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Articles 91 - 120 of 124
Full-Text Articles in Optics
Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross
Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross
Faculty Publications
Results of a method of estimating index of refraction from passive, polarimetric hyperspectral imaging radiance measurements are presented. As off-nadir viewing hyperspectral imaging platforms gain prominence, estimating index of refraction, which is invariant to viewing angle, may prove advantageous to estimating the emissivity, which is not. Results show that index of refraction can be retrieved to within 8% rms error for fused silica and sapphire glass targets, while simultaneously estimating object temperature. The accuracy and self-consistency of this technique for estimating index of refraction are shown to compare favorably to the maximum smoothness temperature–emissivity separation algorithm. Additionally, the results show …
Growth And Magnetooptical Properties Of Anisotropic Tbf3 Single Crystals, Uygun V. Valiev, Denis N. Karimov, Gary W. Burdick, Rakhim Rakhimov, Vasiliy O. Pelenovich, Dejun Fu
Growth And Magnetooptical Properties Of Anisotropic Tbf3 Single Crystals, Uygun V. Valiev, Denis N. Karimov, Gary W. Burdick, Rakhim Rakhimov, Vasiliy O. Pelenovich, Dejun Fu
Faculty Publications
The present paper investigates the Faraday effect and absorption and luminescence spectra of single-crystal TbF3 measured at 90 K and 300 K. The optical-quality single-phase TbF3 crystals (structural type β-YF3) were grown by the Bridgman technique. Faraday rotation angles were measured at remagnetization along the [100] crystallographic axis. Low temperature optical measurements were carried out along the [100] axis. “Quasi-doublet” sublevels with energy at 0 cm-1, 65 cm-1 and 190 cm-1, and also a singlet sublevel with energy at 114 cm-1 located in the ground 7F6 multiplet were determined from the …
Measuring The Reflection Matrix Of A Rough Surface, Kenneth W. Burgi, Michael A. Marciniak, Mark E. Oxley, Stephen E. Nauyoks
Measuring The Reflection Matrix Of A Rough Surface, Kenneth W. Burgi, Michael A. Marciniak, Mark E. Oxley, Stephen E. Nauyoks
Faculty Publications
Phase modulation methods for imaging around corners with reflectively scattered light required illumination of the occluded scene with a light source either in the scene or with direct line of sight to the scene. The RM (reflection matrix) allows control and refocusing of light after reflection, which could provide a means of illuminating an occluded scene without access or line of sight. Two optical arrangements, one focal-plane, the other an imaging system, were used to measure the RM of five different rough-surface reflectors. Intensity enhancement values of up to 24 were achieved. Surface roughness, correlation length, and slope were examined …
Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas
Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas
Faculty Publications
We develop a series of analytical approximations allowing for rapid extraction of the nonlinear parameters from beam deflection measurements. We then apply these approximations to the analysis of cadmium silicon phosphide and compare the results against previously published parameter extraction methods and find good agreement for typical experimental conditions.
