Browsing by Author "Hsu, KY"

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2k-grating-assisted self-pumped phase conjugation: Theoretical and experimental studies
(1996-08-01)
Lin, SUH
;
Lian, YW
;
Yeh, PC
;
Hsu, KY
;
Yong, Z
We investigated 2k-grating-assisted self-pumped phase conjugation in photorefractive Ce:BaTiO3 crystals. The phase-conjugation process involves a combination of four-wave mixing and stimulated photorefractive backscattering. An approximation involving separate interaction regions is used to theoretically calculate the reflectivity of phase conjugation as a function of the coupling strength of four-wave mixing and stimulated photorefractive backscattering. Fn our experiments, grating-erasure techniques are employed at the interaction regions to investigate the dependence of phase-conjugate reflectivity on the coupling strength of four-wave mixing and stimulated photorefractive backscattering. The experimental results are in good agreement with the theoretical prediction.
2k-grating-assisted self-pumped phase conjugation: Theoretical and experimental studies
(1996-08-01)
Lin, SUH
;
Lian, YW
;
Yeh, PC
;
Hsu, KY
;
Yong, Z
We investigated 2k-grating-assisted self-pumped phase conjugation in photorefractive Ce:BaTiO3 crystals. The phase-conjugation process involves a combination of four-wave mixing and stimulated photorefractive backscattering. An approximation involving separate interaction regions is used to theoretically calculate the reflectivity of phase conjugation as a function of the coupling strength of four-wave mixing and stimulated photorefractive backscattering. Fn our experiments, grating-erasure techniques are employed at the interaction regions to investigate the dependence of phase-conjugate reflectivity on the coupling strength of four-wave mixing and stimulated photorefractive backscattering. The experimental results are in good agreement with the theoretical prediction.
3D monochromatic image synthesized with vertical area-partitioned recording of master hologram in multiple-exposure holography
(2001-08-01)
Zhai, HC
;
Mu, GG
;
Wang, MW
;
Liu, FM
;
Pan, D
We report for the first time theoretical analysis and experimental results of a vertical-area partition method for recording master holograms in multiple-exposure rainbow holography to synthesize monochromatic 3D image from a series of medical tomograms. In this novel method, the master hologram is area partitioned into elementary master holograms, which are recorded in a periodic arrangement along the vertical direction. Under the white-light reconstruction, a 3D monochromatic image composed of a series of medical tomograms can be synthesized with wide viewing angle, high resolution, and low color blur. (C) 2001 Published by Elsevier Science B.V.
A hetero-associative memory using phase-multiplexing references
(2000-04-01)
Hsieh, ML
;
Hsu, KY
;
Lin, SH
;
電子物理學系
;
光電工程學系
We present a hetero-associative memory for multiple-associative pairs by using the phase-multiplexing technique. Two methods for reducing the cross-talk between different association pairs are proposed. An optical experiment for the edge-enhancement associative memory is also demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.
Analysis of grating detuning on volume holographic data storage
(2000)
Lin, SH
;
Hsu, KY
;
電機學院
;
College of Electrical and Computer Engineering
Scalar diffraction theory has been utilized to analyze grating detuning effect in a volume holographic data storage system. The general formulas for describing the two-dimensional distribution of the retrieval image under the detuning effect have been derived. Computer simulations show that the smaller writing angle provides better performance for a holographic storage system in terms of the uniformity and the pixel shift of the retrieval image.
Anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals with extended wavelength range
(2002-02-25)
Zaitsev, AK
;
Hsu, KY
;
Lin, SH
;
交大名義發表
;
National Chiao Tung University
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. (C) 2002 Optical Society of America.
Color image recognition by use of a joint transform correlator of three liquid-crystal televisions
(2002-03-10)
Hsieh, ML
;
Hsu, KY
;
Zhai, HC
;
光電工程學系
;
Department of Photonics
We present a joint transform correlator for color image recognition by using three liquid-crystal spatial light modulators. A method for simultaneously obtaining the correlation peaks of red, green, and blue is proposed and experimentally demonstrated. (C) 2002 Optical Society of America.
Comparison of the recording dynamics of phenanthrenequinone-doped poly(methyl methacrplate) materials
(2001-07-01)
Mumbru, J
;
Solomatine, I
;
Psaltis, D
;
Lin, SH
;
Hsu, KY
A comparative analysis of phenanthrenequinone-doped poly(methyl methacrylate) materials fabricated at California Institute of Technology and National Chiao Tung University is performed in order to understand the differences exhibited in their recording and baking dynamics. (C) 2001 Published by Elsevier Science B.V.
