selectivities, and diffracted beam profiles. Volume gratings

Hung-Te Hsieh; Wenhai Liu; Frank Havermeyer; Christophe Moser; Demetri Psaltis

2006-01-01

83

Design of cascaded volume holographic gratings to increase the number of channels for an optical demultiplexer.  

PubMed

The design and demonstration of a holographic optical demultiplexer based on cascaded volume holographic gratings are presented. By serially adding a second holographic grating, which has a different grating period, slant angle, and center wavelength compared with those of the first grating, the operating wavelength range of the optical demultiplexer could be expanded, and, therefore, the number of channels of the holographic demultiplexer is doubled. As a result of the experiment, a 0.4 nm spaced 130- channel demultiplexer with a channel uniformity of 3.5 dB, a 3 dB bandwidth of 0.12 nm, and channel cross talk of -20 dB is experimentally achieved. PMID:17119567

Do, Duc Dung; Kim, Nam; Han, Tae Young; An, Jun Won; Lee, Kwon Yeon

2006-12-01

84

Holographic dark energy: Quantum correlations against thermodynamical description  

NASA Astrophysics Data System (ADS)

Classical and quantum entropic properties of holographic dark energy (HDE) are considered in view of the fact that its entropy is far more restrictive than the entropy of a black hole of the same size. In cosmological settings (in which HDE is promoted to a plausible candidate for being the dark energy of the universe), HDE should be viewed as a combined state composed of the event horizon and the stuff inside the horizon. By any interaction of the subsystems, the horizon and the interior become entangled, raising thereby a possibility that their quantum correlations be responsible for the almost purity of the combined state. Under this circumstances, the entanglement entropy is almost the same for both subsystems, being also of the same order as the thermal (coarse grained) entropy of the interior or the horizon. In the context of thermodynamics, however, only additive coarse grained entropies matter, so we use these entropies to test the generalized second law (GSL) of gravitational thermodynamics in this framework. While we find that the original Li's model passes the GSL test for a special choice of parameters, in a saturated model with the choice for the IR cutoff in the form of the Hubble parameter, the GSL always breaks down.

Horvat, R.

2008-06-01

85

Effect of recording conditions on the anisotropic diffraction of volume holographic gratings  

NASA Astrophysics Data System (ADS)

The anisotropic Bragg diffraction of the volume holographic gratings in photorefractive crystals are investigated based on the model of anisotropic coupled-wave theory. The effect of the initial intensity ratio and the recording angles of the two recording waves on the anisotropic Bragg diffraction properties is discussed. It is shown that both the ratio of the initial intensity and the incident angles of the recording waves are selective action for the anisotropic Bragg diffraction efficiency of the volume holographic gratings, while these two recording conditions are not selective action for the isotropic Bragg diffraction. Furthermore, the Bragg phase matching condition of anisotropic diffraction is analyzed when the recording angles change.

Wang, Xin; Yan, Aimin; Liu, De'an; Liu, Liren; Hu, Zhijuan

2007-08-01

86

Position feedback system for volume holographic storage media  

Microsoft Academic Search

A method of holographic recording in a photorefractive medium wherein stored holograms may be retrieved with maximum signal-to noise ratio (SNR) is disclosed. A plurality of servo blocks containing position feedback information is recorded in the crystal and made non-erasable by heating the crystal. The servo blocks are recorded at specific increments, either angular or frequency, depending whether wavelength or

Nathan J. Hays; James A. Henson; Christopher M. Carpenter; Jr.. William R. Akin; Richard M. Ehrlich; Lance D. Beazley

1998-01-01

87

Volume Holographic Storage and Retrieval of Digital Data  

Microsoft Academic Search

A multiple page fully digital holographic data storage system is demonstrated. This system is used to store and retrieve digital image and compressed video data with a photorefractive crystal. Architecture issues related to spatio-rotational multiplexing and novel error-correcting encoding techniques used to achieve low bit-error rates are discussed.

John F. Heanue; Matthew C. Bashaw; Lambertus Hesselink

1994-01-01

88

Phase volume holographic optical components for high-brightness single-LCD projectors  

NASA Astrophysics Data System (ADS)

Projection systems based on liquid-crystal displays (LCD s) offer new opportunities to display high-definition and large-size TV images. There are two types of LCD projector architectures: the 3-LCD architecture uses one LCD for each primary color, red, green, and blue, whereas a single-LCD configuration employs only one LCD paved with color filters. The single-LCD projector is simple and compact but suffers from a poor luminous efficiency because of losses in the color filters: each filter transmits only 1 3 of the flux emitted by the lamp. To increase this optical efficiency, we propose to introduce volume holographic elements in the architecture of a single-LCD projector. Innovative systems are presented in which volume holographic elements realize the spatiochromatic illumination of the LCD. This illumination consists of selectively directing all the light that corresponds to a primary color, red, green, or blue, in the pixel addressed with the corresponding video composite signal and exploits the spectral selectivity and dispersion properties of volume holographic gratings and lenses. The two main advantages of such illumination are the suppression of the color filters and the recovery of the light lost in a classical architecture by absorption of the color filters. A complete luminous efficiency analysis of spatiochromatic illumination with volume holographic elements is presented. The achieved performances are compared with classical single-LCD projectors.

Joubert, C.; Loiseaux, B.; Delboulbé, A.; Huignard, J. P.

1997-07-01

89

1x16 demultiplexer using volume holographic gratings in iron-doped lithium niobate  

Microsoft Academic Search

A novel photorefractive demultiplexer for dense wavelength division multiplexing (DWDM) applications has been experimentally demonstrated for the first time, by using the narrow-band filtering and demultiplexing properties of a volume holographic gratings formed in lithium niobate crystal. For the multiple recording of the 16-wavelength channels with equal diffraction efficiency, the rotation multiplexing and the exposure time schedule are used. The

Jun-Won An; Nam Kim; Kwon-Yeon Lee; Hyun-Jae Lee; Wan-Seok Seo

2000-01-01

90

Associative memory system based on volume holographic storage and wavelet transform  

Microsoft Academic Search

A novel system for associative memory is proposed and constructed in this paper. It is based on the theory of wavelet matched filtering and the associative characteristic of volume holographic storage in a photorefractive crystal. A primary image can be remembered and recovered from its deformed form or main features with the system. The photorefractive crystal in the system stands

Wenyi Feng; Yingbai Yan; Guofan Jin; Minxian Wu; Qingsheng He

1999-01-01

91

Optical properties of beam-steering elements utilizing volume holographic gratings  

Microsoft Academic Search

An optical beam steering element is a device that is used to control the direction in which a beam of light travels. We have investigated the optical properties of two classes of optical beam steering elements. The first type utilized the polarization dependence of the diffraction efficiency of volume holographic gratings. The second type utilized the fact that the diffraction

James Jay Butler

2000-01-01

92

The influence of wavefront of the writing beams on angle Bragg selectivity in volume holographic storage  

Microsoft Academic Search

Angular selectivity of volume grating limits the capacity of holographic 3-dimensional storage. In this work, we investigated experimentally the influence of wavefront shapes of the writing beams on the angular selectivity of thick grating in a LiNbO3 crystal. The experimental results showed that longer wavefront curvature results in more critical Bragg angular selectivity.

Wenqiang Lu; Yudong Li; Jingjun Xu; Qian Sun

2005-01-01

93

Effect of recording conditions on the anisotropic diffraction of volume holographic gratings  

Microsoft Academic Search

The anisotropic Bragg diffraction of the volume holographic gratings in photorefractive crystals are investigated based on the model of anisotropic coupled-wave theory. The effect of the initial intensity ratio and the recording angles of the two recording waves on the anisotropic Bragg diffraction properties is discussed. It is shown that both the ratio of the initial intensity and the incident

Xin Wang; Aimin Yan; De’an Liu; Liren Liu; Zhijuan Hu

2007-01-01

94

Shaping of ultrashort pulsed beams with volume holographic gratings recorded in anisotropic crystals  

Microsoft Academic Search

A new technique for ultrashort pulsed beams (UPBs) shaping that uses volume holographic gratings (VHGs) recorded in anisotropic crystals by modulating the polarization states of the input UPBs is proposed and analyzed. Our approach is based on the investigation that when a VHG recorded in anisotropic crystals is illuminated by a UPB, the spectral and temporal widths and the shapes

Chunhua Wang; Liren Liu; Aimin Yan; Dean Liu; Zhijuan Hu

2006-01-01

95

Anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals with extended wavelength range  

Microsoft Academic Search

The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mismatch of Bragg condition.

Alexei K. Zaitsev; Ken Y. Hsu; Shian H. Lin

2002-01-01

96

Photochromic polymers for making volume phase holographic gratings: between theory and practice  

NASA Astrophysics Data System (ADS)

Volume Phase Holographic Gratings (VPHGs) are dispersing elements which are finding wide spread in modern optical instrumentations, also in the astronomical field. Since photochromic materials show a change in the refractive index (?n) upon photoirradiation, in principle they can be conveniently applied to produce rewritable holographic devices for the near-IR region. Diarylethene-based photochromic films with ?n large enough to meet the basic requirements have been obtained. Photochromic VPHGs have been written by using a custom made holographic set-up, based on a Lloyd's mirror configuration. The efficiency of the photochromic gratings has been measured at different wavelength in the NIR region. A theoretical model to predict the refractive index profile as function of the substrate features has been developed. Finally, the efficiencies calculated by using the RCWA approach have been compared with the experimental values.

Bianco, Andrea; Pariani, Giorgio; Bertarelli, Chiara; Zerbi, Filippo M.

2010-07-01

97

Low-density parity-check codes for volume holographic memory systems.  

PubMed

We investigate the application of low-density parity-check (LDPC) codes in volume holographic memory (VHM) systems. We show that a carefully designed irregular LDPC code has a very good performance in VHM systems. We optimize high-rate LDPC codes for the nonuniform error pattern in holographic memories to reduce the bit error rate extensively. The prior knowledge of noise distribution is used for designing as well as decoding the LDPC codes. We show that these codes have a superior performance to that of Reed-Solomon (RS) codes and regular LDPC counterparts. Our simulation shows that we can increase the maximum storage capacity of holographic memories by more than 50 percent if we use irregular LDPC codes with soft-decision decoding instead of conventionally employed RS codes with hard-decision decoding. The performance of these LDPC codes is close to the information theoretic capacity. PMID:12593489

Pishro-Nik, Hossein; Rahnavard, Nazanin; Ha, Jeongseok; Fekri, Faramarz; Adibi, Ali

2003-02-10

98

Simulations and experiments of aperiodic and multiplexed gratings in volume holographic imaging systems  

PubMed Central

A new methodology describing the effects of aperiodic and multiplexed gratings in volume holographic imaging systems (VHIS) is presented. The aperiodic gratings are treated as an ensemble of localized planar gratings using coupled wave methods in conjunction with sequential and non-sequential ray-tracing techniques to accurately predict volumetric diffraction effects in VHIS. Our approach can be applied to aperiodic, multiplexed gratings and used to theoretically predict the performance of multiplexed volume holographic gratings within a volume hologram for VHIS. We present simulation and experimental results for the aperiodic and multiplexed imaging gratings formed in PQ-PMMA at 488nm and probed with a spherical wave at 633nm. Simulation results based on our approach that can be easily implemented in ray-tracing packages such as Zemax® are confirmed with experiments and show proof of consistency and usefulness of the proposed models.

Luo, Yuan; Castro, Jose; Barton, Jennifer K.; Kostuk, Raymond K.; Barbastathis, George

2010-01-01

99

Simulations and experiments of aperiodic and multiplexed gratings in volume holographic imaging systems.  

PubMed

A new methodology describing the effects of aperiodic and multiplexed gratings in volume holographic imaging systems (VHIS) is presented. The aperiodic gratings are treated as an ensemble of localized planar gratings using coupled wave methods in conjunction with sequential and non-sequential ray-tracing techniques to accurately predict volumetric diffraction effects in VHIS. Our approach can be applied to aperiodic, multiplexed gratings and used to theoretically predict the performance of multiplexed volume holographic gratings within a volume hologram for VHIS. We present simulation and experimental results for the aperiodic and multiplexed imaging gratings formed in PQ-PMMA at 488 nm and probed with a spherical wave at 633 nm. Simulation results based on our approach that can be easily implemented in ray-tracing packages such as Zemax® are confirmed with experiments and show proof of consistency and usefulness of the proposed models. PMID:20940823

Luo, Yuan; Castro, Jose; Barton, Jennifer K; Kostuk, Raymond K; Barbastathis, George

2010-08-30

100

Volume holographic recording utilizing photo-initiated polymerization for nonvolatile digital data storage  

NASA Astrophysics Data System (ADS)

Volume holographic recording offers an attractive solution for next generation digital storage with high density (>=10 Gb/cm 2) and transfer rate (Gb/sec). In holographic storage, data is recorded as volume phase gratings (refractive index modulation) in an optical medium. The system performance is practically determined by the physical characteristics of the recording medium. Photorefractive crystals, the most extensively investigated volumetric media, offer sensitive but typically volatile recording. Recent advancements in photo-polymerizable media have offered an attractive alternative for nonvolatile storage. This thesis evaluates the important physical properties of volume holographic recording in a photo-polymerizable material. Formation of permanent compositional volume phase gratings through monomer photopolymerization has offered a very sensitive recording mechanism, but limitations were also reported during and after exposure. The previous studies of photopolymerization recording response suggested reciprocity failure at high intensity (I), and large grating spacing (?). Grating formation was described through a photo-induced reaction diffusion model that ignores post- exposure polymerization, suggesting diffusion ( D) limited medium response to improve for longer, e.g. multipulse, recording schedules. In this thesis, the dynamics of grating formation are, for the first time, investigated extensively with respect to I, and ?, in a material utilizing cationing-ring-opening polymerization (CROP Polaroid). Holographic recording is evaluated in standard (pretreated ULSH500) CROP samples for constant exposure energy (15mJ/cm 2), i.e. total number of photons, but for a wide range of different I (mW/cm2 - W/cm2), i.e. incident photon rates, and for a few ? (?m), i.e. diffusion scales. CROP grating evolution is diffusion limited for recording with short (? r) high I (>W/ cm2) pulses. Grating formation, however, is photo-initiated (rather than photo-induced), significantly continuing after short pulse illumination. This previously unaccounted, post-exposure grating development yields strong highly sensitive (~3 cm/mJ) final CROP gratings, without reciprocity or diffusion limitations. Based on these observations, a new physical model for holographic recording in materials utilizing photo- initiated polymerization has been developed, that accounts successfully for grating evolution and post- exposure development. The model explains that diffusive transport (?d = ?2/D) limits grating evolution for ? r < ?d. Nevertheless, high final CROP response arises independent of the temporal recording characteristics, due to the post- exposure contributions. In conclusion, this thesis evaluates the performance of the CROP medium in a non-volatile holographic (WORM) storage digital system. Volume recording of CROP gratings offers attractive additive multi-pulse development, with efficient photo-initiation, and polymerization, independent of I and ?, scaling linearly with exposure (<=15 mJ/ cm2), and allowing flexible recording scheduling.

Paraschis, Loukas

101

Highly transparent ZrO2 nanoparticle-dispersed acrylate photopolymers for volume holographic recording  

Microsoft Academic Search

We demonstrate and characterize volume holographic recording in ZrO2 nanoparticle-dispersed acrylate photopolymer films that have very low scattering loss. More than thirty-fold reduction in the scattering coefficient, as compared with those of previously reported TiO2 nanoparticle-dispersed photopolymers, is achieved. It is shown that the refractive index modulation as high as 5.3×10-3, together with substantive photopolymerization-shrinkage suppression, is obtained at the

Naoaki Suzuki; Yasuo Tomita; Kentaroh Ohmori; Motohiko Hidaka; Katsumi Chikama

2006-01-01

102

Characterization of a spatial and angular multiplexed volume holographic memory in terms of M\\/#  

Microsoft Academic Search

Of the several configurations that have been proposed and studied for the implementation of a high-density, fast- access volume holographic memory system, a 90 degree(s) angular multiplexing configuration that uses a 45 degree(s)-cut iron- doped lithium niobate (LNB:Fe) crystal has attracted much attention in the last few years. In a recent paper, Burr and Psaltis have used this configuration to

Arthur E. Chiou; John H. Hong; Ian C. McMichael

1996-01-01

103

Dynamic range metric for a photorefractive crystal in a volume holographic memory system  

Microsoft Academic Search

An analytical expression for the dynamic range metric of a photorefractive crystal in a volume holographic memory is found on the basis of the coupled mode theory for polarized waves inside crystals and the linearized band transport model of photorefractive effect. Taking LiNbO3:Fe and BaTiO3 as examples, we discuss the influences of the impurity doping level, oxidation-reduction state and geometric

Li Xiaochun; Wu Minxian; Yan Yingbai; He Qingsheng; Jin Guofan

1997-01-01

104

Anisotropic Bragg diffraction of finite-sized volume holographic grating in photorefractive crystals  

Microsoft Academic Search

Anisotropic diffraction of uniform plane wave by finite-sized volume holographic grating in photorefractive crystals is considered. It is found that the anisotropic diffraction can take place when some special conditions are satisfied. The diffracted image is obtained in experiment for the anisotropic Bragg diffraction in Fe:LiNbO3 crystals. A coupled wave analysis is presented to study the properties of anisotropic diffraction.

Aimin Yan; Lingyu Wan; De’an Liu; Liren Liu

2007-01-01

105

Speckle-reduced three-dimensional volume holographic display by use of integral imaging  

Microsoft Academic Search

We propose a method to implement a speckle-reduced coherent three-dimensional (3D) display system by a combination of integral imaging and photorefractive volume holographic storage. The 3D real object is imaged through the microlens array and stored in the photorefractive crystal. During the reconstruction process a phase conjugate reading beam is used to minimize aberration, and a rotating diffuser located on

Seung-Ho Shin; Bahram Javidi

2002-01-01

106

Performance of photonic switching systems based on electro-optic volume holographic diffraction gratings  

Microsoft Academic Search

We report on free-space photonic switches that are based on switched volume holographic diffraction grating for RF and telecommunications applications. For example, a cascade of n independently controlled electro-optic (EO) gratings can be configured in a binary tree structure to route a free-space optical carrier to on of 2n possible output channels. These gratings are comprised of liquid crystal composite

Thomas W. Stone; John C. Kralik; Randall C. Veitch; Michelle S. Malcuit

2000-01-01

107

Modulation characteristics of volume holographic gratings recorded in KCl:Ca crystals  

Microsoft Academic Search

Modulation characteristics of volume holographic gratings stored in KCl:Ca crystals utilizing the F - Z1 color-center conversion have been studied. By means of the Hurter-Driffield curve the absorption and refractive-index modulation amplitudes have been determined at the optimum working point. Further, the experimental and calculated diffraction-efficiency values obtained by using two dissimilar solutions of the coupled wave equations are given.

J. Ruuskanen

1979-01-01

108

Improvement of the wavelength selectivity of volume holographic gratings for optical communication  

Microsoft Academic Search

The wavelength selectivity of volume holographic gratings with different size ratios is presented. The gratings are made in a doubly doped LiNbO3 photorefractive crystal by using the transmissive-writing and orthogonal-readout scheme. The gratings are recorded at the short wavelength of 532 nm and read out at the long communication wavelength, which is tunable between 1520 and 1630 nm. It is

Dong Liu; Dayong Wang; Shiquan Tao; Yuhong Wan; Zhuqing Jiang; Xiaodan Zheng

2009-01-01

109

Narrow bandwidth volume holographic optical filter operating at the Kr transition at 1547.82 nm  

Microsoft Academic Search

We describe and characterize a narrow bandwidth volume holographic optical filter operating at the Krypton transition line (1s2-2p8) at 1547.82 nm, which corresponds to the center wavelength of the proposed International Telecommunications Union wavelength standard. A reflectivity of 98% and a bandwidth full width at half-maximum of 0.18 nm are measured. The filter exhibits clean sideholes with a ?20 dB

Victor Leyva; George A. Rakuljic; Bruce O’Conner

1994-01-01

110

Performance of volume phase holographic transmission grating recorded in DCG for PGP  

Microsoft Academic Search

The volume phase holographic (VPH) transmission grating recorded in dichromate gelatin (DCG) with a specific spectral coverage from 420 nm to 760 nm is designed for a novel prism-grating-prism imaging spectrometer. Based on the Rigorous Coupled-Wave Analysis, its performances are predicted and analyzed. The grating is manufactured and its properties are measured experimentally. The diffraction efficiency over the spectral range,

Ming Li; Minxue Tang; Haohan Xia; Chunhuan Fang; Jianhong Wu; Xunjie Zhao

2010-01-01

111

Generation of tunable-volume transmission-holographic gratings at low light levels  

SciTech Connect

By utilizing giant Kerr nonlinearity obtained by electromagnetically induced transparency (EIT), tunable volume transmission holographic gratings for a weak probe field can be generated by means of a standing-wave signal field at low light levels in a four-level N-type ultracold atomic ensemble. The induced grating can be characterized as a mixed volume holographic grating with a strong phase modulation accompanied by a weak amplitude modulation. Based on Kogelnik's coupled-wave theory in optical holography, we find that high diffraction efficiency (up to 85%) and sensitive angular selectivity (up to {+-}0.000149 rad) can be achieved for the induced grating in the Bragg diffraction regime. And, both of them can be dynamically controlled by tuning the weak standing-wave signal field and the coupling field. Our study not only develops a fundamental understanding of volume diffraction effects in EIT media, but also provides a practical prototype of EIT-based holographic devices for all-optical classical and quantum information processing.

Zhao, L.; Duan, Wenhui [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Yelin, S. F. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States); ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)

2011-09-15

112

Generation of tunable-volume transmission-holographic gratings at low light levels  

NASA Astrophysics Data System (ADS)

By utilizing giant Kerr nonlinearity obtained by electromagnetically induced transparency (EIT), tunable volume transmission holographic gratings for a weak probe field can be generated by means of a standing-wave signal field at low light levels in a four-level N-type ultracold atomic ensemble. The induced grating can be characterized as a mixed volume holographic grating with a strong phase modulation accompanied by a weak amplitude modulation. Based on Kogelnik's coupled-wave theory in optical holography, we find that high diffraction efficiency (up to 85%) and sensitive angular selectivity (up to ±0.000149 rad) can be achieved for the induced grating in the Bragg diffraction regime. And, both of them can be dynamically controlled by tuning the weak standing-wave signal field and the coupling field. Our study not only develops a fundamental understanding of volume diffraction effects in EIT media, but also provides a practical prototype of EIT-based holographic devices for all-optical classical and quantum information processing.

Zhao, L.; Duan, Wenhui; Yelin, S. F.

2011-09-01

113

Shaping of ultrashort pulsed beams with volume holographic gratings recorded in anisotropic crystals  

NASA Astrophysics Data System (ADS)

A new technique for ultrashort pulsed beams (UPBs) shaping that uses volume holographic gratings (VHGs) recorded in anisotropic crystals by modulating the polarization states of the input UPBs is proposed and analyzed. Our approach is based on the investigation that when a VHG recorded in anisotropic crystals is illuminated by a UPB, the spectral and temporal widths and the shapes of the diffracted and transmitted pulsed beams vary with the polarization state of the input UPB, based on the extended coupled wave theory of Kogelnik which combines with the dispersion effect of the crystal materials. By using this approach, the modulation ranges of the spectral and temporal widths of the output UPB can be controlled by the parameters of the grating. Moreover, the diffraction efficiency of the volume holographic grating is analyzed, which also varies with the polarization state of the input UPB. An example of using this approach is given that a linearly polarized Gaussian-shaped UPB with duration of 30fs is effectively shaped with a transmission volume holographic grating recorded in photorefractive LiNbO3 crystals.

Wang, Chunhua; Liu, Liren; Yan, Aimin; Liu, Dean; Hu, Zhijuan

2006-08-01

114

Adaptive bacteriorhodopsin-based holographic correlator for speed measurement of randomly moving three-dimensional objects.  

PubMed

An adaptive correlator system is presented that uses a bacteriorhodopsin film as the active holographic material. Because M-type holography with bacteriorhodopsin films is used, the TV frame rate is met at fairly low intensities. No limitations arising from the heterodyne operation of the dual-axis joint-Fourier-transform correlator were observed. The system's capability to monitor autonomously the speed of an object moving randomly in the whole viewing field of a video camera is demonstrated. PMID:19855522

Thoma, R; Hampp, N

1994-09-01

115

Real-time holographic correlation of two video signals by using bacteriorhodopsin films  

Microsoft Academic Search

A dual-axis joint-Fourier-transform correlator is described with two liquid-crystal television screens as input devices and a bacteriorhodopsin film as the active holographic material in the Fourier plane. The experimental data presented demonstrate that this system is capable of processing two independent video signals in real time with a signal-to-noise ratio of 45 dB.

R. Thoma; N. Hampp

1992-01-01

116

Holographic volume gratings in dye-doped jelly-like gelatin  

NASA Astrophysics Data System (ADS)

Holographic characteristics of a thick self-developing photosensitive medium - dye-doped jelly-like gelatin are investigated by means of pulsed laser exposure. The experiments were performed using aqueous gelatin solutions of Rhodamin 6G with a layer thickness of 1 mm. The slanted holographic gratings were written with two crossed beams from a frequency-doubled (? = 532 nm) and Q-switched YAG:Nd laser (?0.5 ? 17 ns, f <= 50 Hz). In the course of recording the hologram was read with the beam from a single-mode He-Ne laser (? = 632.8 nm) which was not absorbed by the photosensitive medium. The real-time evolution of the grating diffraction efficiency was studied in dependence of the dye and gelatin concentration as well as the writing pulse fluence. It is shown that under appropriate choice of the medium composition and parameters of the recording radiation, it is possible to obtain phase volume holographic gratings with a diffraction efficiency of ~ 87 % and an angular selectivity of ~ 20'.

Efendiev, T. Sh.; Katarkevich, V. M.; Rubinov, A. N.

2007-08-01

117

Bit-Error and Noise Limitations on the Storage Capacity of Volume Holographic Memory Systems and Low Crosstalk Noise Code Criteria for Spatial Light Modulation Hologram Multiplexing  

Microsoft Academic Search

Volume holographic storage takes full advantage of the volume space in a crystal and promises storage capacities on the order of one terabit per centimeter cube. However, efforts to match such a capacity which is based solely on wavelength and geometrical limitations have failed. A practical limit for holographic storage systems is set by the bit-error-rate, the readout speed, the

Adil Lahrichi

1995-01-01

118

Far-off-Bragg reconstruction of volume holographic gratings: A comparison of experiment and theories  

NASA Astrophysics Data System (ADS)

We performed light optical diffraction experiments on a nanoparticle-polymer volume holographic grating in an angular range including far-off-Bragg replay. A comparison of three diffraction theories, on the same level of complexity, with our experimental results shows that the dynamical theory of diffraction and the first-order two-wave coupling theory using the beta-value method fit the data very well. In contrast, the prevalent two-wave coupling theory using the K-vector closure method yields a poor fit with an order of magnitude worse mean squared error. These findings must be considered for accurate determination of coupling strength and grating thickness.

Prijatelj, Matej; Klepp, Jürgen; Tomita, Yasuo; Fally, Martin

2013-06-01

119

Dynamic characterizations of high diffraction efficiency in volume Bragg grating formed by holographic photopolymerization  

NASA Astrophysics Data System (ADS)

Volume Bragg grating with 96% diffraction efficiency (DE) was efficiently formed by holographic photopolymerization in blend syrup of photocurable trimethylolpropane triacrylate monomer and nematic liquid crystal. The formation dynamics of the composite gratings was quantitatively characterized under the frame of one-dimensional reaction-diffusion model with a revision of individual decay constants for monomer diffusion and reaction. Initial parameters of diffusion and reaction were analytically determined from the measured first order DE at the beginning stage. Evolutions of the DE, both in curing and postcuring periods, were excellently simulated, especially with postcuring reaction been taken into account.

Pu, Haihui; Yin, Dejin; Gao, Bin; Gao, Hongyue; Dai, Haitao; Liu, Jianhua

2009-10-01

120

Anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals with extended wavelength range.  

PubMed

The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mismatch of Bragg condition. The wavelength range may extent in several times the range of ordinary isotropic diffraction on the grating of the same spacing and thickness. Theoretical explanation of this phenomena and experimental results of widerange diffraction in BaTiO3 photorefractive crystal are also presented. PMID:19424351

Zaitsev, Alexei; Hsu, Ken; Lin, Shian

2002-02-25

121

Performances of new green sensitive liquid photopolymers for volume phase holographic gratings  

NASA Astrophysics Data System (ADS)

Liquid photopolymers produced by Polygrama-Lynx (SM-532TR and SM-532TRF) have been studied to determine their performances in terms of refractive index modulation, transparency and overall optical quality. Volume phase holographic gratings (VPHGs) based on these materials have been obtained using a 532 DPSS laser and the grating efficiency has been measured at different angles and wavelengths. Using the Kogelnik model and/or the RCWA approach, the thickness and the refractive index modulation has been determined for gratings as function of light exposure, line density, etc. Index modulations up to 0.03 together with good optical quality were obtained.

Zanutta, Alessio; Bianco, Andrea; Zerbi, Filippo M.

2012-02-01

122

Crosstalk noise in speckle-based volume holographic multiplexing  

NASA Astrophysics Data System (ADS)

Recently, we proposed a new speckle-based hologram multiplexing recording technique. In this method, a multi-mode LiNbO3 single crystal fiber is employed to generate speckle patterns which are used as reference beams in hologram recording process. The speckle pattern generation can be precisely controlled by external E-field. Theoretically, this technique can generate thousands of decorrelated reference beams at given practical constraints. The system storage capacity has so far been estimated based on idealized settings. As it is well known that, besides the limitation set by the modulation mechanism capacity the storage density of a volume hologram memory system can be also restricted by many other factors. Among all factors, the crosstalk is a fundamental one that may ultimately put a tighter bound to system storage capacity. This paper is devoted to the theoretical analysis and numerical simulation of crosstalk in this proposed technique.

Liu, Hongbo; Gu, Man; Bhalla, Amar S.; Guo, Ruyan

2007-09-01

123

Anisotropic Bragg diffraction of finite-sized volume holographic grating in photorefractive crystals  

NASA Astrophysics Data System (ADS)

Anisotropic diffraction of uniform plane wave by finite-sized volume holographic grating in photorefractive crystals is considered. It is found that the anisotropic diffraction can take place when some special conditions are satisfied. The diffracted image is obtained in experiment for the anisotropic Bragg diffraction in Fe:LiNbO3 crystals. A coupled wave analysis is presented to study the properties of anisotropic diffraction. An analytical integral solution for the amplitudes of the diffracted beams is submitted. A trade off between high diffraction efficiency and the deterioration of reconstruction fidelity is analyzed. Numerical evaluations also show that the finite-sized anisotropic volume grating exhibits strong angular and wavelength selectivity. All the results are useful for the optimizing design of VHOE based on finite-sized volume grating structures.

Yan, Aimin; Wan, Lingyu; Liu, De'an; Liu, Liren

2007-09-01

124

Diffraction properties study of reflection volume holographic grating in dispersive photorefractive material under ultra-short pulse readout  

Microsoft Academic Search

Based on the modified Kogelnik diffraction efficiency equation, we study the diffraction intensity spectrum and the total diffraction efficiency of reflection volume holographic gratings in photorefractive media. Taking photorefractive LiNbO3 crystal as an example, the effect of the grating parameters and the pulse width on the diffraction properties is presented under the influence of crystal material dispersion. Under the combined

Yingyan Yi; Deming Liu; Hairong Liu

2011-01-01

125

Three Dynamical Photorefractive Systems: a Novelty Filter, Volume Holographic Interconnection, and a Ring Resonator with Photorefractive Gain and Loss  

Microsoft Academic Search

This thesis addresses three dynamic photorefractive systems: a novelty filter, volume holographic interconnection, and a ring resonator with both photorefractive gain and loss. Our interest in dynamical systems is motivated by a desire to understand how to build optical processors for computations difficult for conventional computers. We choose optics as the medium because of the ease of parallelism, and photorefractive

Diana Marie Lininger

1990-01-01

126

Three-dimensional coupled wave study for finite-sized anisotropic volume holographic gratings under ultrashort pulsed beam readout  

Microsoft Academic Search

The three-dimensional coupled wave theory is extended to systematically investigate the diffraction properties of finite-sized anisotropic volume holographic gratings (VHGs) under ultrashort pulsed beam (UPB) readout. The effects of the grating geometrical size and the polarizations of the recording and readout beams on the diffraction properties are presented, in particular under the influence of grating material dispersion. The wavelength selectivity

Chunhua Wang; Liren Liu; Aimin Yan; Dean Liu; Yu Zhou; Cuixia Dai

2007-01-01

127

Holographic Volume Phase, 17-Inch Aperture, On-Axis, Spherical Beamsplitter Mirror: Development of.  

National Technical Information Service (NTIS)

This project was to develop a holographic, spherical beamsplitter mirror, utilizing a high power continuous wave laser. The holographic beamsplitter mirror would be used in a Pancake Window system, replacing the classical beamsplitter mirror which is expe...

J. R. Magarinos

1978-01-01

128

Raman Spectroscopy and Microscopic Raman Imaging with Applications of Volume Holographic Optical Elements  

Microsoft Academic Search

Holographic optical elements are crucial for the development of compact and efficient Raman spectroscopic instrumentation. Holographic optics allow direct coupling of a single-stage spectrograph to a Raman microprobe. The high transmission efficiency and narrow rejection-band characteristics of the holographic beam splitter provide efficient use of low power lasers, while allowing acquisition of low-frequency Raman spectra. The holographic notch filter and

David Mark Pallister

1994-01-01

129

Simulation and analysis of volume holographic gratings integrated in collimation optics for wavelength stabilization  

NASA Astrophysics Data System (ADS)

Integrating volume holographic gratings into micro-optical components such as cylindrical fast-axis collimation lenses (VHG-FAC) for diode lasers constitutes a promising concept for wavelength stabilization by forming an external cavity laser. Compared to standard wavelength stabilization configurations the integrated element reduces the alignment complexity and is furthermore insensitive to the smile-error of diode laser bars. In order to configure and optimize these components the diffraction of the divergent field distribution of a broad area semiconductor laser must be calculated. The present paper presents the extension of the coupled-mode theory in order to calculate the spectral distribution of the diffracted field and the coupling efficiency within the external cavity. The model was extended to three-dimensional space and supplemented to include surface effects, polarization dependency and wave-optical propagation. The asymmetric spectral distribution emitted by an external cavity laser with VBG-FAC is tracked back to the feedback of highly divergent radiation diffracted at the holographic grating. Power losses due to the coupling efficiency within the cavity are also calculated for various field distributions and compared with experimental data. In summary the mathematical model allows to estimate the minimum spectral width and the losses using a VHG-FAC in an external cavity. Thus the injection locking concept using the VHG-FAC can be compared to the spectral characteristics and estimated power losses of standard wavelength stabilization configurations, e.g. the alignment of the grating in the collimated beam.

Hengesbach, S.; Witte, U.; Traub, M.; Hoffmann, D.

2011-02-01

130

Volume phase holographic grating performance on the VIRUS-P instrument  

NASA Astrophysics Data System (ADS)

The Visible Integral-field Replicable Unit Spectrograph Prototype (VIRUS-P) has been in operation on the Harlan J Smith 2.7m Telescope at McDonald Observatory since October of 2006. The prototype was created to test the design and science capabilities of the full VIRUS instrument, wherein 150 copies of the spectrograph will be installed on the Hobby Eberly Telescope (HET). We here discuss the specialized test bench built to assess the blue optimized Volume Phase Holographic (VPH) grating performance. We also give lab and on-telescope efficiency measurements for three such gratings in the wavelength range 3400-6800Å. Two sources of stray light relevant to most spectrograph designs are also discussed.

Adams, Joshua J.; Hill, Gary J.; MacQueen, Phillip J.

2008-08-01

131

Improvement of the wavelength selectivity of volume holographic gratings for optical communication  

NASA Astrophysics Data System (ADS)

The wavelength selectivity of volume holographic gratings with different size ratios is presented. The gratings are made in a doubly doped LiNbO3 photorefractive crystal by using the transmissive-writing and orthogonal-readout scheme. The gratings are recorded at the short wavelength of 532 nm and read out at the long communication wavelength, which is tunable between 1520 and 1630 nm. It is demonstrated that the wavelength selectivity of gratings can be improved by choosing larger grating size ratios. A 3 dB bandwidth of 0.43 nm is achieved with the grating size ratio of 2.5. The experimental results agree well with the prediction of two-dimensional coupled-wave theory.

Liu, Dong; Wang, Dayong; Tao, Shiquan; Wan, Yuhong; Jiang, Zhuqing; Zheng, Xiaodan

2009-06-01

132

Holographic filter with cascaded volume Bragg gratings in photopolymer waveguide film.  

PubMed

A novel holographic filter using a photopolymer-based cascaded volume Bragg gratings (CVBGs) is proposed and experimentally demonstrated in this paper. The filter was designed to attain a narrow spectral bandwidth characteristic without increasing the thickness of photopolymer used, at 1550 nm operating wavelength region. The proposed filter is consisted of a 45° slanted grating working as a surface-normal input/output coupler and a non-slanted reflection grating acting as a narrow-band wavelength selective filter, and it was embedded in the photopolymer film as a waveguide mode. The fabricated filter showed that the bandwidth at the center wavelength of 1547.85 nm was about 0.45 nm. PMID:21164911

Lee, Kwon-Yeon

2010-12-01

133

Performance of volume phase holographic transmission grating recorded in DCG for PGP  

NASA Astrophysics Data System (ADS)

The volume phase holographic (VPH) transmission grating recorded in dichromate gelatin (DCG) with a specific spectral coverage from 420 nm to 760 nm is designed for a novel prism-grating-prism imaging spectrometer. Based on the Rigorous Coupled-Wave Analysis, its performances are predicted and analyzed. The grating is manufactured and its properties are measured experimentally. The diffraction efficiency over the spectral range, the bandwidth, and the angular selectivity of the grating is measured, analyzed and compared with that of the theoretical ones. The results show that by adjusting and controlling the preparation conditions of DCG plates, the exposure time and the post-processing technique of the grating, the VPH transmission grating with high diffraction efficiency approximate to the design requirement can be obtained. The measured peak diffraction efficiency reaches nearly 85% at central wavelength of 590 nm while the average diffraction efficiency is larger than 75% over the required spectral range from 420 nm to 760 nm.

Li, Ming; Tang, Minxue; Xia, Haohan; Fang, Chunhuan; Wu, Jianhong; Zhao, Xunjie

2010-11-01

134

Diffraction properties study of multi-layer reflection volume holographic grating under ultra-short pulse readout  

NASA Astrophysics Data System (ADS)

Based on the modified coupled-wave theory of single volume grating and matrix theory, the time-domain diffraction of multi-layer reflection volume holographic gratings recorded in photorefractive LiNbO3 crystals are theoretically studied when they are illuminated by ultrashort pulse laser. Study shows that the waveforms of the diffracted pulses depend on the readout pulse duration, grating periods, refractive index modulation of the grating, thickness of the buffer layers and gating layers. The diffracted waveforms and intensity can be controlled to satisfy our demands by changing these parameters. Also it is found that the diffracted pulses have a displacement along the time-axis compared with readout pulse. Results of our study can be used in pulse shaping and designing new optical devices based on multiple layers of volume holographic grating.