Synthesizing Time-Evolving Partially-Coherent Schell-Model Sources, Noah R. Van Zandt, Milo W. Hyde Iv, Santasri R. Bose-Pillai, David G. Voelz, Xifeng Xiao, Steven T. Fiorino
Synthesizing Time-Evolving Partially-Coherent Schell-Model Sources, Noah R. Van Zandt, Milo W. Hyde Iv, Santasri R. Bose-Pillai, David G. Voelz, Xifeng Xiao, Steven T. Fiorino
Faculty Publications
Time-evolving simulation of sources with partial spatial and temporal coherence is sometimes instructive or necessary to explain optical coherence effects. Yet, existing time-evolving synthesis techniques often require prohibitive amounts of computer memory. This paper discusses three methods for the synthesis of continuous or pulsed time-evolving sources with nearly arbitrary spatial and temporal coherence. One method greatly reduces computer memory requirements, making this type of synthesis more practical. The utility of all three methods is demonstrated via a modified form of Young's experiment. Numerical simulation and laboratory results for time-averaged irradiance are presented and compared with theory to validate the synthesis …
Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao
Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao
Faculty Publications
A simple and flexible optical system for generating electromagnetic or vector partially coherent sources or beams is presented. The alternative design controls field amplitude (beam shape), coherence, and polarization using only spatial light modulators. This improvement makes the apparatus simpler to construct and significantly increases the flexibility of vector partially coherent source generators by allowing many different types of sources to be produced without changing the physical setup. The system’s layout and theoretical foundations are thoroughly discussed. The utility and flexibility of the proposed system are demonstrated by producing a vector Schell-model and non-Schell-model source. The experimental results are compared …
Dual Role Of Sb Ions As Electron Traps And Hole Traps In Photorefractive Sn2P2S6 Crystals, Brant E. Kananen, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton
Dual Role Of Sb Ions As Electron Traps And Hole Traps In Photorefractive Sn2P2S6 Crystals, Brant E. Kananen, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton
Faculty Publications
Doping photorefractive single crystals of Sn2P2S6 with antimony introduces both electron and hole traps. In as-grown crystals, Sb3+ (5s2) ions replace Sn2+ ions. These Sb3+ ions are either isolated (with no nearby perturbing defects) or they have a charge-compensating Sn2+ vacancy at a nearest-neighbor Sn site. When illuminated with 633 nm laser light, isolated Sb3+ ions trap electrons and become Sb2+ (5s25p1) ions. In contrast, Sb3+ ions with an adjacent Sn vacancy trap holes during illumination. The hole is primarily …
Reflective Inverse Diffusion, Kenneth W. Burgi, Jessica Ullom, Michael A. Marciniak, Mark E. Oxley
Reflective Inverse Diffusion, Kenneth W. Burgi, Jessica Ullom, Michael A. Marciniak, Mark E. Oxley
Faculty Publications
Phase front modulation was previously used to refocus light after transmission through scattering media. This process has been adapted here to work in reflection. A liquid crystal spatial light modulator is used to conjugate the phase scattering properties of diffuse reflectors to produce a converging phase front just after reflection. The resultant focused spot had intensity enhancement values between 13 and 122 depending on the type of reflector. The intensity enhancement of more specular materials was greater in the specular region, while diffuse reflector materials achieved a greater enhancement in non-specular regions, facilitating non-mechanical steering of the focused spot. Scalar …
Unequal A Priori Probability Multiple Hypothesis Testing In Space Domain Awareness With The Space Surveillance Telescope, Tyler J. Hardy, Stephen C. Cain, Travis F. Blake
Unequal A Priori Probability Multiple Hypothesis Testing In Space Domain Awareness With The Space Surveillance Telescope, Tyler J. Hardy, Stephen C. Cain, Travis F. Blake
Faculty Publications
This paper investigates the ability to improve Space Domain Awareness (SDA) by increasing the number of detectable Resident Space Objects (RSOs) from space surveillance sensors. With matched filter based techniques, the expected impulse response, or Point Spread Function (PSF), is compared against the received data. In the situation where the images are spatially undersampled, the modeled PSF may not match the received data if the RSO does not fall in the center of the pixel. This aliasing can be accounted for with a Multiple Hypothesis Test (MHT). Previously, proposed MHTs have implemented a test with an equal a priori prior …