Contradirectional two-wave mixing with partially coherent waves in photorefractive crystals
(1996-08-01)
Yi, XM
;
Lin, SH
;
Yeh, PC
;
Hsu, KY
;
光電工程學系
We investigate contradirectional two-wave mixing with partially coherent waves in photorefractive crystals in the nondepleted pump regime. Equations governing the propagation of the self-coherence function and the mutual-coherence function of the signal wave and the pump wave are derived and simulated numerically. Numerical solutions of these equations are in excellent agreement with the experimental measurements. (C) 1996 Optical Society of America
Creation of weighted volume grating by holographic method
(2001)
Zaitsev, AK
;
Lin, SH
;
Hsu, KY
;
交大名義發表
;
National Chiao Tung University
The creation method of a weighted holographic grating in photopolymer film is discussed, It is based on interference of two beams passed through weighting masks. Due to weighing the grating's response has sidelobe level to be reduced.
Effect of grating detuning on holographic data storage
(2000)
Lin, SH
;
Hsu, KY
;
電子物理學系
;
Department of Electrophysics
We use the scaler diffraction theory to analyze the grating detuning effect in a volume holographic data storage system. The general formulas for describing the two-dimensional distribution of retrieved image under the detuning effect have been derived. In terms of the image uniformity and the pixel shift of the retrieval image, computer simulations are used to perform a quantitative analysis.
Effect of grating detuning on volume holographic memory using photopolymer storage media: Reflection holograms
(2000)
Hsieh, ML
;
Hsu, KY
;
Yeh, P
;
光電工程學系
;
Department of Photonics
We present a study of the grating detuning effect on the volume holographic data storage using photopolymer recording material. By using the Bragg matching condition, the angle shift and the decay of the diffraction efficiency of the reconstructed beam is obtained. Then the distortion of the readout page is described. And a method for pre-compensation of the incident angles of the reading beam is presented.
Effect of ruthenium doping on the optical and photorefractive properties of Bi12TiO20 single crystals
(2002-03-15)
Marinova, V
;
Hsieh, ML
;
Lin, SH
;
Hsu, KY
;
電子物理學系
Bi12TiO20 (BTO) single crystals nominally pure and doped with ruthenium are grown by top-seeded solution growth method. The effect of ruthenium concentration on optical and photorefractive properties is studied. Strong influence of doping on these properties is observed. It is shown that optical transmission of crystal samples with higher ruthenium content is shifted to the near IR spectral region, while the absorption coefficient is considerably increased. The optical activity of Ru doped crystals is further reduced in comparison with undoped BTO. Photochromic effect is observed in strongly doped crystal. Photorefractive properties are experimentally investigated using two-beam coupling. Response time and diffraction efficiency are changed with ruthenium content. (C) 2002 Elsevier Science B.V. All rights reserved.
Effect of the sensitizer on the properties of fully functionalized photorefractive epoxy polymers and their performance in the hologram image storage
(1999-06-01)
Chang, CJ
;
Whang, WT
;
Hsu, KY
;
Hsieh, ML
;
材料科學與工程學系
The 3-amino-9-ethyl carbazole (AEC)/Dispersed Orange 3 (DO3)/diglycidyl 1,2 cyclohexanedicarboxylate (DCD) main chain copolymers are synthesized and studied on their photorefractive (PR), photoconductive, and holographic characteristics. They are good hologram recording media because not only the stored hologram exhibits excellent fringe contrast with the resolution at about 20 mu m, but also the image can be stored, erased, and overwritten. The UV/Vis spectra shows that AEC segments may form charge transfer complexes with either DO3 segments or TNF sensitizers. By incorporating the sensitizer or increasing the charge transfer component concentration, the grating growth rate can be speeded up. Applying an electric field on the polymer film containing no sensitizer helps to elevate the grating growth speed, but it shows little influence on the grating growth speed of the films with sensitizers. More nonlinear optical (NLO) segments in the copolymer result in higher diffraction efficiency. The dark decay of the film depends on the dark conductivity. Incorporating sensitizers or more charge transport segments leads to more dark decay because of increasing dark conductivity. The dark decay of the PR properties at elevated temperature can also be evaluated by the thermal stimulated discharge current (TSDC) spectroscopy technique. (C) 1999 John Wiley & Sons, Inc.