Yi, Yingyan; Li, Min; Chen, Fengxiang; Wang, Lisheng

2011-11-01

135

Instantaneous characteristics study of the diffracted and transmitted light of a static photorefractive reflection volume holographic grating read by an ultrashort pulse laser  

Microsoft Academic Search

The time-domain diffraction and transmission of reflection volume holographic gratings (RVHGs) recorded in photorefractive LiNbO3 crystals are theoretically studied and compared with transmission volume holographic gratings (TVHGs) when they are illuminated by ultrashort pulse laser light. The modified Kogelnik's coupled-wave theory, combining the dispersion effect in the crystal, is used. The results show that larger diffraction intensity can be obtained

Yingyan Yi; Deming Liu; Hairong Liu

2011-01-01

136

Optical properties of beam-steering elements utilizing volume holographic gratings  

NASA Astrophysics Data System (ADS)

An optical beam steering element is a device that is used to control the direction in which a beam of light travels. We have investigated the optical properties of two classes of optical beam steering elements. The first type utilized the polarization dependence of the diffraction efficiency of volume holographic gratings. The second type utilized the fact that the diffraction efficiency of holograms imbibed with a nematic liquid crystal can be controlled by the application of an electric field. In both cases, elements with excellent switching contrasts were fabricated for operation in the visible and near infrared wavelength range including the commonly used telecommunications wavelength of 1.3?m. The holographic recording material that we have used is Polaroid Corporation's DMP-128 photopolymer. This material is porous after exposure and processing, a feature useful in two ways for this work. First, volume gratings with very large refractive index modulations, on the order of 0.2, can be fabricated using this material. Secondly, the pores can be filled with a nematic liquid crystal, resulting in electrically-switchable gratings. In our analysis of polarization-sensitive gratings we have employed several coupled wave theories, each with a different set of approximations. We have found that rigorous coupled wave theory must be used in predicting the diffractive properties of highly modulated volume gratings, where the effects of higher diffraction orders and form birefringence become important. In our analysis of the optical properties of electrically-switchable liquid crystal composite holograms, we have employed a theoretical analysis that treats the birefringent nature of the gratings. The results of Kogelnik theory that neglects the grating anisotropy, a two-wave theory that treats anisotropy, and a formulation of rigorous coupled wave theory that includes anisotropy were compared. We found it was necessary to include the effects of optical anisotropy to explain the diffractive properties of the liquid crystal composite gratings. Furthermore, we have shown that a detailed comparison of experiment and theory provides information about the alignment of the liquid crystal in these composite systems.

Butler, James Jay

2000-06-01

137

Photopolymerization kinetics and volume holographic recording in ZrO2 nanoparticle-polymer composites at 404 nm  

NASA Astrophysics Data System (ADS)

We investigate volume holographic recording in a ZrO2 nanoparticle-polymer composite film at a wavelength of 404 nm. Dependences of the polymerization kinetics on concentrations of an initiator and ZrO2 nanoparticles doped in acrylate monomer are examined by using a photodifferential scanning calorimeter. It is found that there exists the optimum concentration of ZrO2 nanoparticles to maximize the polymerization rate. The diffraction and scattering properties of transmission volume gratings are also investigated. It is found that the refractive index modulation and the material recording sensitivity are as high as 8×10-3 and 9000 cm/J, respectively, at the optimum ZrO2 nanoparticle concentration of 35 vol % and at a recording intensity of 5 mW/cm2. These material parameters are larger than typical minimum ones of 5×10-3 and 500 cm/J, respectively, for optimized performance in holographic data storage.

Omura, Koji; Tomita, Yasuo

2010-01-01

138

A novel WDM optical filter based on volume holographic gratings recorded in transmissive-writing and orthogonal-readout scheme  

Microsoft Academic Search

Using transmissive-writing and orthogonal-readout scheme, a dual-channel wavelength division multiplexer on the bases of two volume holographic gratings is demonstrated for the first time. The two gratings locate in different areas of a piece of doubly doped LiNbO3 photorefractive crystal, so that each grating can reach the maximal diffraction efficiency of the crystal. The gratings are recorded in the crystal

Dong Liu; Da-Yong Wang; Shi-Quan Tao; Yu-Hong Wan; Zhu-Qing Jiang

2009-01-01

139

Silicon oxide nano-particles doped PQ-PMMA for volume holographic imaging filters  

PubMed Central

Holographic imaging filters are required to have high Bragg selectivity to obtain spatial-spectral information within a three-dimensional object. In this Letter, we present the design of holographic imaging filters formed using silicon oxide nano-particles (nano-SiO2) in PQ-PMMA polymer recording material. This combination offers greater angular and spectral selectivity and increases the diffraction efficiency of holographic filters. The holographic filters with optimized ratio of nano-SiO2 in PQ-PMMA can significantly improve the performance of Bragg selectivity and diffraction efficiency by 53% and 16%, respectively. We present experimental results and data analysis demonstrating this technique in use for holographic spatial-spectral imaging filters.

Luo, Yuan; Russo, Juan M.; Kostuk, Raymond K.; Barbastathis, George

2011-01-01

140

High-speed holographic correlation system by a time-division recording method for copyright content management on the internet  

NASA Astrophysics Data System (ADS)

Using a holographic disc memory on which a huge amount of data can be stored, we constructed an ultra-high-speed, all-optical correlation system. In this method, multiplex recording is, however, restricted to "one page" on "one spot." In addition, signal information must be normalized as data of the same size, even if the object data size is smaller. Therefore, this system is difficult to apply to part of the object data scene (i.e., partial scene searching and template matching), while maintaining high accessibility and programmability. In this paper, we develop a holographic correlation system by a time division recording method that increases the number of multiplex recordings on the same spot. Assuming that a four-channel detector is utilized, 15 parallel correlations are achieved by a time-division recording method. Preliminary correlation experiments with the holographic optical disc setup are carried out by high correlation peaks at a rotational speed of 300 rpm. We also describe the combination of an optical correlation system for copyright content management that searches the Internet and detects illegal contents on video sharing websites.

Watanabe, Eriko; Ikeda, Kanami; Kodate, Kashiko

2012-10-01

141

Design and manufacture of transmission volume phase holographic grating used in VIS/NIR wave band  

NASA Astrophysics Data System (ADS)

Due to its uniform dispersion and higher diffraction efficiency, transmission volume phase holographic grating (VPHG) has been widely used for astronomical spectroscopy, ultrafast lasers compressors and wavelength division multiplexers. According to its application requirement and based on the Rigorous Coupled Wave Analysis (RCWA), a transmission VPHG with a frequency of 196lp/mm is designed and manufactured in this paper. The thickness of gelatin and the modulation of refraction index are optimized for high diffraction efficiency over a wavelength range from 420nm to 1000nm. The grating was recorded in dichromate gelatin (DCG) and in a symmetrical light path. By controlling the coating, exposure and post-processing conditions, the thickness of gelatin and the modulation of refraction index can be adjusted. The diffraction efficiency varied within the required wave band and the polarization property of the illumination wave were measured and compared with that of the theoretical ones. From the results, it can be seen that by adjusting and controlling the preparation conditions of DCG plates, the exposure value and post-processing technique, the peak diffraction efficiency of VPHG reaches to 47% and the average diffraction efficiency is above 35% in the spectral coverage, which is close to the theoretical values. This transmission VPHG can be applied in a prism-grating-prism (PGP) imaging spectrometer.

Fang, Chunhuan; Tang, Minxue; Wu, Jianhong

2011-11-01

142

Strongly correlated quantum fluids: ultracold quantum gases, quantum chromodynamic plasmas and holographic duality  

NASA Astrophysics Data System (ADS)

Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical and that do not have a simple description in terms of weakly interacting quasiparticles. Two systems that have recently attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These systems differ by 19 orders of magnitude in temperature, but were shown to exhibit very similar hydrodynamic flows. In particular, both fluids exhibit a robustly low shear viscosity to entropy density ratio, which is characteristic of quantum fluids described by holographic duality, a mapping from strongly correlated quantum field theories to weakly curved higher dimensional classical gravity. This review explores the connection between these fields, and also serves as an introduction to the focus issue of New Journal of Physics on ‘Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to Quantum Chromodynamic Plasmas’. The presentation is accessible to the general physics reader and includes discussions of the latest research developments in all three areas.

Adams, Allan; Carr, Lincoln D.; Schäfer, Thomas; Steinberg, Peter; Thomas, John E.

2012-11-01

143

Progress in read{write fast{access volume holographic data storage  

Microsoft Academic Search

We review recent progress made towards commercializable read{write, fast{access holographic data storage. This includes a recent demonstration of high areal density holographic storage (1), systems architectures for extending this high density to high capacity using phase{conjugate readout (2), and recent experimental progress along these lines. Other topics include using signal processing to relieve alignment and distortion constraints (3), optical elements

Geofirey W. Burr; Erwin Mecher; Thorsten Juchem; Hans Coufal; C. Michael Jefierson; Mark Jurich; Francisco Gallego; Klaus Meerholz; Norbert Hampp; John A. Hofinagle; Roger M. Macfarlane; Robert M. Shelby

2001-01-01

144

From the surface to volume: concepts for the next generation of optical-holographic data-storage materials.  

PubMed

Optical data storage has had a major impact on daily life since its introduction to the market in 1982. Compact discs (CDs), digital versatile discs (DVDs), and Blu-ray discs (BDs) are universal data-storage formats with the advantage that the reading and writing of the digital data does not require contact and is therefore wear-free. These formats allow convenient and fast data access, high transfer rates, and electricity-free data storage with low overall archiving costs. The driving force for development in this area is the constant need for increased data-storage capacity and transfer rate. The use of holographic principles for optical data storage is an elegant way to increase the storage capacity and the transfer rate, because by this technique the data can be stored in the volume of the storage material and, moreover, it can be optically processed in parallel. This Review describes the fundamental requirements for holographic data-storage materials and compares the general concepts for the materials used. An overview of the performance of current read-write devices shows how far holographic data storage has already been developed. PMID:21538730

Bruder, Friedrich-Karl; Hagen, Rainer; Rölle, Thomas; Weiser, Marc-Stephan; Fäcke, Thomas

2011-04-29

145

Polarization of holographic grating diffraction. II. Experiment  

Microsoft Academic Search

The transmittance, ellipsometric parameters, and depolarization of transmission, diffraction, and reflection of two volume holographic gratings (VHGs) are measured at a wavelength of 632.8 nm. The measured data are in good agreement with the theoretical simulated results, which demonstrated the correlation between the diffraction strength and the polarization properties of a VHG. Vector electromagnetic theory and polarization characterization are necessary

Tsu-Wei Nee; Soe-Mie F. Nee; Mark W. Kleinschmit; M. S. Shahriar

2004-01-01

146

Spatio-temporal experiments of volume elastic objects with high speed digital holographic interferometry  

NASA Astrophysics Data System (ADS)

The optical non-destructive digital holographic interferometry (DHI) technique has proven to be a powerful tool in measuring vibration phenomena with a spatial resolution ranging from a few hundreds of nanometers to tens of micrometers. With the aid of high speed digital cameras it is possible to achieve simultaneously spatial and temporal resolution, and thus capable of measuring the entire object mechanical oscillation trajectory from one to several cycles. It is important to mention that due to faster computers with large data storage capacity there is an increasing interest in applying numerical simulation methods to mimic different real life objects for example, in the field of modern elastic materials and biological systems. The complex algorithms involved cannot render significant results mainly due to the rather large number of variables. In order to test these numerical simulations some experiments using optical techniques have been designed and reported. This is very important for example in measurements of the dynamic elastic properties of materials. In this work we present some preliminary results from experiments that use DHI to measure vibrations of an elastic spherical object subject to a mechanical excitation that induces resonant vibration modes in its volume. We report on the spatial and temporal effects that by their nature have a non-linear mechanical response. The use of a high speed CMOS camera in DHI assures the measurement of this nonlinear behavior as a sum of linear effects that happen during very short time lapses and with very small displacement amplitudes. We conclude by stating that complex numerical models may be compared to results using DHI, thus proposing an alternative method to prove and verify the mathematical models vs. real measurements on volumetric elastic objects.

Pérez López, C.; Hernández Montes, M. S.; Mendoza Santoyo, F.; Gutiérrez Hernandez, D. A.

2011-08-01

147

Storage density estimation for the phase-encoding and shift multiplexing holographic optical correlator  

NASA Astrophysics Data System (ADS)

Holographic optical correlator (HOC) is applicable in occasion where the instant search throughout a huge database is demanded. The primary advantage of the HOC is its inherent parallel processing ability and large storage capacity. The HOC's searching speed is proportional to the storage density. This paper proposes a phase-encoding method in the object beam to increase the storage density. A random phase plate (RPP) is used to encode the phase of the object beam before uploading the data pages to the object beam. By shifting the RPP at a designed interval, the object beam is modulated into an orthogonal object beam to the previous one and a new group of database can be stored. Experimental results verify the proposed method. The maximum storage number of the data pages with a RPP at a fixed position can be as large as 7,500. The crosstalk among different groups of the databases can be unnoticeable. The increase in the storage density of the HOC depends on the number of the orthogonal positions from the different portions of a same RPP.

Zheng, Tianxiang; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2013-09-01

148

Volume holographic data storage and processing using phase-coded multiplexing  

Microsoft Academic Search

We present a novel, compact and fully automated architecture of a phase-coded holographic memory capable of storing up to 480 data pages in a single interaction region of a photorefractive LiNbO3 crystal. The architecture of the system is described and a short overview of the principle of phase-coded multiplexing is given

T. Tschudi; C. Deuz; K.-O. Muller; T. Heimann

1998-01-01

149

Volume holographic storage and animation based on addressing with an elastomer phase mask  

Microsoft Academic Search

A novel technique for phase-multiplexed holographic storage is reported. Phase codes for recording individual images are generated with an elastomer mask fabricated from silicone. The mask is imprinted with a random phase distribution by using a mold with a nonuniform surface profile. By displacing the elastomer from equilibrium, the optical path length traversed by each point on the reference beam

Raphael A. Guerrero

2005-01-01

150

Dichromated gelatin for volume holographic recording with high sensitivity. Part I  

Microsoft Academic Search

Dichromated gelatin would be the most suitable irreversible medium for holographic recording but for its low sensitivity. The efficiency of the photoinduced reduction of the chromium ion increases considerably if superfine grains of silver halide crystals are present in the layer. The light sensitivity achieved is about 10 times better than that of dichromated gelatin layers, obtained and processed in

M. Mazakova; M. Pancheva; P. Kandilarov; P. Sharlandjiev

1982-01-01

151

Diffraction of an ultrashort pulsed beam with arbitrary polarization state from a volume holographic grating in LiNbO3 crystals  

Microsoft Academic Search

Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crystals. The results indicate that the diffracted intensity distributions in the spectral and temporal domains and the diffraction efficiency of the grating are both changed by the polarization

Wang Chun-Hua; Liu Li-Ren; Yan Ai-Min; Zhou Yu; Liu De-An; Hu Zhi-Juan

2007-01-01

152

Polarization simultaneous readout for volume holographic storage in LiNbO3  

NASA Astrophysics Data System (ADS)

We have successfully demonstrated a holographic memory in a single LiNbO3 crystal with two simultaneous but individual readout channels. A special scheduled exposure model is derived to obtain equal diffraction efficiency of each hologram in this memory. The simultaneous readout technique is achieved in a hybrid-multiplexed memory using angular multiplexing and the polarization multiplexing. Polarization multiplexing offers the mechanism of simultaneous readout for two individual orthogonally polarized images. In each angular position of the holographic memory, these two orthogonally polarized images can be reconstructed simultaneously and each of them can be viewed independently. After our proposed scheduled exposure, experimental result of diffraction efficiency in each hologram becomes equal and the result is consistent with our prediction.

Su, Wei-Chia; Chen, Chien-Yue; Liu, Yau-Wen; Lin, Ching-Huang; Ouyang, Yueh

2008-05-01

153

Polarization simultaneous readout for volume holographic storage in LiNbO3  

Microsoft Academic Search

We have successfully demonstrated a holographic memory in a single LiNbO3 crystal with two simultaneous but individual readout channels. A special scheduled exposure model is derived to obtain equal diffraction efficiency of each hologram in this memory. The simultaneous readout technique is achieved in a hybrid-multiplexed memory using angular multiplexing and the polarization multiplexing. Polarization multiplexing offers the mechanism of

Wei-Chia Su; Chien-Yue Chen; Yau-Wen Liu; Ching-Huang Lin; Yueh Ouyang

2008-01-01

154

Polarization simultaneous readout for volume holographic storage in LiNbO3  

Microsoft Academic Search

A hybrid-multiplexed holographic memory using polarization multiplexing accompanied with angle multiplexing in a LiNbO3 crystal is demonstrated. In the configuration, the signal beams are normal incident on the crystal, and incident angle of the reference beam for recording both TM and TE polarized images is kept around 25deg in the air. The saturation diffraction efficiency for both TM and TE

Wei-Chia Su; Chung-Ming Chen; Yueh Ouyang

2007-01-01

155

Beyond volume holographic storage: applications of phase-coded multiplexing to image processing and encryption  

Microsoft Academic Search

We present several encryption techniques for holographic data storage, using orthogonal phase-code multiplexing and random phase encoding. Our system is capable of storing page-oriented data based on the selectivity of orthogonal phase-codes in a photorefractive LiNbO3 storage crystal. In order to encrypt data, random phase multiplexing is added to the system. We proof that the combination of deterministic and random

Cornelia Denz; Kai-Oliver Mueller; Franz Visinka; Gernot Berger; Theo T. Tschudi

2000-01-01

156

Optimisation of a stirred bioreactor through the use of a novel holographic correlation velocimetry flow measurement technique.  

PubMed

We describe a method for measuring three dimensional (3D) velocity fields of a fluid at high speed, by combining a correlation-based approach with in-line holography. While this method utilizes tracer particles contained within the flow, our method does not require the holographic reconstruction of 3D images. The direct flow reconstruction approach developed here allows for measurements at seeding densities in excess of the allowable levels for techniques based on image or particle reconstruction, thus making it suited for biological flow measurement, such as the flow in bioreactor. We outline the theory behind our method, which we term Holographic Correlation Velocimetry (HCV), and subsequently apply it to both synthetic and laboratory data. Moreover, because the system is based on in-line holography, it is very efficient with regard to the use of light, as it does not rely on side scattering. This efficiency could be utilized to create a very high quality system at a modest cost. Alternatively, this efficiency makes the system appropriate for high-speed flows and low exposure times, which is essential for imaging dynamic systems. PMID:23776534

Ismadi, Mohd-Zulhilmi; Higgins, Simon; Samarage, Chaminda R; Paganin, David; Hourigan, Kerry; Fouras, Andreas

2013-06-11

157

Generation of laser-polarized xenon using fiber-coupled laser-diode arrays narrowed with integrated volume holographic gratings.  

PubMed

Volume holographic gratings (VHGs) can be exploited to narrow the spectral output of high-power laser-diode arrays (LDAs) by nearly an order of magnitude, permitting more efficient generation of laser-polarized noble gases for various applications. A approximately 3-fold improvement in (129)Xe nuclear spin polarization, P(Xe), (compared to a conventional LDA) was achieved with the VHG-LDA's center wavelength tuned to a wing of the Rb D(1) line. Additionally, an anomalous dependence of P(Xe) on the xenon density within the OP cell is reported-including high P(Xe) values (>10%) at high xenon partial pressures (approximately 1000 torr). PMID:19162517

Nikolaou, Panayiotis; Whiting, Nicholas; Eschmann, Neil A; Chaffee, Kathleen E; Goodson, Boyd M; Barlow, Michael J

2008-12-24

158

Diffraction properties study of reflection volume holographic grating in dispersive photorefractive material under ultra-short pulse readout  

NASA Astrophysics Data System (ADS)

Based on the modified Kogelnik diffraction efficiency equation, we study the diffraction intensity spectrum and the total diffraction efficiency of reflection volume holographic gratings in photorefractive media. Taking photorefractive LiNbO3 crystal as an example, the effect of the grating parameters and the pulse width on the diffraction properties is presented under the influence of crystal material dispersion. Under the combined effects, the diffraction pulse profiles and the total diffraction efficiency are compared with and without crystal material dispersion. The results show that the dispersion will decrease the diffraction intensity. Moreover, when pulse width is smaller or the grating spacing and the grating thickness are larger, the influence of dispersion on diffraction is large. The results of our paper can be used in pulse shaping applications.

Yi, Yingyan; Liu, Deming; Liu, Hairong

2011-02-01

159

A novel WDM optical filter based on volume holographic gratings recorded in transmissive-writing and orthogonal-readout scheme  

NASA Astrophysics Data System (ADS)

Using transmissive-writing and orthogonal-readout scheme, a dual-channel wavelength division multiplexer on the bases of two volume holographic gratings is demonstrated for the first time. The two gratings locate in different areas of a piece of doubly doped LiNbO3 photorefractive crystal, so that each grating can reach the maximal diffraction efficiency of the crystal. The gratings are recorded in the crystal by using green laser. During the readout, the input infrared light is incident on a surface of the material perpendicularly, and the light beam diffracted by one of the two channels emerge from a surface adjacent the input one. The two diffracted beams both propagate normally to the output surface. This makes it easier to couple the communication light beams into and out of the device. The filter works at the third window of optical communication with a channel space of 0.72 nm.

Liu, Dong; Wang, Da-Yong; Tao, Shi-Quan; Wan, Yu-Hong; Jiang, Zhu-Qing

2009-07-01

160

Holographic entanglement plateaux  

NASA Astrophysics Data System (ADS)

We consider the entanglement entropy for holographic field theories in finite volume. We show that the Araki-Lieb inequality is saturated for large enough subregions, implying that the thermal entropy can be recovered from the knowledge of the region and its complement. We observe that this actually is forced upon us in holographic settings due to non-trivial features of the causal wedges associated with a given boundary region. In the process, we present an infinite set of extremal surfaces in Schwarzschild-AdS geometry anchored on a given entangling surface. We also offer some speculations regarding the homology constraint required for computing holographic entanglement entropy.

Hubeny, Veronika E.; Maxfield, Henry; Rangamani, Mukund; Tonni, Erik

2013-08-01

161

Physical properties of volume holographic recording utilizing photo-initiated polymerization for nonvolatile digital data storage  

NASA Astrophysics Data System (ADS)

The physical properties of photopolymer grating formation are, for the first time, investigated elaborately with respect to I, and (Lambda) . The dynamics of holographic recording with constant exposure energy (15mJ/cm2), are evaluated for a wide range of different I (mW/cm2 - W/cm2), and for a few typical (Lambda) (0.5 - 3.5 micrometer), in a material utilizing cationing-ring-opening polymerization (Polaroid CROP ULSH-500B). Diffusion was evaluated to limit the photo- initiated recording sensitivity at high I(greater than W/cm2 approximately (Lambda) -2). At the same time, however, the significant post-exposure grating development observed for diffusion limited recordings, was identified to allow eventually for equally high sensitive final gratings (approximately 3 - 5 cm/mJ) without reciprocity, or diffusion limitations. Based on these observations, a new physical model was developed that describes more accurately holographic recording utilizing photo-initiated polymerization, and accounts successfully for the observed physical properties of grating formation.

Paraschis, Loukas; Sugiyama, Yasuyuki; Hesselink, Lambertus

1999-11-01

162

Diffraction of an ultrashort pulsed beam with arbitrary polarization state from a volume holographic grating in LiNbO3 crystals  

NASA Astrophysics Data System (ADS)

Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crystals. The results indicate that the diffracted intensity distributions in the spectral and temporal domains and the diffraction efficiency of the grating are both changed by the polarization state and spectral bandwidth of the input pulsed beam. A method is given of choosing the grating parameters and input conditions to obtain a large variation range of the spectral bandwidth of the diffracted pulsed beam with an appropriate diffraction efficiency. Our study presents a possibility of using a volume holographic grating recorded in anisotropic materials to shape a broadband ultrashort pulsed beam by modulating its polarization state.

Wang, Chun-Hua; Liu, Li-Ren; Yan, Ai-Min; Zhou, Yu; Liu, De-An; Hu, Zhi-Juan

2007-01-01

163

High-sensitivity read-write volume holographic storage in Bi12SiO20 and Bi12GeO20 crystals  

Microsoft Academic Search

Bi12SiO20 and Bi12GeO20 present the best known photorefractive sensitivity for read-write volume holographic storage (S-1~=300 muJ\\/cm2) combined with high-quality image reconstruction. Recording processes by photocarrier diffusion (no applied field) and by photocarrier drift are identified. The high photosensitivity is attributed to photocarrier displacements comparable to or larger than fringe spacings. Saturation diffraction efficiency at light power densities larger than 600

J. P. Huignard; F. Micheron

1976-01-01

164

Three Dynamical Photorefractive Systems: a Novelty Filter, Volume Holographic Interconnection, and a Ring Resonator with Photorefractive Gain and Loss  

NASA Astrophysics Data System (ADS)

This thesis addresses three dynamic photorefractive systems: a novelty filter, volume holographic interconnection, and a ring resonator with both photorefractive gain and loss. Our interest in dynamical systems is motivated by a desire to understand how to build optical processors for computations difficult for conventional computers. We choose optics as the medium because of the ease of parallelism, and photorefractive materials because of their very high nonlinearity. The novelty filter displays the time-dependent features of a scene. The device consists of a Michelson interferometer with phase conjugating mirrors. The interferometer may be used to monitor time- and space-dependent optical phase changes. With a modified liquid crystal television used as a spatial light phase modulator we detect time -dependent features of an image viewed by a video camera. A real-time volume holographic medium is a programmable two-port device that operates on an optical electric field. A photorefractive two-port operator establishes the interconnects required by neural network models. The index grating that forms in the medium serves to fully interconnect two layers of processing units and at the same time sums the input signals to the output layer. We experimentally demonstrate a projection operator whereby we store and recall seven one-dimensional images. A ring resonator with both photorefractive gain and loss exhibits bistability and self-pulsing. Two-beam coupling loss plays the role of a programmable saturable absorber. The dynamic behavior of the system can be described as a competitive interaction between gain and loss; if the gain wins, the resonator turns on, and if the loss wins the resonator remains off. Self pulsing occurs when the winner alternates between the gain and the loss. We present theory and experiment for a ring resonator with photorefractive two-beam coupling gain and loss. The choice of pump intensities, gain coefficients, and time constants determines the time behavior of the resonator field. Experimental observations of reversible and irreversible bistability and self pulsing comply with the theory.

Lininger, Diana Marie

1990-01-01

165

Application of three-dimensional spatial correlation properties of coherent noise in phase noise suppression for digital holographic microscopy  

NASA Astrophysics Data System (ADS)

The inherited coherent noise degrades the phase imaging quality in digital holographic microscopy (DHM). To overcome the problem, an experimental investigation on the three-dimensional (3D) spatial correlation properties of coherent noise is carried out. Multiple blank holograms are recorded without any specimen in DHM setup by consecutively shifting camera along the optical axis, and a series of phase distribution of coherent noise can be obtained by numerical reconstruction. Then, based on the phase distributions, the lateral and longitudinal correlation properties of coherent noise are analyzed by a discrete correlation algorithm. Furthermore, a method for reducing phase noise is proposed by use of multiple holograms. Firstly, a series of holograms are recorded by shifting the camera longitudinally with the step more than longitudinal correlation length of coherent noise field. Secondly, the reconstruction of the holograms leads to a series of phase images of object, in which the coherent noise has different patterns. Consequently, by averaging the phase images, the reductions of phase noise are achieved. The applicability of the method is demonstrated by imaging of the resolution targets and the grating.

Pan, Feng; Xiao, Wen; Liu, Shuo; Rong, Lu

2013-10-01

166

Three-dimensional coupled wave study for finite-sized anisotropic volume holographic gratings under ultrashort pulsed beam readout  

NASA Astrophysics Data System (ADS)

The three-dimensional coupled wave theory is extended to systematically investigate the diffraction properties of finite-sized anisotropic volume holographic gratings (VHGs) under ultrashort pulsed beam (UPB) readout. The effects of the grating geometrical size and the polarizations of the recording and readout beams on the diffraction properties are presented, in particular under the influence of grating material dispersion. The wavelength selectivity of the finite-sized VHG is analyzed. The wavelength selectivity determines the intensity distributions of the transmitted and diffracted pulsed beams along the output face of the VHG. The distortion and widening of the diffracted pulsed beams are different for different points on the output face, as is numerically shown for a VHG recorded in a LiNbO3 crystal. The beam quality is analyzed, and the variations of the total diffraction efficiency are shown in relation to the geometrical size of the grating and the temporal width of the readout UPB. In addition, the diffraction properties of the finite-sized and one-dimensional VHG for pulsed and continuous-wave readout are compared. The study shows the potential application of VHGs in controlling spatial and temporal features of UPBs simultaneously.

Wang, Chunhua; Liu, Liren; Yan, Aimin; Liu, Dean; Zhou, Yu; Dai, Cuixia

2007-06-01

167

Cross-correlations in volume space: Differences between buy and sell volumes  

NASA Astrophysics Data System (ADS)

We study the cross-correlations of buy and sell volumes on the Korean stock market in high frequency. We observe that the pulling effects of volumes are as small as that of returns. The properties of the correlations of buy and sell volumes differ. They are explained by the degree of synchronization of stock volumes. Further, the pulling effects on the minimal spanning tree are studied. In minimal spanning trees with directed links, the large pulling effects are clustered at the center, not uniformly distributed. The Epps effect of buy and sell volumes are observed. The reversal of the cross-correlations of buy and sell volumes is also detected.

Lee, Sun Young; Hwang, Dong Il; Kim, Min Jae; Koh, In Gyu; Kim, Soo Yong

2011-03-01

168

Diffraction study of volume holographic gratings in dispersive photorefractive material for femtosecond pulse readout  

Microsoft Academic Search

Based on the modified Kogelnik diffraction efficiency equation, the diffraction intensity spectrum and the total diffraction efficiency of volume gratings in photorefractive media are studied systematically. Taking photorefractive InP:Fe crystal as an example, the effect of the grating parameters and the pulse width on the diffraction properties are presented, in particular under the influence of crystal material dispersion. Under the

Chen Yang; Xiaona Yan; Rong Zhu; Hua Zou; Feng Han

2010-01-01

169

All-optical fiber sensing system based on random phase encoding and volume holographic interconnection  

Microsoft Academic Search

We propose what we believe is the first all-optical fiber sensing system without any electronic processing. A multiple-mode fiber detects external perturbations and serves as a random phase generator. A crystal serves as the volume hologram recorder and database and provides the interconnections between a specific incoming random phase and the corresponding output pattern indicating the external perturbation on the

Ching-Cherng Sun; Yi-Ming Chen; Wei-Chia Su

2001-01-01

170

Application of the fast-Fourier-transform-based volume integral equation method to model volume diffraction in shift-multiplexed holographic data storage.  

PubMed

Numerical simulation of diffraction on thick holographic gratings in shift-multiplexed optical data storage application is presented. The grating is generated by the interference of a spherical reference wave and a plane signal wave corresponding to a single pixel of the input data page. To describe diffraction on this weak-index-modulated grating, we use the volume integral equation in the first Born approximation. This description yields a convolution integral that can be efficiently evaluated by a 3D fast Fourier transform (FFT) technique. For a 51.2 microm recording layer thickness, a serial-divided single personal computer code was built based on parallel FFT coding principles. Diffracted electric field and Poynting-vector distributions are calculated for probe beams spatially shifted with respect to the reference beams. The shift selectivity curves show significant differences from previous analytical calculations based on paraxial propagation and infinite gratings, as they have monotonic decrease in all three directions instead of sinclike functions with Bragg nulls. With the chosen numerical aperture of 0.6 and linear polarization, both the scalar and vector calculations provided similar results within 5%. PMID:17047723

Gombköto, Balázs; Koppa, Pál; Maák, Pál; Lorincz, Emoke

2006-11-01

171

Performance analysis of the FDTD method applied to holographic volume gratings: Multi-core CPU versus GPU computing  

NASA Astrophysics Data System (ADS)

The finite-difference time-domain method (FDTD) allows electromagnetic field distribution analysis as a function of time and space. The method is applied to analyze holographic volume gratings (HVGs) for the near-field distribution at optical wavelengths. Usually, this application requires the simulation of wide areas, which implies more memory and time processing. In this work, we propose a specific implementation of the FDTD method including several add-ons for a precise simulation of optical diffractive elements. Values in the near-field region are computed considering the illumination of the grating by means of a plane wave for different angles of incidence and including absorbing boundaries as well. We compare the results obtained by FDTD with those obtained using a matrix method (MM) applied to diffraction gratings. In addition, we have developed two optimized versions of the algorithm, for both CPU and GPU, in order to analyze the improvement of using the new NVIDIA Fermi GPU architecture versus highly tuned multi-core CPU as a function of the size simulation. In particular, the optimized CPU implementation takes advantage of the arithmetic and data transfer streaming SIMD (single instruction multiple data) extensions (SSE) included explicitly in the code and also of multi-threading by means of OpenMP directives. A good agreement between the results obtained using both FDTD and MM methods is obtained, thus validating our methodology. Moreover, the performance of the GPU is compared to the SSE+OpenMP CPU implementation, and it is quantitatively determined that a highly optimized CPU program can be competitive for a wider range of simulation sizes, whereas GPU computing becomes more powerful for large-scale simulations.

Francés, J.; Bleda, S.; Neipp, C.; Márquez, A.; Pascual, I.; Beléndez, A.

2013-03-01

172

Dynamic theory of volume holographic recording and readout in electro-optic crystals  

Microsoft Academic Search

The dynamic theory of volume holography was found to qualitatively and, to some extent, quantitatively describe all aspects of experimentally observed thick (phase) hologram terminal (output) characteristics measured in electro-optic crystals such as LiNbO3. The description of the formation (recording), static readout (angular selectivity), and dynamic readout of the hologram are all contained in the dynamic theory formalism. The experimentally

R. Magnusson

1976-01-01

173

Electro-optical switching of volume holographic gratings recorded in polymer dispersed liquid crystals  

Microsoft Academic Search

In this paper, we describe a novel liquid crystal-polymer composite material system which allows fast, single-step recording of volume holograms with diffraction efficiency approaching 100% and narrow angular selectivity. The diffraction efficiencies (DE) are controllable by applied electric fields. We have achieved complete switching of a first-order Bragg diffracted beam into the zero-order with an applied field of ~8 V\\/?m

L. V. Natarajan; R. L. Sutherland; V. P. Tondiglia; T. Bunning; W. W. Adams

1996-01-01

174

Polarization of holographic grating diffraction. II. Experiment  

Microsoft Academic Search

The diffraction of volume holographic gratings is investigated experimentally. We report the measured optical and polarization properties of two volume holographic grating samples and the substrate material. Sample A has a single grating and sample B has three gratings. The Mueller matrices of the transmission (t), diffraction (d) and reflection (r) are measured at a wavelength of 632.8 nm. The

Tsu-Wei Nee; Soe-Mie F. Nee; Mark W. Kleinschmit; M. S. Shahriar

2004-01-01

175

Analysis of the effects of viscosity, volume, and temperature in photopolymer material for holographic applications  

NASA Astrophysics Data System (ADS)

In recent work carried out, we introduced the developments made to the Non-local Photo-polymerization Driven Diffusion model, and illustrate some of the useful trends, which the model predicts and then analyse their implications on photopolymer improvement. The model was improved in its physicality through the inclusion of viscosity effects (changes in fractional free volume), multiple components and their photo-kinetic and photo-physical behaviour, and free space vacuoles. In this paper, we further explore this model to provide a more rigorous and informed basis for predicting the behaviours of photopolymer materials in both photo-chemical and photo-physical sides. Such improvements include a) the analysis of the effects of viscosity on the refractive index modulation, b) the effects of the introduction of free space holes, e.g. the volumetric changes, and c) an examination of the effects of local temperatures and various concentration ratios to optimise material performance.

Guo, Jinxin; Gleeson, Michael R.; Sheridan, John T.

2013-05-01

176

Anatomical and functional correlates of human hippocampal volume asymmetry.  

PubMed

Hemispheric asymmetry of the human hippocampus is well established, but poorly understood. We studied 110 healthy subjects with 3-Tesla MRI to explore the anatomical and functional correlates of the R>L volume asymmetry. We found that the asymmetry is limited to the anterior hippocampus (hemisphere×region interaction: F(1,109)=42.6, p<.001). Anterior hippocampal volume was correlated strongly with the volumes of all four cortical lobes. In contrast, posterior hippocampal volume was correlated strongly only with occipital lobe volume, moderately with the parietal and temporal lobe volumes and not with the frontal lobe volume. The degree of R>L anterior hippocampal volume asymmetry predicted performance on a measure of basic cognitive abilities. This provides evidence for regional specificity and functional implications of the well-known hemispheric asymmetry of hippocampal volume. We suggest that the developmental profile, genetic mechanisms and functional implications of R>L anterior hippocampal volume asymmetry in the human brain deserve further study. PMID:22285719

Woolard, Austin A; Heckers, Stephan

2012-01-27

177

Anatomical and functional correlates of human hippocampal volume asymmetry  

PubMed Central

Hemispheric asymmetry of the human hippocampus is well established, but poorly understood. We studied 110 healthy subjects with 3-Tesla MRI to explore the anatomical and functional correlates of the R>L volume asymmetry. We found that the asymmetry is limited to the anterior hippocampus (hemisphere × region interaction: F(1,109) = 42.6, p < .001). Anterior hippocampal volume was correlated strongly with the volumes of all four cortical lobes. In contrast, posterior hippocampal volume was correlated strongly only with occipital lobe volume, moderately with the parietal and temporal lobe volumes and not with the frontal lobe volume. The degree of R>L anterior hippocampal volume asymmetry predicted performance on a measure of basic cognitive abilities. This provides evidence for regional specificity and functional implications of the well-known hemispheric asymmetry of hippocampal volume. We suggest that the developmental profile, genetic mechanisms and functional implications of R>L anterior hippocampal volume asymmetry in the human brain deserve further study.

Woolard, Austin; Heckers, Stephan

2011-01-01

178

Access control holographic system based on joint transform correlator and image encoding  

Microsoft Academic Search

New lay-out for the access control system based on joint transform correlator (jtc) is presented. The carrier-key should consist\\u000a of several tested holograms. Each of the holograms stores a part of entire image, stored in the reference hologram. Image\\u000a domain jtc is used to match the images retrieved from the holograms. Being recorded and retrieved, the images provides correlation\\u000a peaks

S. B. Odinokov

2008-01-01

179

Dynamic pattern recognition and data storage using localized holographic recording  

NASA Astrophysics Data System (ADS)

A new technique for optical pattern recognition with two-center recording of persistent holograms in doubly doped LiNbO3:Fe:Mn crystal is presented, by which the holograms are localized in separate slices along the recording medium. The localized recording method has the distinctive advantage of selective recording and erasure of the individual holograms without affecting the entire holographic recording medium. This capability enables dynamic content modification of the optical pattern recognition systems. Also, the diffraction efficiency of localized holograms is much larger than that of the normal volume multiplexed holograms. It is theoretically shown that the localized holographic correlator (LHC) outperforms the conventional volume holographic correlators in terms of crosstalk, shift invariance, and capacity. The LHC is experimentally demonstrated. Several persistent holograms are localized within separate slices as close as 33 mum apart along the crystal. The excessive diffraction efficiency of the localized holograms is employed to enhance the LHC robustness through multiplexing several holograms per pattern within individual slices of the recording medium. A holographic data storage system based on two-center holographic recording in a doubly doped LiNbO3:Fe:Mn crystal is developed with angular multiplexing capability. The associated imaging system has been optimized for the pixel matching of pixelated bit patterns generated by a spatial light modulator (SLM) through the recording medium onto a camera. The initial multiplexed holograms show promising contrast of dark and bright pixels. With the optimized imaging system of the developed holographic memory, the implementation of a dynamic read/write data storage system with localized recording is envisioned. The large diffraction efficiency of the localized holograms enables multilevel (M-ary) data coding to improve the storage density of the system.

Karbaschi, Arash

180

Holographic correlation functions of hexagon Wilson loops with one local operator  

NASA Astrophysics Data System (ADS)

We consider the ratio of the correlation function of a hexagon light-like Wilson loop with one local operator over the expectation value of the Wilson loop within the strong-coupling regime of the AdS/CFT correspondence. We choose the hexagon Wilson loop within a class of minimal solutions obtained by cutting and gluing light-like quadrangle loops. These surfaces do not have an interpretation in terms of dual scattering amplitudes but they still exhibit general features of the mixed correlation function. In the case of a regular null hexagon conformal symmetry constrains the space-time dependence of the correlator up to a function of three conformal cross-ratios. We obtain the leading-order contribution to the correlation function in the semiclassical approximation of large string tension, and express the result in terms of three conformal ratios in the case where the local operator is taken to be the dilaton. We include the analysis of an irregular Wilson loop obtained after a boost of the regular hexagon.