Modeled And Measured Image-Plane Polychromatic Speckle Contrast, Noah R. Van Zandt, Jack E. Mccrae, Steven T. Fiorino
Modeled And Measured Image-Plane Polychromatic Speckle Contrast, Noah R. Van Zandt, Jack E. Mccrae, Steven T. Fiorino
Faculty Publications
The statistical properties of speckle relevant to short- to medium-range (tactical) active tracking involving polychromatic illumination are investigated. A numerical model is developed to allow rapid simulation of speckled images including the speckle contrast reduction effects of illuminator bandwidth, surface slope, and roughness, and the polarization properties of both the source and the reflection. Regarding surface slope (relative orientation of the surface normal and illumination/observation directions), Huntley’s theory for speckle contrast, which employs geometrical approximations to decrease computation time, is modified to increase accuracy by incorporation of a geometrical correction factor and better treatment of roughness and polarization. The resulting …
Comparison Of Microfacet Brdf Model To Modified Beckmann-Kirchhoff Brdf Model For Rough And Smooth Surfaces, Samuel D. Butler, Stephen E. Nauyoks, Michael A. Marciniak
Comparison Of Microfacet Brdf Model To Modified Beckmann-Kirchhoff Brdf Model For Rough And Smooth Surfaces, Samuel D. Butler, Stephen E. Nauyoks, Michael A. Marciniak
Faculty Publications
A popular class of BRDF models is the microfacet models, where geometric optics is assumed. In contrast, more complex physical optics models may more accurately predict the BRDF, but the calculation is more resource intensive. These seemingly disparate approaches are compared in detail for the rough and smooth surface approximations of the modified Beckmann-Kirchhoff BRDF model, assuming Gaussian surface statistics. An approximation relating standard Fresnel reflection with the semi-rough surface polarization term, Q, is presented for unpolarized light. For rough surfaces, the angular dependence of direction cosine space is shown to be identical to the angular dependence in the microfacet …
Experimentally Generating Any Desired Partially Coherent Schell-Model Source Using Phase-Only Control, Milo W. Hyde Iv, Santasri Basu, David G. Voelz, Xifeng Xiao
Experimentally Generating Any Desired Partially Coherent Schell-Model Source Using Phase-Only Control, Milo W. Hyde Iv, Santasri Basu, David G. Voelz, Xifeng Xiao
Faculty Publications
A technique is presented to produce any desired partially coherent Schell-model source using a single phase-only liquid-crystal spatial light modulator (SLM). Existing methods use SLMs in combination with amplitude filters to manipulate the phase and amplitude of an initially coherent source. The technique presented here controls both the phase and amplitude using a single SLM, thereby making the amplitude filters unnecessary. This simplifies the optical setup and significantly increases the utility and flexibility of the resulting system. The analytical development of the technique is presented and discussed. To validate the proposed approach, experimental results of three partially coherent Schell-model sources …
Two-Dimensional Temperature Analysis Of Nuclear Fireballs Using Digitized Film, Robert C. Slaughter, Tyler R. Peery, John W. Mcclory
Two-Dimensional Temperature Analysis Of Nuclear Fireballs Using Digitized Film, Robert C. Slaughter, Tyler R. Peery, John W. Mcclory
Faculty Publications
Researchers at Lawrence Livermore National Laboratory have begun digitizing technical films spanning the atmospheric nuclear testing operations conducted by the United States from 1945 through 1962. Each atmospheric nuclear test was filmed by Edgerton, Germeshausen, and Grier, Inc., using between 20 to 40 cameras per test. These technical film test data represent a primary source for advancing the knowledge of nuclear weapon output as well as the understanding of nonnuclear high-temperature gases. This manuscript outlines the procedures followed in order to perform two-dimensional temperature calculations for early time nuclear fireballs using digitized film. The digitized optical densities of the film …
Image Deblurring And Near-Real-Time Atmospheric Seeing Estimation Through The Employment Of Convergence Of Variance, Brian J. Neff, Quentin D. Macmanus, Stephen C. Cain, Richard K. Martin
Image Deblurring And Near-Real-Time Atmospheric Seeing Estimation Through The Employment Of Convergence Of Variance, Brian J. Neff, Quentin D. Macmanus, Stephen C. Cain, Richard K. Martin