Epoxy/polyhedral oligomeric silsesquioxane nanocomposites from octakis(glycidyidimethylsiloxy)octasilsesquioxane and small-molecule curing agents
(2006-06-15)
Liu, YL
;
Chang, GP
;
Hsu, KY
;
Chang, FC
;
應用化學系
Epoxy/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were obtained from octakis(glycidyldimethylsiloxy)octasilsesquioxane (OG) and diglycidyl ether of bisphenol A cured with small-molecule curing agents of diethylphosphite (DEP) and dicyandiamide (DICY). An increase in the POSS contents of the nanocomposites and an improvement in the nanocomposite homogeneity were observed with the use of the small-molecule curing agents. Phosphorus in DEP and nitrogen in DICY also performed synergism with POSS for thermal stability enhancement and flammability improvement in the nanocomposites. The nanocomposites possessing high OG contents exhibited good thermal stability, improved flammability, and high storage moduli. (c) 2006 Wiley Periodicals, Inc.
Experimental characterization of phenanthrenequinone-doped poly(methyl methacrylate) photopolymer for volume holographic storage
(2003-05-01)
Hsu, KY
;
Lin, SH
;
Hsiao, YN
;
Whang, WT
;
材料科學與工程學系
We present an experimental study on the photopolymer poly(methyl methacrylate) doped with phenathrenequinone molecules. Material characteristics for holographic data storage, including optical characteristics, scattering effect, relation between diffraction efficiency and number of holograms, and exposure schedule for multiple storage, are investigated. An experimental demonstration of multiple storage of digital data pages in a polymer cube is presented. (C) 2003 Society of Photo-Optical Instrumentation Engineers.
Experimental observation of the slowdown of optical beams by a volume-index grating in a photorefractive LiNbO3 crystal
(2000-11-01)
Lin, SH
;
Hsu, KY
;
Yeh, P
;
電子物理學系
;
光電工程學系
We investigate the group velocity of light in a one-dimensional volume-index grating inside a photorefractive LiNbO3 crystal. The slowdown of the group electromagnetic propagation is observed experimentally by tuning of the wave number of the optical beam close to the outside edge of the forbidden bandgap. We obtain a large group index of up to 7.5 in a 3.5-cm crystal sample. The group index is compared with the result of a theoretical derivation. The results are presented and discussed. (C) 2000 Optical Society of America OCIS codes: 050.7330, 260.2030, 190.5530, 160.3730.
Exposure schedule for multiplexing holograms in photopolymer
(1999)
Lin, SAH
;
Hsu, KY
;
Chen, WZ
;
Whang, WT
;
光電工程學系
We present dynamics of the grating formation process in phenanthrenequinone- (PQ-) doped poly(methyl methacrylate) (PMMA) photo-polymer. The exposure schedule for multiplexing holograms to achieve equal-strength storage in a single location is described. The analysis method is valid for any saturated media, thus the results can be applied to other photo-polymer materials with similar kinetics.
General solution of contradirectional two-wave mixing with partially coherent waves in photorefractive crystals
(1997-06-01)
Yi, XM
;
Yang, CX
;
Yeh, PC
;
Lin, SH
;
Hsu, KY
We investigate contradirectional two-wave mixing with partially coherent waves in photorefractive crystals. By use of a statistical theory on linear systems, a general formulation of the problem in the space and frequency domain is derived and implemented numerically. We obtain results on beam intensity and mutual coherence. The results on the enhancement of mutual coherence are compared with previous theoretical results on simpler cases and with experimental measurements. Excellent agreements are achieved. The results also indicate that the effective interaction length can be significantly longer than the coherence length of the waves. (C) 1997 Optical Society of America.
Grating detuning effect on holographic memory in photopolymers
(2001-10-01)
Hsieh, ML
;
Hsu, KY
;
光電工程學系
;
Department of Photonics
We present a study of the grating detuning effect on the transmission and reflection holographic memories recorded in a photopolymer material. By using the Bragg matching condition, we analyze the angular shift and the degradation of the diffraction efficiency of the reconstructed Images. Based on these results, a method for precompensating the detuning effect has been proposed. (C) 2001 Society of Photo-Optical Instrumentation Engineers.