Hernández, Rafael; Nieto, Juan Miguel

2013-10-01

181

Instantaneous characteristics study of the diffracted and transmitted light of a static photorefractive reflection volume holographic grating read by an ultrashort pulse laser  

NASA Astrophysics Data System (ADS)

The time-domain diffraction and transmission of reflection volume holographic gratings (RVHGs) recorded in photorefractive LiNbO3 crystals are theoretically studied and compared with transmission volume holographic gratings (TVHGs) when they are illuminated by ultrashort pulse laser light. The modified Kogelnik's coupled-wave theory, combining the dispersion effect in the crystal, is used. The results show that larger diffraction intensity can be obtained by choosing a larger grating period, grating thickness and modulation index for a given pulse duration. The RVHG has higher diffraction intensity than the TVHG with the same grating parameters. Also, it is found that the diffracted pulse of the RVHG and the TVHG shift in opposite directions along the time-axis. The values of the shifts are functions of the readout pulse duration and grating parameters. The overmodulation phenomenon appears in the diffracted pulse of the TVHG at high values of the grating thickness and refractive index modulation, but it does not occur in the RVHG. The results of our study can be used in choosing proper grating parameters for pulse shaping and signal processing applications.

Yi, Yingyan; Liu, Deming; Liu, Hairong

2011-03-01

182

Holographic thinking  

NASA Astrophysics Data System (ADS)

Holographic thinking is everywhere although we do not realize it. Turn on your TV and you will see many representations of holographic images. It is in many science fiction movies, as well as in books and the news. Now, start your computer and search the Web. What do you see, a screen with plenty of little boxes or frames, each one containing information. You can choose to go deeper by clicking here and there, but ultimately all the little boxes are related to each other. What do you have? A holographic principle where each point stands by itself, containing the whole entity while composing part of it at the same time. The following paragraphs, discussing and evaluating the characteristics of holographic thinking can be read in any order you wish. Each paragraph contributes an understanding of just one aspect of all the ideas which cannot be limited to this paper alone.

Meulien-Ohlmann, Odile

2000-10-01

183

Holographic technidilaton  

SciTech Connect

Technidilaton, a pseudo-Nambu-Goldstone boson of scale symmetry, was predicted long ago in the scale-invariant/walking/conformal technicolor (SWC-TC) as a remnant of the (approximate) scale symmetry associated with the conformal fixed point, based on the conformal gauge dynamics of ladder Schwinger-Dyson (SD) equation with nonrunning coupling. We study the technidilaton as a flavor-singlet bound state of technifermions by including the technigluon condensate (tGC) effect into the previous (bottom-up) holographic approach to the SWC-TC, a deformation of the holographic QCD with {gamma}{sub m{approx_equal}}0 by large anomalous dimension {gamma}{sub m{approx_equal}}1. With including a bulk scalar field corresponding to the gluon condensate, we first improve the operator product expansion of the current correlators so as to reproduce gluonic 1/Q{sup 4} term both in QCD and SWC-TC. We find in QCD about 10% (negative) contribution of gluon condensate to the {rho} meson mass. We also calculate the oblique electroweak S-parameter in the presence of the effect of the tGC and find that for the fixed value of S the tGC effects dramatically reduce the flavor-singlet scalar (technidilaton) mass M{sub TD} (in the unit of F{sub {pi}}), while the vector and axial-vector masses M{sub {rho}}and M{sub a{sub 1}} are rather insensitive to the tGC, where F{sub {pi}}is the decay constant of the technipion. If we use the range of values of tGC implied by the ladder SD analysis of the nonperturbative scale anomaly in the large N{sub f} QCD near the conformal window, the phenomenological constraint S{approx_equal}0.1 predicts the technidilaton mass M{sub TD{approx}}600 GeV which is within reach of LHC discovery.

Haba, Kazumoto [Department of Physics, Nagoya University, Nagoya, 464-8602 (Japan); Matsuzaki, Shinya [Department of Physics, Pusan National University, Busan 609-735 (Korea, Republic of); Yamawaki, Koichi [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602 (Japan)

2010-09-01

184

Holographic diffusers  

NASA Astrophysics Data System (ADS)

Holographic diffusers are prepared using silver halide (Agfa 8E75 and Kodak 649F) and photopolymer (Polaroid DMP 128 and DuPont 600, 705, and 150 series) media. It is possible to control the diffusion angle in three ways: by selection of the properties of the source diffuser, by control of its subtended angle, and by selection of the holographic medium. Several conventional diffusers based on refraction or scattering of light are examined for comparison.

Wadle, Stephen; Wuest, Daniel; Cantalupo, John; Lakes, Roderic S.

1994-01-01

185

Extreme-ultraviolet Bragg holographic structures: theory and experiments  

Microsoft Academic Search

A theoretical analysis of extreme-ultraviolet (XUV) Bragg (volume) holographic diffraction structures with arbitrary periodic spatial-modulation profiles is presented, and two basic approaches for the fabrication of XUV holographic optical elements suggested by the theory are discussed. The theoretical results are compared with preliminary experimental observations from XUV Bragg holographic structures recently fabricated in the laboratory, and fairly good agreement is

Tomasz Jannson; Gajendra Savant; Liping Wang

1991-01-01

186

A low-resolution 3D holographic volumetric display  

NASA Astrophysics Data System (ADS)

A simple low resolution volumetric display is presented, based on holographic volume-segments. The display system comprises a proprietary holographic screen, laser projector, associated optics plus a control unit. The holographic screen resembles a sheet of frosted glass about A4 in size (20x30cm). The holographic screen is rear-illuminated by the laser projector, which is in turn driven by the controller, to produce simple 3D images that appear outside the plane of the screen. A series of spatially multiplexed and interleaved interference patterns are pre-encoded across the surface of the holographic screen. Each illumination pattern is capable of reconstructing a single holographic volume-segment. Up to nine holograms are multiplexed on the holographic screen in a variety of configurations including a series of numeric and segmented digits. The demonstrator has good results under laboratory conditions with moving colour 3D images in front of or behind the holographic screen.

Khan, Javid; Underwood, Ian; Greenaway, Alan; Halonen, Mikko

2010-04-01

187

Holographic assembly of nanoparticles in polymers for 3D recording and patterning  

NASA Astrophysics Data System (ADS)

Holographic manipulation of nanoparticle assembly in polymer and its applications to holographic 3D recording and patterning are described. A statistical thermodynamic model is used to study the kinetics of multidimensional nanoparticle assembling in polymer under holographic illumination. Volume holographic storage using peristrophic multiplexing and nanoparticle pattering in silica nanoparticles-polymer composite films are also demonstrated experimentally.

Tomita, Yasuo; Suzuki, Naoaki; Endoh, Yutaka; Kurozumi, Shin-ichi; Miki, Mayu; Chikama, Katsumi

2007-09-01

188

Holographic thermalization  

NASA Astrophysics Data System (ADS)

We consider the transition of a quantum field system toward the state of thermal equilibrium based on the holographic description using the duality between the quantum field system in the d-dimensional Minkowski space and the gravity theory in the (d+ 1)-dimensional anti-de Sitter space. In this construction, the thermalization in the d-dimensional space is described in the holographic language as the formation of a black hole in the (d+ 1)-dimensional space. We use a holographic model of thermalization of the quark-gluon plasma describing the black hole formation by the Vaidya metric. We show that evaporation of the black hole, also modeled by the Vaidya metric, leads to an interesting effect in the d-dimensional space: thermalization occurs only at small distances and is impossible in the infrared region. In the considered model, the thermal behavior at small distances is possible only during a certain time, after which the dethermalization process begins.

Arefeva, I. Ya.; Volovich, I. V.

2013-02-01

189

Holographic LEED  

SciTech Connect

We propose a new electron holographic scheme for the three-dimensional imaging of the atomic environment of disordered adsorbate atoms on a crystal surface, in which the object acts as its own beam splitter. The technique may be regarded as a direct method in low-energy electron diffraction, or even, in a sense, as a form of lensless electron microscopy.''

Saldin, D.K. (Department of Physics and Laboratory for Surface Studies, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (USA)); de Andres, P.L. (Center for Advanced Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (USA))

1990-03-12

190

Extreme-ultraviolet Bragg holographic structures: theory and experiments  

SciTech Connect

A theoretical analysis of extreme-ultraviolet (XUV) Bragg (volume) holographic diffraction structures with arbitrary periodic spatial-modulation profiles is presented, and two basic approaches for the fabrication of XUV holographic optical elements suggested by the theory are discussed. The theoretical results are compared with preliminary experimental observations from XUV Bragg holographic structures recently fabricated in the laboratory, and fairly good agreement is found. This comparison indicates that our holographic materials can reach very high refractive-index modulation ({Delta}n{similar to}0.4) and are thus good candidates for the production of high-efficiency XUV holographic optical elements.

Jannson, T.; Savant, G.; Wang, L. (Physical Optics Corporation, Suite 103, 20600 Gramercy Place, Torrance, California (USA))

1991-10-01

191

Intelligent holographic databases  

NASA Astrophysics Data System (ADS)

Memory is a key component of intelligence. In the human brain, physical structure and functionality jointly provide diverse memory modalities at multiple time scales. How could we engineer artificial memories with similar faculties? In this thesis, we attack both hardware and algorithmic aspects of this problem. A good part is devoted to holographic memory architectures, because they meet high capacity and parallelism requirements. We develop and fully characterize shift multiplexing, a novel storage method that simplifies disk head design for holographic disks. We develop and optimize the design of compact refreshable holographic random access memories, showing several ways that 1 Tbit can be stored holographically in volume less than 1 m3, with surface density more than 20 times higher than conventional silicon DRAM integrated circuits. To address the issue of photorefractive volatility, we further develop the two-lambda (dual wavelength) method for shift multiplexing, and combine electrical fixing with angle multiplexing to demonstrate 1,000 multiplexed fixed holograms. Finally, we propose a noise model and an information theoretic metric to optimize the imaging system of a holographic memory, in terms of storage density and error rate. Motivated by the problem of interfacing sensors and memories to a complex system with limited computational resources, we construct a computer game of Desert Survival, built as a high-dimensional non-stationary virtual environment in a competitive setting. The efficacy of episodic learning, implemented as a reinforced Nearest Neighbor scheme, and the probability of winning against a control opponent improve significantly by concentrating the algorithmic effort to the virtual desert neighborhood that emerges as most significant at any time. The generalized computational model combines the autonomous neural network and von Neumann paradigms through a compact, dynamic central representation, which contains the most salient features of the sensory inputs, fused with relevant recollections, reminiscent of the hypothesized cognitive function of awareness. The Declarative Memory is searched both by content and address, suggesting a holographic implementation. The proposed computer architecture may lead to a novel paradigm that solves 'hard' cognitive problems at low cost.

Barbastathis, George

192

Holographic Quantum Liquid  

SciTech Connect

Quantum liquids are characterized by the distinctive properties such as the low-temperature behavior of heat capacity and the spectrum of low-energy quasiparticle excitations. In particular, at low temperature, Fermi liquids exhibit the zero sound, predicted by Landau in 1957 and subsequently observed in liquid He-3. In this Letter, we ask whether such characteristic behavior is present in theories with a holographically dual description. We consider a class of gauge theories with fundamental matter fields whose holographic dual in the appropriate limit is given in terms of the Dirac-Born-Infeld action in anti-de Sitter space. We find that these systems also exhibit a sound mode at zero temperature despite having a non-Fermi-liquid behavior of the specific heat. These properties suggest that holography identifies a new type of quantum liquid which potentially could be experimentally realized in strongly correlated systems.

Karch, A. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Son, D. T. [Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1550 (United States); Starinets, A. O. [School of Natural Sciences, Institute for Advanced Study, Einstein Drive, Princeton, New Jersey 08540 (United States); School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

2009-02-06

193

Analytic holographic superconductor  

SciTech Connect

We investigate a holographic superconductor that admits an analytic treatment near the phase transition. In the dual 3+1-dimensional field theory, the phase transition occurs when a scalar operator of scaling dimension two gets a vacuum expectation value. We calculate current-current correlation functions along with the speed of second sound near the critical temperature. We also make some remarks about critical exponents. An analytic treatment is possible because an underlying Heun equation describing the zero mode of the phase transition has a polynomial solution. Amusingly, the treatment here may generalize for an order parameter with any integer spin, and we propose a Lagrangian for a spin-two holographic superconductor.

Herzog, Christopher P. [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

2010-06-15

194

Holographic microrefractometer  

NASA Astrophysics Data System (ADS)

In-line holographic microscopy of micrometer-scale colloidal spheres yields heterodyne scattering patterns that may be interpreted with Lorenz-Mie theory to obtain precise time-resolved information on the refractive index of the suspending medium. We demonstrate this method's efficacy with measurements on calibrated refractive index standards, and apply it to measurements of varying Sucrose concentration in a microfluidic channel. Using commercial colloidal spheres as probe particles and a standard video camera for detection yields volumetric refractive index measurements with a resolution approaching 10-3 RIU for each probe particle in each holographic snapshot. The combination of spatial resolution, temporal resolution, multi-point in situ access and technical simplicity favor this approach for cost-effective lab-on-a-chip applications.

Shpaisman, Hagay; Krishnatreya, Bhaskar J.; Grier, David G.

2012-02-01

195

Photopolymer Use For Holographic Data Storage  

NASA Astrophysics Data System (ADS)

Holographic data storage (HDS), which makes use of the full volume of the recording medium, possesses high potential by promising fast transfer rates of hundreds of Megabytes/sec and storage densities greater than 200 Gbytes per 120mm disk. The restrictions that are placed on the holographic media, however, are stringent. Described here is a high performance photopolymer based medium that has the properties necessary to enable this technology. Through the use of several different holographic techniques, the material characteristics that are necessary for holographic storage products may be determined. The two different systems that are discussed here include Plane Wave and Digital Holographic Data Storage. These measured characteristics include high dynamic range (M/#), sensitivity, and small recording-induced Bragg detuning. In addition, results of archival and shelf-life environmental testing of the media will be discussed.

Schnoes, Melinda; Ihas, Benjamin; Dhar, Lisa; Michaels, David; Setthachayanon, Songvit; Schomberger, Gayle L.; Wilson, William L.

2003-12-01

196

Holographic memory in solid state architecture  

NASA Astrophysics Data System (ADS)

Number of applications require technology that allows storing, retrieving, and processing a large volume of information. Holographic memory offers high-density data storage with parallel access and high throughput. Several methods exist for data multiplexing based on the fundamental principles of volume hologram selectivity. We recently demonstrated that a spatial (amplitude-phase) encoding of the reference wave (SERW) looks promising as a way to increase the storage density. The SERW hologram offers a method other than traditional methods of selectivity, such as spatial de-correlation between recorded and reconstruction fields. In this report we present the experimental results of the SERW-hologram memory module with solid-state architecture, which is of particular interest for space operations.

Markov, Vladimir B.

2002-01-01

197

Holographic photolysis of caged neurotransmitters  

PubMed Central

Stimulation of light-sensitive chemical probes has become a powerful tool for the study of dynamic signaling processes in living tissue. Classically, this approach has been constrained by limitations of lens–based and point-scanning illumination systems. Here we describe a novel microscope configuration that incorporates a nematic liquid crystal spatial light modulator (LC-SLM) to generate holographic patterns of illumination. This microscope can produce illumination spots of variable size and number and patterns shaped to precisely match user-defined elements in a specimen. Using holographic illumination to photolyse caged glutamate in brain slices, we demonstrate that shaped excitation on segments of neuronal dendrites and simultaneous, multi-spot excitation of different dendrites enables precise spatial and rapid temporal control of glutamate receptor activation. By allowing the excitation volume shape to be tailored precisely, the holographic microscope provides an extremely flexible method for activation of various photosensitive proteins and small molecules.

Lutz, Christoph; Otis, Thomas S.; DeSars, Vincent; Charpak, Serge; DiGregorio, David A.; Emiliani, Valentina

2009-01-01

198

Quantitative measurement of absolute cell volume and intracellular integral refractive index (RI) with dual-wavelength digital holographic microscopy (DHM)  

NASA Astrophysics Data System (ADS)

Quantitative Phase Imaging techniques including DHM have been applied recently in the field of cell imaging to monitor and quantify non-invasively dynamic cellular processes modifying cell morphology and/or content . Concretely, the DHM phase signal is highly sensitive to cell thickness and intracellular integral RI variations associated with transmembrane water movements. As net water flow across the cell membrane leads at the same time to changes in cell thickness and intracellular RI, the interpretation of phase signal variations remains difficult. To overcome this drawback, we have developed a Dual-wavelength Digital Holographic Microscopy (DHM) setup allowing to separately measure, with a single CCD camera acquisition, thickness and integral RI of living cells. The method is based on the use of an absorbing dye that enhances the refractive index dispersion of the extracellular medium. Practically, two significantly different phase signals can be obtained when measuring at two appropriate wavelengths. From the two phase measurements, both cell RI and thickness can be univocally determined.

Boss, Daniel; Kühn, Jonas; Depeursinge, Christian; Magistretti, Pierre J.; Marquet, Pierre

2012-05-01

199

Holographic microscopy.  

PubMed

An off-axis transmission holographic scheme, in which a 1:1 lens and a hologram are treated as a single rigid entity, is found to reconstruct a 3-D diffraction-limited image when reconstructed, with a reference beam reversed back through the original lens-hologram unit. Reconstruction can be performed with wavelengths other than the recording wavelength, provided achromatic lenses are used, and the reference beam angle is properly changed for reconstruction. Comparisons are made between He-Ne and ruby laser holograms. Two-micron resolution of the combustion of solid rocket propellants at high pressures is achieved at a working distance of 6 cm. PMID:20197904

Briones, R A; Heflinger, L O; Wuerker, R F

1978-03-15

200

Holographic optics: Design and applications; Proceedings of the Meeting, Los Angeles, CA, Jan. 13, 14, 1988  

NASA Astrophysics Data System (ADS)

The present conference discusses topics in design and analysis methods for holographic optics, as well as their materials and fabrication techniques and their applications. Attention is given to novel holographic helmet display designs, holographic optics optimization by damped least-squares and wavefront matching, the optical performance of holographic kinoforms, a cascaded transmission hologram for HUDs, a multilayer thin film simulation of volume holograms, and the DMP-128 holographic-recording photopolymer. Also discussed are a uniform hologram construction layout, diffractive optics with incoherent optical systems, holographic laser-protective eyewear, novel applications for embossed holograms, and hologon deflectors with dispersive optical elements for scan line bow correction.

Cindrich, Ivan

1988-01-01

201

Real Time Holographic Interferometry.  

National Technical Information Service (NTIS)

The thesis presents an introduction into holographic interferometry with its history and applications. Problems involved with recording, developing, and reconstructing real time holographic interferograms are presented. Reconstruction was accomplished usi...

J. W. Somers

1974-01-01

202

Iterative correction of holographic lenses  

NASA Astrophysics Data System (ADS)

Holographic optical lens elements (HOEs) are volume grating in thick material such as dichromated gelatine (DCG) which suffer from the wavelength mismatch between the recording process and the practical application e.g., at laser diode wavelengths. Wavelength mismatch between recording and reconstruction is caused by the fact that the best recording materials are sensitive only in the blue region of the spectrum. The advantage of volume gratings (thickness 13 micrometers ) is the large angle of deflection of the first diffraction order with a high diffraction efficiency. An optimized recording geometry using only spherical wave fronts allows on the one hand for the elimination of one of the third order aberrations (predominantly: astigmatism) or on the other hand for the fulfillment of the Bragg condition. To optimize the properties of holographic optical lens elements with one aspheric recording wave a kind of iterative procedure for the manufacturing is proposed. Each iteration consists of three different steps.

Falkenstoerfer, Oliver; Keinonen, T.; Lindlein, Norbert; Schwider, Johannes; Streibl, Norbert

1994-10-01

203

Holographic storage using phase-code and rotation multiplexing  

Microsoft Academic Search

Multiple holograms can be storage in a volume holographic medium such as photorefractive crystal or photopolymers by using phase-code multiplexing. However, due to the limited performance of currently available spatial phase encoders, only a small number of orthogonal phase codes can be implemented. This significantly limits the capacity of holographic systems based on phase-code multiplexing scheme. In this paper, a

Zhiqing Wen; Nan Li; Yu Xu; Xiangyang Yang

1996-01-01

204

Mask designs for multiple-holographic-grating optical devices  

Microsoft Academic Search

In this paper, we propose and examine mask design methods for fabricating optical devices containing multiple holographic gratings. As the conventional fiber Bragg grating fabrication, the mask is also required to achieve compactness and accuracy in this case. However, for the case where there needs multiplexing of several holographic gratings in the same volume of the recording medium, the mask

Seunghoon Han; Kyongsik Choi; Hwi Kim; Jung W. Paek; Byoungho Lee

2003-01-01

205

Air impurity in holographic photonic crystals made with dichromated gelatin  

NASA Astrophysics Data System (ADS)

The physical mechanism of the air impurity in volume holographic photonic crystals was investigated in this paper. The photonic forbidden band with the air impurity was analyzed and calculated by the transfer matrix method. Verifications were carried out using one dimensional holographic photonic crystals made with Dichromated Gelatin (DCG), and the impurity modes were observed.

Ren, Zhi; Li, Songtao; Liu, Dahe

2010-11-01

206

Holographic 3-D printer  

Microsoft Academic Search

This paper proposes a holographic printer, which produces 3-D hard copies of computer processed objects. For the purpose of automatic making of 3-D hard copies of distortion free, a new method to synthesize holographic stereogram is proposed. It is is flat format and lippmann type holographic stereogram which can be printed by one optical step. The proposed hologram has not

Masahiro Yamaguchi; Nagaaki Ohyama; Toshio Honda

1990-01-01

207

Holographic MQCD  

SciTech Connect

We study a brane configuration of D4-branes and NS5-branes in weakly coupled type IIA string theory, which describes in a particular limit d=4 N=1 SU(N+p) supersymmetric QCD with 2N flavors and a quartic superpotential. We describe the geometric realization of the supersymmetric vacuum structure of this gauge theory. We focus on the confining vacua of the gauge theory, whose holographic description is given by the MQCD brane configuration in the near-horizon geometry of N D4-branes. This description, which gives an embedding of MQCD into a field theory decoupled from gravity, is valid for 1<

Aharony, Ofer [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel); Kutasov, David [EFI and Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Lunin, Oleg [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States); Sonnenschein, Jacob; Yankielowicz, Shimon [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 69978 (Israel); Albert Einstein Minerva Center, Weizmann Institute of Science, Rehovot 76100 (Israel)

2010-11-15

208

Holographic mutual information is monogamous  

NASA Astrophysics Data System (ADS)

We identify a special information-theoretic property of quantum field theories with holographic duals: the mutual informations among arbitrary disjoint spatial regions A, B, C obey the inequality I(A?B?C)?I(A?B)+I(A?C), provided entanglement entropies are given by the Ryu-Takayanagi formula. Inequalities of this type are known as monogamy relations and are characteristic of measures of quantum entanglement. This suggests that correlations in holographic theories arise primarily from entanglement rather than classical correlations. We also show that the Ryu-Takayanagi formula is consistent with all known general inequalities obeyed by the entanglement entropy, including an infinite set recently discovered by Cadney et al.; this constitutes strong evidence in favor of its validity.

Hayden, Patrick; Headrick, Matthew; Maloney, Alexander

2013-02-01

209

Holographic superconductors with various condensates  

SciTech Connect

We extend earlier treatments of holographic superconductors by studying cases where operators of different dimension condense in both 2+1 and 3+1 superconductors. We also compute a correlation length. We find surprising regularities in quantities such as {omega}{sub g}/T{sub c} where {omega}{sub g} is the gap in the frequency dependent conductivity. In special cases, new bound states arise corresponding to vector normal modes of the dual near-extremal black holes.

Horowitz, Gary T.; Roberts, Matthew M. [Department of Physics, UCSB, Santa Barbara, California 93106 (United States)

2008-12-15

210

Holographic Observation of Crystal Growth from the Melt.  

National Technical Information Service (NTIS)

A holographic recording technique is used to observe the interface morphology of transparent crystals during growth from the melt. Microscopic detail with spatial resolution of 300 line pairs/mm can be recorded within a volume several centimeters long by ...

R. H. McFee

1969-01-01

211

Volume reconstruction techniques improve the correlation between histological and in vivo tumor volume measurements in mouse models of human gliomas.  

PubMed

Assessment of therapy efficacy using animal models of tumorigenic cancer requires the ability to accurately measure changes in tumor volume over the duration of disease course. In order to be meaningful, in vivo tumor volume measurements by non-invasive techniques must correlate with tumor volume measurements from endpoint histological analysis. Tumor volume is frequently assessed by endpoint histological analyses approximating the tumor volume with geometric primitives such as spheroids and ellipsoids. In this study we investigated alternative techniques for quantifying histological volume measurements of tumors in a xenograft orthotopic mouse model of human glioblastoma multiforme, and compared these to in vivo tumor volume measurements based on magnetic resonance imaging (MRI) data. Two techniques leveraging three-dimensional (3D) image analysis methods were investigated. The first technique involves the reconstruction of a smoothed polygonal model representing the tumor volume from histological section images and is intended for accuracy and qualitative assessment of tumor burden by visualization, while a second technique which approximates the tumor volume as a series of slabs is presented as an abbreviated process intended to produce quantitatively similar volume measurements with a minimum of effort required on behalf of the investigator. New software (QuickVol) designed for use in the first technique, is also discussed. In cases where tumor growth is asymmetric and invasive, we found that 3D analysis techniques using histological section images produced volume measurements more consistent with in vivo volume measurements based on MRI data, than approximation of tumor volume using geometric primitives. Visualizations of the volumes represented by each of these techniques qualitatively support this finding, and suggest that future research using mouse models of glioblastoma multiforme (genetically engineered or xenograft) will benefit from the use of these or similar alternative tumor volume measurement techniques. PMID:15332323

Schmidt, Karl F; Ziu, Mateo; Schmidt, Nils Ole; Vaghasia, Pramil; Cargioli, Theresa G; Doshi, Sameer; Albert, Mitchell S; Black, Peter McL; Carroll, Rona S; Sun, Yanping

2004-07-01

212

Bragg holographic structures for XUV applications: a new approach  

SciTech Connect

We report a new technique for producing high-efficiency XUV Bragg (volume) holographic optical elements by recording interference patterns in a photosensitive coating in either the visible or XUV region. Theoretical calculations and analysis of experimental results have successfully demonstrated the significance of this new fabrication methodology for XUV holographic optical elements, with over 25% diffraction efficiency achieved. In addition, volume holographic optics offer high flexibility in conventional and nonconventional operations, high laser-damage threshold and temperature stability, low surface roughness, and cost effectiveness in mass production.

Jannson, T.; Savant, G.; Qiao, Y.

1989-04-01

213

Unitary matrices for phase-coded holographic memories  

Microsoft Academic Search

Volume holographic data storage based on phase-code multiplexing is a promising technology for next generation optical storage devices. Volume holographic memories offer high storage capacities and short data access times through multiplexing and a page-oriented storage principle. Multiple holograms can be recorded in the storage media through various multiplexing techniques, such as angular, phase-code, wavelength or shift multiplexing. Among the

W. Horn; G. Berger; M. Dietz; X. Zhang; C. Denz

2007-01-01

214

Holographic dark energy reexamined  

SciTech Connect

We have reexamined the holographic dark energy model by considering the spatial curvature. We have refined the model parameter and observed that the holographic dark energy model does not behave as phantom model. Comparing the holographic dark energy model to the supernova observation alone, we found that the closed Universe is favored. Combining with the Wilkinson microwave anisotropy probe (WMAP) data, we obtained the reasonable value of the spatial curvature of our Universe.

Gong Yungui; Wang Bin; Zhang Yuanzhong [College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Department of Physics, Fudan University, Shanghai 200433 (China); CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, China and Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080 (China)

2005-08-15

215

Holographic optical disc  

NASA Astrophysics Data System (ADS)

The holographic disc is a high capacity, disk-based data storage device that can provide the performance for next generation mass data storage needs. With a projected capacity approaching 1 terabit on a single 12 cm platter, the holographic disc has the potential to become a highly efficient storage hardware for data warehousing applications. The high readout rate of holographic disc makes it especially suitable for generating multiple, high bandwidth data streams such as required for network server computers. Multimedia applications such as interactive video and HDTV can also potentially benefit from the high capacity and fast data access of holographic memory.

Zhou, Gan; An, Xin; Pu, Allen; Psaltis, Demetri; Mok, Fai H.

1999-11-01

216

Computer-generated holographic optical tweezer arrays  

Microsoft Academic Search

Holographic techniques significantly extend the capabilities of laser tweezing, making possible extended trapping patterns for manipulating large numbers of particles and volumes of soft matter. We describe practical methods for creating arbitrary configurations of optical tweezers using computer-generated diffractive optical elements. While the discussion focuses on ways to create planar arrays of identical tweezers, the approach can be generalized to

Eric R. Dufresne; Gabriel C. Spalding; Matthew T. Dearing; Steven A. Sheets; David G. Griera

2001-01-01

217

Price–volume cross-correlation analysis of CSI300 index futures  

NASA Astrophysics Data System (ADS)

We investigate the cross-correlation between price returns and trading volumes for the China Securities Index 300 (CSI300) index futures, which are the only stock index futures traded on the China Financial Futures Exchange (CFFEX). The basic statistics suggest that distributions of these two time series are not normal but exhibit fat tails. Based on the detrended cross-correlation analysis (DCCA), we obtain that returns and trading volumes are long-range cross-correlated. The existence of multifractality in the cross-correlation between returns and trading volumes has been proven with the multifractal detrended cross-correlation analysis (MFDCCA) algorithm. The multifractal analysis also confirms that returns and trading volumes have different degrees of multifractality. We further perform a cross-correlation statistic to verify whether the cross-correlation significantly exists between returns and trading volumes for CSI300 index futures. In addition, results of the test for lead-lag effect demonstrate that contemporaneous cross-correlation of return and trading volume series is stronger than cross-correlations of leaded or lagged series.

Wang, Dong-Hua; Suo, Yuan-Yuan; Yu, Xiao-Wen; Lei, Man

2013-03-01

218

Correlation between Serum PSA and Cancer Volume in Prostate Glands of Different Sizes  

PubMed Central

OBJECTIVES Although early studies showed a strong correlation between PSA and tumor volume, it has been suggested that PSA is no longer a valid marker for PCa and only correlates with prostate size. The objective of this study was to further evaluate the relationship of PSA with prostate size and tumor volume in a contemporary surgical series. METHODS From 2003 to 2009, 1234 men with data on prostate weight and total tumor volume underwent radical prostatectomy by a single surgeon. Prostate size was classified into tertiles: small (?41.2 grams), medium (41.3–54.5 grams) and large (?54.6 grams). Pearson correlation coefficients were used to examine the relationship of PSA with prostate size and tumor volume across different prostate sizes. RESULTS Median preoperative PSA was 4.9 ng/ml (SD ± 4.6), mean prostate size was 51.7 grams, and mean tumor volume was 5.6 cc. PSA had a significant correlation with prostate size only at a prostate weight ?54.6 gm (p=0.01). Regardless of prostate size, PSA had a more robust significant correlation with tumor volume than with prostate size (all p<0.0001). CONCLUSIONS PSA was significantly correlated with prostate size only in the largest prostate glands, but was significantly associated with tumor volume in small, medium, or large prostates. Thus, PSA continues to be a better marker for tumor volume than for prostate size.

Carvalhal, Gustavo F.; Daudi, Saima N.; Kan, Donghui; Mondo, Dana; Roehl, Kimberly A.; Loeb, Stacy; Catalona, William J.

2010-01-01

219

Clinical correlates of caudate volume in drug-naïve adult patients with obsessive-compulsive disorder.  

PubMed

The neurobiological basis of obsessive-compulsive disorder (OCD) has been theorized to reflect a dysfunction of cortico-striato-thalamo-cortical circuits, of which the caudate nucleus forms a critical component. However, structural imaging studies of the caudate in OCD are relatively scarce. To ascertain the clinical correlates of caudate volume in OCD, we report magnetic resonance imaging findings in a large sample of drug-naïve OCD patients in comparison with group-matched healthy controls. In this study, caudate volume was measured in coronal magnetic resonance brain images (high resolution 1-mm slice thickness) of 49 DSM-IV OCD patients and compared with that of 39 matched healthy controls. The caudate volume was measured separately for the head and body of the caudate. Analysis of covariance (ANCOVA) did not reveal significant differences in caudate volume between OCD patients and controls (whole group), with age, sex and intracranial volume as covariates. However, on examining the sexual dimorphism in the volume differences, male patients compared to male controls had significantly larger right caudate volume. The volume of the left caudate body showed a significant negative correlation with the total severity score on the Yale-Brown Obsessive-Compulsive Scale (YBOCS) on partial correlation analysis. Our study failed to show significant differences in caudate volumes between OCD patients and controls. However, it demonstrated a robust relationship between volume of the left caudate body and the severity of OCD. Additionally, there was a sexual dimorphism in caudate volume in OCD. PMID:23489673

Narayanaswamy, Janardhanan C; Jose, Dania A; Kalmady, Sunil V; Venkatasubramanian, Ganesan; Janardhana Reddy, Y C

2013-03-13

220

Preterm infant hippocampal volumes correlate with later working memory deficits  

Microsoft Academic Search

Children born preterm exhibit working memory deficits.These deficits may be associated with structural brain changes observed in the neonatal period. In this study, the relationship between neonatal regional brain volumes and working memory deficits at age 2 years were investigated, with a particular interest in the dorsolateral prefrontal cortex, parietal cortex and the hippocampus.While the eligible sample consisted of 227

Miriam H. Beauchamp; Deanne K. Thompson; Kelly Howard; Lex W. Doyle; Gary F. Egan; Terrie E. Inder; Peter J. Anderson

2008-01-01

221

Holographic data storage systems  

Microsoft Academic Search

In this paper, we discuss fundamental issues underlying holographic data storage: grating formation, recording and readout of thick and thin holograms, multiplexing techniques, signal-to-noise ratio considerations, and readout techniques suitable for conventional, phase conjugate, and associative search data retrieval. Next, we consider holographic materials characteristics for digital data storage, followed by a discussion on photorefractive media, fixing techniques, and noise

LAMBERTUS HESSELINK; SERGEI S. ORLOV; MATTHEW C. BASHAW

2004-01-01

222

Spin and holographic metals  

NASA Astrophysics Data System (ADS)

In this paper, we discuss two-dimensional holographic metals from a condensed matter physics perspective. We examine the spin structure of the Green's function of the holographic metal, demonstrating that the excitations of the holographic metal are “chiral,” lacking the inversion symmetry of a conventional Fermi surface, with only one spin orientation for each point on the Fermi surface aligned parallel to the momentum. While the presence of a Kramer's degeneracy across the Fermi surface permits the formation of a singlet superconductor, it also implies that ferromagnetic spin fluctuations are absent from the holographic metal, leading to a complete absence of Pauli paramagnetism. In addition, we show how the Green's function of the holographic metal can be regarded as a reflection coefficient in anti-de Sitter space, relating the ingoing and outgoing waves created by a particle moving on the external surface.

Alexandrov, Victor; Coleman, Piers

2012-09-01

223

Focal Volume Optics and Experimental Artifacts in Confocal Fluorescence Correlation Spectroscopy  

Microsoft Academic Search

Fluorescence correlation spectroscopy (FCS) can provide a wealth of information about biological and chemical systems on a broad range of time scales (<1?s to >1s). Numerical modeling of the FCS observation volume combined with measurements has revealed, however, that the standard assumption of a three-dimensional Gaussian FCS observation volume is not a valid approximation under many common measurement conditions. As

Samuel T. Hess; Watt W. Webb

2002-01-01

224

Clinical correlates of high intraprostatic brachytherapy dose volumes  

Microsoft Academic Search

Purpose: To determine if high intraprostatic dose regions correlate with postimplant urinary or rectal morbidity, potentially providing some objective basis for recommendations regarding dose homogeneity.Methods: Eighty-two patients with 1997 AJC clinical stage T1c–T2a prostatic carcinoma (Gleason Grade 2–6, PSA 4–10 ng\\/ml) were randomized to implantation with 125I (144 Gy) vs. 103Pd (125 Gy, NIST-1999). Isotope implantation was performed by standard

Shaleah Jones; Kent Wallner; Gregory Merrick; Jacques Corriveau; Steven Sutlief; Laurence True; Wayne Butler

2002-01-01

225

Correlation between MR imaging-derived nasopharyngeal carcinoma tumor volume and TNM system  

SciTech Connect

Purpose: To measure nasopharyngeal carcinoma tumor volume based on magnetic resonance images using a validated semiautomated measurement methodology and correlate tumor volume with TNM T classification. Methods and Materials: The study population consisted of 206 consecutive nasopharyngeal carcinoma patients who had magnetic resonance imaging staging scans. Tumor volume was measured using a semisupervised knowledge-based fuzzy clustering algorithm. Patients were divided into 4 groups according to TNM T classification. The difference in tumor volumes among the various TNM T-classification groups was examined. Results: The mean tumor volume in each T-classification group is as follows: T1, 8.6 mL {+-} 5.0 (standard deviation [SD]); T2, 18.1 mL {+-} 8.1 (SD); T3, 25.8 mL {+-} 14.1 (SD); and T4, 36.2 mL {+-} 18.9 (SD). The mean tumor volume increased significantly with advancing T classification (p < 0.0001). Tumor volume in a more advanced T group was significantly larger than that in an adjacent early T group (p < 0.01). Conclusion: Validated magnetic resonance imaging-based tumor volume shows positive correlation between tumor volume and advancing T-classification groups. It may be possible to incorporate tumor volume as an additional prognostic factor into the existing TNM system.

Chong, Vincent F.H. [Department of Diagnostic Radiology, Faculty of Medicine, National University of Singapore, Singapore (Singapore)]. E-mail: dnrcfhv@nus.edu.sg; Zhou, J.-Y. [Biomedical Engineering Research Centre, Nanyang Technological University, Singapore (Singapore); Khoo, James B.K. [Department of Oncologic Imaging, National Cancer Centre, Singapore (Singapore); Chan, K.-L. [Biomedical Engineering Research Centre, Nanyang Technological University, Singapore (Singapore); Huang Jing [Department of Oncologic Imaging, National Cancer Centre, Singapore (Singapore)

2006-01-01

226

Portable holographic interferometric device for aircraft inspecting  

NASA Astrophysics Data System (ADS)

A new single-beam technique for a continuous reconstruction of volume holograms in photorefractive crystals of symmetry 23 is presented. The doped crystal Bi12TiO20 (Fe,P) possessing diffraction efficiency above 70% is used for real-time holographic interferometry. The major advantage of this technique is an automatic self-adjustment of diffraction in volume holograms, continuous reconstruction of volume holograms, high diffraction efficiency without application of external electric field, high resolution (more than 3000 lines/mm), high vibroprotection stability, low cost using of He-Ne or diode lasers, and portability (single-beam device). A 1 mm crack was detected at a depth of 1.5 mm in airplane wings near a rivet zone using protable adaptive holographic interferometer.

Dovgalenko, George E.; Onischenko, Yuri I.; Loutchkina, Irina I.; Salamo, Gregory J.

1995-06-01

227

Holographic rugate structures for x-ray optics applications  

Microsoft Academic Search

XUV Bragg Holographic Optical Elements (HOEs), based on a single-step volume holographic recording, have been proposed by Physical Optic Corporation (POC), as an entirely new approach to x-ray optics. Their theory, as well as the first experimental proof-of-concept, have been demonstrated in Phase 1 of the DOE program. During the first year (exactly, 8-month duration) of the on-going Phase 2,

T. Jannson; Gajendra. Savant; Yong. Qiao

1988-01-01

228

Holographic testing of fluorescent photosensitive glass–ceramics  

Microsoft Academic Search

In this paper we investigate the holographic recording properties of the fluorescent photosensitive glass–ceramics. The materials described here, stable up to 400°C, represent a substantial advancement in the development of long lifetime media for holographic data storage. A detailed physical–chemical characterization of the proposed material is presented. It is shown that volume holograms were obtained after the recording process using

E. Pavel; M. Mihailescu; V. B. Nicolae; S. Jinga; E. Andronescu; E. Rotiu; L. Ionescu; C. Mazilu

2011-01-01

229

Holographic optical trapping  

SciTech Connect

Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps that are useful for capturing, moving, and transforming mesoscopic objects. Through a combination of beam-splitting, mode-forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on objects ranging in size from a few nanometers to hundreds of micrometers. Offering nanometer-scale spatial resolution and real-time reconfigurability, holographic optical traps provide unsurpassed access to the microscopic world and have found applications in fundamental research, manufacturing, and materials processing.