Faculty Publications
A new image reconstruction algorithm is presented that will remove the effect of atmospheric turbulence on motion compensated frame average images. The primary focus of this research was to develop a blind deconvolution technique that could be employed in a tactical military environment where both time and computational power are limited. Additionally, this technique can be employed to measure atmospheric seeing conditions. In a blind deconvolution fashion, the algorithm simultaneously computes a high resolution image and an average model for the atmospheric blur parameterized by Fried’s seeing parameter. The difference in this approach is that it does not assume a …
Clustering Hyperspectral Imagery For Improved Adaptive Matched Filter Performance, Jason P. Williams, Kenneth W. Bauer, Mark A. Friend
Clustering Hyperspectral Imagery For Improved Adaptive Matched Filter Performance, Jason P. Williams, Kenneth W. Bauer, Mark A. Friend
Faculty Publications
This paper offers improvements to adaptive matched filter (AMF) performance by addressing correlation and non-homogeneity problems inherent to hyperspectral imagery (HSI). The estimation of the mean vector and covariance matrix of the background should be calculated using “target-free” data. This statement reflects the difficulty that including target data in estimates of the mean vector and covariance matrix of the background could entail. This data could act as statistical outliers and severely contaminate the estimators. This fact serves as the impetus for a 2-stage process: First, attempt to remove the target data from the background by way of the employment of …
Design, Development, And In-Flight Testing Of A Pointer/Tracker For In-Flight Experiments To Measure Aero-Optical Effects Over A Scaled Turret, Matthew J. Krizo, Salvatore J. Cusumano, Steven T. Fiorino, Ryan Heap, Victor Velten, Joshua Brown, Richard J. Bartell
Design, Development, And In-Flight Testing Of A Pointer/Tracker For In-Flight Experiments To Measure Aero-Optical Effects Over A Scaled Turret, Matthew J. Krizo, Salvatore J. Cusumano, Steven T. Fiorino, Ryan Heap, Victor Velten, Joshua Brown, Richard J. Bartell
Faculty Publications
We address the design, development, and testing of a pointer/tracker as a probe beam for the purpose of making high-speed, aero-optical measurements of the flow over a scaled beam director turret. The tracker uses retro-reflection of the probe beam off of a Reflexite annulus surrounding the turret. The constraints of the design required a near-total-commercial off the shelf system that could be quickly installed and removed in a rented aircraft. Baseline measurements of environmental vibrations are used to predict pointing performance; mitigation of line-of-sight jitter on the probe beam is achieved through passive isolation and the design of relay optics. …
Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. J. Metting, Johnathan K. Bunn, Ellen A. Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason R. Hattrick-Simpers
Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. J. Metting, Johnathan K. Bunn, Ellen A. Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason R. Hattrick-Simpers
Faculty Publications
A gradient annealing cell has been developed for the high-throughput study of thermalannealing effects on thin-film libraries in different environments. The inexpensive gradientannealing unit permits temperature gradients as large as 28 °C/mm and can accommodate samples ranging in length from 13 mm to 51 mm. The system was validated by investigating the effects of annealing temperature on the crystallinity, resistivity, and transparency of tin-doped indium oxide deposited on a glass substrate by magnetron sputtering. The unit developed in this work will permit the rapid optimization of materials properties such as crystallinity, homogeneity, and conductivity across a variety of applications.
Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal
Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal
Faculty Publications
No abstract provided.
Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang
Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang
Faculty Publications
In this paper, we demonstrate the variation of donut-shaped depletion pattern which influenced by multiple primary aberrations. The simulation is base on a common stimulation emission of depletion (STED) system composed by Gaussian laser and vortex phase plate. The simulation results are helpful guidelines for analyzing the aberration of depletion patterns in real situations.