Grier, David G.; Roichman, Yael

2006-02-10

230

Holographic string encoding.  

PubMed

In this article, we apply a special case of holographic representations to letter position coding. We translate different well-known schemes into this format, which uses distributed representations and supports constituent structure. We show that in addition to these brain-like characteristics, performances on a standard benchmark of behavioral effects are improved in the holographic format relative to the standard localist one. This notably occurs because of emerging properties in holographic codes, like transposition and edge effects, for which we give formal demonstrations. Finally, we outline the limits of the approach as well as its possible future extensions. PMID:21428993

Hannagan, Thomas; Dupoux, Emmanuel; Christophe, Anne

2010-11-19

231

Fast electrically switchable holographic optical elements in LiNbO3  

NASA Astrophysics Data System (ADS)

We present here the realization of fast electrically switchable holographic optical elements based on electric field multiplexing of volume holograms in lithium niobate crystals. We demonstrate the electrical control of holographic lenses and holographic mirrors for fast switching of the focal length and the direction of the reconstructed light beam, respectively. The switching time in the range of few hundred microseconds has been demonstrated using this technique.

Arora, P.; Petrov, V. M.; Petter, J.; Tschudi, T.

2008-03-01

232

A Holographic Road Show.  

ERIC Educational Resources Information Center

|Describes the viewing sessions and the holograms of a holographic road show. The traveling exhibits, believed to stimulate interest in physics, include a wide variety of holograms and demonstrate several physical principles. (GA)|

Kirkpatrick, Larry D.; Rugheimer, Mac

1979-01-01

233

Holographic Testing Techniques.  

National Technical Information Service (NTIS)

Applications of holographic interferometry to vibration analysis, composite component evaluation, and precision cylinder inspection developed under In-House Laboratory Independent Research funding in the Research Directorate, Weapons Laboratory at Rock Is...

R. D. Schulz R. G. Arnold R. J. Iversen

1971-01-01

234

Holographic Recording Materials Development.  

National Technical Information Service (NTIS)

Organic photorefractive materials were evaluated for application in a reversible holographic memory system. Representative indigo and thioindigo derivatives and several stilbene derivatives were studied as well as 15, 16-dialkyldihydropyrene derivatives t...

C. M. Verber R. E. Schwerzel P. J. Perry R. A. Craig

1976-01-01

235

Simplification of Holographic Procedures.  

National Technical Information Service (NTIS)

The present state of the holographic art has set many stringent parameters on the production of holograms, such as extreme mechanical, temperature, and air stability for long periods of time, and slow film emulsions with extremely high resolution. The Phy...

J. T. Carcel A. H. Rodemann E. Florman S. Domeshek

1966-01-01

236

Holographic anyonic superfluidity  

NASA Astrophysics Data System (ADS)

Starting with a holographic construction for a fractional quantum Hall state based on the D3-D7' system, we explore alternative quantization conditions for the bulk gauge fields. This gives a description of a quantum Hall state with various filling fractions. For a particular alternative quantization of the bulk gauge fields, we obtain a holographic anyon fluid in a vanishing background magnetic field. We show that this system is a superfluid, exhibiting the relevant gapless excitation.

Jokela, Niko; Lifschytz, Gilad; Lippert, Matthew

2013-10-01

237

Correlated volume-energy fluctuations of phospholipid membranes: a simulation study.  

PubMed

This paper reports all-atom computer simulations of five phospholipid membranes (DMPC, DPPC, DMPG, DMPS, and DMPSH) with focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and chain order. At constant temperature and pressure, volume and energy exhibit strong correlations of their slow fluctuations (defined by averaging over 0.5 ns). These quantities, on the other hand, do not correlate significantly with area, thickness, or chain order. The correlations are mainly reported for the fluid phase, but we also give some results for the ordered (gel) phase of two membranes, showing a similar picture. The cause of the observed strong correlations is identified by splitting volume and energy into contributions from tails, heads, and water, and showing that the slow volume-energy fluctuations derive from van der Waals interactions of the tail region; they are thus analogous to the similar strong correlations recently observed in computer simulations of the Lennard-Jones and other simple van der Waals type liquids (U. R. Pedersen et al., Phys. Rev. Lett. 2008, 100, 015701). The strong correlations reported here confirm one crucial assumption of a recent theory for nerve signal propagation proposed by Heimburg and Jackson (T. Heimburg and A. D. Jackson, Proc. Natl. Acad. Sci. 2005, 102, 9790-9795). PMID:20095587

Pedersen, Ulf R; Peters, Günther H; Schrøder, Thomas B; Dyre, Jeppe C

2010-02-18

238

Digital holographic microscopy for the evaluation of human sperm structure.  

PubMed

Summary The morphology of the sperm head has often been correlated with the outcome of in vitro fertilization, and has been shown to be the sole parameter in semen of value in predicting the success of intracytoplasmic sperm injection and intracytoplasmic morphologically selected sperm injection. In this paper, we have studied whether digital holographic microscopy (DHM) may be useful to obtain quantitative data on human sperm head structure and compared this technique with high-power digitally enhanced Nomarski optics. The main advantage of digital holography is that high-resolution three-dimensional quantitative sample imaging may be automatically produced by numerical refocusing of a two-dimensional image at different object planes without any mechanical scanning. We show that DHM generates useful information on the dimensions and structure of human sperm, not revealed by conventional phase-contrast microscopy, in particular the volume of vacuoles, and suggest its use as an additional prognostic tool in assisted reproduction technology. PMID:23469807

Coppola, G; Di Caprio, G; Wilding, M; Ferraro, P; Esposito, G; Di Matteo, L; Dale, R; Coppola, G; Dale, B

2013-03-01

239

Holographic thermalization from Kerr-AdS  

NASA Astrophysics Data System (ADS)

We study thermalization of a strongly coupled theory holographically dual to a thin shell of null dust with non-zero angular momentum collapsing to Kerr-AdS. We calculate thermalization time for two point correlation functions. It happens that in the 3-dimensional case the thermalization time is just proportional to the distance between points where the correlator is evaluated. This is a very surprising and rather unexpected generalization of the same relation in the case of zero momentum.

Aref'eva, Irina; Bagrov, Andrey; Koshelev, Alexey S.

2013-07-01

240

Assessment of correlation between knee notch width index and the three-dimensional notch volume  

Microsoft Academic Search

This study was done to determine whether there is a correlation between the notch volume and the notch width index (NWI) as\\u000a measured on the three most frequently used radiographic views: the Holmblad 45°, Holmblad 70°, and Rosenberg view. The notch\\u000a volume of 20 cadaveric knees was measured using Computed Tomography (CT). The Holmblad 45°, Holmblad 70°, and Rosenberg notch

Carola F. van Eck; Cesar A. Q. Martins; Stephan G. F. Lorenz; Freddie H. Fu; P. Smolinski

2010-01-01

241

Assessment of correlation between knee notch width index and the three-dimensional notch volume.  

PubMed

This study was done to determine whether there is a correlation between the notch volume and the notch width index (NWI) as measured on the three most frequently used radiographic views: the Holmblad 45 degrees, Holmblad 70 degrees, and Rosenberg view. The notch volume of 20 cadaveric knees was measured using Computed Tomography (CT). The Holmblad 45 degrees, Holmblad 70 degrees, and Rosenberg notch view radiographs were digitally re-created from the CT scans for each specimen, and the NWI was measured by two observers. The Pearson correlation coefficient between the NWI and notch volume was calculated, as well as between the three views. An independent t test was performed to determine the difference in NWI and notch volume between male and female specimens. The reliability for each view was also determined. There was no correlation between the NWI as measured on the Holmblad 45 degrees, Holmblad 70 degrees, or Rosenberg view and the notch volume. All three radiographic views proved reliable, but showed only a moderate correlation with each other. Men had larger notch volumes than women, but there was no difference in NWI. A knee with a small intercondylar notch is often considered an increased risk for ACL rupture. The NWI is a frequently used two-dimensional method to determine notch size. However, in the present study, this index was not positively correlated with the overall volume of the notch. Based on the results of the current study, the authors would advice to use caution when using notch view radiographs in a clinical setting to predict risk of ACL rupture. PMID:20376620

van Eck, Carola F; Martins, Cesar A Q; Lorenz, Stephan G F; Fu, Freddie H; Smolinski, P

2010-04-08

242

Holographic rugate structures for x-ray optics applications  

SciTech Connect

XUV Bragg Holographic Optical Elements (HOEs), based on a single-step volume holographic recording, have been proposed by Physical Optic Corporation (POC), as an entirely new approach to x-ray optics. Their theory, as well as the first experimental proof-of-concept, have been demonstrated in Phase 1 of the DOE program. During the first year (exactly, 8-month duration) of the on-going Phase 2, the high-efficiency XUV Lippmann holographic mirrors have been fabricated and their optical, physical, and material properties have been investigated over the entire XUV region (1--100nm). The XUV Bragg HOEs, based on dichromated gelatin (DCG) and on DCG/polymer grafts, have been recorded in the visible region (using an Innova Argo laser) and reconstructed using twelve XUV wavelengths. In addition, these phase high-resolution holographic materials have been shown to be suitable to direct x-ray laser holographic recording (using Princeton's x-ray laser). The volume x-ray holographic recording will be realized within the second year of the program effort.

Jannson, T.; Savant, Gajendra.; Qiao, Yong.

1988-07-01

243

In-line color digital holographic microscope for water quality measurements  

NASA Astrophysics Data System (ADS)

We introduce a color digital holographic microscope for measuring the biological content of water samples. Our approach uses single shot RGB exposure in an in-line holographic setup to obtain color images. With the application of appropriate numerical algorithms we can fulfill color crosstalk compensation, segmentation, and twin image removal tasks, and we obtain good quality color image reconstructions with 1?m resolution from a 1mm3 volume. We briefly compare the conventional color CCD/CMOS and the Foveon X3 sensor for color digital holographic applications. The in-line holographic setup and reconstruction algorithms are presented with demonstrative simulations, experimentally captured and numerically reconstructed images.

Göröcs, Zoltán; Orzó, László; Kiss, Márton; Tóth, Veronika; T?kés, Szabolcs

2010-06-01

244

Correlation of gross tumor volume excursion with potential benefits of respiratory gating  

SciTech Connect

Purpose: To test the hypothesis that the magnitude of thoracic tumor motion can be used to determine the desirability of respiratory gating. Methods and materials: Twenty patients to be treated for lung tumors had computed tomography image data sets acquired under assisted breath hold at normal inspiration (100% tidal volume), at full expiration (0% tidal volume), and under free breathing. A radiation oncologist outlined gross tumor volumes (GTVs) on the breath-hold computed tomographic images. These data sets were registered to the free-breathing image data set. Two sets of treatment plans were generated: one based on an internal target volume explicitly formed from assessment of the excursion of the clinical target volume (CTV) through the respiratory cycle, representing an ungated treatment, and the other based on the 0% tidal volume CTV, representing a gated treatment with little margin for residual motion. Dose-volume statistics were correlated to the magnitude of the motion of the center of the GTV during respiration. Results: Patients whose GTVs were >100 cm{sup 3} showed little decrease in lung dose under gating. The other patients showed a correlation between the excursion of the center of the GTV and a reduction in potential lung toxicity. As residual motion increased, the benefits of respiratory gating increased. Conclusion: Gating seems to be advantageous for patients whose GTVs are <100 cm{sup 3} and for whom the center of the GTV exhibits significant motion, provided residual motion under gating is kept small.

Starkschall, George [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)]. E-mail: gstarksc@mdanderson.org; Forster, Kenneth M. [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Kitamura, Kei [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Department of Radiology, Hokkaido University, Graduate School of Medicine, Sapporo (Japan); Cardenas, Alex [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Tucker, Susan L. [Department of Biomathematics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Stevens, Craig W. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

2004-11-15

245

Holographic rugate structures for x-ray optics applications. Phase 2 Annual report.  

National Technical Information Service (NTIS)

XUV Bragg Holographic Optical Elements (HOEs), based on a single-step volume holographic recording, have been proposed by Physical Optic Corporation (POC), as an entirely new approach to x-ray optics. Their theory, as well as the first experimental proof-...

T. Jannson G. Savant Y. Qiao

1988-01-01

246

Digital data storage in a phase-encoded holographic memory system: data quality and security  

Microsoft Academic Search

ABSTRACT We review the crucial properties of a phase-encoded volume holographic storage system in terms of data quality and security, which are the key issues of any bulk memory system. Two major problems which need to be tackled in holographic storage systems in terms of data quality are the hologram erasure during readout and the data encoding schemes for error-free

G. Berger; K.-O. Muller; C. Denz; I. Foldvari; A. Peter

247

Holographic dark energy and late cosmic acceleration  

NASA Astrophysics Data System (ADS)

It has been persuasively argued that the number of effective degrees of freedom of a macroscopic system is proportional to its area rather than to its volume. This entails interesting consequences for cosmology. Here we present a model based on this 'holographic principle' that accounts for the present stage of accelerated expansion of the Universe and significantly alleviates the coincidence problem also for non-spatially flat cosmologies. Likewise, we comment on a recently proposed late transition to a fresh decelerated phase.

Pavón, Diego

2007-06-01

248

Lippmann-Bragg broadband holographic mirrors  

SciTech Connect

Lippmann-Bragg broadband volume holographic mirrors, with chirp normal to the surface, represent an entirely new class of grating. These gratings are presented and analyzed theoretically by using a combination of the multiple-beam interference method and Kogelnik's local solution for uniform gratings. Particularly noteworthy is the new grating's combination of a very high Bragg diffraction efficiency (> 99.5%) with a large tunable bandwidth (from 5 to > 300 nm).

Jannson, T.; Tengara, I.; Qiao, Y.; Savant, G. (Physical Optics Corp., Torrance, CA (United States))

1991-01-01

249

High-Transfer-Rate High-Capacity Holographic Disk Data-Storage System  

Microsoft Academic Search

We describe the design and implementation of a high-data-rate high-capacity digital holographic storage disk system. Various system design trade-offs that affect density and data-rate performance are described and analyzed. In the demonstration system that we describe, high-density holographic recording is achieved by use of high-resolution short-focal-length optics and correlation shift multiplexing in photopolymer disk media. Holographic channel decoding at a

Sergei S. Orlov; William Phillips; Eric Bjornson; Yuzuru Takashima; Padma Sundaram; Lambertus Hesselink; Robert Okas; Darren Kwan; Raymond Snyder

2004-01-01

250

RELAP5/MOD3 code manual. Volume 4, Models and correlations  

SciTech Connect

The RELAP5 code has been developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents. The code models the coupled behavior of the reactor coolant system and the core for loss-of-coolant accidents and operational transients such as anticipated transient without scram, loss of offsite power, loss of feedwater, and loss of flow. A generic modeling approach is used that permits simulating a variety of thermal hydraulic systems. Control system and secondary system components are included to permit modeling of plant controls, turbines, condensers, and secondary feedwater systems. RELAP5/MOD3 code documentation is divided into seven volumes: Volume I presents modeling theory and associated numerical schemes; Volume II details instructions for code application and input data preparation; Volume III presents the results of developmental assessment cases that demonstrate and verify the models used in the code; Volume IV discusses in detail RELAP5 models and correlations; Volume V presents guidelines that have evolved over the past several years through the use of the RELAP5 code; Volume VI discusses the numerical scheme used in RELAP5; and Volume VII presents a collection of independent assessment calculations.

NONE

1995-08-01

251

Diffused holographic information storage and retrieval using photorefractive optical materials  

NASA Astrophysics Data System (ADS)

Holography offers a tremendous opportunity for dense information storage, theoretically one bit per cubic wavelength of material volume, with rapid retrieval, of up to thousands of pages of information simultaneously. However, many factors prevent the theoretical storage limit from being reached, including dynamic range problems and imperfections in recording materials. This research explores new ways of moving closer to practical holographic information storage and retrieval by altering the recording materials, in this case, photorefractive crystals, and by increasing the current storage capacity while improving the information retrieved. As an experimental example of the techniques developed, the information retrieved is the correlation peak from an optical recognition architecture, but the materials and methods developed are applicable to many other holographic information storage systems. Optical correlators can potentially solve any signal or image recognition problem. Military surveillance, fingerprint identification for law enforcement or employee identification, and video games are but a few examples of applications. A major obstacle keeping optical correlators from being universally accepted is the lack of a high quality, thick (high capacity) holographic recording material that operates with red or infrared wavelengths which are available from inexpensive diode lasers. This research addresses the problems from two positions: find a better material for use with diode lasers, and reduce the requirements placed on the material while maintaining an efficient and effective system. This research found that the solutions are new dopants introduced into photorefractive lithium niobate to improve wavelength sensitivities and the use of a novel inexpensive diffuser that reduces the dynamic range and optical element quality requirements (which reduces the cost) while improving performance. A uniquely doped set of 12 lithium niobate crystals was specified and procured for this research. Transmission spectra and diffraction efficiencies were measured for each of the crystals using wavelengths in the visible spectrum. The diffraction efficiency was increased by as much as two orders of magnitude by using a new dopant combination. A new optical diffuser was designed, modeled, fabricated, and tested as a means of improving storage capacity for angularly multiplexed holograms in photorefractive crystals. The diffuser reduced the dynamic range requirement by over three orders of magnitude, increased the storage capacity by more than 400%, and dramatically improved the correlation signals.

McMillen, Deanna Kay

252

Correlation between nasopharyngeal carcinoma tumor volume and the 2002 International Union Against Cancer tumor classification system  

PubMed Central

Background The correlation between primary tumor volume and nasopharyngeal carcinoma (NPC) UICC 2002 T classification, N classification and distant metastasis after radiation therapy was discussed to provide further evidence for the inclusion of tumor volume into the TNM classification staging system. Methods Between February 2001 and December 2008, 666 patients with NPC treated with intensity-modulated radiation therapy (IMRT) were analyzed retrospectively. Primary gross tumor volume was calculated from treatment planning computed tomography scans. The Kruskal-Wallis and Mann–Whitney tests were used for comparison of continuous variables and the chi-square test was used for categorical variables. A logistic regression model was used for multivariate analysis. Results Median primary tumor volume of the 666 patients was 20.35 ml (range, 0.44???192.63 ml), and it gradually increased with T classification. Statistically significant differences in tumor volume were observed between patients with different T classifications (p?volume between patients with or without lymph node metastasis were statistically significant (p?volume (p?=?0.007) were the main factors influencing distant metastasis. Conclusion Tumor volume was correlated with T classification, cervical lymph node mestastasis and distant metastasis after radiation therapy in nasopharyngeal carcinoma, suggesting that tumor volume should be included into the TNM staging system.

2013-01-01

253

Incidence of radiation pneumonitis after thoracic irradiation: Dose-volume correlates  

SciTech Connect

Purpose: To define clinical and dosimetric parameters correlated with the risk of clinically relevant radiation pneumonitis (RP) after thoracic radiotherapy. Methods and Materials: Records of consecutive patients treated with definitive thoracic radiotherapy were retrospectively reviewed for the incidence of RP of Grade 2 or greater by the Common Toxicity Criteria. Dose-volume histograms using total lung volume (TL) and TL minus gross tumor volume (TL-G) were created with and without heterogeneity corrections. Mean lung dose (MLD), effective lung volume (V{sub eff}), and percentage of TL or TL-G receiving greater than or equal to 10, 13, 15, 20, and 30 Gy (V10-V30, respectively) were analyzed by logistic regression. Receiver operating characteristic (ROC) curves were generated to estimate RP predictive values. Results: Twelve cases of RP were identified in 92 eligible patients. Mean lung dose, V10, V13, V15, V20, and V{sub eff} were significantly correlated to RP. Combinations of MLD, V{sub eff}, V20, and V30 lost significance using TL-G and heterogeneity corrections. Receiver operating characteristic analysis determined V10 and V13 as the best predictors of RP risk, with a decrease in predictive value above those volumes. Conclusions: Intrathoracic radiotherapy should be planned with caution when using radiotherapy techniques delivering doses of 10 to 15 Gy to large lung volumes.

Schallenkamp, John M. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Miller, Robert C. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Brinkmann, Debra H. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Foote, Tyler [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Garces, Yolanda I. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States)

2007-02-01

254

Sex, Ecology and the Brain: Evolutionary Correlates of Brain Structure Volumes in Tanganyikan Cichlids  

Microsoft Academic Search

Analyses of the macroevolutionary correlates of brain structure volumes allow pinpointing of selective pressures influencing specific structures. Here we use a multiple regression framework, including phylogenetic information, to analyze brain structure evolution in 43 Tanganyikan cichlid species. We analyzed the effect of ecological and sexually selected traits for species averages, the effect of ecological traits for each sex separately and

Alejandro Gonzalez-Voyer; Niclas Kolm

2010-01-01

255

Correlation between Gray/White Matter Volume and Cognition in Healthy Elderly People  

ERIC Educational Resources Information Center

|This study applied volumetric analysis and voxel-based morphometry (VBM) of brain magnetic resonance (MR) images to assess whether correlations exist between global and regional gray/white matter volume and the cognitive functions of semantic memory and short-term memory, which are relatively well preserved with aging, using MR image data from…

Taki, Yasuyuki; Kinomura, Shigeo; Sato, Kazunori; Goto, Ryoi; Wu, Kai; Kawashima, Ryuta; Fukuda, Hiroshi

2011-01-01

256

Clinical Correlations of Diffusion and Perfusion Lesion Volumes in Acute Ischemic Stroke  

Microsoft Academic Search

The aim of this study was to describe the clinico-radiological correlations of magnetic resonance (MR) perfusion and diffusion-weighted imaging (DWI) abnormalities in ischemic stroke. Eighteen patients had undergone MR imaging and clinical evaluation within 24 h of symptom onset and at or after 7 days. During the first 24 h the volume of perfusion abnormality (measured on the relative mean

Alison E. Baird; Karl-Olof Lövblad; John F. Dashe; Ann Connor; Cara Burzynski; Gottfried Schlaug; Irina Straroselskaya; Robert R. Edelman; Steven Warach

2000-01-01

257

Early Cell Death Detection with Digital Holographic Microscopy  

PubMed Central

Background Digital holography provides a non-invasive measurement of the quantitative phase shifts induced by cells in culture, which can be related to cell volume changes. It has been shown previously that regulation of cell volume, in particular as it relates to ionic homeostasis, is crucially involved in the activation/inactivation of the cell death processes. We thus present here an application of digital holographic microscopy (DHM) dedicated to early and label-free detection of cell death. Methods and Findings We provide quantitative measurements of phase signal obtained on mouse cortical neurons, and caused by early neuronal cell volume regulation triggered by excitotoxic concentrations of L-glutamate. We show that the efficiency of this early regulation of cell volume detected by DHM, is correlated with the occurrence of subsequent neuronal death assessed with the widely accepted trypan blue method for detection of cell viability. Conclusions The determination of the phase signal by DHM provides a simple and rapid optical method for the early detection of cell death.

Pavillon, Nicolas; Kuhn, Jonas; Moratal, Corinne; Jourdain, Pascal; Depeursinge, Christian

2012-01-01

258

Holographic optical components for laser spectroscopy applications  

Microsoft Academic Search

The successful introduction of the Holographic Notch Filter was the critical first step in the development of a new generation of holographic optical components suitable for laser spectroscopy applications. This paper looks at the characteristics, structure, specification, and performance of an improved version of the Holographic Notch Filter and two new components. The Holographic SuperNotchTM Filter, Holographic Beamsplitter, and the

Harry Owen

1993-01-01

259

What is Holographic Storage?  

NSDL National Science Digital Library

InPhase Technologies, a company based outside of Denver, Colorado, recently unveiled the product of several years' research. Its "holographic data storage media" is shown to be capable of much greater storage capacity than DVDs, and is scheduled for a limited commercial release in 2003. This page on the InPhase Web site explains some of the underlying concepts involved in holographic storage. There are two main sections: one is a brief overview of the technology's features and benefits, while the other is a more thorough description of the process of reading and recording data. A video demonstrating the technology is planned to appear on the site.

260

Holographic non-Fermi-liquid fixed points.  

PubMed

Techniques arising from string theory can be used to study assemblies of strongly interacting fermions. Via this 'holographic duality', various strongly coupled many-body systems are solved using an auxiliary theory of gravity. Simple holographic realizations of finite density exhibit single-particle spectral functions with sharp Fermi surfaces, of a form distinct from those of the Landau theory. The self-energy is given by a correlation function in an infrared (IR) fixed-point theory that is represented by a two-dimensional anti de Sitter space (AdS(2)) region in the dual gravitational description. Here, we describe in detail the gravity calculation of this IR correlation function. PMID:21422019

Faulkner, Tom; Iqbal, Nabil; Liu, Hong; McGreevy, John; Vegh, David

2011-04-28

261

Improving the clinical correlation of multiple sclerosis black hole volume change by paired-scan analysis.  

PubMed

The change in T 1-hypointense lesion ("black hole") volume is an important marker of pathological progression in multiple sclerosis (MS). Black hole boundaries often have low contrast and are difficult to determine accurately and most (semi-)automated segmentation methods first compute the T 2-hyperintense lesions, which are a superset of the black holes and are typically more distinct, to form a search space for the T 1w lesions. Two main potential sources of measurement noise in longitudinal black hole volume computation are partial volume and variability in the T 2w lesion segmentation. A paired analysis approach is proposed herein that uses registration to equalize partial volume and lesion mask processing to combine T 2w lesion segmentations across time. The scans of 247 MS patients are used to compare a selected black hole computation method with an enhanced version incorporating paired analysis, using rank correlation to a clinical variable (MS functional composite) as the primary outcome measure. The comparison is done at nine different levels of intensity as a previous study suggests that darker black holes may yield stronger correlations. The results demonstrate that paired analysis can strongly improve longitudinal correlation (from -0.148 to -0.303 in this sample) and may produce segmentations that are more sensitive to clinically relevant changes. PMID:24179734

Tam, Roger C; Traboulsee, Anthony; Riddehough, Andrew; Li, David K B

2012-09-05

262

Improving the clinical correlation of multiple sclerosis black hole volume change by paired-scan analysis?  

PubMed Central

The change in T1-hypointense lesion (“black hole”) volume is an important marker of pathological progression in multiple sclerosis (MS). Black hole boundaries often have low contrast and are difficult to determine accurately and most (semi?)automated segmentation methods first compute the T2-hyperintense lesions, which are a superset of the black holes and are typically more distinct, to form a search space for the T1w lesions. Two main potential sources of measurement noise in longitudinal black hole volume computation are partial volume and variability in the T2w lesion segmentation. A paired analysis approach is proposed herein that uses registration to equalize partial volume and lesion mask processing to combine T2w lesion segmentations across time. The scans of 247 MS patients are used to compare a selected black hole computation method with an enhanced version incorporating paired analysis, using rank correlation to a clinical variable (MS functional composite) as the primary outcome measure. The comparison is done at nine different levels of intensity as a previous study suggests that darker black holes may yield stronger correlations. The results demonstrate that paired analysis can strongly improve longitudinal correlation (from -0.148 to -0.303 in this sample) and may produce segmentations that are more sensitive to clinically relevant changes.

Tam, Roger C.; Traboulsee, Anthony; Riddehough, Andrew; Li, David K.B.

2012-01-01

263

Prostate volumes derived from MRI and volume-adjusted serum prostate-specific antigen: correlation with Gleason score of prostate cancer.  

PubMed

OBJECTIVE. The purpose of this article is to study relationships between MRI-based prostate volume and volume-adjusted serum prostate-specific antigen (PSA) concentration estimates and prostate cancer Gleason score. MATERIALS AND METHODS. The study included 61 patients with prostate cancer (average age, 63.3 years; range 52-75 years) who underwent MRI before prostatectomy. A semiautomated and MRI-based technique was used to estimate total and central gland prostate volumes, central gland volume fraction (central gland volume divided by total prostate volume), PSA density (PSAD; PSA divided by total prostate volume), and PSAD for the central gland (PSA divided by central gland volume). These MRI-based volume and volume-adjusted PSA estimates were compared with prostatectomy specimen weight and Gleason score by using Pearson (r) or Spearman (?) correlation coefficients. RESULTS. The estimated total prostate volume showed a high correlation with reference standard volume (r = 0.94). Of the 61 patients, eight (13.1%) had a Gleason score of 6, 40 (65.6%) had a Gleason score of 7, seven (11.5%) had a Gleason score of 8, and six (9.8%) had a Gleason score of 9 for prostate cancer. The Gleason score was significantly correlated with central gland volume fraction (? = -0.42; p = 0.0007), PSAD (? = 0.46; p = 0.0002), and PSAD for the central gland (? = 0.55; p = 0.00001). CONCLUSION. Central gland volume fraction, PSAD, and PSAD for the central gland estimated from MRI examinations show a modest but significant correlation with Gleason score and have the potential to contribute to personalized risk assessment for significant prostate cancer. PMID:24147475

Karademir, Ibrahim; Shen, Dinggang; Peng, Yahui; Liao, Shu; Jiang, Yulei; Yousuf, Ambereen; Karczmar, Gregory; Sammet, Steffen; Wang, Shiyang; Medved, Milica; Antic, Tatjana; Eggener, Scott; Oto, Aytekin

2013-11-01

264

Holographic interferometry in radiation dosimetry, microprocessor assisted  

NASA Astrophysics Data System (ADS)

In this paper the applications of holographic interferometry to ionizing radiation dosimetry are presented. The determination of the accurate value of dose delivered by an ionizing radiation source (released energy per mass unit) is a complex problem which imposes different solutions depending on the experimental parameters and it is solved with a double exposure holographic interferometric method associated with an optoelectronic interface and Z-80 microprocessor. The method can determine the integral absorbed dose as well as the tridimensional distribution of dose in a given volume. The paper presents some results obtained in radiation dosimetry. Different transparent liquids were used as ionizing radiation transducers. Integral dose and spatial dose-distribution were recorded for equivalent tissue liquids and blood plasma. Boundary phenomena, during a irradiation of successive layers of liquids having different atomic numbers, were investigated.

Nicolau, Silvia; Sporea, Dan G.; Niculescu, V. I.

1999-08-01

265

Holographic optics for space laser communications  

NASA Astrophysics Data System (ADS)

Two distinctly different applications of holographic technology are proposed. The first is a near-term, low technology, zone plate optic (ZPO) technology which can serve as a direct replacement for imaging reflector/refractor optics. It can benefit the imager by repartitioning the communication space based on fields of view and resolution requirements. It provides a degree of countermeasure performance and is much more easily produced than aspheric optics. The second application, called Volume Holographic Multiplexing Optics, offers considerably more imaging and mapping capability. The VHMO may significantly reduce the technology requirements of the detector array, but it also introduces material and fabrication technology problems which make it a long-term candidate for space communications.

East, James H.; Oetting, John D.

1988-01-01

266

Baryons in holographic QCD  

NASA Astrophysics Data System (ADS)

We study baryons in holographic QCD with D4/D8/D8¯ multi-D-brane system. In holographic QCD, the baryon appears as a topologically nontrivial chiral soliton in a four-dimensional effective theory of mesons. We call this topological soliton brane-induced Skyrmion. Some review of D4/D8/D8¯ holographic QCD is presented from the viewpoints of recent hadron physics and QCD phenomenologies. A four-dimensional effective theory with pions and ? mesons is uniquely derived from the non-Abelian Dirac-Born-Infeld (DBI) action of D8 brane with D4 supergravity background at the leading order of large Nc, without small amplitude expansion of meson fields to discuss chiral solitons. For the hedgehog configuration of pion and ?-meson fields, we derive the energy functional and the Euler-Lagrange equation of brane-induced Skyrmion from the meson effective action induced by holographic QCD. Performing the numerical calculation, we obtain the soliton solution and figure out the pion profile F(r) and the ?-meson profile G˜(r) of the brane-induced Skyrmion with its total energy, energy density distribution, and root-mean-square radius. These results are compared with the experimental quantities of baryons and also with the profiles of standard Skyrmion without ? mesons. We analyze interaction terms of pions and ? mesons in brane-induced Skyrmion, and find a significant ?-meson component appearing in the core region of a baryon.

Nawa, Kanabu; Suganuma, Hideo; Kojo, Toru

2007-04-01

267

Holographic spectral selectors  

Microsoft Academic Search

The paper presents an analysis of hologram parameters required to obtain highly selective holographic spectral filers, both reflective and transmissive. For two particular cases of spectral filters recorded and operating at the wavelengths of 488 nm and 633 nm grating parameters were analyzed as functions of the recording geometry. The spectral selectivity as a function of layer thickness was also

Irina V. Semenova; Nadya O. Reinhand

1998-01-01

268

Beyond DVD: Holographic Storage  

NSDL National Science Digital Library

InPhase Technologies is exploring holographic storage; however, its goal is to create a device that could be the successor to the DVD. In this article, the potential capabilities and specifications of such a device are discussed. A working prototype has already been demonstrated, paving the way for future commercially viable drives based on the technology.

Whitmer, Clair

2008-02-15

269

Holographic fractional topological insulators  

SciTech Connect

We give a holographic realization of the recently proposed low-energy effective action describing a fractional topological insulator. In particular we verify that the surface of this hypothetical material supports a fractional quantum Hall current corresponding to half that of a Laughlin state.

Hoyos, Carlos; Jensen, Kristan; Karch, Andreas [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2010-10-15

270

Deriving Particle Distributions from In-Line Fraunhofer Holographic Data  

SciTech Connect

Holographic data are acquired during hydrodynamic experiments at the Pegasus Pulsed Power Facility at the Los Alamos National Laboratory. These experiments produce a fine spray of fast-moving particles. Snapshots of the spray are captured using in-line Fraunhofer holographic techniques. Roughly one cubic centimeter is recorded by the hologram. Minimum detectable particle size in the data extends down to 2 microns. In a holography reconstruction system, a laser illuminates the hologram as it rests in a three-axis actuator, recreating the snapshot of the experiment. A computer guides the actuators through an orderly sequence programmed by the user. At selected intervals, slices of this volume are captured and digitized with a CCD camera. Intermittent on-line processing of the image data and computer control of the camera functions optimizes statistics of the acquired image data for off-line processing. Tens of thousands of individual data frames (30 to 40 gigabytes of data) are required to recreate a digital representation of the snapshot. Throughput of the reduction system is 550 megabytes per hour (MB/hr). Objects and associated features from the data are subsequently extracted during off-line processing. Discrimination and correlation tests reject noise, eliminate multiple counting of particles, and build an error model to estimate performance. Objects surviving these tests are classified as particles. The particle distributions are derived from the data base formed by these particles, their locations and features. Throughput of the off-line processing exceeds 500 MB/hr. This paper describes the reduction system, outlines the off-line processing procedure, summarizes the discrimination and correlation tests, and reports numerical results for a sample data set.

C.A. Ciarcia; D.E. Johnson; D.S. Sorenson; R.H. Frederickson, A.D. Delanoy; R.M. Malone; T.W. Tunnel

1997-08-01

271

Deriving particle distributions from in-line Fraunhofer holographic data  

SciTech Connect

Holographic data are acquired during hydrodynamic experiments at the Pegasus Pulsed Power Facility at the Los Alamos National Laboratory. These experiments produce a fine spray of fast-moving particles. Snapshots of the spray are captured using in-line Fraunhofer holographic techniques. Roughly one cubic centimeter is recorded by the hologram. Minimum detectable particle size in the data extends down to 2 microns. In a holography reconstruction system, a laser illuminates the hologram as it rests in a three axis actuator, recreating the snapshot of the experiment. A computer guides the actuators through an orderly sequence programmed by the user. At selected intervals, slices of this volume are captured and digitized with a CCD camera. Intermittent on-line processing of the image data and computer control of the camera functions optimizes statistics of the acquired image data for off-line processing. Tens of thousands of individual data frames (30 to 40 gigabytes of data) are required to recreate a digital representation of the snapshot. Throughput of the reduction system is 550 megabytes per hour (MB/hr). Objects and associated features from the data are subsequently extracted during off-line processing. Discrimination and correlation tests reject noise, eliminate multiple particles, and build an error model to estimate performance. Objects surviving these tests are classified as particles. The particle distributions are derived from the data base formed by these particles, their locations and features. Throughput of the off-line processing exceeds 500 MB/hr. This paper describes the reduction system, outlines the off-line processing procedure, summarizes the discrimination and correlation tests, and reports numerical results for a sample data set.

Tunnell, T.W.; Malone, R.M.; Fredericson, R.H.; DeLanoy, A.D.; Johnson, D.E.; Ciarcia, C.A. [Bechtel Nevada, Los Alamos Operations, Los Alamos, NM (United States); Sorenson, D.S. [Los Alamos National Lab., NM (United States)

1997-07-01

272

Quantitative analysis of the corpus callosum in children with cerebral palsy and developmental delay: correlation with cerebral white matter volume  

Microsoft Academic Search

Background: The direct quantitative correlation between thickness of the corpus callosum and volume of cerebral white matter in children with cerebral palsy and developmental delay has not been demonstrated. Objective: This study was conducted to quantitatively correlate the thickness of the corpus callosum with the volume of cerebral white matter in children with cerebral palsy and developmental delay. Material and

Ashok Panigrahy; Patrick D. Barnes; Robert L. Robertson; Lynn A. Sleeper; James W. Sayre

2005-01-01

273

Emergent spacetime and holographic CFTs  

NASA Astrophysics Data System (ADS)

We discuss universal properties of conformal field theories with holographic duals. A central feature of these theories is the existence of a low-lying sector of operators whose correlators factorize. We demonstrate that factorization can only hold in the large central charge limit. Using conformal invariance and factorization we argue that these operators are naturally represented as fields in AdS as this makes the underlying linearity of the system manifest. In this class of CFTs the solution of the conformal bootstrap conditions can be naturally organized in structures which coincide with Witten diagrams in the bulk. The large value of the central charge suggests that the theory must include a large number of new operators not captured by the factorized sector. Consequently we may think of the AdS hologram as an effective representation of a small sector of the CFT, which is embedded inside a much larger Hilbert space corresponding to the black hole microstates.

El-Showk, Sheer; Papadodimas, Kyriakos

2012-10-01

274

Self-correlation fiber specklegram sensor using volume characteristics of speckle patterns  

NASA Astrophysics Data System (ADS)

Tuning of the dynamic range of a micro-displacement fiber specklegram sensor based on two-wave mixing on a photorefractive material Bi12SiO20 (BSO) and self-correlation operations of speckle patterns is experimentally demonstrated. The high modal interference present in a standard plastic optical fiber (POF) allows generating a Gaussian pattern of subjective speckle, which is recorded in the volume crystal. The volume characteristics of the fiber speckle are changed using a pupil aperture adjacent to the imaging lens of the speckle. A notorious effect of the three dimensional structure of the speckle on the dynamic range of the metrological system is observed, such that, the performance of the sensor can be improved by a simple mechanical action on the pupil aperture. The behavior of the self-correlation loss of the sensor can be adequately described by a squared normalized Bessel function.

Gómez, Jorge A.; Salazar, Ángel

2012-05-01

275

Correlations among Brain Gray Matter Volumes, Age, Gender, and Hemisphere in Healthy Individuals  

Microsoft Academic Search

To determine the relationship between age and gray matter structure and how interactions between gender and hemisphere impact this relationship, we examined correlations between global or regional gray matter volume and age, including interactions of gender and hemisphere, using a general linear model with voxel-based and region-of-interest analyses. Brain magnetic resonance images were collected from 1460 healthy individuals aged 20–69

Yasuyuki Taki; Benjamin Thyreau; Shigeo Kinomura; Kazunori Sato; Ryoi Goto; Ryuta Kawashima; Hiroshi Fukuda

2011-01-01

276

Finite volume and asymptotic methods for stochastic neuron models with correlated inputs  

Microsoft Academic Search

We consider a pair of stochastic integrate and fire neurons receiving correlated stochastic inputs. The evolution of this\\u000a system can be described by the corresponding Fokker–Planck equation with non-trivial boundary conditions resulting from the\\u000a refractory period and firing threshold. We propose a finite volume method that is orders of magnitude faster than the Monte\\u000a Carlo methods traditionally used to model

Robert Rosenbaum; Fabien Marpeau; Jianfu Ma; Aditya Barua; Krešimir Josi?

277

Brain T2 relaxation times correlate with regional cerebral blood volume  

Microsoft Academic Search

We previously reported cerebellar and putaminal transverse relaxation time (T2) differences in children with ADHD and in adults with childhood trauma. As brain T2 can be altered by deoxyhemoglobin concentration ([dHb]) and because [dHb] is proportional to regional cerebral blood volume (rCBV), at steady state we attributed those differences to rCBV changes. Studies in other species have established a correlation

C. M. Anderson; M. J. Kaufman; S. B. Lowen; M. Rohan; P. F. Renshaw; M. H. Teicher

2005-01-01

278

Holographic GB gravity in arbitrary dimensions  

NASA Astrophysics Data System (ADS)

We study the properties of the holographic CFT dual to Gauss-Bonnet gravity in general D(? 5) dimensions. We establish the AdS/CFT dictionary and in particular relate the couplings of the gravitational theory to the universal couplings arising in correlators of the stress tensor of the dual CFT. This allows us to examine constraints on the gravitational couplings by demanding consistency of the CFT. In particular, one can demand positive energy fluxes in scattering processes or the causal propagation of fluctuations. We also examine the holographic hydrodynamics, commenting on the shear viscosity as well as the relaxation time. The latter allows us to consider causality constraints arising from the second-order truncated theory of hydrodynamics.

Buchel, Alex; Escobedo, Jorge; Myers, Robert C.; Paulos, Miguel F.; Sinha, Aninda; Smolkin, Michael

2010-03-01

279

Molecular weights of individual proteins correlate with molecular volumes measured by atomic force microscopy.  

PubMed

Proteins are usually identified by their molecular weights, and atomic force microscopy (AFM) produces images of single molecules in three dimensions. We have used AFM to measure the molecular volumes of a number of proteins and to determine any correlation with their known molecular weights. We used native proteins (the TATA-binding protein Tbp, a fusion protein of glutathione-S-transferase and the renal potassium channel protein ROMK1, the immunoglobulins IgG and IgM, and the vasodilator-stimulated phosphoprotein VASP) and also denatured proteins (the red blood cell proteins actin, Band 3 and spectrin separated by SDS-gel electrophoresis and isolated from nitrocellulose). Proteins studied had molecular weights between 38 and 900 kDa and were imaged attached to a mica substrate. We found that molecular weight increased with an increasing molecular volume (correlation coefficient = 0.994). Thus, the molecular volumes measured with AFM compare well with the calculated volumes of the individual proteins. The degree of resolution achieved (lateral 5 nm, vertical 0.2 nm) depended upon the firm attachment of the proteins to the mica. This was aided by coating the mica with suitable detergent and by imaging using the AFM tapping mode which minimizes any lateral force applied to the protein. We conclude that single (native and denatured) proteins can be imaged by AFM in three dimensions and identified by their specific molecular volumes. This new approach permits detection of the number of monomers of a homomultimeric protein and study of single proteins under physiological conditions at the molecular level. PMID:9426291

Schneider, S W; Lärmer, J; Henderson, R M; Oberleithner, H

1998-02-01

280

Holographic phase transition in a noncritical holographic model  

SciTech Connect

We consider a holographic model constructed from the intersecting brane configuration D4-D4/D4 in noncritical string theory. We study the chiral phase diagram of this holographic QCD-like model with a finite baryon chemical potential through the supergravity dual approximation.

Cui Shengliang; Gao Yihong [Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, P.O. Box 2735, Beijing 100080 (China); Xu Weishui [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Center for Quantum Spacetime, Sogang University, Seoul 121-742 (Korea, Republic of)

2010-01-15

281

Introduction to Holographic Superconductors  

Microsoft Academic Search

\\u000a These lectures give an introduction to the theory of holographic superconductors. These are superconductors that have a dual\\u000a gravitational description using gauge\\/gravity duality. After introducing a suitable gravitational theory, we discuss its properties\\u000a in various regimes: the probe limit, the effects of backreaction, the zero temperature limit, and the addition of magnetic\\u000a fields. Using the gauge\\/gravity dictionary, these properties reproduce

Gary T. Horowitz

282

Holographic microscope interferometer  

NASA Astrophysics Data System (ADS)

A simple and easy to use holographic microscope interferometer (HMI) for biological and material science applications is described. The unit is based on an ordinary microscope accomplished by He-Ne laser, several optical elements, a photothermoplastic (PTP) recorder, and a CCD-camera. Blood and plant cells, as well as internal solid bodies defect images, are demonstrated. Characteristics and application of the unit are discussed.

Babenko, Veronika A.; Konst, Elena V.; Konstantinov, Vladimir B.

1995-02-01

283

Holographic gravitational anomalies  

Microsoft Academic Search

In the AdS\\/CFT correspondence one encounters theories that are not invariant under diffeomorphisms. In the boundary theory this is a gravitational anomaly, and can arise in 4k+2 dimensions. In the bulk, there can be gravitational Chern-Simons terms which vary by a total derivative. We work out the holographic stress tensor for such theories, and demonstrate agreement between the bulk and

Per Kraus; Finn Larsen

2006-01-01

284

Holographic wavefront sensor  

US Patent & Trademark Office Database

A holographic wavefront sensor inclusive of a multiplexed hologram that can reconstruct one or more diffracted beams from a single object or input beam onto a distant image plane. The position of the reconstructed beams on the distant image plane indicates the relative amounts of different aberrations present in the input beam. Optical and computer realization of the employed hologram are accomplished along with sensor configurations in simple and more complex uses.

Andersen; Geoff P. (Colorado Springs, CO); Reibel; Randy (Bozeman, MT)

2007-09-11

285

Holographic subsonic flow visualization.  

PubMed

A pulsed ruby laser holographic interferometer was used to detect density gradients in the airflow around an airfoil at subsonic speeds in a low speed wind tunnel. These experiments proved that vibration of the optical components or object between exposures of the interferometric hologram does not destroy the detection of density gradients but actually can aid in the flow visualization. The density gradients determined from the fringe pattern analysis are consistent with the anticipated flow pattern. PMID:20094197

Reinheimer, C J; Wiswall, C E; Schmiege, R A; Harris, R J; Dueker, J E

1970-09-01

286

Geochemical correlation of three large-volume ignimbrites from the Yellowstone hotspot track, Idaho, USA  

NASA Astrophysics Data System (ADS)

Three voluminous rhyolitic ignimbrites have been identified along the southern margin of the central Snake River Plain. As a result of wide-scale correlations, new volume estimates can be made for these deposits: ~350 km3 for the Steer Basin Tuff and Cougar Point Tuff XI, and ~1,000 km3 for Cougar Point Tuff XIII. These volumes exclude any associated regional ashfalls and correlation across to the north side of the plain, which has yet to be attempted. Each correlation was achieved using a combination of methods including field logging, whole rock and mineral chemistry, magnetic polarity, oxygen isotope signature and high-precision 40Ar/39Ar geochronology. The Steer Basin Tuff, Cougar Point Tuff XI and Cougar Point Tuff XIII have deposit characteristics typical of `Snake River (SR)-type' volcanism: they are very dense, intensely welded and rheomorphic, unusually well sorted with scarce pumice and lithic lapilli. These features differ significantly from those of deposits from the better-known younger eruptions of Yellowstone. The ignimbrites also exhibit marked depletion in ?18O, which is known to characterise the SR-type rhyolites of the central Snake River Plain, and cumulatively represent ~1,700 km3 of low ?18O rhyolitic magma (feldspar values 2.3-2.9‰) erupted within 800,000 years. Our work reduces the total number of ignimbrites recognised in the central Snake River Plain by 6, improves the link with the ashfall record of Yellowstone hotspot volcanism and suggests that more large-volume ignimbrites await discovery through detailed correlation work amidst the vast ignimbrite record of volcanism in this bimodal large igneous province.

Ellis, Ben S.; Branney, M. J.; Barry, T. L.; Barfod, D.; Bindeman, I.; Wolff, J. A.; Bonnichsen, B.

2012-01-01

287

Nearshore Sediment Budget: Correlating Volume to Shoreline Change, Outer Banks, North Carolina  

NASA Astrophysics Data System (ADS)

Though the importance of understanding the exchange of sediment between the shoreline and the nearshore has long been recognized, data capable of addressing the three-dimensional character of the system are lacking. The response of traditional cross-shore profiles to forcing is not representative of the entire beach because of alongshore variability of the beach and nearshore sandbar. Measuring changes in shoreline position along the coast permits analysis of alongshore shoreline variability, but does not account for the actual volume of sediment lost from and restored to the beach. Temporally and spatially variable erosional hotspots identified by List and Farris (1999) along the Outer Banks, North Carolina further confound the study of coastal sediment exchange in the region of interest. A geophysical survey (from Duck to Oregon Inlet) was carried out in order to understand the role of geological characteristics in the transport of sediment between the shoreline and nearshore. Contrary to the assumptions of many shoreline and shoreface change models, the modern sand layer observed over the 40-km study area is not infinitely thick and is highly variable. Modern sediment thicknesses were calculated to a continuous seismic reflection surface that spanned the survey area, the average being 0.42m ± 0.19m. Higher standard deviations (variability) in sediment thickness seem to be loosely related to the presence of shore-oblique sandbars as described by McNinch (in press). Nearshore sediment volume was calculated and relationships to nearshore morphology were explored. Though shore-oblique bars may not represent a large percentage of the total sand regionally (7.9%), locally their influence is much greater. Of the three areas in which bars were identified, the volume of sediment contained within the bars represented 44% of the total volume in the largest bar field, and 14% and 11%, respectively, in more minor bar fields. Nearshore sediment volumes correlated well (correlation coefficient ˜0.60) with long-term shoreline change data (50 year data set, NC Division of Coastal Management) suggesting that long-term trends in shoreline change may be related to the total amount of available sediment in the nearshore. Correlation analyses with short-term shoreline change data will also be explored. These preliminary data suggest that volume calculations considering the total amount of nearshore sediment above a continuous, non-sandy seismic reflection surface may be useful in the prediction of long-term shoreline change trends. The utility of this approach in predicting changes over shorter temporal and spatial scales is the subject of current research.

Miselis, J. L.; McNinch, J. E.

2004-12-01

288

Left atrial volume index in healthy subjects: clinical and echocardiographic correlates.  

PubMed

Left atrial (LA) size is related to cardiovascular morbidity and mortality. The relative role of multiple determinants of LA morphology in healthy subjects remains incompletely defined. The aim of this study is to define normal ranges for LA diameters and volume index (LAVi), and to investigate clinical and echocardiographic correlates. A total of 1480 healthy individuals (mean age 36.1 ± 15.5 years, range 20-80; 61% males) underwent a comprehensive transthoracic echocardiography exam including assessment of LAVi calculated using the biplane area-length method at the apical four-chamber and two-chamber views at ventricular end systole (maximum LA size) and indexed for body surface area (BSA). Mean LAVi in the overall population was 29.5 ± 10.8 mL/m(2) (range: 26.1-41.8 mL/m(2) ). Distinct higher values were found in subjects ?50 years as compared with those <50 years of age (33.4 ± 12.5 vs. 29.1 ± 13.5; P < 0.001). On univariate analysis, LA volume was significantly associated with age (r = 0.48, P < 0.0001), male gender (r = 0.28, P < 0.05), BSA (r = 0.51, P < 0.0001), mitral E/E' (r = 0.47, P < 0.0001), LV end-diastolic volume (r = 0.52, P < 0.0001), and LV mass index (r = 0.31, P < 0.05). Multivariable analysis identified age, BSA, LV end-diastolic volume, and mitral E/E' ratio as the only independent determinants of LA volume (model R(2)  = 0.54, P < 0.0001). Gender was an independent predictor of most absolute LA volume, but following normalization to BSA, some associations became nonsignificant. In healthy individuals LAVi vary significantly by age, BSA, diastolic function, and LV dimensions, with lesser effects of gender. PMID:23594028

D'Andrea, Antonello; Riegler, Lucia; Rucco, Maria Antonietta; Cocchia, Rosangela; Scarafile, Raffaella; Salerno, Gemma; Martone, Francesca; Vriz, Olga; Caso, Pio; Calabrò, Raffaele; Bossone, Eduardo; Russo, Maria Giovanna

2013-04-18

289

Large-scale DCG transmission holographic gratings for astronomy  

NASA Astrophysics Data System (ADS)

The recent interest of the astronomer community for volume phase holographic gratings is directly related to the enhancement of spectrograph throughput since this kind of grating can rise higher diffraction efficiency. Indeed, dichromated gelatine technology has demonstrated capability for 70-90% efficiency. From the heritage of several diffractive and holographic projects and applications, the Centre Spatial de Liege has recently decided to invest in the large-scale DCG grating technology. This paper will present the new facility which is now fully operational, its capability and first results obtained.

Blanche, Pierre-Alexandre; Habraken, Serge L.; Lemaire, Philippe C.; Jamar, Claude A. J.

2003-02-01

290

Holographic medical imaging: the laser as a visual scalpel-issues and observations on 3-D display  

Microsoft Academic Search

Holographic techniques are being applied to medical imaging with greater focus and increasing benefit than ever before. Exploratory uses for the hologram in medicine go back more than 15 years, but the recent increased appreciation of three-dimensional (3-D) rendering of medical radiological data has provided the opportunity to employ holographic rendering as an additional means of displaying the radiological volume.

Ronald R. Erickson

1996-01-01

291

Lower Hemoglobin Correlates with Larger Stroke Volumes in Acute Ischemic Stroke  

PubMed Central

Background Hemoglobin tetramers are the major oxygen-carrying molecules within the blood. We hypothesized that a lower hemoglobin level and its reduced oxygen-carrying capacity would associate with larger infarction in acute ischemic stroke patients. Methods We studied 135 consecutive patients with acute ischemic stroke and perfusion brain MRI. We explored the association of admission hemoglobin with initial infarct volumes on acute images and the volume of infarct expansion on follow-up images. Multivariable linear regression was performed to analyze the independent effect of hemoglobin on imaging outcomes. Results Bivariate analyses showed a significant inverse correlation between hemoglobin and initial volume in diffusion-weighted imaging (r = ?0.20, p = 0.02) and absolute infarct growth (r = ?0.20, p = 0.02). Multivariable linear regression modeling revealed that hemoglobin remained independently predictive of larger infarct volumes acutely (p < 0.005) and with greater infarct expansion (p < 0.01) after adjusting for known covariates. Conclusions Hemoglobin level at the time of acute ischemic stroke associates with larger infarcts and increased infarct growth. Clarification of the mechanism of this effect may yield novel insights for therapy.

Kimberly, W. Taylor; Wu, Ona; Arsava, E. Murat; Garg, Priya; Ji, Ruijun; Vangel, Mark; Singhal, Aneesh B.; Ay, Hakan; Sorensen, A. Gregory

2011-01-01

292

Characteristic free volumes of bulk metallic glasses: Measurement and their correlation with glass-forming ability  

SciTech Connect

A convenient method is proposed for the measurement of the characteristic free volumes, viz., the amount of excess free volume annihilation in structural relaxation V{sub f-sr} and the amount of new free volume production in glass transition V{sub f-gt} of bulk metallic glasses (BMGs) by thermal dilation (DIL) test. Through the DIL tests, the characteristic free volumes are found to be sensitive to the change of glass forming ability (GFA). The Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} BMG has a quite small V{sub f-sr}. For a series of Fe-Cr-Mo-C-B-(Er) BMGs, Fe{sub 48}Cr{sub 15}Mo{sub 14}C{sub 15}B{sub 6}Er{sub 2} with the largest GFA is identified to have the largest V{sub f-gt} and smallest V{sub f-sr}. The correlation between V{sub f-sr} and the squares of critical diameters of these iron-based BMGs can be fitted as a negative exponential function with high accuracy.

Hu Qiang [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072 (China); Zeng Xierong [College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060 (China) and Shenzhen Key Laboratory of Special Functional Materials, Shenzhen 518060 (China); Fu, M. W. [Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

2011-03-01

293

Partially coherent light-emitting diode illumination for video-rate in-line holographic microscopy.  

PubMed

The light of a light-emitting diode or a common thermal source, such as a tungsten filament lamp, is known to be quasi-incoherent. We generated partially coherent light of these sources with a volume of coherence in the micrometer range of 5-100 ?m3 by spatial and spectral filtering. The corresponding degree of partial coherence was adapted for microscopic interference setups, such as a digital in-line holographic microscope. The practicability of the sources was determined by the spectral emittance and the resulting signal-to-noise ratio (SNR) of the detector. The microscale coherence in correlation with the SNR and its resolution for microscopy were analyzed. We demonstrate how low-light-level, non-laser sources enable holographic imaging with a video frame rate (25 frames/s), an intermediate SNR of 8 dB, and a volume of coherence of 3.4×10(4) ?m3. Holograms of objects with a lateral resolution of 1 ?m were achieved using a microscope lens (50×/NA=0.7) and a CCD camera featuring a 4-12 bit dynamic range. PMID:22614408

Petruck, Paul; Riesenberg, Rainer; Kowarschik, Richard

2012-05-01

294

Correlation of neurocognitive function and brain parenchyma volumes in children surviving cancer  

NASA Astrophysics Data System (ADS)

This research builds on our hypothesis that white matter damage and associated neurocognitive symptoms, in children treated for cancer with cranial spinal irradiation, spans a continuum of severity that can be reliably probed using non-invasive MR technology. Quantitative volumetric assessments of MR imaging and psychological assessments were obtained in 40 long-term survivors of malignant brain tumors treated with cranial irradiation. Neurocognitive assessments included a test of intellect (Wechsler Intelligence Test for Children, Wechsler Adult Intelligence Scale), attention (Conner's Continuous Performance Test), and memory (California Verbal Learning Test). One-sample t-tests were conducted to evaluate test performance of survivors against age-adjusted scores from the test norms; these analyses revealed significant impairments in all apriori selected measures of intelligence, attention, and memory. Partial correlation analyses were performed to assess the relationships between brain tissues volumes (normal appearing white matter (NAWM), gray matter, and CSF) and neurocognitive function. Global intelligence (r = 0.32, p = 0.05) and global attentional (r = 0.49, p < 0.01) were significantly positively correlated with NAWM volumes, whereas global memory was significantly positively correlated with overall brain parenchyma (r = 0.38, p = 0.04). We conclude that quantitative assessment of MR examinations in survivors of childhood cancer treated with cranial irradiation reveal that loss of NAWM is associated with decreased intellectual and attentional deficits, whereas overall parenchyma loss, as reflected by increased CSF and decreased white matter, is associated with memory-related deficits.

Reddick, Wilburn E.; White, Holly A.; Glass, John O.; Mulhern, Raymond K.

2002-04-01

295

Holographic moiré in real time  

Microsoft Academic Search

The body of knowledge necessary to observe holographic-moiré patterns in real time is introduced. The basic factors influencing fringe visibility in holographic moiré are analyzed and expressions to evaluate fringe visibility for any given displacement and deformation are given. The application of the introduced theory in the case of real-time observation is discussed. It is shown that the maximum benefits

C. A. Sciammarella; P. K. Rastogi; P. Jacquot; R. Narayanan

1982-01-01

296

Digital holographic video for studies of plankton dynamics  

NASA Astrophysics Data System (ADS)

The procedure, capabilities, and applicability limits of digital holographic video for the determination of the velocity and reconstruction of the trajectory of motion of plankton species in the habitat are considered. Results of experimental investigations of zooplankton in laboratory conditions are presented. Two species that differ by the morphology and sizes are examined, including Epischura baicalensis for the trajectory construction and Daphnia magna for an experiment on dual-view hologram recording. The position of a plankton species in the examined volume is suggested to be determined based on the coordinates of the center of gravity of its holographic image. Preliminary results of recording of a dual-view digital holographic video of plankton species are discussed.

Dyomin, V. V.; Olshukov, A. S.; Dzyuba, E. V.

2011-01-01

297

KTN as a holographic storage material  

SciTech Connect

The holographic storage properties of potassium tantalate niobate (KTN) single crystals have been deduced from photoelectric measurements employing incoherent light. The light energy density necessary to record an elementary volume phase grating with a 1% read-out efficiency was found to be of the order of 100 ..mu..J/cm/sup 2/ for KTN is either the ferroelectric or nonferroelectric phase. These results compare favorably with those reported for other electro-optic materials. Dark storage times of up to one year were found for the most sensitive KTN crystals.

Boatner, L.A. (Oak Ridge National Lab., TN); Kratzig, E.; Orlowski, R.

1980-01-01

298

Correlation between the release characteristics of theophylline and the free volume of polyvinylpyrrolidone.  

PubMed

The purpose of this work was to study the drug-release properties of an amorphous polymer, polyvinylpyrrolidone applied conventionally as a binder in tablets. In order to gain data on the wearing properties of tablets, they were stored for a 30 days period under different humidity conditions before the drug-release measurements. The active material chosen for the release study was theophylline. An exponential relationship was found, with good correlation, between the relative humidity of the storage medium and the mean dissolution time of theophylline from polyvinylpyrrolidone tablets and the size of free volume holes. Positron annihilation lifetime spectroscopy (PALS) measurements, performed parallel with the theophylline release study, showed that the main reason for this correlation is the rearrangement of the pore structure of PVP. The results suggest that the water-induced glassy to rubbery transition of the polymer plays a significant role in the drug-release characteristics. PMID:15734301

Zelkó, Romána; Süvegh, Károly

2005-01-12

299

Utilization of volume correlation filters for underwater mine identification in LIDAR imagery  

NASA Astrophysics Data System (ADS)

Underwater mine identification persists as a critical technology pursued aggressively by the Navy for fleet protection. As such, new and improved techniques must continue to be developed in order to provide measurable increases in mine identification performance and noticeable reductions in false alarm rates. In this paper we show how recent advances in the Volume Correlation Filter (VCF) developed for ground based LIDAR systems can be adapted to identify targets in underwater LIDAR imagery. Current automated target recognition (ATR) algorithms for underwater mine identification employ spatial based three-dimensional (3D) shape fitting of models to LIDAR data to identify common mine shapes consisting of the box, cylinder, hemisphere, truncated cone, wedge, and annulus. VCFs provide a promising alternative to these spatial techniques by correlating 3D models against the 3D rendered LIDAR data.

Walls, Bradley

2008-05-01

300

Holographic recording in LiNbO3 using various polarized lights  

NASA Astrophysics Data System (ADS)

Holographic recordings in a LiNbO3 crystal using ordinary and extraordinary light in transmission-type geometry were performed. The system parameters of storage capacity ( M/#), sensitivity, and signal-to-noise ratio were measured. Although extraordinary light will induce stronger fanning light (nonlinear enhanced scattered light) in LiNbO3, our experimental results indicate that the system using extraordinary light is superior to that using ordinary light. Our demonstrations and results can help to optimize the holographic recording in some applications of volume holographic optical element (VHOE), such as wavelength division multiplexing (WDM) filters in optical communication.

Chen, Hong-Shyuan; Lin, Tzu-Wei; Liu, Jung-Ping; Ouyang, Yueh; Chang, Hsiu-Fong

2009-05-01

301

Digital color management in full-color holographic three-dimensional printer.  

PubMed

We propose a new method of color management for a full-color holographic, three-dimensional (3D) printer, which produces a volume reflection holographic stereogram using red, green, and blue three-color lasers. For natural color management in the holographic 3D printer, we characterize its color reproduction characteristics based on the spectral measurement of reproduced light. Then the color conversion formula, which comprises a one-dimensional lookup table and a 3×3 matrix, was derived from the measurement data. The color reproducibility was evaluated by printing a color chart hologram, and the average CIELAB ?E=13.19 is fairly small. PMID:22772106

Yang, Fei; Murakami, Yuri; Yamaguchi, Masahiro

2012-07-01

302

Holographic chemical vapor sensor  

NASA Astrophysics Data System (ADS)

A holographic interferometer senses vapor-induced optical path length changes in polymer or other chemically sensitive films. The interferometer is inherently sensitive to changes in chemical vapor content, self-compensates for drifts, and accommodates a large array of sensor elements. A sniff-locked-loop synchronous detection method takes advantage of the interferometer's rapid response to achieve vapor concentration sensitivity in the parts-per-billion (ppb, parts in 10^9) range. We demonstrate, for example, 40 ppb sensitivity to ethyl alcohol using poly(N-vinyl pyrrolidone) with a measurement time of 5 s.

Ye, Hongke; Nilsen, Oyvind; Bright, Victor M.; Anderson, Dana Z.

2005-06-01

303

Holographic isotropization linearized  

NASA Astrophysics Data System (ADS)

The holographic isotropization of a highly anisotropic, homogeneous, strongly coupled, non-Abelian plasma was simplified in ref. [1] by linearizing Einstein's equations around the final, equilibrium state. This approximation reproduces the expectation value of the boundary stress tensor with a 20% accuracy. Here we elaborate on these results and extend them to observables that are directly sensitive to the bulk interior, focusing for simplicity on the entropy production on the event horizon. We also consider next-to-leading-order corrections and show that the leading terms alone provide a better description of the isotropization process for the states that are furthest from equilibrium.

Heller, Michal P.; Mateos, David; van der Schee, Wilke; Triana, Miquel

2013-09-01

304

Digital holographic confocal microscope  

NASA Astrophysics Data System (ADS)

We demonstrate experimentally a scanning confocal microscopy technique based on digital holographic recording of the scanned spot. The data collected in this way contains all the information to produce three-dimensional images. Several methods to treat the data are presented, such as the dynamic placement of the pinhole. Examples of reflection and transmission images of epithelial cells and mouse brain tissue are shown. The computations can be performed in real time, the speed being limited only by the frame rate of the camera. This method enables a convenient implementation of confocal microscopy, especially in transmission as no de-scan device is required.

Goy, Alexandre S.; Psaltis, Demetri

2013-02-01

305

Experimental observation of one-dimensional quantum holographic imaging  

NASA Astrophysics Data System (ADS)

We report the experimental observation of quantum holographic imaging of one-dimensional object with entangled photon pairs, generated in a spontaneous parametric down-conversion process. The signal photons play both roles of ``object wave'' and ``reference wave'' in holography but are recorded by a point detector providing only encoding information, while the idler photons travel freely and are locally manipulated with spatial resolution. The holographic image is formed by the two-photon correlation measurement, although both the signal and idler beams are incoherent. Three types of quantum holography schemes are analyzed according to the detection regime of the signal photons.

Song, Xin-Bing; Xu, De-Qin; Wang, Hai-Bo; Xiong, Jun; Zhang, Xiangdong; Cao, De-Zhong; Wang, Kaige

2013-09-01

306

Microwave holographic measurements of large reflector antennas in Russia  

Microsoft Academic Search

The results of holographic correlational measurements of the characteristics of several large Russian reflector antennas are submitted. Similar measurements with subsequent adjustment of mirrors are necessary for successful use of these antennas in the various international projects. Some features are considered of measurements using the signals of natural radiosources and geostationary satellites. The automated setup developed in NIRFI for antenna

ANDREY V. KALININ; Nizhny Novgorod

2000-01-01

307

Holographic Labeling And Reading Machine For Authentication And Security Appications  

DOEpatents

A holographic security label and automated reading machine for marking and subsequently authenticating any object such as an identification badge, a pass, a ticket, a manufactured part, or a package is described. The security label is extremely difficult to copy or even to read by unauthorized persons. The system comprises a holographic security label that has been created with a coded reference wave, whose specification can be kept secret. The label contains information that can be extracted only with the coded reference wave, which is derived from a holographic key, which restricts access of the information to only the possessor of the key. A reading machine accesses the information contained in the label and compares it with data stored in the machine through the application of a joint transform correlator, which is also equipped with a reference hologram that adds additional security to the procedure.

Weber, David C. (Rancho Santa Margarita, CA); Trolinger, James D. (Costa Mesa, CA)

1999-07-06

308

Applications of Multiplexed real time permanent holographic recording in photorefractive BSO.  

PubMed

Photochromic effects in crystals of photorefractive bismuth silicon oxide have been used for the recording of permanent holograms. The combination of this permanent recording with the usual photorefractive real time recording has revealed some novel techniques in information processing and interferometry. These are based on the possibilities of multiplexing two distinct holographic gratings having identical grating wave vectors within the same crystal volume. Techniques ranging from image synthesis and logic operations to holographic interferometry and all-optical switching are demonstrated. PMID:20555881

Vainos, N A; Clapham, S L; Eason, R W

1989-10-15

309

High-density recording of full-color full-parallax holographic stereogram  

Microsoft Academic Search

We demonstrate a high quality 3D image reproduced by a full-color, full-parallax holographic stereogram (HS) with high-density light-ray recording. The full-parallax HS is produced by a holographic 3D printer, which is an electronic controlled optical system for automatic recording. The HS consists of a 2D array structure of volume type elementary holograms, and full-parallax 3D image can be observed under

Shingo Maruyama; Yuji Ono; Masahiro Yamaguchi

2008-01-01

310

New holographic overlays  

NASA Astrophysics Data System (ADS)

This paper discusses a new type of holographic overlay, FLASHPRINT, which may be used in both security and packaging applications. Unlike the more common embossed holograms currently used, FLASHPRINT leads to reduced set-up costs and offers a simpler process. This reduces the long lead times characteristic of the existing technology and requires the customer to provide only two-dimensional artwork. The overlay material contains a covert 2-D image. The image may be switched on or off by simply tilting the overlay in a light source. The overlay is replayed in the 'on' position to reveal the encoded security message as a highly saturated gold colored image. This effect is operable for a wide range of lighting conditions and viewing geometries. In the 'off' position the overlay is substantially transparent. These features make the visual effect of the overlay attractive to incorporate into product design. They may be laminated over complex printed artwork such as labels and security passes without masking the printed message. When switched 'on' the image appears both sharp and more than seven times brighter than white paper. The image remains sharp and clear even in less favorable lighting conditions. Although the technique offers a low set-up cost for the customer, through its simplicity, it remains as technically demanding and difficult to counterfeit as any holographic process.

Hopwood, Anthony I.

1991-10-01

311

Engineering holographic graphene  

SciTech Connect

We present a top-down string theory holographic model of strongly interacting relativistic 2 + 1-dimensional fermions, paying careful attention to the discrete symmetries of parity and time reversal invariance. Our construction is based on probe D7-branes in AdS{sub 5} Multiplication-Sign S{sup 5}, stabilized by internal fluxes. We find three solutions, a parity and time reversal invariant conformal field theory which can be viewed as a particular deformation of Coulomb interacting graphene, a parity and time reversal violating but gapless field theory and a system with a parity and time reversal violating charge gap. We show that the Chern-Simons-like electric response function, which is generated perturbatively at one-loop order by parity violating fermions and which is protected by a no-renormalization theorem at orders beyond one loop, indeed appears with the correctly quantized coefficient in the charge gapped theory. In the gapless parity violating solution, the Chern-Simons response function obtains quantum corrections which we compute in the holographic theory.

Semenoff, Gordon W. [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada)

2012-09-24

312

d + id holographic superconductors  

NASA Astrophysics Data System (ADS)

A holographic model of d+ id superconductors based on the action proposed by Benini, Herzog, and Yarom [arXiv:1006.0731] is studied. This model has a charged spin two field in an AdS black hole spacetime. Working in the probe limit, the normalizable solution of the spin two field in the bulk gives rise to a d+ id superconducting order parameter at the boundary of the AdS. We calculate the fermion spectral function in this superconducting background and confirm the existence of fermi arcs for non-vanishing Majorana couplings. By changing the relative strength ? of the d and id condensations, the position and the size of the fermi arcs are changed. When ? = 1, the spectrum becomes isotropic and the spectral function is s-wave like. By changing the fermion mass, the fermi momentum is changed. We also calculate the conductivity for these holographic d + id superconductors where time reversal symmetry has been broken spontaneously. A non-vanishing Hall conductivity is obtained even without an external magnetic field.

Chen, Jiunn-Wei; Liu, Yu-Sheng; Maity, Debaprasad

2011-05-01

313

Epicardial fat volume correlates with severity of coronary artery disease in nonobese patients.  

PubMed

OBJECTIVE: It has been reported that epicardial adipose tissue could locally modulate the coronary artery functions through secretion of proinflammatory and anti-inflammatory cytokines. Epicardial fat tissue is further implicated in the pathogenesis of coronary artery disease (CAD) because of its proximity to the adventitia of the major epicardial coronary arteries. We investigated the relationship between epicardial fat volume (EFV) and severity of CAD in nonobese patients using 64-slice multidetector computed tomography (MDCT). METHODS: One hundred and forty nonobese patients (BMI <25?kg/m) were enrolled. EFV and visceral fat area were measured by MDCT. Patients were classified according to the plaque components (noncalcified, mixed and calcified) and severity of CAD. Inflammatory biomarkers were also measured, and compared with each CT parameter. RESULTS: EFV was significantly correlated with the extent or severity of CAD. Patients with noncalcified or mixed plaque had a greater EFV than those with calcified plaque. Log-transferred high sensitivity C-reactive protein (CRP) was significantly correlated with EFV (r?=?0.24, P?=?0.04). Adiponectin level was significantly inversely correlated with visceral fat area (r?=?0.38, P?=?0.0001). CONCLUSION: Increased EFV is associated with more severe CAD and noncalcified or mixed coronary plaques in nonobese patients. PMID:23549277

Okada, Koji; Ohshima, Satoru; Isobe, Satoshi; Harada, Ken; Hirashiki, Akihiro; Funahashi, Hidehito; Arai, Kosuke; Hayashi, Daisuke; Hayashi, Mutsuharu; Ishii, Hideki; Murohara, Toyoaki

2013-04-01

314

Grey matter volume correlates with virtual water maze task performance in boys with androgen excess.  

PubMed

Major questions remain about the specific role of testosterone in human spatial navigation. We tested 10 boys (mean age 11.65 years) with an extremely rare disorder of androgen excess (Familial Male Precocious Puberty, FMPP) and 40 healthy boys (mean age 12.81 years) on a virtual version of the Morris Water Maze task. In addition, anatomical magnetic resonance images were collected for all patients and a subsample of the controls (n=21) after task completion. Behaviourally, no significant differences were found between both groups. However, in the MRI analyses, grey matter volume (GMV) was correlated with performance using voxel-based morphometry (VBM). Group differences in correlations of performance with GMV were apparent in medial regions of the prefrontal cortex as well as the middle occipital gyrus and the cuneus. By comparison, similar correlations for both groups were found in the inferior parietal lobule. These data provide novel insight into the relation between testosterone and brain development and suggest that morphological differences in a spatial navigation network covary with performance in spatial ability. PMID:21964472

Mueller, S C; Merke, D P; Leschek, E W; Fromm, S; Grillon, C; Cornwell, B R; Vanryzin, C; Ernst, M

2011-09-21

315

Grey matter volume correlates with virtual water maze task performance in boys with androgen excess  

PubMed Central

Major questions remain about the specific role of testosterone in human spatial navigation. We tested 10 boys (mean age 11.65 years) with an extremely rare disorder of androgen excess (Familial Male Precocious Puberty, FMPP) and 40 healthy boys (mean age 12.81 years) on a virtual version of the Morris Water Maze task. In addition, anatomical magnetic resonance images were collected for all patients and a subsample of the controls (n=21) after task completion. Behaviourally, no significant differences were found between both groups. However, in the MRI analyses, grey matter volume (GMV) was correlated with performance using voxel-based morphometry (VBM). Group differences in correlations of performance with GMV were apparent in medial regions of the prefrontal cortex as well as the middle occipital gyrus and the cuneus. By comparison, similar correlations for both groups were found in the inferior parietal lobule. These data provide novel insight into the relation between testosterone and brain development and suggest that morphological differences in a spatial navigation network covary with performance in spatial ability.

Mueller, Sven C.; Merke, Deborah P.; Leschek, Ellen W.; Fromm, Stephen; Grillon, Christian; Cornwell, Brian R.; VanRyzin, Carol; Ernst, Monique

2011-01-01

316

Holographic models for undoped Weyl semimetals  

NASA Astrophysics Data System (ADS)

We continue our recently proposed holographic description of single-particle correlation functions for four-dimensional chiral fermions with Lifshitz scaling at zero chemical potential, paying particular attention to the dynamical exponent z = 2. We present new results for the spectral densities and dispersion relations at non-zero momenta and temperature. In contrast to the relativistic case with z = 1, we find the existence of a quantum phase transition from a non-Fermi liquid into a Fermi liquid in which two Fermi surfaces spontaneously form, even at zero chemical potential. Our findings show that the boundary system behaves like an undoped Weyl semimetal.

Gürsoy, Umut; Jacobs, Vivian; Plauschinn, Erik; Stoof, Henk; Vandoren, Stefan

2013-04-01

317

Antisymmetric tensors in holographic approaches to QCD  

SciTech Connect

We study real (massive) antisymmetric tensors of rank two in holographic models of QCD based on the gauge/string duality. Our aim is to understand in detail how the anti-de Sitter/conformal field theory correspondence describes correlators with tensor currents in QCD. To this end we study a set of bootstrapped correlators with spin-1 vector and tensor currents, imposing matching to QCD at the partonic level. We show that a consistent description of this set of correlators yields a very predictive picture. For instance, it imposes strong constraints on infrared boundary conditions and precludes the introduction of dilatonic backgrounds as a mechanism to achieve linear confinement. Additionally, correlators with tensor currents turn out to be especially sensitive to chiral symmetry breaking, thus offering an ideal testing ground for genuine QCD effects. Several phenomenological consequences are explored, such as the nontrivial interplay between 1{sup +-} states and conventional 1{sup --} vector mesons.

Cappiello, Luigi [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Via Cintia, 80126 Napoli (Italy); INFN-Sezione di Napoli, Via Cintia, 80126 Napoli (Italy); Cata, Oscar [Departament de Fisica Teorica and IFIC, Universitat de Valencia-CSIC, Apt. Correus 22085, E-46071 Valencia (Spain); INFN, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); D'Ambrosio, Giancarlo [INFN-Sezione di Napoli, Via Cintia, 80126 Napoli (Italy)

2010-11-01

318

Microdisplays in holographic mastering applications  

NASA Astrophysics Data System (ADS)

We demonstrate implementation and performance of microdisplay systems based on liquid-crystal technology in a variety of applications in holographic mastering. These displays can encode 2D objects information in grey scale or address holographic patterns in amplitude or phase. The main advantage is here to address any content dynamically with typically 60 Hz. Furthermore they show a resolution up to 1920×1200 pixels with a pixel size as small as 6.4 microns. Therefore they are extremely suitable for a dynamic or multi-exposure mastering process, to incorporate image content, phase-encode objects or any holographic features. This technology is already being used in holographic security applications as well as in commercial and display holography. We report about a few applications/implementations and show experimental results and performance parameters.

Plöger, Sven; Krüger, Sven; Osten, Stefan; Wernicke, Günther K. G.; Ackermann, Gerhard K.; Eichler, Jürgen

2009-05-01

319

Holographic Interferometry of Exploding Wires.  

National Technical Information Service (NTIS)

A short pulse (2 nsec) ruby laser has been used to make holographic interferograms of exploding-wire events. At atmospheric pressure the interferograms exhibit both shock waves and ionization. In a vacuum the vaporization and subsequent ionization of the ...

J. L. Seftor

1973-01-01

320

A Holographic Motion Picture Camera.  

National Technical Information Service (NTIS)

A holographic motion picture camera for producing three dimensional images was disclosed. The camera employs an elliptical optical system and a motion compensator is present in one of the beam paths; the compensator allows the camera to photograph fast mo...