Internal Electric Fields Due To Piezoelectric And Spontaneous Polarizations In Cdzno/Mgzno Quantum Well, H. C. Jeon, S. J. Lee, Tae Won Kang, S. H. Park, Yung Kee Yeo, T. F. George
Internal Electric Fields Due To Piezoelectric And Spontaneous Polarizations In Cdzno/Mgzno Quantum Well, H. C. Jeon, S. J. Lee, Tae Won Kang, S. H. Park, Yung Kee Yeo, T. F. George
Faculty Publications
We have investigated optical properties as a function of internal and external fields in the quantum well (QW). Optical properties of CdZnO/MgZnO QW structures are investigated by using many‐body effects. The CdZnO/MgZnO QW structure with high Cd composition is found to have smaller optical gain because the strain‐induced piezoelectric polarization and the spontaneous polarization in the well increase with the inclusion of Cd. These results demonstrate that high performance laser diode operation can be realized in CdZnO/MgZnO QW structures by reducing those polarizations adopting dipole reverse method.
Comparison Of Line-Peak And Line-Scanning Excitation In Two-Color Laser-Induced-Fluorescence Thermometry Of Oh, Stanislav Kostka, Sukesh Roy, Patrick J. Lakusta, Terrence Meyer, Michael W. Renfro, James R. Gord, Richard D. Branam
Comparison Of Line-Peak And Line-Scanning Excitation In Two-Color Laser-Induced-Fluorescence Thermometry Of Oh, Stanislav Kostka, Sukesh Roy, Patrick J. Lakusta, Terrence Meyer, Michael W. Renfro, James R. Gord, Richard D. Branam
Faculty Publications
Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made possible the rapid scanning of molecular rovibrational transitions and, hence, the potential to extract information on gas-phase temperatures. In the current study, two-line OH LIF thermometry is performed in a well-calibrated reacting flow for the purpose of comparing the relative accuracy of various line-pair selections from the literature and …
An Infrared Imaging Method For High-Throughput Combinatorial Investigation Of Hydrogenation-Dehydrogenation And New Phase Formation Of Thin Films, H. Oguchi, Jason R. Hattrick-Simpers, I. Takeuchi, E. J. Heilweil, L. A. Bendersky
An Infrared Imaging Method For High-Throughput Combinatorial Investigation Of Hydrogenation-Dehydrogenation And New Phase Formation Of Thin Films, H. Oguchi, Jason R. Hattrick-Simpers, I. Takeuchi, E. J. Heilweil, L. A. Bendersky
Faculty Publications
We have developed an infrared imaging setup enabling in situ infrared images to be acquired, and expanded on capabilities of an infrared imaging as a high-throughput screening technique, determination of a critical thickness of a Pd capping layer which significantly blocks infrared emission from below, enhancement of sensitivity to hydrogenation and dehydrogenation by normalizing raw infrared intensity of a Mg thin film to an inert reference, rapid and systematic screening of hydrogenation and dehydrogenation properties of a Mg–Ni composition spread covered by a thickness gradient Pd capping layer, and detection of formation of a Mg2Si phase in a …
The Effect Of Copt Crystallinity And Grain Texturing On Properties Of Exchange-Coupled Fe/Copt Systems, H. Oguchi, A. Zambano, M. Yu, Jason R. Hattrick-Simpers, D. Banerjee, Y. Liu, Z. L. Wang, J. P. Liu, S. E. Lofland, D. Josell, I. Takeuchi
The Effect Of Copt Crystallinity And Grain Texturing On Properties Of Exchange-Coupled Fe/Copt Systems, H. Oguchi, A. Zambano, M. Yu, Jason R. Hattrick-Simpers, D. Banerjee, Y. Liu, Z. L. Wang, J. P. Liu, S. E. Lofland, D. Josell, I. Takeuchi
Faculty Publications
The effect of the crystallinity and the grain texturing of CoPt hard layers on exchange coupled Fe/CoPt soft/hard magnetic systems was studied using gradient thickness multilayer thin films. We have studied the hard layer structures by transmission electron microscopy and x-ray diffraction, and characterized the exchange coupling interaction through magnetization loops obtained by the magneto-optical Kerr effect measurement. We found that exchange coupling strongly depends on the crystalline characteristics of the CoPt hard layer. There is correlation between the mixture of different grain orientations of the CoPt hard layer and coupling efficiency. In particular, interlayer coupling is enhanced when there …
Optical Phase Unwrapping In The Presence Of Branch Points, Todd M. Venema, Jason D. Schmidt
Optical Phase Unwrapping In The Presence Of Branch Points, Todd M. Venema, Jason D. Schmidt
Faculty Publications