R. L. Kurtz

1974-01-01

321

Positron age-momentum correlation studies of free volumes in toughened cyanate resin networks  

NASA Astrophysics Data System (ADS)

Positron age-momentum correlation (AMOC) spectroscopy is applied to study the associations between the momentum distributions and positron annihilation in the toughened CE networks. The Doppler profile of the positron annihilation process is much broader for the toughened CE than pure CE network. This is due to positron trapping on high polar groups of the added elastomers or nano-CaCO3 and annihilation with the electrons of high momenta. The broadening momentum distribution of ortho-positronium annihilation process indicates that the pick-off annihilation process is strongly influenced by the added high polar elastomers or nano-CaCO3. The potential of AMOC spectroscopy for free volume analysis in polymer blends was demonstrated.

Minfeng, Zeng; Xudong, Sun; Cuiyun, Lu; Zhuoxin, Li; Baoyi, Wang; Chenze, Qi

2012-06-01

322

Dynamic volume vs respiratory correlated 4DCT for motion assessment in radiation therapy simulation  

SciTech Connect

Purpose: Conventional (i.e., respiratory-correlated) 4DCT exploits the repetitive nature of breathing to provide an estimate of motion; however, it has limitations due to binning artifacts and irregular breathing in actual patient breathing patterns. The aim of this work was to evaluate the accuracy and image quality of a dynamic volume, CT approach (4D{sub vol}) using a 320-slice CT scanner to minimize these limitations, wherein entire image volumes are acquired dynamically without couch movement. This will be compared to the conventional respiratory-correlated 4DCT approach (RCCT). Methods: 4D{sub vol} CT was performed and characterized on an in-house, programmable respiratory motion phantom containing multiple geometric and morphological ''tumor'' objects over a range of regular and irregular patient breathing traces obtained from 3D fluoroscopy and compared to RCCT. The accuracy of volumetric capture and breathing displacement were evaluated and compared with the ground truth values and with the results reported using RCCT. A motion model was investigated to validate the number of motion samples needed to obtain accurate motion probability density functions (PDF). The impact of 4D image quality on this accuracy was then investigated. Dose measurements using volumetric and conventional scan techniques were also performed and compared. Results: Both conventional and dynamic volume 4DCT methods were capable of estimating the programmed displacement of sinusoidal motion, but patient breathing is known to not be regular, and obvious differences were seen for realistic, irregular motion. The mean RCCT amplitude error averaged at 4 mm (max. 7.8 mm) whereas the 4D{sub vol} CT error stayed below 0.5 mm. Similarly, the average absolute volume error was lower with 4D{sub vol} CT. Under irregular breathing, the 4D{sub vol} CT method provides a close description of the motion PDF (cross-correlation 0.99) and is able to track each object, whereas the RCCT method results in a significantly different PDF from the ground truth, especially for smaller tumors (cross-correlation ranging between 0.04 and 0.69). For the protocols studied, the dose measurements were higher in the 4D{sub vol} CT method (40%), but it was shown that significant mAs reductions can be achieved by a factor of 4-5 while maintaining image quality and accuracy. Conclusions: 4D{sub vol} CT using a scanner with a large cone-angle is a promising alternative for improving the accuracy with which respiration-induced motion can be characterized, particularly for patients with irregular breathing motion. This approach also generates 4DCT image data with a reduced total scan time compared to a RCCT scan, without the need for image binning or external respiration signals within the 16 cm scan length. Scan dose can be made comparable to RCCT by optimization of the scan parameters. In addition, it provides the possibility of measuring breathing motion for more than one breathing cycle to assess stability and obtain a more accurate motion PDF, which is currently not feasible with the conventional RCCT approach.

Coolens, Catherine; Bracken, John; Driscoll, Brandon; Hope, Andrew; Jaffray, David [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada) and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

2012-05-15

323

On the correlation between droplet volume and irradiation conditions in the laser forward transfer of liquids  

NASA Astrophysics Data System (ADS)

The analysis of the morphology of droplets printed through laser-induced forward transfer (LIFT) of liquid films shows that: (i) the droplet volume is linearly related with the energy of the laser pulse that originated it, (ii) the liquid ejection process is activated by an energy density threshold F 0, and (iii) the droplet volume can be correlated with a dimensional parameter of the laser beam through an oversimple model that states that the amount of printed liquid equals the liquid contained in the cylindrical portion of an irradiated film whose base corresponds to the cross-sectional area of the beam with energy density higher than F 0. Although these issues seem to describe correctly the LIFT process, some problematic instances arise from them. Thus, the linear relation between droplet volume and laser pulse energy seems to be inconsistent with the existence of the threshold F 0. On the other hand, the compatibility between the model and the aforementioned linear relation requires to be explained. Finally, the model is based on the idea that transfer takes place in a way analogous to the LIFT of solid films, but time-resolved imaging studies have demonstrated that liquid ejection follows a dynamics which seems quite unsuited with that idea. In this work previous results are re-analyzed and new experiments are performed in an attempt to clarify these questions. It is then shown that the inconsistencies pointed out are only apparent, and that the validity of the model is limited to irradiation conditions where the beam dimensions are significantly larger than the thickness of the liquid film. Furthermore, an explanation is provided for the dependence of the success and failure of the model on those irradiation conditions in terms of the diverse liquid ejection dynamics taking place.

Duocastella, M.; Patrascioiu, A.; Fernández-Pradas, J. M.; Morenza, J. L.; Serra, P.

2012-10-01

324

Testicular volume is inversely correlated with nurturing-related brain activity in human fathers.  

PubMed

Despite the well-documented benefits afforded the children of invested fathers in modern Western societies, some fathers choose not to invest in their children. Why do some men make this choice? Life History Theory offers an explanation for variation in parental investment by positing a trade-off between mating and parenting effort, which may explain some of the observed variance in human fathers' parenting behavior. We tested this hypothesis by measuring aspects of reproductive biology related to mating effort, as well as paternal nurturing behavior and the brain activity related to it. Both plasma testosterone levels and testes volume were independently inversely correlated with paternal caregiving. In response to viewing pictures of one's own child, activity in the ventral tegmental area-a key component of the mesolimbic dopamine reward and motivation system-predicted paternal caregiving and was negatively related to testes volume. Our results suggest that the biology of human males reflects a trade-off between mating effort and parenting effort, as indexed by testicular size and nurturing-related brain function, respectively. PMID:24019499

Mascaro, Jennifer S; Hackett, Patrick D; Rilling, James K

2013-09-09

325

Control of DCG and nonsilver holographic materials  

NASA Astrophysics Data System (ADS)

We review the properties and relative usefulness of three nonsilver volume holographic recording materials that are available today. Dichromated gelatin (DCG) receives the most attention followed by Dupont Omnidex products and a light treatment of polyvinyl carbazole (PVK). Enhancement and control of color, bandwidth and diffraction efficiency of volume reflection holograms recorded in DCG, and photopolymers are discussed. Methods of increasing the bandwidth while shifting the center frequency toward the red are given for photopolymers. Red pseudo color is covered thoroughly so that the practitioner has all the elementary tools to make full color and broadband DCG holograms from scratch. The entire DCG technology is disclosed as it relates to production of high quality display holograms that span the spectrum and may be narrowband and very deep or shallow and broadband.

Rallison, Richard D.

1992-01-01

326

Stability of holographic superconductors  

SciTech Connect

We study the dynamical stability of holographic superconductors. We first classify perturbations around black hole background solutions into vector and scalar sectors by means of a 2-dimensional rotational symmetry. We prove the stability of the vector sector by explicitly constructing the positive definite Hamiltonian. To reveal a mechanism for the stabilization of a superconducting phase, we construct a quadratic action for the scalar sector. From the action, we see the stability of black holes near a critical point is determined by the equation of motion for a charged scalar field. We show the effective mass of the charged scalar field in hairy black holes is always above the Breitenlohner-Freedman bound near the critical point due to the backreaction of a gauge field. It implies the stability of the superconducting phase. We also argue that the stability continues away from the critical point.

Kanno, Sugumi [Centre for Particle Theory, Department of Mathematical Sciences, Durham University, Science Laboratories, South Road, Durham, DH1 3LE (United Kingdom); Soda, Jiro [Department of Physics, Kyoto University, Kyoto, 606-8501 (Japan)

2010-10-15

327

A Holographic Collaboration  

NASA Astrophysics Data System (ADS)

In the Fall of '87 Rudie Berkhout and myself started a very intense and fruitful collaboration producing a series of holographic art pieces that were experimental but that reflected our different artistic sensibilities. The masters were made in my portrait studio in the Museum of Holography in New York using a pulse laser and later transferred in my Long Island City Studio. These pieces were shown at the Holocenter in 2009 and poignantly, it was the last show that Rudie had while he was alive. My paper details the process of an artistic collaboration, its pitfalls and advantages, its conflicts and compromises. It will illuminate the creative process that from two separate and very different streams melded into beautiful and evocative art.

Nicholson, Ana Maria

2013-02-01

328

Narrow-band holographic optical filter using thick efficient holographic gratings  

NASA Astrophysics Data System (ADS)

RL Associates in conjunction with Hybrid Technologies is developing a narrow linewidth optical filter employing extremely thick volume holographic diffraction gratings. The gratings are written in MEMPLEX, a new holographic materia invented by Laser Photonics Technology, Inc. and licensed to Hybrid Technologies. MEMPLEX has the following characteristics: (1) Excellent optical clarity, (2) Preparable at any thickness up to 10 mm, (3) Large dynamic range for plane wave holograms, (4) Hard, freestanding, stable, polishable and coatable. We have written and characterized numerous gratings in 1.8 mm thick samples to study the effect of writing geometry on the spectral linewidth and field-of-view of a single grating in the reflection geometry. We have succeeded in writing some very efficient gratings at 15 degrees internal write angles with external slant angles of 5 degrees. These gratings exhibit linewidths of < 0.2 nm and diffraction efficiencies of better than 70 percent. The measured angular acceptance of these gratings ranges from 0.1 to 0.24 degrees. We have also written some initial angle multiplexed gratings which include 3 efficient gratings in the same volume in an attempt to increase the angular acceptance. In this manner we hope to achieve a highly efficient optical filter with extremely narrow spectral linewidth and wide angular acceptance. Filters based on thick volume holograms show great promise in Lidar applications and should result in superior S/N ratios.

Billmers, Richard I.; Billmers, Elizabeth J.; Burzynski, Ryszard; Weibel, John F.; Heverley, L. H.; Casstevens, Martin K.; Curran, Thomas P.; Contarino, V. Michael

2002-06-01

329

Effects of Wavelength Change in Holographic Reconstructions.  

National Technical Information Service (NTIS)

Holographic imaging is necessary in some particulate measurements in test facilities at AEDC. Additionally, projection of holographic images of infrared (IR) test objects is being considered to enhance the IR sensor test capability at AEDC. Lasers of diff...

R. W. Menzel

1981-01-01

330

Real-Time Holographic Stereogram Display.  

National Technical Information Service (NTIS)

To evaluate the feasibility of a prototype real-time display capable of projecting a 3-dimensional image holographically, researchers modified the design of a previously developed system to holographically project computer-generated or optically recorded ...

K. S. Kollin S. C. Hill

1990-01-01

331

Multiplexed phase{conjugate holographic storage using an intermediate bufier hologram  

Microsoft Academic Search

1. ABSTRACT Volume holographic storage combines fast, parallel readout (because each hologram stores a large data page) with high density (because many holograms are multiplexed within the same volume). Phase-conjugate readout has been proposed as a way to eliminate the precision optics that recent demonstrations have relied upon to image the pixels of the input spatial light modulator (SLM) onto

Geofirey W. Burr; Hans Coufal; John A. Hofinagle; C. Michael Jefierson; Mark Jurich; Roger M. Macfarlane; Robert M. Shelby

2000-01-01

332

Reusable holographic velocimetry system based on polarization multiplexing in bacteriorhodopsin  

NASA Astrophysics Data System (ADS)

We present a novel holographic particle image velocimetry (HPIV) system using a reversible holographic material as the recording medium. In HPIV the three-dimensional flow field throughout a volume is detected by adding small tracer particles to a normally transparent medium. By recording the particle distribution twice with a known time shift the displacement and the velocity of the tracer particles can be retrieved. From this information the instantaneous three-dimensional flow field can be found. Our measurement system records double exposure particle holograms in a film based on the photo-chromic protein bacteriorhodopsin (BR). Polarization multiplexing is used to separate the two constituent holograms. We believe it is the first time that this type of multiplexing is used in (particle) velocimetry measurements. By using a polarization sensitive material we are able to simplify our setup and increase the storage capacity of our holographic medium. BR is a fully reversible recording material that does not require any chemical processing. This allows for fast experiments that require minimal operator involvement. A full measurement cycle can typically be completed within several minutes. We present our experimental system in detail and we will discuss how the material and optical properties of BR affect the holographic recording system. We will point out the advantages, disadvantages, and practical issues involved when working with BR.

Koek, W. D.; Chan, V. S. S.; Ooms, T. A.; Bhattacharya, N.; Westerweel, J.; Braat, J. J. M.

2005-04-01

333

Fabrication of photonic quasicrystals using holographic lithography method  

NASA Astrophysics Data System (ADS)

Photonic crystals, which can mold the flow of light, have attracted a great deal of attention from physicists and engineers. Fabricating mesoscale photonic crystals of large area and high quality is still a great challenge. In this thesis, I report the fabrication of photonic quasicrystals using the holographic lithography method, a good method for fabricating mesoscale structures. Based on the fabrication of 2-D quasicrystals with a Penrose structure, a ten-beam interference lithography method was used to fabricate 3-D periodic quasicrystals in photoresist SU-8. The 3-D periodic quasicrystals showed quasiperiodicity of a Penrose in the x-y plane, but were periodic in the z direction. The samples exhibited photonic band gaps in the visible range and displayed a simple relation between periodicities and polymeric volume fractions, revealing agreement with Bragg's Diffraction Relation. Submicron-sized icosahedral quasicrystals were fabricated using a novel seven-beam holographic lithography in both photoresist SU-8 and holographic plate DCG emulsions. Electron micrographs of the photoresist samples showed clearly the symmetries of icosahedral quasicrystals, resembling computer simulation results. More importantly, the holographic plate samples exhibited band gaps in the visible range, which could be interpreted by the reflection planes inside the icosahedral quasicrystal.

Xu, Jun

334

Holographic k-string Tensions in Higher Representations  

NASA Astrophysics Data System (ADS)

We investigate holographic k-string representations in 3+1 and 2+1 dimensions of field theories dual to confining geometries of the Maldacena-Nuñez and Maldacena-Nastase supergravity backgrounds via D5 branes with world volume fluxes. The D5 brane tensions are computed in qualitative agreement with totally symmetric and totally anti-symmetric representations with results from lattice QCD and the Hamiltonian method used by Karabali and Nair.

Button, Bradly; Lee, Seo Jun; Pando Zayas, Leopoldo; Rodgers, Vincent; Stiffler, Kory

2013-04-01

335

Holographic Information Storage and Retrieval. Final Report.  

ERIC Educational Resources Information Center

|A four-month investigation was made of holographic information storage and retrieval. After an extensive review of the state of the art of various holographic systems, it was concluded that digital holographic storage techniques hold the greatest promise for commercial development, especially since they are particularly well suited to computer…

Spencer, J. R.

336

Three-Dimensional TV Using Holographic Stereogram  

Microsoft Academic Search

Computer holographic stereogram (CHS) is useful for holographic 3D TV because it is constructed from the multi camera horizontal viewpoint plane images and is compatible to the multi holographic stereogram image. Each hologram is recorded as a slit hologram (element hologram) but total viewing area and the number of the element holograms have been limited to some extent by the

Koki Sato; Masataka Tozuka; Makoto Ohki; Kunihiko Takano

2010-01-01

337

Holographic bound from second law of thermodynamics  

Microsoft Academic Search

A necessary condition for the validity of the holographic principle is the holographic bound: the entropy of a system is bounded from above by a quarter of the area of a circumscribing surface measured in Planck areas. This bound cannot be derived at present from consensus fundamental theory. We show with suitable gedanken experiments that the holographic bound follows from

Jacob D. Bekenstein

2000-01-01

338

Initiation of the transcriptional response to hyperosmotic shock correlates with the potential for volume recovery.  

PubMed

The control of activity and localization of transcription factors is critical for appropriate transcriptional responses. In eukaryotes, signal transduction components such as mitogen-activated protein kinase (MAPK) shuttle into the nucleus to activate transcription. It is not known in detail how different amounts of nuclear MAPK over time affect the transcriptional response. In the present study, we aimed to address this issue by studying the high osmolarity glycerol (HOG) system in Saccharomyces cerevisiae. We employed a conditional osmotic system, which changes the period of the MAPK Hog1 signal independent of the initial stress level. We determined the dynamics of the Hog1 nuclear localization and cell volume by single-cell analysis in well-controlled microfluidics systems and compared the responses with the global transcriptional output of cell populations. We discovered that the onset of the initial transcriptional response correlates with the potential of cells for rapid adaptation; cells that are capable of recovering quickly initiate the transcriptional responses immediately, whereas cells that require longer time to adapt also respond later. This is reflected by Hog1 nuclear localization, Hog1 promoter association and the transcriptional response, but not Hog1 phosphorylation, suggesting that a presently uncharacterized rapid adaptive mechanism precedes the Hog1 nuclear response. Furthermore, we found that the period of Hog1 nuclear residence affects the amplitude of the transcriptional response rather than the spectrum of responsive genes. PMID:23758973

Geijer, Cecilia; Medrala-Klein, Dagmara; Petelenz-Kurdziel, Elzbieta; Ericsson, Abraham; Smedh, Maria; Andersson, Mikael; Goksör, Mattias; Nadal-Ribelles, Mariona; Posas, Francesc; Krantz, Marcus; Nordlander, Bodil; Hohmann, Stefan

2013-07-05

339

Polarization-holographic protection system  

NASA Astrophysics Data System (ADS)

With the purpose to increase a level of protection of the important documents, securities, industrial goods, etc. from counterfeiting the polarization-holographic system of protection is developed. The suggested approach is based on new physical principles and allows a level of protection against counterfeiting to be increased. The technology of obtaining protective elements and also a device for the definition of authenticity of these elements has been developed. The suggested system of protection uses specially synthesized polarization-sensitive materials and polarization-holographic elements with special properties. The definition of authenticity is made by means of the analysis of the polarization state of light diffracted on the protective element. The essential advantage of this system is that the copying of polarization-holographic protective element by optical methods is impossible in principle which complicates their counterfeiting.

Kakauridze, George A.; Kilosanidze, Barbara N.

2007-04-01

340

Holographic Photolysis for Multiple Cell Stimulation in Mouse Hippocampal Slices  

PubMed Central

Background Advanced light microscopy offers sensitive and non-invasive means to image neural activity and to control signaling with photolysable molecules and, recently, light-gated channels. These approaches require precise and yet flexible light excitation patterns. For synchronous stimulation of subsets of cells, they also require large excitation areas with millisecond and micrometric resolution. We have recently developed a new method for such optical control using a phase holographic modulation of optical wave-fronts, which minimizes power loss, enables rapid switching between excitation patterns, and allows a true 3D sculpting of the excitation volumes. In previous studies we have used holographic photololysis to control glutamate uncaging on single neuronal cells. Here, we extend the use of holographic photolysis for the excitation of multiple neurons and of glial cells. Methods/Principal Findings The system combines a liquid crystal device for holographic patterned photostimulation, high-resolution optical imaging, the HiLo microscopy, to define the stimulated regions and a conventional Ca2+ imaging system to detect neural activity. By means of electrophysiological recordings and calcium imaging in acute hippocampal slices, we show that the use of excitation patterns precisely tailored to the shape of multiple neuronal somata represents a very efficient way for the simultaneous excitation of a group of neurons. In addition, we demonstrate that fast shaped illumination patterns also induce reliable responses in single glial cells. Conclusions/Significance We show that the main advantage of holographic illumination is that it allows for an efficient excitation of multiple cells with a spatiotemporal resolution unachievable with other existing approaches. Although this paper focuses on the photoactivation of caged molecules, our approach will surely prove very efficient for other probes, such as light-gated channels, genetically encoded photoactivatable proteins, photoactivatable fluorescent proteins, and voltage-sensitive dyes.

Papagiakoumou, Eirini; Ventalon, Cathie; Angulo, Maria Cecilia; Emiliani, Valentina

2010-01-01

341

Cylindrical holographic radar camera  

NASA Astrophysics Data System (ADS)

A novel personnel surveillance system has been developed to rapidly obtain 360 degree, full-body images of humans for the detection and identification of concealed threats. Detectable threats include weapons fabricated with metal, plastic, and ceramic, as well as explosive solids and liquids. This new system uses a cylindrical mechanical scanner to move a seven-foot, 384 element, Ka band (26 - 30 GHz) array circumferentially around a person in four to seven seconds. Low power millimeter-waves, which are nonionizing and not harmful to humans, are employed because they readily penetrate clothing barriers and reflect from concealed threats. The reflected waves provide information that is reconstructed into 3-D cylindrical holographic images with high-speed, digital signal processing (DSP) boards. This system is capable of displaying in an animation format eight, sixteen, thirty-two or sixty-four image frames at various aspect angles around the person under surveillance. This new prototype surveillance system is operational and is presently under laboratory testing and evaluation.

McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.

1998-12-01

342

Scanning holographic lidar telescope  

NASA Astrophysics Data System (ADS)

We have developed a unique telescope for lidar using a holographic optical element (HOE) as the primary optic. The HOE diffracts 532 nm laser backscatter making a 43 deg angle with a normal to its surface to a focus located 130 cm along the normal. The field of view scans a circle as the HOE rotates about the normal. The detector assembly and baffling remain stationary, compared to conventional scanning lidars in which the entire telescope and detector assembly require steering, or which use a large flat steerable mirror in front of the telescope to do the pointing. The spectral bandpass of our HOE is 50 nm (FWHM). Light within that bandpass is spectrally dispersed at 0.6 nm/mm in the focal plane. An aperture stop reduces the bandpass of light reaching the detector from one direction to 1 nm while simultaneously reducing the field of view to 1 mrad. Wavelengths outside the 50 nm spectral bandpass pass undiffracted through HOE to be absorbed by a black backing. Thus, the HOE combines three functions into one optic: the scanning mirror, the focusing mirror, and a narrowband filter.

Schwemmer, Geary K.; Wilkerson, Thomas D.

343

Holographic Raman sensor for process-control application  

Microsoft Academic Search

Holographic Optical Components including the Holographic Notch and SuperNotchTM Filter, Holographic Bandpass Filter and the Holographic Transmission Grating have been developed to meet the needs of Raman spectroscopy applications. Combined as an integrated assembly, these holographic components in conjunction with a laser diode, CCD array or discrete detector and suitable collection and imaging optics form the basis of a new

Harry Owen

1992-01-01

344

Holographic renormalization of cascading gauge theories  

NASA Astrophysics Data System (ADS)

We perform a holographic renormalization of cascading gauge theories. Specifically, we find the counterterms that need to be added to the gravitational action of the backgrounds dual to the cascading theory of Klebanov and Tseytlin, compactified on an arbitrary four-manifold, in order to obtain finite correlation functions (with a limited set of sources). We show that it is possible to truncate the action for deformations of this background to a five-dimensional system coupling together the metric and four scalar fields. Somewhat surprisingly, despite the fact that these theories involve an infinite number of high-energy degrees of freedom, we find finite answers for all one-point functions (including the conformal anomaly). We compute explicitly the renormalized stress tensor for the cascading gauge theories at high temperature and show how our finite answers are consistent with the infinite number of degrees of freedom. Finally, we discuss ambiguities appearing in the holographic renormalization we propose for the cascading gauge theories; our finite results for the one-point functions have some ambiguities in curved space (including the conformal anomaly) but not in flat space.

Aharony, Ofer; Buchel, Alex; Yarom, Amos

2005-09-01

345

Numerical reconstruction of full parallax holographic stereograms  

NASA Astrophysics Data System (ADS)

Holographic printers based on holographic stereograms are constantly gaining popularity. A holographic stereogram is recorded using 2D images of the 3D object or scene that are captured from multiple perspectives. Separation of capture and recording steps as well as checking of quality of the achieved 3D representation requires replaying of the composed holographic stereogram by computer. This paper presents a simulator which, as a first step, builds a full parallax holographic stereogram from the perspective images and, as a second step, reconstructs the hologram numerically for any viewer location by using a reconstruction algorithm proposed in the paper. To check the performance of the simulator we made a holographic stereogram of a test 3D object from images acquired by a virtual re-centering camera which was translated along a virtual camera track and compared the result from the numerical reconstruction with the optical reconstruction from the printed holographic stereogram of the same object. [Figure not available: see fulltext.

Park, Jiyung; Stoykova, Elena; Kang, Hoonjong; Hong, Sunghee; Lee, Seunghyun; Jung, Kwangmo

2012-09-01

346

Application of color digital holographic microscopy for analysis of stained tissue sections  

NASA Astrophysics Data System (ADS)

The analysis of stained tissue sections represents an important tool in medical diagnostics. Color digital holographic microscopy offers subsequent multi-focus true color imaging with simultaneous quantitative phase contrast analysis. Investigations on digital recording and numerical reconstructions of color digital holographic images have been performed by applying a transmission microscope experimental setup in holographic off-axis geometry. Three monochromatic digital holograms with different wavelengths in red, green and blue spectral range are recorded. After digital holographic refocusing and compensation for aberrations of the microscope imaging system by digital image correlation the numerically reconstructed amplitude distributions are combined into color images. The applicability of the method is demonstrated by results obtained from stained intestine tissue sections.

Mo, Xiaoli; Kemper, Björn; Langehanenberg, Patrik; Vollmer, Angelika; Xie, Jinghui; von Bally, Gert

2009-07-01

347

Hadron physics in holographic QCD  

NASA Astrophysics Data System (ADS)

Hadron physics deals with the study of strongly interacting subatomic particles such as neutrons, protons, pions and others, collectively known as baryons and mesons. Physics of strong interaction is difficult. There are several approaches to understand it. However, in the recent years, an approach called, holographic QCD, based on string theory (or gauge-gravity duality) is becoming popular providing an alternative description of strong interaction physics. In this article, we aim to discuss development of strong interaction physics through QCD and string theory, leading to holographic QCD.

Santra, A. B.; Lombardo, U.; Bonanno, A.

2012-07-01

348

Invisible engineering of holographic illusion  

NASA Astrophysics Data System (ADS)

Recent developments in production techniques of pulsed holograms and holographic stereograms have ameliorated to provide high quality three dimensional illusions that echo the apparently innate need of society to replicate itself through artificial means. A commercial platform has been found for these archetypical illusions through the mass production and distribution of embossed stereograms that depict popular celebrities from the music industry. As pulse recordings of the rich and famous become better known, and as former presidents queue to join the holographic hall of fame, the author asks `is it documentation or entertainment that is shaping the future of holography?'

Richardson, Martin J.

1993-03-01

349

Evaluation of bladder diary parameters based on correlation with the volume at strong desire to void in filling cystometry.  

PubMed

Accurate assessment of patient bladder capacity is important in determining the proper initial treatment for lower urinary tract dysfunctions and as well as for monitoring therapeutic outcomes. However, urodynamic study is an invasive procedure. Thus, it is important to find a surrogate for invasive urodynamic study, and the aim of this study is to identify the parameter from patient-recorded bladder diary that is best correlated to the volume at strong desire to void (VSD) derived from urodynamic studies. A total of 900 women who underwent urodynamic studies at a university hospital between January 2009 and December 2011. Correlation between bladder diary parameters and VSD was investigated by Spearman rank-correlation coefficient. Days 1 to 3 average maximum daytime voided volumes excluding the first morning void (DVVmaxavg) (mean 263 ml) had the highest correlation with VSD (mean 261 ml; ??=?0.51, p<0.001). The predictive value of VSD was 146+0.44 × DVVmaxavg. The days 1, 2, and 3 daytime maximum voided volumes excluding the first morning void (DVVmax) were all significantly associated with VSD and had similar mean volumes (??=?0.43-0.46, all p<0.001). DVVmaxavg had the highest area under the receiver operating characteristic curve (0.75; 95% confidence interval?=?0.72-0.78) for predicting bladder oversensitivity. The threshold of DVVmaxavg <250 ml had good predictive value for detecting bladder oversensitivity (sensitivity 70.9%; specificity 65.8%), and day 1 DVVmax <250 ml had similar sensitivity (70.6%) and specificity (59.1%). Besides, the correlation coefficients (?) between day 1, day 2 and day 3 DVVmax and DVVmaxavg were good with a range of 0.70-0.89. In conclusion, DVVmaxavg was the bladder diary parameter best correlated with VSD. DVVmaxavg and day 1 DVVmax may be useful in screening for bladder oversensitivity. PMID:23922866

Hsiao, Sheng-Mou; Hsiao, Chin-Fen; Chen, Chi-Hau; Chang, Ting-Chen; Wu, Wen-Yih; Lin, Ho-Hsiung

2013-07-29

350

Evaluation of Bladder Diary Parameters Based on Correlation with the Volume at Strong Desire to Void in Filling Cystometry  

PubMed Central

Accurate assessment of patient bladder capacity is important in determining the proper initial treatment for lower urinary tract dysfunctions and as well as for monitoring therapeutic outcomes. However, urodynamic study is an invasive procedure. Thus, it is important to find a surrogate for invasive urodynamic study, and the aim of this study is to identify the parameter from patient-recorded bladder diary that is best correlated to the volume at strong desire to void (VSD) derived from urodynamic studies. A total of 900 women who underwent urodynamic studies at a university hospital between January 2009 and December 2011. Correlation between bladder diary parameters and VSD was investigated by Spearman rank-correlation coefficient. Days 1 to 3 average maximum daytime voided volumes excluding the first morning void (DVVmaxavg) (mean 263 ml) had the highest correlation with VSD (mean 261 ml; ??=?0.51, p<0.001). The predictive value of VSD was 146+0.44 × DVVmaxavg. The days 1, 2, and 3 daytime maximum voided volumes excluding the first morning void (DVVmax) were all significantly associated with VSD and had similar mean volumes (??=?0.43–0.46, all p<0.001). DVVmaxavg had the highest area under the receiver operating characteristic curve (0.75; 95% confidence interval?=?0.72–0.78) for predicting bladder oversensitivity. The threshold of DVVmaxavg <250 ml had good predictive value for detecting bladder oversensitivity (sensitivity 70.9%; specificity 65.8%), and day 1 DVVmax <250 ml had similar sensitivity (70.6%) and specificity (59.1%). Besides, the correlation coefficients (?) between day 1, day 2 and day 3 DVVmax and DVVmaxavg were good with a range of 0.70–0.89. In conclusion, DVVmaxavg was the bladder diary parameter best correlated with VSD. DVVmaxavg and day 1 DVVmax may be useful in screening for bladder oversensitivity.

Hsiao, Sheng-Mou; Hsiao, Chin-Fen; Chen, Chi-Hau; Chang, Ting-Chen; Wu, Wen-Yih; Lin, Ho-Hsiung

2013-01-01

351

Clinical correlates of nucleus accumbens volume in drug-naive, adult patients with obsessive-compulsive disorder.  

PubMed

Background: Reward-processing deficits have been demonstrated in obsessive-compulsive disorder (OCD) and this has been linked to ventral striatal abnormalities. However, volumetric abnormalities of the nucleus accumbens (NAcc), a key structure in the reward pathway, have not been examined in OCD. We report on the volumetric abnormalities of NAcc and its correlation with illness severity in drug-naïve, adult patients with OCD. Method: In this cross-sectional study of case-control design, the magnetic resonance imaging (MRI) 1.5-T (1-mm) volume of NAcc was measured using 3D Slicer software in drug-naïve OCD patients (n = 44) and age, sex and handedness-matched healthy controls (HCs) (n = 36) using a valid and reliable method. OCD symptoms were assessed using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) Symptom checklist and severity and the Clinical Global Impression-Severity (CGI-S) scale. Results: There was no significant difference in NAcc volumes on either side between OCD patients and HCs (F = 3.45, p = 0.07). However, there was significant negative correlation between the right NAcc volume and Y-BOCS compulsion score (r = -0.48, p = 0.001). Conclusions: Study observations suggest involvement of the NAcc in the pathogenesis of OCD, indicating potential reward-processing deficits. Correlation between the right NAcc volume deficit and severity of compulsions offers further support for this region as a candidate for deep brain stimulation treatment in OCD. PMID:23737599

Narayanaswamy, Janardhanan C; Jose, Dania; Kalmady, Sunil; Venkatasubramanian, Ganesan; Reddy, Yc Janardhan

2013-06-04

352

Anisotropic Diffraction in Photorefractive Volume Hologram.  

National Technical Information Service (NTIS)

Recently, there are extensive studies on applying the photorefractive effect for optical data storage and processing. One of the most important applications is for the volume holographic storage. In this paper we report theoretical derivations and experim...

C. C. Sun M. W. Chang

1992-01-01

353

Mean Platelet Volume Reflect Hematopoietic Potency and Correlated Blood Group O in Cord Blood from Healthy Newborn  

PubMed Central

We evaluated the relationship between mean platelet volume (MPV) and characteristics of 10,577 cord blood (CB) units in a public CB bank in Korea. Blood group O has the highest MPV (P = 0.002). MPV correlated with CB volume (r = 0.121), Hb (r = 0.377), WBC (r = 0.111), TNCs (r = 0.110), CD34+ cell (r = 0.174), CD34+ cells/TNCs (r = 0.157), gestational age (r = ?0.102), and birth weight (r = 0.023); (P < 0.001 in all). MPV may be one of the useful decision parameters of process priority in CB bank.

Lee, Hye Ryun; Park, Jeong Su; Shin, Sue; Roh, Eun Youn; Yoon, Jong Hyun; Song, Eun Young; Kim, Byung Jae; Chang, Ju Young

2013-01-01

354

Off-axis transmission holographic system for recording aquatic particles  

NASA Astrophysics Data System (ADS)

We describe a holographic system for recording particles suspended in water. The hologram plate is located in air, separated from the test tank by an air/glass/water boundary. The holographic emulsion is therefore unaffected by adverse aquatic conditions within the tank (i.e. surface contamination, non-uniform swelling). The design geometry is intended to minimize the aberrations that arise from recording subjects located in water and replaying their hologram image in air. Third order aberrations, most crucially spherical aberration and astigmatism, are suppressed to give an experimental resolution of 7 lp/mm using USAF 1951 target in water 600 mm from the boundary. Particles (plankton species) in the sub-millimeter to several millimeters size range are observed at planar sections within the recording volume by visual inspection of the hologram replayed in real image mode.

Krantz, Eric P.; Watson, John; Hobson, Peter R.; Lampitt, R. S.; Rogerson, A.

1996-08-01

355

REVIEW ARTICLE: Photopolymerizable sol-gel nanocomposites for holographic recording  

NASA Astrophysics Data System (ADS)

The research into new photosensitive materials with advanced performance for holographic applications is an active branch in material science and photonics, still challenging the field. We proposed a new class of volume hologram recording materials, sol-gel nanocomposites, with important advantages for various holographic applications, including data storage. Here we review several aspects of different types of photosensitive sol-gel glasses that we have developed. Our photopolymerizable glasses exhibit high refractive index modulation, diffraction efficiencies close to the theoretical maxima, along with low scattering and negligible shrinkage. Beside these and other practical advantages discussed in this paper, our recently developed nanocomposite glass incorporating high refractive index species has enabled fundamental studies of new optical phenomena such as the Pendellösung effect, which was observed for the first time in the optical band.

Calvo, María L.; Cheben, Pavel

2009-02-01

356

Dynamic holographic imaging of the beating human heart  

PubMed

Background--Currently, the reporting and archiving of echocardiographic data suffer from the difficulty of representing heart motion on printable 2-dimensional (2D) media. Methods and Results--We studied the capability of holography to integrate motion into 2D echocardiographic prints. Images of normal human hearts and of a variety of mitral valve function abnormalities (mitral valve prolapse, systolic anterior motion of the mitral leaflets, and obstruction of the mitral valve by a myxoma) were acquired digitally on standard echocardiographic machines. Images were processed into a data format suitable for holographic printing. Angularly multiplexed holograms were then printed on a prototype holographic "laser" printer, with integration of time in vertical parallax, so that heart motion became visible when the hologram was tilted up and down. The resulting holograms displayed the anatomy with the same resolution as the original acquisition and allowed detailed study of valve motion with side-by-side comparison of normal and abnormal findings. Comparison of standard echocardiographic measurements in original echo frames and corresponding hologram views showed an excellent correlation of both methods (P<0.0001, r2=0.979, mean bias=2.76 mm). In this feasibility study, both 2D and 3D holographic images were produced. The equipment needed to view these holograms consists of only a simple point-light source. Conclusions--Holographic representation of myocardial and valve motion from echocardiographic data is feasible and allows the printing on a 2D medium of the complete heart cycle. Combined with the recent development of online holographic printing, this novel technique has the potential to improve reporting, visualization, and archiving of echocardiographic imaging. PMID:9950651

Hunziker; Smith; Scherrer-Crosbie; Liel-Cohen; Levine; Nesbitt; Benton; Picard

1999-02-01

357

Fabrication of Holographic Optical Elements for Achromatic Matched Filtering System.  

National Technical Information Service (NTIS)

Holographic optical elements such as lenses, gratings and holographic matched filters were fabricated for an achromatic matched filtering system. Diffraction efficiencies of more than 90% were obtained in all these elements. These holographic elements wer...

T. G. Georgekutty J. G. Duthie

1982-01-01

358

Holographic gunsight: the next generation  

NASA Astrophysics Data System (ADS)

Holographic gunsight was first conceived in the 1970s and prototypes were fabricated using a He-Ne laser as the illuminating source. The laser source was too costly and fragile and these prototype units were too bulky to be viable as a commercial product. With the advent of low cost laser diodes, EOTech introduced into the commercial market a compact holographic gunsight for small arms in 1996 which has since become one of the most popular gunsight in the U.S. and in Europe. In this paper, the design of the second generation holographic gunsight is described. The optical path travels predominantly in the vertical direction which reduces the length and the weight of the sight by a third. The optical design challenges include the generation of a stable holographic image with changes in the laser emission wavelength, circularization of the laser elliptical beam profile, and the production of high quality optics at low cost. The opto-mechanical design challenges include very fine angular adjustments, stability over large temperature range and the ability to withstand the recoil of powerful handguns.

Tai, Anthony M.; Sieczka, Eric J.; Upatnieks, Juris

2000-03-01

359

Music holographic physiotherapy by laser  

NASA Astrophysics Data System (ADS)

Based on the relationship between music and nature, the paper compares laser and light with music sound on the principles of synergetics, describes music physically and objectively, and proposes a music holographic therapy by laser. Maybe it will have certain effects on mechanism study and clinical practice of the music therapy.

Liao, Changhuan

1996-09-01

360

A holographic charged preon model  

Microsoft Academic Search

The Standard Model (SM) is a successful approach to particle physics calculations. However, there are indications that the SM is only a good approximation to an underlying non-local reality involving fundamental entities (preons) that are not point particles. Furthermore, our universe seems to be dominated by a vacuum energy\\/cosmological constant. The holographic principle then indicates only a finite number of

T. R. Mongan

2008-01-01

361

Universality class of holographic superconductors  

SciTech Connect

We study ''holographic superconductors'' in various spacetime dimensions. We compute most of the static critical exponents in the linear perturbations and show that they take the standard mean-field values. We also consider the dynamic universality class for these models and show that they belong to model A with dynamic critical exponent z=2.

Maeda, Kengo; Natsuume, Makoto; Okamura, Takashi [Department of Engineering, Shibaura Institute of Technology, Saitama, 330-8570 (Japan); Theory Division, Institute of Particle and Nuclear Studies, KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801 (Japan); Department of Physics, Kwansei Gakuin University, Sanda, Hyogo, 669-1337 (Japan)

2009-06-15

362

Dynamic digital holographic wavelength filtering  

Microsoft Academic Search

This paper describes the theory and results of a new generic technology for use in optical telecommunications and wavelength division multiplexing (WDM): dynamic digital holographic wavelength filtering. The enabling component is a polarization-insensitive ferroelectric liquid crystal (FLC) spatial light modulator (SLM) in conjunction with a highly wavelength-dispersive fixed diffractive element. The technology has been used to perform demultiplexing of single

Michael C. Parker; Adam D. Cohen; Robert J. Mears

1998-01-01

363

Holographic Detection of Latent Defects.  

National Technical Information Service (NTIS)

This project was aimed at seeing whether holographic interferometry (H.I.) could be used in evaluation standard environmental stress screening methods currently used to select and qualify printed circuit boards (PCB). To do that it should be proven that H...

K. A. Arunkumar J. D. Trolinger

1986-01-01

364

Cineholographie Interferometrique (Interferometric Holographic Cinematography).  

National Technical Information Service (NTIS)

Double exposition holographic interferometry was employed to obtain a 35 mm scientific film. The deformations and deplacements of a loudspeaker were visualized at 20 to 70 Hz vibration frequencies. A 30 mJ YAG laser was used. The two successive pulses of ...

H. Fagot

1985-01-01

365

Automated thermoplastic holographic camera development  

Microsoft Academic Search

The development of an automated thermoplastic holographic camera, which gives reproducible results from cycle to cycle and from sample to sample, is reported. The thermoplastic device has a conventional sandwich geometry consisting of a thin transparent conductor, a thin layer of organic photoconductor, and a thermoplastic layer with a softening temperature of roughly 70 C. A major innovation of the

T. C. Lee; J. Skogen; R. Schulze; E. Bernal; G. J. Lin; T. Daehlin; M. Campbell

1980-01-01

366

Correlation between high-sensitivity C-reactive protein and brain gray matter volume in healthy elderly subjects.  

PubMed

Although elevated serum high-sensitivity C-reactive protein (hsCRP) is related to atherosclerosis, brain infarction, and cognitive decline, it has not been clarified whether increased hsCRP is associated with the decline in brain gray matter volume. Therefore, the purpose of this study was to determine the relationship between hsCRP levels and brain regional gray matter volume using brain magnetic resonance imaging (MRI) data from 109 community-dwelling healthy elderly subjects. Brain MRIs were processed with voxel-based morphometry using a custom template by applying diffeomorphic anatomical registration using the exponentiated lie algebra (DARTEL) procedure. We found a significant negative correlation between regional gray matter volume of the posterior and lateral aspects of the left temporal cortex and hsCRP level after adjusting for age, gender, and intracranial volume. Our results suggest that subjects who have mild inflammation related to arteriosclerosis have decreased regional gray matter volume in the posterior and lateral aspects of the left temporal cortex. Thus, preventing the progression of arteriosclerosis may be important for preventing a decrease in gray matter volume in healthy elderly subjects. Hum Brain Mapp 34:2418-2424, 2013. © 2012 Wiley Periodicals, Inc. PMID:22438310

Taki, Yasuyuki; Thyreau, Benjamin; Kinomura, Shigeo; Sato, Kazunori; Goto, Ryoi; Wu, Kai; Kakizaki, Masako; Tsuji, Ichiro; Kawashima, Ryuta; Fukuda, Hiroshi

2012-03-22

367

Holographic studies of photoinduced anisotropy in molecular glassy films containing diphenylamine azochromophores  

NASA Astrophysics Data System (ADS)

Photoinduced anisotropy (PA) is experimentally studied in three molecular glassy films synthesized in our Faculty and containing diphenylamine based azochromophores {4-((4-nitrophenyl)diazenyl)-N-(4-((4-nitrophenyl)diazenyl)phenyl)-N-(2-trityloxy)ethyl) benzeneamine (shortly K-D-24), 4-((2-chloro-4-tritylphenyl)diazenyl)-N-(4-((2-chloro-4-tritylphenyl)diazenyl)phenyl)-N-(2-(trityloxy)ethyl)benzenamine (shortly K-D-25), 4,4'-(2-(trityloxy)ethylazanediyl)bis(4,1-phenylene)bis(diazene-2,1-diyl)dibenzonitrile (shortly K-D-32) } and, for comparison, in an a-As2S3 film. Holographic method enabling simultaneous measurements of s- and p-polarized diffracted light powers was applied in both transmission and reflection modes. Holographic grating recording with the period of 2 ?m was made by two equally strong 532 nm p- polarized laser beams with total light intensity of 0.81 W/cm2. The readout was made by 633 nm circularly polarized beam, and the s- and p-polarized components of diffracted light were separated by polarization beam splitter prism. PA was characterized by diffracted power difference (DPD), Ps - Pp, and by anisotropy contrast A = (ns - np)/(ns + np), ns and np being the diffraction efficiencies for s- and p-polarized light. DPD exhibited markedly different kinetic behaviour in transmission and reflection modes. There was a negative minimum in transmission mode in all samples, and a growth with oscillations up to saturation in reflection mode. Small initial DPD maxima were specific to a-As2S3 film. The highest PA was found in K-D-24 film in transmission mode (A=-0.23) and in K-D-25 film in reflection mode (A=0.49). Holographic recording efficiency and PA do not correlate. In our opinion, PA in transmission mode of molecular glasses is due to the photoinduced volume processes including trans-cis photoisomerization, chromophore orientation and mechanical stress modulation. In the case of a-As2S3 film these photoinduced volume processes include photoinduced structural changes, D-centre orientation and, again, mechanical stress modulation. All these processes lead to a photoinduced birefringence. Surface relief grating recording and polarization-dependent reflection are responsible for diffractive anisotropy in reflection mode.

Ozols, A.; Kokars, V.; Augustovs, P.; Traskovskis, K.; Saharov, D.

2012-08-01

368

Fluctuations in finite density holographic quantum liquids  

NASA Astrophysics Data System (ADS)

We study correlators of the global U(1) currents in holographic models which involve {N}=4 SYM coupled to the finite density matter in the probe brane sector. We find the spectral density associated with the longitudinal response to be exhausted by the zero sound pole and argue that this could be consistent with the behavior of Fermi liquid with vanishing Fermi velocity. However the transversal response shows an unusual momentum independent behavior. Inclusion of magnetic field leads to a gap in the dispersion relation for the zero sound mode propagating in the plane of magnetic field. For small values of the magnetic field B the gap in the spectrum scales linearly with B, which is consistent with Kohn's theorem for nonrelativistic fermions with pairwise interaction. We do not find sig- natures of multiple Landau levels expected in Landau Fermi liquid theory. We also consider the influence of generic higher derivative corrections on the form of the spectral function.

Goykhman, Mikhail; Parnachev, Andrei; Zaanen, Jan

2012-10-01

369

Water-soluble gases as partitioning tracers to investigate the pore volume–transmissivity correlation in a fracture  

Microsoft Academic Search

Hydraulically equivalent fractures may show striking differences when a gas-migration experiment is performed because of the different correlations between transmissivity, pore volume and entry pressure. We numerically simulate gas migration between injection and extraction boreholes in a parallel plate fracture with a heterogeneous fault gouge, in a rough-walled fracture filled with homogeneous material, and in a rough-walled empty fracture. The

Ivan Lunati; Wolfgang Kinzelbach

2004-01-01

370

Lack of correlation between mdr-1 expression and volume-activation of cloride-currents in rat colon cancer cells  

Microsoft Academic Search

Correlation between expression of the mdr-1 genes (a and b) at the mRNA and protein level and volume-activation of chloride-channels was studied in rat colon cancer CC531 cells by means of RT-PCR, Western blotting and patch clamp, respectively. Three different kinds of cell lines were used: CC531-PAR, CC531-COL and CC531-REV. At the mRNA level, the parental cell line CC531-PAR showed

C. De Greef; S. Heyden; F. Viana; J. Eggermont; E. A. Bruijn; L. Raeymaekers; G. Droogmans; B. Nilius

1995-01-01

371

Holographic characteristics of citrate ion modified gold nano-particles dispersed photopolymer  

NASA Astrophysics Data System (ADS)

Hydrophilic photopolymers with AA as the monomer are versatile materials for use as holographic recording media. It has demonstrated a possibility to improve the refractive index modulation by doping inorganic nanoparticles into the polymer matrix. But the agglomerate effect of inorganic nanoparticles always deteriorate the holographic storage characteristics of the inorganic nanoparticle dispersed photopolymer compound materials. monodisperse hydrophilic gold nanoparticles are fabricated by the method of sodium citrate reduction, and then were dispersed into the PVA/AA photopolymer. Our results indicate that citrate ions coated on the surface of gold nanoparticles can effectively prevent the agglomerate effect, so that the gold nanoparticles can uniformly dispersed in the sol-gel photopolymer. The permanent refractive index grating can be formed owing to a spatial distribution of the effective refractive index with periodically distributed nanoparticles and polymerized monomers during the holographic recording. Furthermore, the citrate ion modified gold nanoparticles and polymer chain can induce the formation of hydrogen bonds which can prevent the material from distortion and at the same time improve the stability of the material by the coordination effect of carboxylate. Therefore, the incorporation of gold nanoparticles leads to a significantly improvement in the holographic properties of the materials, so that the volume shrinkage during the holographic exposure can be well suppressed. Additionally, there exists the optimum concentration of gold nanoparticles, at which the maximum diffraction efficiency can be as high as 90% and the volume shrinkage can be reduced to 0.8%.

Xue, Xiao-yu; Hai, Fu-Sheng; Gao, Li-Zhen; He, Fei; Li, Chun-Liu; Li, Yun-Xi; Huang, Ming-Ju

372

Dynamic optical correlation using localized holography  

NASA Astrophysics Data System (ADS)

A new technique for optical correlation using gated holographic recording is demonstrated. Several persistent holograms are localized within separate slices as close as 33 ?m apart along the crystal. Individual holograms can be dynamically erased and rerecorded with no need to refresh all other recorded holograms. Experimental results showing the correlation capability, cross talk, shift invariance, and dynamicity of the localized holographic correlator demonstrate unique performance and capabilities for these correlators.

Karbaschi, Arash; Momtahan, Omid; Adibi, Ali

2007-03-01

373

Electromagnetic baryon form factors from holographic QCD  

Microsoft Academic Search

In the holographic model of QCD suggested by Sakai and Sugimoto, baryons are chiral solitons sourced by D4 instantons in bulk of size 1\\/(lambda)1\\/2 with lambda = g2Nc. We quantize the D4 instanton semiclassically using hbar = 1\\/(Nclambda) and non-rigid constraints on the vector mesons. The holographic baryon is a small chiral bag in the holographic direction with a Cheshire

Keun-Young Kim; Ismail Zahed

2008-01-01

374

Compact holographic printer using RGB waveguide holographic optical elements  

NASA Astrophysics Data System (ADS)

We propose compact holographic printer using RGB waveguide hologram while reducing overall device size and quantity of elements with integrated functionality of each optical element. For glasses-free 3D experience anywhere anytime, it is critical to make holography device that can be as compact and integrated as possible. Compared to the conventional optics-based structure, our RGB WGH-based one reduces the overall size by 20 times, the number of components by 10 times, and improves the optical efficiency by 3 times, with comparable holographic quality to the conventional optics-based approaches. Proposed research can be useful for both general consumers and professionals like 3D photography and medical 3D image printing applications.

Pyun, Kyungsuk P.; Choi, Chilsung; Morozov, Alexander V.; Kim, Sunil; An, Jungkwuen

2013-03-01

375

[Correlation between the gradient constant of the theoretical pressure volume diagram (PVD) and the pressure volume index (PVI) in relation to brain pulse amplitude-mean pressure function].  

PubMed

In 54 neurosurgical patients--suffering from intracranial tumors, hydrocephalus or different kinds of brain injury--a catheter was implanted in the lateral ventricle for continuously monitoring of the intracranial pressure (ICP). The intraventricular injection of defined amounts of sodium clearance (1-2 cm3) was followed by increased values of intracranial mean pressure--(pm) and pulse-amplitude- (PA). The recorded data showed a high significant correlation after regression analysis. After determination of the pressure-volume-index (PVI) and the theoretical pressure-volume-diagram it was examined whether there is a linear correlation between the parameters of the craniospinal space (id) reserves (constant of gradient, (PVI, K of PVD)) and the gradients (CA) of the linear PA-PM-function. A significant linear relationship, however of weak degree, could be found between these two parameters. The linear PA-PM-function, therefore, can only be understood in restricted circumstances as a direct parameter of the intracranial spacial reserves. The underlying facts of these problems are dealt within this paper. PMID:7771132

Rieger, A; Ebel, H; Laun, A

1995-01-01

376

Stereologic estimates of volume-weighted mean nuclear volume in colorectal adenocarcinoma: correlation with histologic grading, Dukes' staging, cell proliferation activity and p53 protein expression.  

PubMed

Colorectal cancer has been studied from the point of view of the relationships between several variables, including proliferative activity and p53 protein expression. However, stereologic evaluation of nuclear size has not been thoroughly described. In the present study, measurements of the volume-weighted mean nuclear volume (nuclear Vv), have been performed in well, moderately and poorly differentiated colorectal adenocarcinomas and correlated with the Dukes' stage and other factors such as proliferative activity and p53 protein immunoreactivity. Although the mean values of nuclear Vv were higher in poorly differentiated cancers or Dukes' C&D stage than in well and moderately differentiated tumors or Dukes' A&B stage, these differences were not significant. However, the variability of nuclear size in colorectal cancers was more relevant than the mean values of nuclear Vv with respect to their invasive classification. The carcinomas which extended beyond the serosa (Dukes' stage C&D) had higher biologic variation than those grouped as Dukes' stage A&B. The results of the present study also indicate that nuclear size in colorectal cancers has a positive correlation with both proliferative activity and p53 protein expression. The relationship between nuclear Vv and proliferative activity emphasizes the possible prognostic relevance of this stereologic estimate of nuclear size in colorectal adenocarcinoma. PMID:9269906

Martín, R; Nieto, S; Santamaría, L

1997-07-01

377

Holographic duality: Stealing dimensions from metals  

NASA Astrophysics Data System (ADS)

Although electrically charged black holes seem remote from superconductors and strange metals in the laboratory, they might be intimately related by the holographic dualities discovered in string theory.

Zaanen, Jan

2013-10-01

378

Holographic QCD: Past, present, and future  

NASA Astrophysics Data System (ADS)

At the dawn of a new theoretical tool based on the AdS/CFT correspondence for non-perturbative aspects of quantum chromodynamics, we give an interim review on the new tool, holographic QCD, with some of its accomplishment. We try to give an A-to-Z picture of the holographic QCD, from string theory to a few selected top-down holographic QCD models with one or two physical applications in each model. We may not attempt to collect diverse results from various holographic QCD model studies.

Kim, Youngman; Shin, Ik Jae; Tsukioka, Takuya

2013-01-01

379

Label-Free Cytotoxicity Screening Assay by Digital Holographic Microscopy  

PubMed Central

Abstract We introduce a label-free technology based on digital holographic microscopy (DHM) with applicability for screening by imaging, and we demonstrate its capability for cytotoxicity assessment using mammalian living cells. For this first high content screening compatible application, we automatized a digital holographic microscope for image acquisition of cells using commercially available 96-well plates. Data generated through both label-free DHM imaging and fluorescence-based methods were in good agreement for cell viability identification and a Z?-factor close to 0.9 was determined, validating the robustness of DHM assay for phenotypic screening. Further, an excellent correlation was obtained between experimental cytotoxicity dose–response curves and known IC50 values for different toxic compounds. For comparable results, DHM has the major advantages of being label free and close to an order of magnitude faster than automated standard fluorescence microscopy.

Kuhn, Jonas; Shaffer, Etienne; Mena, Julien; Breton, Billy; Parent, Jerome; Rappaz, Benjamin; Chambon, Marc; Emery, Yves; Magistretti, Pierre; Depeursinge, Christian; Marquet, Pierre

2013-01-01

380

Hippocampal subfield volumes: age, vascular risk, and correlation with associative memory.  

PubMed

Aging and age-related diseases have negative impact on the hippocampus (HC), which is crucial for such age-sensitive functions as memory formation, maintenance, and retrieval. We examined age differences in hippocampal subfield volumes in 10 younger and 19 older adults, and association of those volumes with memory performance in the older participants. We manually measured volumes of HC regions CA1 and CA2 (CA1-2), sectors CA3 and CA4 plus dentate gyrus (CA3-4/DG), subiculum, and the entorhinal cortex using a contrast-optimized high-resolution PD-weighted MRI sequence. Although, as in previous reports, the volume of one region (CA1-2) was larger in the young, the difference was due to the presence of hypertensive subjects among the older adults. Among older participants, increased false alarm rate in an associative recognition memory task was linked to reduced CA3-4/DG volume. We discuss the role of the DG in pattern separation and the formation of discrete memory representations. PMID:21331174

Shing, Yee Lee; Rodrigue, Karen M; Kennedy, Kristen M; Fandakova, Yana; Bodammer, Nils; Werkle-Bergner, Markus; Lindenberger, Ulman; Raz, Naftali

2011-02-04

381

Efficient nonlinear amplitude recording of holographic gratings in electrolytically colored potassium bromide crystals.  

PubMed

The nonlinear amplitude recording of volume holographic gratings is theoretically and experimentally studied in electrolytically colored potassium bromide crystals. A maximum diffraction efficiency of 10.8% is obtained, which substantially exceeds the 3.7% maximum diffraction efficiency for linear recording. PMID:21037602

Raita, E; Ozols, A; Salminen, O

1995-02-10

382

Imaging mechanisms analysis of compact digital holographic microscope for microparticles measurement  

Microsoft Academic Search

Conventional optical microscopy suffers from small depth of focus due to its high numerical aperture and magnification of the microscope objective. In comparison, digital in-line holographic microscopy (DIHM) provides information about the entire 3D volume through numerical reconstruction of the single hologram at several depths. This advantage makes DIHM an effective tool for the measurement of microparticles in suspension. Recently,

Jianglei Di; Arvind Rajendran; Vinay Kariwala; Anand Krishna Asundi; Jianlin Zhao

2011-01-01

383

Wideband millimeter-wave holographic weapons surveillance systems  

NASA Astrophysics Data System (ADS)

A new wideband millimeter wave holographic imaging technqiue is under developement for use in concealed weapons detection system. This new wideband technique provides far superior images than single frequency holographic techniques on thick objects such as the human body. The wideband technique obtains fully focused images over a designated volume and provides excellent lateral and depth resolution. Using this method, a 3D volumetric hologram is gathered with a millimeter wave linear array, a mechanical scanner, and a sweep frequency tranceiver. The 3D volumetric hologram is then processed by high-speed computational processors to reconstruct the fully focused image. Two prototype wide band millimeter wave holographic arrays have been developed at the Pacific Northwest Laboratory. The two arrays consist of sequentially switched 2 by 37 Ku band (12.5-18 GHz) and 2 by 64 Ka band (26.5-40 GHz) systems which are coupled to high-speed sweep frequency heterodyne transceivers. The arrays are used to obtain volumetric imaging data at high speeds by electronically sequencing and frequency sweeping the array antennas along 1D while performing a mechanical scan along the other dimension. The current prototype system scans an aperture the size of a large human body in about one second. Extensive laboratory testing has been performed with people carrying various concealed weapons and innocuous items with both imaging arrays during the first quarter of 1995.

McMakin, Douglas L.; Sheen, David M.; Collins, H. D.; Hall, Thomas E.; Severtsen, Ronald H.

1995-09-01

384

Volume flow calculations on gas leaks imaged with infrared gas-correlation.  

PubMed

Two methods for volume flow calculation from images of methane leakages to the atmosphere are presented. The images contain calibrated gas concentration × path length pixel information, and are processed with a block matching method and a theoretical velocity field method. Results from known methane flow in two laboratory setups and one unknown real leakage from a gas processing plant are compared with the image processing methods. The methods are generic and can be implemented in common infrared systems for gas visualization. This work provides a new tool for estimating and reporting volume flow emissions from gas processing plants to the authorities. PMID:23037083

Sandsten, Jonas; Andersson, Martin

2012-08-27

385

The Accurate Ultrasonic Measurement of the Volume Flow of Blood by Time Domain Correlation  

Microsoft Academic Search

A new ultrasonic flow measurement method employing time domain correlation of consecutive pairs of echoes has been developed. The time shift between a pair of range gated echoes is determined by searching for t he shift with the maximum correlation. This shift indicates the distance a group of scatterers has moved between pulses. The high precision and good resolution of

P. M. Embree

1985-01-01

386

Properties of causal holographic information  

NASA Astrophysics Data System (ADS)

In the context of the AdS/CFT correspondence, there are two natural bulk surfaces associated to a subregion of the CFT: the minimal area surface and the "causal information surface" [1]. While the area of the minimal area surface appears to compute the entanglement entropy of the subregion, it is not yet clear what CFT quantity the causal information surface computes. We investigate the properties of causal holographic information, focusing in particular on the universal coefficient of the logarithmically divergent term. We find that this coefficient contains a novel conformal invariant that cannot be written as an integral of local quantities. By considering higher curvature corrections in the bulk, we identify the coefficient of the a and c central charges in 4 dimensions. Finally, we speculate about which CFT quantity could correspond to causal holographic information.

Freivogel, Ben; Mosk, Benjamin

2013-09-01

387

Holographic type II Goldstone bosons  

NASA Astrophysics Data System (ADS)

The Goldstone theorem implies the appearance of an ungapped mode whenever a continuous global symmetry is spontaneously broken. In general it does not say anything about the precise form of the dispersion relation nor does it imply that there is one massless mode for each broken symmetry generator. It is a well-established fact that even for relativistic field theories in the presence of a chemical potential Goldstone modes with quadratic dispersion relation, the type II Goldstone bosons, appear in the spectrum. We develop two holographic models that feature type II Goldstone modes as part of the quasinormal mode spectrum. The models are based on simple generalizations with U(2) symmetry of the well-studied holographic s-wave superfluid. Our results include Goldstone modes without broken generators but with unusual realization of symmetries and a frequency dependent conductivity of striking resemblance to the one of Graphene.

Amado, Irene; Areán, Daniel; Jimenez-Alba, Amadeo; Landsteiner, Karl; Melgar, Luis; Landea, Ignacio Salazar

2013-07-01

388

Membrane Paradigm and Holographic Hydrodynamics  

NASA Astrophysics Data System (ADS)

We discuss recent work showing that in certain cases the membrane paradigm equations governing the dynamics of black hole horizons can be recast as relativistic conservation law equations. In the context of gauge/gravity dualities, these equations are interpreted as defining the viscous hydrodynamics of a holographically dual relativistic field theory. Using this approach, one can derive the viscous transport coefficients and the form of the entropy current for field theories dual to gravity plus matter fields.

Eling, Christopher; Neiman, Yasha; Oz, Yaron

2011-09-01

389

The holographic life of the ??  

Microsoft Academic Search

In the string holographic dual of large-Nc QCD with Nf flavours of [1], the ?? meson is massless at infinite Nc and dual to a collective fluctuation of Nf D6-brane probes in a supergravity background. Here we identify the string diagrams responsible for the generation of a mass of order Nf\\/Nc, consistent with the Witten-Veneziano formula, and show that the

José L. F. Barbón; Carlos Hoyos; David Mateos; Robert C. Myers

2004-01-01

390

A holographic charged preon model  

Microsoft Academic Search

The Standard Model (SM) is a successful approach to particle physics\\u000acalculations. However, there are indications that the SM is only a good\\u000aapproximation to an underlying non-local reality involving fundamental entities\\u000a(preons) that are not point particles. Furthermore, our universe seems to be\\u000adominated by a vacuum energy\\/cosmological constant. The holographic principle\\u000athen indicates only a finite number of

T. R. Mongan

2008-01-01

391

Pion condensation in holographic QCD  

SciTech Connect

We study pion condensation at zero temperature in a hard-wall holographic model of hadrons with isospin chemical potential. We find that the transition from the hadronic phase to the pion condensate phase is first order except in a certain limit of model parameters. Our analysis suggests that immediately across the phase boundary the condensate acts as a stiff medium approaching the Zel'dovich limit of equal energy density and pressure.

Albrecht, Dylan; Erlich, Joshua [Particle Theory Group, Department of Physics, College of William and Mary, Williamsburg, Virginia 23187-8795 (United States)

2010-11-01

392

Electromagnetic holographic imaging of bioimpedance  

NASA Astrophysics Data System (ADS)

The electromagnetic bioimpedance method has successfully measured the very subtle conductivity changes associated with brain edema and prostate tumor. This method provides noninvasive measurements using non-ionizing magnetic fields applied with a small coil that avoids the use of contact electrodes. This paper introduces results from combining a holographic signal processing algorithm and a low power coil system that helps provide the 3D image of impedance contrast that should make the noninvasive electromagnetic bioimpedance method useful in health care.

Smith, Dexter G.; Ko, Harvey W.; Lee, Benjamin R.; Partin, Alan W.

1998-05-01

393

Optical performance of holographic kinoforms  

Microsoft Academic Search

The optical properties of holographic kinoforms are described. It is shown that paraxial designs are not adequate for flNos. less than -F\\/10. A nonparaxial design is introduced that retains the high diffraction efficiency of the paraxial designs, yet also produces an unaberrated diffracted wavefront for the design wavelength. Aberration calculations and computer calculations, based on the Huygens-Fresnel principle, of the

Dale A. Buralli; G. Michael Morris; John R. Rogers

1989-01-01

394

Sound modes in holographic superfluids  

SciTech Connect

Superfluids support many different types of sound waves. We investigate the relation between the sound waves in a relativistic and a nonrelativistic superfluid by using hydrodynamics to calculate the various sound speeds. Then, using a particular holographic scalar gravity realization of a strongly interacting superfluid, we compute first, second, and fourth sound speeds as a function of the temperature. The relativistic low temperature results for second sound differ from Landau's well known prediction for the nonrelativistic, incompressible case.

Herzog, Christopher P.; Yarom, Amos [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

2009-11-15

395

Glucose-sensitive holographic sensors.  

PubMed

Holographic sensors for monitoring glucose were fabricated from hydrogel films containing chemical ligands based on phenylboronic acid. The films were transformed into reflection holograms using a diffusion method coupled with exposure to laser light. The diffraction wavelength of the holograms was used to monitor the swelling of the hydrogel film in the presence of glucose. Fully reversible changes in diffraction wavelength were demonstrated, highlighting the potential for using these holograms as glucose sensors. PMID:15137024

Kabilan, S; Blyth, J; Lee, M C; Marshall, A J; Hussain, A; Yang, X-P; Lowe, C R

396

Creatine Kinase Activity Weakly Correlates to Volume Completed Following Upper Body Resistance Exercise  

ERIC Educational Resources Information Center

|In the current study, we examined the relationship between serum creatine kinase (CK) activity following upper body resistance exercise with a 1- or 3-min rest between sets. Twenty men performed two sessions, each consisting of four sets with a 10-repetition maximum load. The results demonstrated significantly greater volume for the 3-min…

Machado, Marco; Willardson, Jeffrey M.; Silva, Dailson P.; Frigulha, Italo C.; Koch, Alexander J.; Souza, Sergio C.

2012-01-01

397

Maternal Iodine Status and Thyroid Volume during Pregnancy: Correlation with Neonatal Iodine Intake  

Microsoft Academic Search

Differences in pregnancy-associated alterations in thyroid vol- ume and urinary iodine (UI) excretion have been attributed to geographical variations in dietary iodine intake. In this study, ultrasound-measured thyroid volume and UI excretion were as- sessed during the 3 trimesters of pregnancy, at delivery, and at 6 weeks postpartum. Urine specimens also were obtained from moth- ers and both breast- and

P. P. A. Smyth; A. M. T. HETHERTON; D. F. SMITH; M. RADCLIFF; C. O'HERLIHY

1997-01-01

398

The influence of correlated protein-water volume fluctuations on the apparent compressibility of proteins determined by ultrasonic velocimetry.  

PubMed

The elasticity of proteins, expressed by the compressibility, is potentially one of the most important properties of proteins because of the close relationship with its functionality. The compressibility of solutions can be determined by measurements of sound velocity and density. These quantities are related by the Newton-Laplace equation. In order to interpret the apparent compressibility of solutes in highly dilute solutions, it is required to consider the relation between compressibility and sound velocity of the solution using an appropriate reference system. The classical approach usually gives too small values for the apparent compressibility when compared with other methods. We show that the difference can partially be explained if the correlated volume fluctuations of the solvent are taken into consideration. A special attention is given to the compressibility of proteins. Finally, the present paper is not intended to replace established approaches, but it wants to create awareness that the classical mixing rules refer to ideal gasses assuming uncorrelated volume fluctuations and that a considerable part of the hydration effects could be explained by correlated volume fluctuations. PMID:18773977

Pfeiffer, Helge; Heremans, Karel; Wevers, Martine

2008-08-16

399

Holographic evolution of entanglement entropy  

NASA Astrophysics Data System (ADS)

We study the evolution of entanglement entropy in a 2-dimensional equilibration process that has a holographic description in terms of a Vaidya geometry. It models a unitary evolution in which the field theory starts in a pure state, its vacuum, and undergoes a perturbation that brings it far from equilibrium. The entanglement entropy in this set up provides a measurement of the quantum entanglement in the system. Using holographic techniques we recover the same result obtained before from the study of processes triggered by a sudden change in a parameter of the hamiltonian, known as quantum quenches. Namely, entanglement in 2-dimensional conformal field theories propagates with velocity v 2 = 1 [1]. Both in quantum quenches and in the Vaidya model equilibration is only achieved at the local level. Remarkably, the holographic derivation of this last fact requires information from behind the apparent horizon generated in the process of gravitational collapse described by the Vaidya geometry. In the early stages of the evolution the apparent horizon seems however to play no relevant role with regard to the entanglement entropy. We speculate on the possibility of deriving a thermalization time for occupation numbers from our analysis.

Abajo-Arrastia, Javier; Aparício, João; López, Esperanza

2010-11-01

400

Holographic pomeron: Saturation and DIS  

NASA Astrophysics Data System (ADS)

We briefly review the approach to dipole-dipole scattering in holographic QCD developed in G. Basar , Phys. Rev. D 85, 105005 (2012), based on a stringy Schwinger mechanism. The pomeron emerges through the exchange of closed strings between the dipoles and yields Regge behavior for the elastic amplitude. We calculate curvature corrections to this amplitude in both a conformal and confining background, identifying the holographic direction with the virtuality of the dipoles. The wee-dipole density is related to the string tachyon diffusion in both virtuality and the transverse directions. We give an explicit derivation of the dipole saturation momentum both in the conformal and confining background. Our holographic result for the dipole-dipole cross section and the wee-dipole density in the conformal limit are shown to be identical in form to the BFKL pomeron result when the noncritical string transverse dimension is D?=3. The total dipole-dipole cross section is compared to DIS data from HERA.

Stoffers, Alexander; Zahed, Ismail

2013-04-01

401

Computation of full-field displacements in a scaffold implant using digital volume correlation and finite element analysis.  

PubMed

Measurements of three-dimensional displacements in a scaffold implant under uniaxial compression have been obtained by two digital volume correlation (DVC) methods, and compared with those obtained from micro-finite element models. The DVC methods were based on two approaches, a local approach which registers independent small volumes and yields discontinuous displacement fields; and a global approach where the registration is performed on the whole volume of interest, leading to continuous displacement fields. A customised mini-compression device was used to perform in situ step-wise compression of the scaffold within a micro-computed tomography (?CT) chamber, and the data were collected at steps of interest. Displacement uncertainties, ranging from 0.006 to 0.02 voxel (i.e. 0.12-0.4 ?m), with a strain uncertainty between 60 and 600 ??, were obtained with a spatial resolution of 32 voxels using both approaches, although the global approach has lower systematic errors. Reduced displacement and strain uncertainties may be obtained using the global approach by increasing the element size; and using the local approach by increasing the number of intermediary sub-volumes. Good agreements between the results from the DVC measurements and the FE simulations were obtained in the primary loading direction as well as in the lateral directions. This study demonstrates that volumetric strain measurements can be obtained successfully using DVC, which may be a useful tool to investigate mechanical behaviour of porous implants. PMID:23473631

Madi, K; Tozzi, G; Zhang, Q H; Tong, J; Cossey, A; Au, A; Hollis, D; Hild, F

2013-03-06

402

Correlation  

NSDL National Science Digital Library

The applets, created by Virginia Tech's Department of Statistics, allow you to see how different bivariate data look under different correlation structures. The "Movie" applet either creates data for a particular correlation or animates a multitude data sets ranging correlations from -1 to 1. The "Creation" applet allows the user to create a data set by adding or deleting points from the screen.

Anderson-Cook, C.; Robinson, T.; Dorai-Raj, S.

2009-09-14

403

Monitoring by holographic radar systems  

NASA Astrophysics Data System (ADS)

Nowadays, radar technology represents a significant opportunity to collect useful information for the monitoring and conservation of critical infrastructures. Radar systems exploit the non-invasive interaction between the matter and the electromagnetic waves at microwave frequencies. Such an interaction allows obtaining images of the region under test from which one can infer the presence of potential anomalies such as deformations, cracks, water infiltrations, etc. This information turns out to be of primary importance in practical scenarios where the probed structure is in a poor state of preservation and renovation works must be planned. In this framework, the aim of this contribution is to describe the potentialities of the holographic radar Rascan 4/4000, a holographic radar developed by Remote Sensing Laboratory of Bauman Moscow State Technical University, as a non-destructive diagnostic tool capable to provide, in real-time, high resolution subsurface images of the sounded structure [1]. This radar provides holograms of hidden anomalies from the amplitude of the interference signal arising between the backscattered signal and a reference signal. The performance of the holographic radar is appraised by means of several experiments. Preliminary tests concerning the imaging below the floor and inside wood structures are carried out in controlled conditions at the Electromagnetic Diagnostic Laboratory of IREA-CNR. After, with reference to bridge monitoring for security aim, the results of a measurement campaign performed on the Musmeci bridge are presented [2]. Acknowledgments This research has been performed in the framework of the "Active and Passive Microwaves for Security and Subsurface imaging (AMISS)" EU 7th Framework Marie Curie Actions IRSES project (PIRSES-GA-2010-269157). REFERENCES [1] S. Ivashov, V. Razevig, I. Vasilyev, A. Zhuravlev, T. Bechtel, L. Capineri, The holographic principle in subsurface radar technology, International Symposium to Commemorate the 60th Anniversary of the Invention of Holography, Springfield, Massachusetts USA, October 27-29, pp. 183-197, 2008. [2] I. Catapano, L. Crocco, A. F. Morabito, F. Soldovieri, "Tomographic imaging of holographic GPR data for non-invasive structural assessment: the Musmeci bridge investigation", Nondestructive testing and evaluation, vol. 27, pp. 229-237, 2012.

Catapano, Ilaria; Crocco, Lorenzo; Affinito, Antonio; Gennarelli, Gianluca; Soldovieri, Francesco

2013-04-01

404

Web service for digital holographic video processing  

NASA Astrophysics Data System (ADS)

A web-service for digital video hologram processing based on Berkeley Open Infrastructure for Network Computing (BOINC) is proposed. Proof-of-concept is confirmed for broad spectrum of applications such as digital holographic particle image velocimetry, water biomonitoring by means zooplankton analysis and digital holographic disdrometry. The snapshots presented in this paper were reconstructed using the proposed web-service.

Ekimov, Dmitry; Mäkynen, Anssi

2013-05-01

405

3D TV by holographic stereogram (II)  

Microsoft Academic Search

Computer holographic stereogram (CHS) is useful for holographic 3D TV because it is constructed from the multi horizontal viewpoint plane images and is compatible to the multi-view point images. Each hologram is recorded as a slit hologram (element hologram) but total viewing area and the number of the element holograms have been limited to some extent by the size and

Koki Sato; Lan Tian; Hongming Zhao; Kunihiko Takano

2007-01-01

406

Strange Metals and Holographic Entanglement Entropy  

NASA Astrophysics Data System (ADS)

In this paper, we will explain an application of holographic entanglement entropy to Fermi surface physics. These holographic arguments show that Landau-Fermi liquids do not have any gravity duals in the purely classical limit [N. Ogawa, T. Takayanagi and T. Ugajin, J. High Energy Phys.125, 1 (2012), arXiv:1111.1023 [hep-th

Takayanagi, Tadashi

2013-02-01

407

Holographic television by liquid-crystal device  

Microsoft Academic Search

In the past, the transmission of holograms via television was executed but no holographic TV was realized because there was no suitable recording material. Now a 3-D TV is expected, and recent research on real time holography using a high-resolution liquid crystal device (LCD) is active. In this research we consider the possibility of holographic television and construct the best

Koki Sato; Kazuhito Higuchi; Hidetoshi Katsuma

1992-01-01

408

Quantum holographic imaging by entangled photons  

Microsoft Academic Search

Principle of quantum holographic imaging is explained. While one of the entangled twin photons interacts with an object, the other one carries the holographic image of the object. While this scheme does not work for simple scattering objects, it works for absorbing objects with selective coincidence detection. Generalization of this scheme to state-transforming objects is also proposed.

Jaewan Kim; Hai-Woong Lee

2004-01-01

409

The Holographic Screen at Low Temperatures  

NASA Astrophysics Data System (ADS)

A permissible spectrum of transverse vibrations for the holographic screen modifies both a distribution of thermal energy over bits at low temperatures and the law of gravitation at small accelerations of free fall in agreement with observations of flat rotation curves in spiral galaxies. This modification relates holographic screen parameters in de Sitter spacetime with the Milgrom acceleration in MOND.

Kiselev, V. V.; Timofeev, S. A.

410

Holographic Three Dimensional Printer Using Galvanometer Scanners  

Microsoft Academic Search

To make holograms from computer graphic (CG) in a short time, a new holographic three dimensional (3D) printer is proposed here. This printer consists of galvanometer scanners, a micro computer and a laser, and uses a holographic contact duplicating method. Experiments have shown that a hologram of 39 × 41 mm can be obtained in 4 min.

Masahide Monde; Tsuyoshi Uematsu; Toshiki Toda; Kazuhiko Ohnuma; Yoshizumi Yasuda

1995-01-01

411

Holographic Three Dimensional Printer Using Galvanometer Scanners  

NASA Astrophysics Data System (ADS)

To make holograms from computer graphic (CG) in a short time, a new holographic three dimensional (3D) printer is proposed here. This printer consists of galvanometer scanners, a micro computer and a laser, and uses a holographic contact duplicating method. Experiments have shown that a hologram of 39 × 41 mm can be obtained in 4 min.

Monde, Masahide; Uematsu, Tsuyoshi; Toda, Toshiki; Ohnuma, Kazuhiko; Yasuda, Yoshizumi

1995-05-01

412

Rewritable collinear holographic image storage with BR-D96N film  

NASA Astrophysics Data System (ADS)

Rewritable collinear holographic image storage was realized in a genetically mutated bacteriorhodopsin BR-D96N film by using its photochromic property. For a BR-D96N film with 3.0 optical density, under 632.8nm, 700mW/cm2 recording light (optical reference ratio is about 1:1.2), the optimum recording time is about 3s, and optimum reconstruction light intensity is about 50mW/cm2, and the safe-time of the hologram is about 10min. The experiment shows that, in collinear holographic storage system, simple optical setup, small volume, low environmental effect and the high density storage can be realized; and it is proved that the BR-D96N film has advantages like short storage time, high light sensitivity, high reversibility, long-term stability and easy used, which can be used as a high sensitive dynamic rewritable collinear holographic storage media.

Ning, Anqi; Menke, Neimule; Yan, Su; Hampp, Norbert

2010-11-01

413

Direct laser writing defects in holographic lithography-created photonic lattices.  