Strong turbulence causes phase discontinuities known as branch points in an optical field. These discontinuities complicate the phase unwrapping necessary to apply phase corrections onto a deformable mirror in an adaptive optics (AO) system. This paper proposes a non-optimal but effective and implementable phase unwrapping method for optical fields containing branch points. This method first applies a least-squares (LS) unwrapper to the field which isolates and unwraps the LS component of the field. Four modulo-2π-equivalent non-LS components are created by subtracting the LS component from the original field and then restricting the result to differing ranges. 2π phase jumps known …
Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya
Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya
Faculty Publications
A high-throughput high-sensitivity optical technique for measuringmagnetostriction of thin-film composition-spread samples has been developed. It determines the magnetostriction by measuring the induced deflection of micromachined cantilever unimorph samples. Magnetostrictionmeasurements have been performed on as-deposited Fe–Ga and Fe–Ga–Al thin-film composition spreads. The thin-film Fe–Ga spreads display a similar compositional variation of magnetostriction as bulk. A previously undiscovered peak in magnetostriction at low Ga content was also observed and attributed to a maximum in the magnetocrystalline anisotropy. Magnetostrictive mapping of the Fe–Ga–Al ternary system reveals the possibility of substituting up to 8at.%Al in Fe70Ga30 without significant degradation of magnetostriction.
High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi
High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi
Faculty Publications
We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the …
Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt
Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt
Faculty Publications
A near-field room temperature scanning magnetic probe microscope has been developed using a laminated magnetoelectric sensor. The simple trilayer longitudinal-transverse mode sensor, fabricated using Metglas as the magnetostrictive layer and polyvinylidene fluoride as the piezoelectric layer, shows an ac field sensitivity of 467±3μV∕Oe in the measured frequency range of 200Hz–8kHz. The microscope was used to image a 2mm diameter ring carrying an ac current as low as 10−5A. ac fields as small as 3×10−10T have been detected.
Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. J. Long, Jason R. Hattrick-Simpers, M. Murakami, R. C. Srivastava, I. Takeuchi, V. L. Karen, X. Li
Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. J. Long, Jason R. Hattrick-Simpers, M. Murakami, R. C. Srivastava, I. Takeuchi, V. L. Karen, X. Li
Faculty Publications
We are developing a procedure for the quick identification of structural phases in thin film composition spread experiments which map large fractions of compositional phase diagrams of ternary metallic alloy systems. An in-house scanning x-ray microdiffractometer is used to obtain x-ray spectra from 273 different compositions on a single composition spread library. A cluster analysissoftware is then used to sort the spectra into groups in order to rapidly discover the distribution of phases on the ternary diagram. The most representative pattern of each group is then compared to a database of known structures to identify known phases. Using this method, …
Terahertz Studies Of The Dielectric Response And Second-Order Phonons In A Gase Crystal, B. L. Yu, F. Zeng, V. Kartazayev, R. R. Alfano, K. C. Mandal
Terahertz Studies Of The Dielectric Response And Second-Order Phonons In A Gase Crystal, B. L. Yu, F. Zeng, V. Kartazayev, R. R. Alfano, K. C. Mandal
Faculty Publications
No abstract provided.
Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan
Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan
Faculty Publications
We discuss techniques for managing and visualizing x-ray diffraction spectrum data for thin film composition spreads which map large fractions of ternary compositional phase diagrams. An in-house x-ray microdiffractometer is used to obtain spectra from over 500 different compositions on an individual spread. The MATLAB software is used to quickly organize the data and create various plots from which one can quickly grasp different information regarding structural and phase changes across the composition spreads. Such exercises are valuable in rapidly assessing the “overall” picture of the structural evolution across phase diagrams before focusing in on specific composition regions for detailed …