PubMed

As a well-established laser fabrication approach, holographic lithography, or multibeam interference patterning, is known for its capability to create long-range ordered large-volume photonic crystals (PhCs) rapidly. Its broad use is, however, hampered by difficulty in inducing artificially designed defects for device functions. We use pinpoint femtosecond laser ablation to remove and two-photon photopolymerization to add desired defective features to obtain photonic acceptors and photonic donors, respectively, in an otherwise complete PhC matrix produced by holographic lithography. The combined use of the two direct laser writing technologies would immediately make holographic lithography a promising industrial tool for PhC manufacture. PMID:15865386

Sun, Hong-Bo; Nakamura, Atsushi; Kaneko, Koshiro; Shoji, Satoru; Kawata, Satoshi

2005-04-15

414

Cerebral blood volume in Alzheimer's disease and correlation with tissue structural integrity  

Microsoft Academic Search

A vascular component is increasingly recognized as important in Alzheimer's disease (AD). We measured cerebral blood volume (CBV) in patients with probable AD or Mild Cognitive Impairment (MCI) and in elderly non-demented subjects using a recently developed Vascular-Space-Occupancy (VASO) MRI technique. While both gray and white matters were examined, significant CBV deficit regions were primarily located in white matter, specifically

Jinsoo Uh; Kelly Lewis-Amezcua; Kristin Martin-Cook; Yamei Cheng; Myron Weiner; Ramon Diaz-Arrastia; Michael Devous Sr.; Dinggang Shen; Hanzhang Lu

2010-01-01

415

Prostate Volume and Its Correlation with Histopathological Outcomes in Prostate Cancer  

Microsoft Academic Search

Introduction: There is a paucity of data investigating the relationship between histopathological variables of oncologic importance and prostate volume, and we aimed to investigate this. Patients and Methods: 2,207 consecutive patients who underwent robotic-assisted radical prostatectomy were studied. Preoperative demographic and both pre- and postoperative histopathological parameters were compared among the small (<40 cm3), intermediate (40–70 cm3), and large (>70

Prasanna Sooriakumaran; Abhishek Srivastava; Dhristie Bhagat; Majnu John; Sonal Grover; Youssef El-Douaihy; Sivaram Rajan; Robert Leung; Ashutosh Tewari

2011-01-01

416

Large holographic displays as an alternative to stereoscopic displays  

NASA Astrophysics Data System (ADS)

3D displays comprise stereoscopic displays and holographic displays. Eye convergence and accommodation are important depth cues for human vision. Stereoscopic displays provide only convergence information whereas holographic displays also provide accommodation information. Due to the inherently better 3D quality we consider holographic displays as the preferred alternative to stereoscopic displays. Our new approach to holographic displays omits unnecessary wavefront information and significantly reduces the requirements on the resolution of the spatial light modulator and the computation effort compared to conventional holographic displays. We verified our concept with holographic display prototypes and measurements. SeeReal's approach makes holographic displays feasible as a consumer product for mass-market applications.

Häussler, R.; Schwerdtner, A.; Leister, N.

2008-03-01

417

Microbial population dynamics by digital in-line holographic microscopy  

PubMed Central

Measurements of population dynamics are ubiquitous in experiments with microorganisms. Studies with microbes elucidating adaptation, selection, and competition rely on measurements of changing populations in time. Despite this importance, quantitative methods for measuring population dynamics microscopically, with high time resolution, across many replicates remain limited. Here we present a new noninvasive method to precisely measure microbial spatiotemporal population dynamics based on digital in-line holographic (DIH) microscopy. Our inexpensive, replicate DIH microscopes imaged hundreds of swimming algae in three dimensions within a volume of several microliters on a time scale of minutes over periods of weeks.

Frentz, Zak; Kuehn, Seppe; Hekstra, Doeke; Leibler, Stanislas

2010-01-01

418

Microbial population dynamics by digital in-line holographic microscopy  

NASA Astrophysics Data System (ADS)

Measurements of population dynamics are ubiquitous in experiments with microorganisms. Studies with microbes elucidating adaptation, selection, and competition rely on measurements of changing populations in time. Despite this importance, quantitative methods for measuring population dynamics microscopically, with high time resolution, across many replicates remain limited. Here we present a new noninvasive method to precisely measure microbial spatiotemporal population dynamics based on digital in-line holographic (DIH) microscopy. Our inexpensive, replicate DIH microscopes imaged hundreds of swimming algae in three dimensions within a volume of several microliters on a time scale of minutes over periods of weeks.

Frentz, Zak; Kuehn, Seppe; Hekstra, Doeke; Leibler, Stanislas

2010-08-01

419

Holographic imaging of 3D objects on dichromated polymer systems  

NASA Astrophysics Data System (ADS)

Conventional volume transmission holograms of a 3D scene were recorded on dichromated poly(acrylic acid) (DCPAA) films under 488 nm light. The holographic characterization and quality of reconstruction have been studied by varying the influencing parameters such as concentration of dichromate and electron donor, and the molecular weight of the polymer matrix. Ammonium and potassium dichromate have been employed to sensitize the poly(acrylic) matrix. the recorded hologram can be efficiently reconstructed either with red light or with low energy in the blue region without any post thermal or chemical processing.

Lemelin, Guylain; Jourdain, Anne; Manivannan, Gurusamy; Lessard, Roger A.

1996-01-01

420

Holographic brain: a good analogy gone bad  

NASA Astrophysics Data System (ADS)

One way of honoring the world's two greatest holographers is to remove from their field the association with the offbeat world of the holographic mind. Basing itself on analogical musings of two very creative scientists who were themselves not holographers, this 'field' of the holographic brain has strayed far from science and into the absurd. So much absurdity has been written by so many people that the one legitimate study of holographic principle in dolphins has been grouped too often with the nonsense. Here is taken most of the 'target statements' form one book. We could not bear to read them all this closely. We will attempt to determine what tidbit of fact led to the statements and to suggest alternative explanations when there is something to explain.

Caulfield, H. John

2002-07-01

421

Holographic optical elements and grazing incidence mirrors in XUV region  

Microsoft Academic Search

A new approach to X-ray optics has been proposed, based on single-step holographic fabrication of highly-efficient X-ray diffraction elements. These elements include holographic gratings and mirrors, slanted (non-Snellian) mirrors, uniform and chirped gratings, holographic optical elements (HOE's), lenses, and beam splitters which effectively demonstrated the proof of concept of POC's holographic technologies. In our approach, the holographic recording of the

Tomasz P. Jannson

1988-01-01

422

Spatioangular-multiplexing scheme for dense holographic storage.  

PubMed

A novel multiplexing scheme for dense holographic storage in photorefractive crystals, spatioangular multiplexing, is described in detail. Compared with spatial multiplexing, spatioangular multiplexing increases the storage capacity by fully utilizing the volume of the storage medium. On the other hand, spatioangular multiplexing reduces the number of holograms overlapping any one hologram in a given volume and so increases the diffraction efficiency achievable as compared with angular multiplexing. Using this scheme, we succeeded in storing 756 high-resolution patterns in an Fe:LiNbO(3) crystal of volume 1 cm(3), with an average diffraction efficiency of 0.5%. This large database is designed for practical use in a novel associative-memory system, called a high-order feedback neural network. PMID:21060528

Tao, S; Song, Z H; Selviah, D R; Midwinter, J E

1995-10-10

423

Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed  

Microsoft Academic Search

e recently showed that the correlation of gray and white matter volume with full scale IQ and the Working Memory dimension are completely mediated by common genetic factors (Posthuma et al., 2002). Here we examine whether the other WAIS III dimensions (Verbal Comprehension, Perceptual Organization, Processing Speed) are also related to gray and white matter volume, and whether any of

Daniëlle Posthuma; W. F. C. Baare; Hilleke E. Hulshoff Pol; René S. Kahn; Dorret I. Boomsma; Geus de E. J. C

2003-01-01

424

Cosmetic Surgery Volume and Its Correlation With the Major US Stock Market Indices  

Microsoft Academic Search

Background: As a consumer-driven industry, cosmetic plastic surgery is subject to ebbs and flows as the economy changes. There have been many predictions about the short, intermediate, and long-term impact on cosmetic plastic surgery as a result of difficulties in the current economic climate, but no studies published in the literature have quantified a direct correlation.Objectives: The authors investigate a

Chad R. Gordon; Landon Pryor; Ahmed M. Afifi; Paul X. Benedetto; C. J. Langevin; Francis Papay; Randall Yetman; James E. Zins

2010-01-01

425

Holographic fermionic liquid with lattices  

NASA Astrophysics Data System (ADS)

We investigate the holographic fermions over a gravitational lattice background with a rather low temperature. Since the rotation symmetry is broken on the plane, the lattice effects change the shape of the Fermi surface within the first Brillouin zone from a circle to an ellipse. When the Fermi surface intersects with the Brillouin zone boundary, the band structure with a band gap is observed through a numerical analysis. We construct a lattice model sourced by a scalar field as well as an ionic lattice model without the scalar field. In both cases we find the similar physical results.

Ling, Yi; Niu, Chao; Wu, Jian-Pin; Xian, Zhuo-Yu; Zhang, Hongbao

2013-07-01

426

Holographic superconductors with hyperscaling violation  

NASA Astrophysics Data System (ADS)

We investigate holographic superconductors in asympototically geometries with hyperscaling violation. The mass of the scalar field decouples from the UV dimension of the dual scalar operator and can be chosen as negative as we want, without disturbing the Breitenlohner-Freedman bound. We first numerically find that the scalar condenses below a critical temperature and a gap opens in the real part of the conductivity, indicating the onset of superconductivity. We further analytically explore the effects of the hyperscaling violation on the superconducting transition temperature. We find that the critical temperature increases with the increasing of hyperscaling violation.

Fan, ZhongYing

2013-09-01

427

Artist Projects at Holographics North  

NASA Astrophysics Data System (ADS)

The New York Times has declared the concept of holography in art as "laughably dated". And yet fine art remains one of the most durable applications of the medium. Holographics North Inc. has produced work for over 50 artists in 28 years. In many cases, new techniques and systems were required in order to implement the client's vision. The technical and conceptual challenges involved in several of these projects will be discussed, including photos of the work and the systems built to produce it. Among the artists addressed will be James Turrell, Michael Snow, Frank Stella, Michael Hayden, Harriet Casdin-Silver and Chris Levine.

Perry, John, Dr

2013-02-01

428

Holographic quarterwave plates in photoresist  

NASA Astrophysics Data System (ADS)

Sinusoidal holographic gratings recorded in photoresist exhibit strong phase retardation and can be used as low cost quarterwave plates. It was found that the two most important fabrication parameters are, in order of importance, the spatial frequency and the modulation depth. It is not possible to achieve a sufficient phase retardation into photoresist with a single grating showing no rotation of the incident polarization, but the cascade configuration shows the required phase retardation without diffracted orders and is a good candidate for the fabrication of high quality quarterwave plates.

Capolla, Nadia; Beauregard, Alain; Lavoie, Jean-Marc; Brousseau, Nicole

1994-01-01

429

Holographic Read-Only Memory  

NASA Astrophysics Data System (ADS)

The most successful use of optical memories so far has been as read-only memories (ROM). A main reason for this success has been the availability of inexpensive methods to mass-produce copies of recorded disks. This has made it possible to publish data (audio, video, databases, computer games) and distribute it widely through normal retail channels. In this chapter, we show results of a holographic read-only memory (HROM) of which digital data on a master disk can be copied onto replicate disks efficiently.

Mok, F.; Zhou, G.; Psaltis, D.

430

Correlation of Volume Transfer Coefficient Ktrans with Histopathologic Grades of Gliomas  

PubMed Central

Purpose To evaluate the roles of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and optimum tracer kinetic parameters in the noninvasive grading of the glial brain tumors with histopathological grades (I–IV). Materials and Methods Twenty eight patients with histopathologically graded gliomas were imaged. Images with five flip angles were acquired before injection of gadolinium-DTPA and were processed to calculate the T1 value of each regions of interest (ROI). All the DCE-MRI data acquired during the injection were processed based on the MRI signal and pharmacokinetic models to establish concentration-time curves in the ROIs drawn within the tumors, counterlateral normal areas, and area of the individual artery input functions (iAIF) of each patient. A nonlinear least square fitting method was used to obtain tracer kinetic parameters. Kruskal-Wallis H-test and Mann-Whitney U-test were applied to these parameters in different histopathological grade groups for statistical differences (P<0.05). Results Volume transfer coefficient (Ktrans) and extravascular extracellular space volume fraction (Ve) calculated by using iAIFs can be used not only to distinguish the low (i.e., I and II) from the high (i.e., III and IV) grade gliomas (P(Ktrans) <0.001 and PVe<0.001), but also grade II from III (P(Ktrans) =0.016 and PVe=0.033). Conclusion Ktrans is the most sensitive and specific parameter in the noninvasive grading, distinguishing the high (III and IV) from the low (I and II) grade and high grade III from low grade II gliomas.

Zhang, Na; Zhang, Lijuan; Qiu, Bensheng; Meng, Li; Wang, Xiaoyi; Hou, Bob L.

2012-01-01

431

Wavefront conversion by 90-degree geometry volume holograms between plane and spherical waves  

NASA Astrophysics Data System (ADS)

The volume holograms recorded by use of 90-degree geometry with reference and signal beams entering orthogonal crystal faces, have been widely used in fields such as waveguide couplers, holographic lenses, high-density holographic data storage. They posses the peculiar advantageous of small volume, ease of integrating and cascading. In fabrication of volume holograms are capable of converting various wavefronts into each other with high efficiency. But most of the researches were based on on-axis holographic optical elements such as cylindrical lens or spherical lens but not 90-degree geometry. In this paper, we investigate the properties of holographic lenses capable of converting plane waves into spherical waves in a perpendicular direction. Our research submits an analytical integral solution for the wavefront conversion problem in 90-degree geometry. The results can be of great practical importance in the design of volume holographic optical elements.

Yan, Aimin; Liu, Liren; Liu, De'an; Zhou, Yu; Luan, Zhu

2006-09-01

432

Holographic evolution of the mutual information  

NASA Astrophysics Data System (ADS)

We compute the time evolution of the mutual information in out of equilibrium quantum systems whose gravity duals are Vaidya spacetimes in three and four dimensions, which describe the formation of a black hole through the collapse of null dust. We find the holographic mutual information to be non monotonic in time and always monogamous in the ranges explored. We also find that there is a region in the configuration space where it vanishes at all times. We show that the null energy condition is a necessary condition for both the strong subadditivity of the holographic entanglement entropy and the monogamy of the holographic mutual information.

Allais, Andrea; Tonni, Erik

2012-01-01

433

Holographic properties of DMP-128 photopolymers  

NASA Astrophysics Data System (ADS)

Ever since the discovery of the principles of wavefront reconstruction (orholography) in 1948, efforts have been made to improve the quality of the reconstructed holographic image. In the early 60's, the performance of holography was improved by using separate object and reference beams. The invention of the laser shortly thereafter spurred increased research activity in holography as more powerful coherent sources made quality images practicable. As in most developing technologies, a major field of continuing interest is the search for better materials. This thesis is dedicated to the characterization of a promising new development in holographic recording materials: Polaroid's DMP-128 holographic recording system.

Guenther, B. D.; Hay, William

1986-09-01

434

Holographically generated twisted nematic liquid crystal gratings  

SciTech Connect

A reflection holographic method is introduced to fabricate an electro-optically tunable twisted nematic (TN) liquid crystal (LC) grating, forgoing the geometrical drawing. The photoisomerization process occurring on the LC alignment layers of an LC cell in the reflection holographic configuration gives a control over the twist angle, and the grating spacing is determined by the slant angle of reflection holographic configuration. The resulting diffraction grating is in a structure of a reverse TN LC, permitting a polarization-independent diffraction efficiency. The electro-optic tunability of the diffraction efficiency is also demonstrated.

Choi, Hyunhee; Wu, J.W.; Chang, Hye Jeong; Park, Byoungchoo [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Department of Electrophysics, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

2006-01-09

435

Influence of the dichromate concentration on the holographic properties of dichromated gelatin layers  

NASA Astrophysics Data System (ADS)

Dichromated gelatin (DCG) is a commonly used material for recording holographic optical elements. DCG has good optical properties as for example low scattering and high resolution. A photochemical effect causes a change of the refractive index after exposure and development of the DCG- layer. An important parameter for the holographic properties of the DCG-layer, e.g. maximum attainable modulation of the refractive index and swelling of the layer after development, is the concentration of dichromate in the DCG- layer. A further advantage of DCG is the attainable high modulation of the refractive index. In this paper we present experimental results, which give the maximum modulation of the refractive index and the swelling of the DCG-layer as a function of the concentration of dichromate. The results are obtained by analyzing volume phase gratings. The 'coupled wave theory' of Kogelnik gives a formal connection between the modulation of the refractive index and the diffraction efficiency of volume phase gratings. The latter is determined by analyzing the dependance of the diffraction efficiency on reconstruction angle. The exposure energy was varied to attain the maximum modulation of the refractive index for every dichromate concentration. The angular deviation of the Bragg-angle compared with the recording parameters yields the swelling of the DCG-layer. The diffraction gratings were recorded with a holographic copying process. the knowledge of these dependencies is necessary to facilitate optimization of the DCG-layer for different applications of holographic optical elements.

Schulat, Jochen; Froehlich, Klaus; Stojanoff, Christo G.

1998-03-01

436

Correlating anterior insula gray matter volume changes in young people with clinical and neurocognitive outcomes: an MRI study  

PubMed Central

Background The anterior insula cortex is considered to be both the structural and functional link between experience, affect, and behaviour. Magnetic resonance imaging (MRI) studies have shown changes in anterior insula gray matter volume (GMV) in psychosis, bipolar, depression and anxiety disorders in older patients, but few studies have investigated insula GMV changes in young people. This study examined the relationship between anterior insula GMV, clinical symptom severity and neuropsychological performance in a heterogeneous cohort of young people presenting for mental health care. Methods Participants with a primary diagnosis of depression (n?=?43), bipolar disorder (n?=?38), psychosis (n?=?32), anxiety disorder (n?=?12) or healthy controls (n?=?39) underwent structural MRI scanning, and volumetric segmentation of the bilateral anterior insula cortex was performed using the FreeSurfer application. Statistical analysis examined the linear and quadratic correlations between anterior insula GMV and participants’ performance in a battery of clinical and neuropsychological assessments. Results Compared to healthy participants, patients had significantly reduced GMV in the left anterior insula (t?=?2.05, p?=?.042) which correlated with reduced performance on a neuropsychological task of attentional set-shifting (??=?.32, p?=?.016). Changes in right anterior insula GMV was correlated with increased symptom severity (r?=?.29, p?=?.006) and more positive symptoms (r?=?.32, p?=?.002). Conclusions By using the novel approach of examining a heterogeneous cohort of young depression, anxiety, bipolar and psychosis patients together, this study has demonstrated that insula GMV changes are associated with neurocognitive deficits and clinical symptoms in such young patients.

2012-01-01

437

Long-term declarative memory deficits in diffuse TBI: correlations with cortical thickness, white matter integrity and hippocampal volume.  

PubMed

We investigated structural brain damage in subjects who had suffered severe and diffuse traumatic brain injury (TBI), and examined its relationship with declarative memory impairment. Cortical thickness, diffusion tensor imaging (DTI), and volumetric and shape data of the hippocampus were assessed in a group of 26 adults with severe TBI in the chronic stage and 22 healthy matched controls. Declarative memory was evaluated by Rey's Auditory Verbal Learning Test (RAVLT). TBI patients performed significantly worse than controls on all RAVLT measures. The group comparison for cortical thickness and DTI revealed a pattern of widespread atrophy in TBI patients. In the TBI group DTI measures correlated with cortical thickness in the prefrontal and parietal regions, including the precuneus. Declarative memory correlated with both cortical thickness and DTI measures. However, although hippocampal volume was significantly decreased in TBI patients, no correlations were found. Multiple regression analysis of all the structural measures revealed that decreases in Fractional anisotropy (FA) and thinning of the left parietal region were the best predictors of memory impairment. In conclusion, cortical thickness reductions in the left hemisphere and a lack of white matter integrity are the main contributors to long-term impairment in declarative memory among patients suffering from severe and diffuse TBI. In this study the hippocampus did not make a significant contribution to memory dysfunctions, suggesting that damage to this structure is compensated for by other regions, with the definitive sequelae being mainly explained by alterations in cortico-subcortical connectivity. PMID:22482692

Palacios, Eva M; Sala-Llonch, Roser; Junque, Carme; Fernandez-Espejo, Davinia; Roig, Teresa; Tormos, Jose M; Bargallo, Nuria; Vendrell, Pere

2012-03-08

438

Holographic opto-fluidic microscopy  

PubMed Central

Over the last decade microfluidics has created a versatile platform that has significantly advanced the ways in which micro-scale organisms and objects are controlled, processed and investigated, by improving the cost, compactness and throughput aspects of analysis. Microfluidics has also expanded into optics to create reconfigurable and flexible optical devices such as reconfigurable lenses, lasers, waveguides, switches, and on-chip microscopes. Here we present a new opto-fluidic microscopy modality, i.e., Holographic Opto-fluidic Microscopy (HOM), based on lensless holographic imaging. This imaging modality complements the miniaturization provided by microfluidics and would allow the integration of microscopy into existing on-chip microfluidic devices with various functionalities. Our imaging modality utilizes partially coherent in-line holography and pixel super-resolution to create high-resolution amplitude and phase images of the objects flowing within micro-fluidic channels, which we demonstrate by imaging C. elegans, Giardia lamblia, and Mulberry pollen. HOM does not involve complicated fabrication processes or precise alignment, nor does it require a highly uniform flow of objects within microfluidic channels.

Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan

2010-01-01

439

Holographic grating: a useful tool  

NASA Astrophysics Data System (ADS)

Holography enables us to create various optical elements, in a simply way. They can be used for any purpose that conventional optical elements can be used for. Especially holographic gratings can demonstrate the advantage of such an approach. To make the dense line structure of a grating classically, a special ruling engine had to be used. Instead mechanically ruled grating grooves a hologram of a plane wave with plane reference wave can be recorded. The interference pattern has the form of regular parallel strips - intensity maxims and the grating interval can be changed very simply, by choosing a proper angle between the interfering waves. Exposition allows us to form the grating profile. The contribution is to present some of our results, applicable during educational process (master study - Optics, lasers and optical spectroscopy), too. A holographic grating may become a simple and useful tool to reveal real temporal coherence properties of widely used laser diode modules and determine frequency spacing ?? when more longitudinal modes are generated. Moreover, when choosing a proper angle between two interfering waves creating the grating, the grating interval ? may become less than the wavelength ?, and a sub-wavelength structure can be created in a simply way if a proper recording medium is accessible. That enables us to model light spreading phenomena when approaching sub-wavelength structures.

Senderáková, Dagmar; Drzik, Milan; Strba, Anton; Mesaros, Vladimir

2011-09-01

440

Holographic Description of Vacuum Bubbles  

NASA Astrophysics Data System (ADS)

We discuss a holographic description of vacuum bubbles, with possible implications for a consistent description of the multiverse. In particular, we elaborate on the recent observation by Maldacena, that the interior of AdS bubbles can be described in terms of CFT degrees of freedom living on the worldsheet of the bubble wall. We consider the scattering of bulk gravitons in the ambient parent vacuum, off the bubble wall. In the dual description, the transmission coefficient is interpreted as the probability that a graviton is absorbed by the worldsheet CFT degrees of freedom. The result is in agreement with intuitive expectations. Conformal invariance is not exact in this setup, and the leading corrections due to the IR and UV cut-offs are displayed. Aside from bulk scattering states, we find that when a bubble nucleates within a parent dS vacuum, there is a zero mode of the graviton which describes lower dimensional gravity with a finite Newton's constant. This massless graviton lives within one Hubble radius away from the bubble wall. Possible implications for a fully holographic description of the inflating multiverse are briefly discussed.

Garriga, J.

441

Simulating the energy performance of holographic glazings.  

National Technical Information Service (NTIS)

The light diffraction properties of holographic diffractive structures present an opportunity to improve the daylight performance in side-lit office spaces by redirecting and reflecting sunlight off the ceiling, providing adequate daylight illumination up...

K. Papamichael L. Beltran R. Furler E. S. Lee S. Selkowitz

1994-01-01

442

Planar holographic configuration for efficient imaging  

NASA Astrophysics Data System (ADS)

A planar holographic configuration that can be exploited for imaging with high light throughput efficiency is presented. The configuration is comprised of two elements - a linear grating and a corrected holographic lens. The design and recording of the holographic lens are based on a technique, where a desired grating function, with low aberrations, is transferred from a thin hologram to one recorded in thick recording materials, so the Bragg condition is fulfilled over a broad range of incidence angles. As a result, it is possible to get a holographic lens having low aberrations and uniform high diffraction efficiency over a relatively large field of view. When combined with the linear grating, the overall planar optics configuration can be exploited for imaging information displayed with quasi monochromatic light source, as in a visor display application. Such a configuration was designed, recorded and evaluated experimentally, demonstrating a uniform, and relatively high diffraction efficiency over a field of view of 16 degrees.

Shechter, R.; Amitai, Y.; Friesem, A. A.; Reinhorn, S.

1996-02-01

443

Scaling and Resolution of Senic Holographic Stereograms.  

National Technical Information Service (NTIS)

Scaling of holographic stereograms in the ratio d/d' can be accomplished by using a spacing, d, between component photographs and a different spacing, d', between corresponding holograms. Scaling down of scenic holograms is desirable in order to increase ...

N. George J. T. McCrickerd M. M. T. Chang

1968-01-01

444

Two Color Holographic Interferometry for Microgravity Application.  

National Technical Information Service (NTIS)

Holographic interferometry is a primary candidate for determining temperature and concentration in crystal growth experiments designed for space. The method measures refractive index changes within the fluid of an experimental test cell resulting from tem...

J. D. Trolinger D. C. Weber

1995-01-01

445

Holographic secret codes made with moire technique  

NASA Astrophysics Data System (ADS)

Techniques of making visible and concealed holographic secret codes based on optical moire phenomenon are described. Theoretical analysis, experimental results and the sample holograms with the secret codes are presented.

Liu, Shou; Zhang, Xiangsu; Lai, Hongkai

1996-12-01

446

Spectral and Angle Selective Holographic Devices.  

National Technical Information Service (NTIS)

This report results from a contract tasking A F loffe Physical Technical Institute as follows: The contractor will investigate the development of several holographic solutions to aerospace problems including laser satellite communication and day-lighting,...

I. Semenova

1997-01-01

447

Meson wave function from holographic approaches  

SciTech Connect

We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.

Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2010-08-04

448

Holographic Interferometric Tomography for Reconstructing Flow Fields.  

National Technical Information Service (NTIS)

Holographic interferometric tomography is a technique for instantaneously capturing and quantitatively reconstructing three-dimensional flow fields. It has a very useful application potential for high-speed aerodynamics. However, three major challenging t...

S. S. Cha

1994-01-01

449

Channel codes for digital holographic data storage  

NASA Astrophysics Data System (ADS)

Various channel codes, including binary, gray-scale, threshold, and differential techniques, are compared for digital holographic data storage. The tradeoffs among bit error rate, storage capacity, and system complexity are discussed. Copyright (c) 1995 Optical Society of America

Heanue, J. F.; Bashaw, M. C.; Hesselink, L.

1995-11-01

450

Holographically observed torsion in a cylindrical shaft.  

PubMed

Using holographic interferometry, the rotation of a rigid cylinder and the torsion of a flexible shaft (RTV silastic rubber) have been observed. The experimentally generated fringe patterns are compared with computed ones and good agreement is obtained. PMID:20094202

Wilson, A D

1970-09-01

451

MRI Study of Caudate Nucleus Volume and Its Cognitive Correlates in Neuroleptic-Naive Patients With Schizotypal Personality Disorder  

PubMed Central

Objective “Cognitive” circuits anatomically link the frontal lobe to subcortical structures; therefore, pathology in any of the core components of these circuits, such as in the caudate nucleus, may result in neurobehavioral syndromes similar to those of the frontal lobe. Neuroleptic medication, however, affects the size of the caudate nucleus. For this reason, individuals diagnosed with schizotypal personality disorder offer an ideal group for the measurement of the caudate nucleus because they may be genetically related to individuals with schizophrenia but do not require neuroleptic treatment because of their less severe symptoms. Method Magnetic resonance imagining (MRI) scans obtained on a 1.5-T magnet with 1.5-mm contiguous slices were used to measure the caudate nucleus and lateral ventricles in 15 right-handed male subjects with schizotypal personality disorder who had no previous neuroleptic exposure and in 14 normal comparison subjects. Subjects were group matched for parental socioeconomic status, handedness, and gender. Results First, the authors found significantly lower left and right absolute (13.1%, 13.2%) and relative (9.1%, 9.2%) caudate nucleus volumes in never-medicated subjects with schizotypal personality disorder than in normal subjects. Second, they found significant, inverse correlations between caudate nucleus volume and the severity of perseveration in two distinct working memory tasks in these neuroleptic-naive subjects with schizotypal personality disorder. Conclusions These data are consistent with the findings of reduced caudate nucleus volume reported in studies of neuroleptic-naive patients experiencing their first episode of schizophrenia and support the association of intrinsic pathology in the caudate nucleus with abnormalities in working memory in the schizophrenia spectrum.

Levitt, James J.; McCarley, Robert W.; Dickey, Chandlee C.; Voglmaier, Martina M.; Niznikiewicz, Margaret A.; Seidman, Larry J.; Hirayasu, Yoshio; Ciszewski, Aleksandra A.; Kikinis, Ron; Jolesz, Ferenc A.; Shenton, Martha E.

2010-01-01

452

Correlation between mean platelet volume and fasting plasma glucose levels in prediabetic and normoglycemic individuals  

PubMed Central

Background Prediabetes is an independent risk factor for cardiovascular diseases. Mean platelet volume (MPV) can reflect platelet activity, and high MPV is associated with thrombogenic activation and an increased risk of cardiovascular disease. In diabetic patients, MPV is higher when compared with normal subjects. However, the relationship between MPV and prediabetes is poorly understood. The purpose of the present study was to compare MPV in prediabetic and normoglycemic subjects, and to evaluate the relationship between MPV and fasting plasma glucose (FPG) levels in these two groups. Methods We retrospectively studied 1876 Japanese subjects who had undergone health checks at Iida Municipal Hospital. Age, sex, body mass index (BMI), blood pressure, medical history, smoking habits, alcohol intake, lipid profiles, FPG levels, and MPV were evaluated. Subjects were categorized into four groups according to FPG: Q1 (70 mg/dL ? FPG < 90 mg/dL, n = 467), Q2 (90 mg/dL ? FPG < 95 mg/dl, n = 457), Q3 (95 mg/dL ? FPG < 100 mg/dL, n = 442), and Q4 (100 mg/dL ? FPG < 126 mg/dL, n = 512). Q1, Q2, and Q3 were defined as normal FPG groups and Q4 was defined as prediabetic group. Results The MPV increased with the increasing FPG levels, in the following order: Q1 (9.89 ± 0.68 fl), Q2 (9.97 ± 0.69 fl), Q3 (10.02 ± 0.72 fl), and Q4 (10.12 ± 0.69 fl). After adjusting for the confounding parameters, MPV of the prediabetic group was higher than that in other groups (P < 0.001 for Q4 vs. Q1 and Q2, and P < 0.05 for Q4 vs. Q3). MPV in the high-normal glucose group (Q3) was significantly higher than in the low-normal glucose group (Q1). MPV was independently and positively associated with FPG, not only in prediabetic subjects but also in normal FPG subjects (? = 0.020 and ? = 0.006, respectively). Conclusions MPV in patients with prediabetes was higher than that in normal subjects, and was positively associated with FPG levels in prediabetic and normal subjects.

2013-01-01

453

Serum YKL-40 Levels Correlate with Infarct Volume, Stroke Severity, and Functional Outcome in Acute Ischemic Stroke Patients  

PubMed Central

Background and Purpose YKL-40 is associated with various neurological disorders. However, circulatory YKL-40 levels early after onset of acute ischemic stroke (AIS) have not been systematically assessed. We aimed to identify the temporal changes and clinical usefulness of measuring serum YKL-40 immediately following AIS. Methods Serum YKL-40 and C-reactive protein (CRP) levels were monitored over time in AIS patients (n?=?105) and compared with those of stroke-free controls (n?=?34). Infarct volume and stroke severity (National Institutes of Health Stroke Scale; NIHSS) were measured within 48 hours of symptom onset, and functional outcome (modified Rankin Scale; mRS) was measured 3 months after AIS. Results Within 12 hours of symptom onset, levels of YKL-40 (251 vs. 41 ng/mL) and CRP (1.50 vs. 0.96 µg/mL) were elevated in AIS patients compared to controls. The power of YKL-40 for discriminating AIS patients from controls was superior to that of CRP (area under the curve 0.84 vs. 0.64) and YKL-40 (r?=?0.26, P<0.001) but not CRP levels were correlated with mRS. On day 2 of admission (D2), YKL-40 levels correlated with infarct volume and NIHSS. High YKL-40 levels predicted poor functional outcome (odds ratio 5.73, P?=?0.03). YKL-40 levels peaked on D2 and declined on D3, whereas CRP levels were highest on D3. Conclusions Our results demonstrate serial changes in serum YKL-40 levels immediately following AIS and provide the first evidence that it is a valid indicator of AIS extent and an early predictor of functional outcome.

Park, Hyun Young; Jun, Chang-Duk; Jeon, Se-Jeong; Choi, See-Sung; Kim, Hak-Ryul; Choi, Dan-Bee; Kwak, Seongae; Lee, Hak-Seung; Cheong, Jin Sung; So, Hong-Seob; Lee, Young-Jin; Park, Do-Sim

2012-01-01

454

Multilayered poly(vinylidene fluoride) composite membranes with improved interfacial compatibility: correlating pervaporation performance with free volume properties.  

PubMed

A spin-coating process integrated with an ozone-induced graft polymerization technique was applied in this study. The purpose was to improve the poor interfacial compatibility between a selective layer of poly(2-hydroxyethyl methacrylate) (PHEMA) and the surface of a poly(vinylidene fluoride) (PVDF) substrate. The composite membranes thus fabricated were tested for their pervaporation performance in dehydrating an ethyl acetate/water mixture. Furthermore, the composite membranes were characterized by field emission scanning electron microscopy (FE-SEM) for morphological change observation and by Fourier transform infrared spectroscopy equipped with attenuated total reflectance (ATR-FTIR) for surface chemical composition analysis. Effects of grafting density and spin-coating speed on pervaporation performance were examined. The composite membrane pervaporation performance was elucidated by means of free volume and depth profile data obtained with the use of a variable monoenergy slow positron beam (VMSPB). Results indicated that a smaller free volume was correlated with a higher pervaporation performance of a composite membrane consisting of a selective layer of spin-coated PHEMA on a PHEMA-grafted PVDF substrate (S-PHEMA/PHEMA-g-PVDF). The composite membrane depth profile illustrated that an S-PHEMA layer spin-coated at a higher revolutions per minute (rpm) was thinner and denser than that at a lower rpm. PMID:21740064

An, Quanfu; Chen, Jung-Tsai; De Guzman, Manuel; Hung, Wei-Song; Lee, Kueir-Rarn; Lai, Juin-Yih

2011-08-04

455

Human experience seeking correlates with hippocampus volume: convergent evidence from manual tracing and voxel-based morphometry  

PubMed Central

Experience-seekers continuously pursue novel environmental stimuli, a tendency linked to genetic variation in mesolimbic dopamine transmission. However, the neuroantomical basis accompanying these genetic and neurochemical associations is unknown. Animal and human experimental results suggest a central role for the hippocampus in processing novel stimuli. Here, we explored whether differences in human experience seeking are related to variations in hippocampal volume. High resolution anatomic MR images were analyzed in 40 individuals who ranged from low through high on a validated experience seeking personality scale. Manual tracing analysis demonstrated positive correlation between right hippocampal volumes and scores on the experience seeking scale. A separate voxel-based morphometric analysis confirmed these results and localized the significant increase to the anterior portion of right hippocampal grey matter. We tested and were able to reject the possibility that results were mediated by a personality trait related to, but distinct from, experience seeking. The present data provide the first direct evidence for a relationship between human experience seeking and brain structure. In addition, these results provide new ecologically relevant evidence for a link between right anterior hippocampus and novelty processing.

Martin, Sarah B.; Covell, D. Jeff; Joseph, Jane E.; Chebrolu, Himachandra; Smith, Charles D.; Kelly, Thomas H.; Jiang, Yang; Gold, Brian T.

2010-01-01

456

Post-traumatic stress symptoms correlate with smaller subgenual cingulate, caudate, and insula volumes in unmedicated combat veterans  

PubMed Central

Prior studies have examined differences in brain volume between PTSD and control subjects. Convergent findings include smaller hippocampus and medial prefrontal cortex volumes in PTSD. However, post-traumatic stress symptoms (PTSS) exist on a spectrum, and neural changes may occur beyond the diagnostic threshold of PTSD. We examined the relationship between PTSS and gray matter among combat-exposed U.S. military veterans. Structural brain MRI was obtained on 28 combat veterans from Operations Enduring and Iraqi Freedom. PTSS were assessed using the Clinician-Administered PTSD Scale (CAPS). Thirteen subjects met criteria for PTSD. Subjects were unmedicated, and free of major comorbid psychiatric disorders. Images were analyzed using voxel-based morphometry, and regressed against the total CAPS score and trauma load. Images were subsequently analyzed by diagnosis of PTSD vs. non-PTSD. CAPS scores were inversely correlated with subgenual cingulate (sgACC), caudate, hypothalamus, insula, and left middle temporal gyrus (MTG). Group contrast revealed smaller sgACC, caudate, hypothalamus, left insula, left MTG, and right MFG in the PTSD group. PTSS are associated with abnormalities in limbic structures that may underlie the pathophysiology of PTSD. These abnormalities exist on a continuum with PTSS, beyond a diagnosis of PTSD.

Herringa, Ryan; Phillips, Mary; Almeida, Jorge; Insana, Salvatore; Germain, Anne

2012-01-01

457

Analyticity and the Holographic S-Matrix  

SciTech Connect

We derive a simple relation between the Mellin amplitude for AdS/CFT correlation functions and the bulk S-Matrix in the flat spacetime limit, proving a conjecture of Penedones. As a consequence of the Operator Product Expansion, the Mellin amplitude for any unitary CFT must be a meromorphic function with simple poles on the real axis. This provides a powerful and suggestive handle on the locality vis-a-vis analyticity properties of the S-Matrix. We begin to explore analyticity by showing how the familiar poles and branch cuts of scattering amplitudes arise from the holographic description. For this purpose we compute examples of Mellin amplitudes corresponding to 1-loop and 2-loop Witten diagrams in AdS. We also examine the flat spacetime limit of conformal blocks, implicitly relating the S-Matrix program to the Bootstrap program for CFTs. We use this connection to show how the existence of small black holes in AdS leads to a universal prediction for the conformal block decomposition of the dual CFT.

Fitzpatrick, A.Liam; /Stanford U., Phys. Dept.; Kaplan, Jared; /SLAC

2012-04-03

458

Holographic surface gratings in iron-doped lithium niobate  

SciTech Connect

Surface gratings associated with holographic volume gratings in photorefractive crystals of iron-doped lithium niobate have been studied using diffraction of a reflected probe beam and high-resolution phase-shifted interferometric profilometry. Both techniques show that the surface gratings exist in the form of periodical corrugations of the same period as that of the volume grating. The maximum amplitude of the periodical surface relief measured by both techniques is close to 6.5 nm. We also demonstrated that the periodical electric forces on the surface were capable of assembling polystyrene microspheres along the fringes of the grating. Large amplitude of the periodic electric field (1.6 x 10{sup 4}V/cm) is associated with the photogalvanic effect. {copyright} 2001 American Institute of Physics.

Sarkisov, S. S.; Curley, M. J.; Kukhtarev, N. V.; Fields, A.; Adamovsky, G.; Smith, C. C.; Moore, L. E.

2001-08-13

459

The fast life of holographic mesons  

Microsoft Academic Search

Holographic techniques are used to study the dispersion relation of meson quasiparticles moving through a thermal plasma in {\\\\cal N}=2 super-Yang-Mills theory with Nc colours and coupled to Nf flavours of fundamental matter in the regime Nf\\/Nc Lt 1. The meson states are destabilized by introducing a small quark density nq. Holographic spectral functions are used to investigate the dispersion

Aninda Sinha

2008-01-01

460

The fast life of holographic mesons  

Microsoft Academic Search

We use holographic techniques to study meson quasiparticles moving through a thermal plasma in Script N = 2 super-Yang-Mills theory, with gauge group SU(Nc) and coupled to Nf flavours of fundamental matter. This holographic approach reliably describes the system at large Nc, large 't Hooft coupling and Nf\\/Nc << 1. The meson states are destabilized by introducing a small quark

Aninda Sinha

2008-01-01

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