Joy Perkinson - Academia.edu (original) (raw)

Papers by Joy Perkinson

Research paper thumbnail of Sawtooth structure formation under nonlinear-regime ion bombardment

Journal of Physics: Condensed Matter

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Research paper thumbnail of Tunable infrared spectral imaging system

Electro-Optical and Infrared Systems: Technology and Applications XVII, 2020

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Research paper thumbnail of 30‐4: Electroholographic Display Based on a Horizontal Array of Edge‐Emitting Surface Acoustic Wave Modulators

SID Symposium Digest of Technical Papers, 2021

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Research paper thumbnail of Nanoscale Pattern Self-Organization Under Ion Bombardment

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Research paper thumbnail of Faraday effect in polycrystalline Mn-doped InSb for LWIR applications

Optical Materials Express, 2021

The Faraday rotation (FR) in Mn-doped InSb (Mn-InSb) depends on extremely low doping of Mn into t... more The Faraday rotation (FR) in Mn-doped InSb (Mn-InSb) depends on extremely low doping of Mn into the InSb lattice. The polycrystalline Mn-InSb was prepared by direct alloying of InSb and Mn2Sb, followed by slow cooling of the melt. X-ray diffraction confirms the incorporation of Mn into the In sites, whereas the non-uniform precipitation of MnSb micro-nanoprecipitates was observed via SEM images. The FR of Mn-InSb was measured at room temperature in the 8 to 12 µm spectral range and compared to commercially-available undoped InSb as well as Te-doped InSb (Te-InSb) references and found to be about 1.27 - 1.35 times stronger than that of Te-InSb measured under the same conditions.

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Research paper thumbnail of Gravity Waves : The Kelvin Wedge and Related Problems

Gravity waves in water present many interesting phenomena that are not immediately intuitive. Cer... more Gravity waves in water present many interesting phenomena that are not immediately intuitive. Certain applied mathematics and physics concepts that arise throughout the study of gravity waves, such as the method of stationary phase, can be used to analyze and explain a variety of situations. This paper discusses some of the basic mathematical concepts of wave analysis, and then applies these concepts to gravity waves in water. In particular, this paper works through the derivation of the angle that confines the wake behind a moving boat on deep water, known as the Kelvin wedge. Behavior of the waves near the border of this wake is also discussed. Finally, an overview is given of two related wedge problems.

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Research paper thumbnail of Dynamic Light Scattering Study of Polymer Chain Dimensions

The long, string-like nature of polymers causes them to take on a variety of complex, coiled conf... more The long, string-like nature of polymers causes them to take on a variety of complex, coiled conformations. The conformations of polymers in solution depend on three characteristics: 1) the chain flexibility (some chains are stiff like piano wires, others are flexible like silk thread, depending on bond stiffness), 2) interactions between monomers in the chains (attractive or repulsive), and 3) interactions between monomers and the solvent. These conformations can be modeled using random walk statistics. An ideal random walk denotes a path of successive steps in which the direction of each step is uncorrelated with or independent of the previous steps: steps forward and backward, left and right, up and down are all equally probable (Figure 1). In the ideal random walk, the root mean squared (rms) end-to-end distance characterizes the average spacial dimension traversed. Given a step length of l, the rms end-to-end distance is shown to be

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Research paper thumbnail of Magneto-Optical Properties of InSb for Spectral Filtering in the Far-Infrared

arXiv: Optics, 2020

We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determin... more We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determined for a range of carrier concentrations near 101710^{17}1017 cm−3cm^{-3}cm−3 in the lambda\lambdalambda = 8 mu\mumum - 12 mu\mumum far-infrared regime. The absorption coefficient was measured and a figure of merit calculated for each sample. From these measurements, we calculated the carrier effective mass and illustrate the variation of the figure of merit with wavelength. A method for creating a tunable bandpass filter via the Faraday rotation is discussed along with preliminary results from a prototype device.

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Research paper thumbnail of Magneto-optical properties of InSb for infrared spectral filtering

Journal of Applied Physics, 2021

We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determin... more We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determined for a range of carrier concentrations near 1017 cm−3 in the λ=8–12μm long-wave infrared regime. The absorption coefficient was measured and a figure of merit was calculated for each sample. From these measurements, we calculated the carrier effective mass and illustrated the variation of the figure of merit with the wavelength. A method for creating a tunable bandpass filter via the Faraday rotation is discussed along with preliminary results from a prototype device.

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Research paper thumbnail of Surface-emitting electroholographic SAW modulator

Optics Express, 2019

We report the design and operation of a surface-emitting surface acoustic wave (SAW) acousto-opti... more We report the design and operation of a surface-emitting surface acoustic wave (SAW) acousto-optical modulator which behaves as a cm-scale linear hologram in response to an applied electronic waveform. The modulator is formed by an optical waveguide, transducer, and out-coupling surface grating on a 1 mm-thick lithium niobate substrate. We demonstrate the ability to load and illuminate a 9-region linear hologram into the modulator's 8 mm-long interaction region using applied waveforms of 280–320 MHz. To the best of the authors’ knowledge, this is the first demonstration of a monolithically-integrated, surface-emitting SAW modulator fabricated using lithographic techniques. Applications include practical implementations of a holographic display.

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Research paper thumbnail of Simulation of redistributive and erosive effects in a-Si under Ar+ irradiation

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2018

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Research paper thumbnail of Distinguishing physical mechanisms using GISAXS experiments and linear theory: the importance of high wavenumbers

Scientific reports, Jan 17, 2017

In this work we analyze GISAXS measurements of the structure factor of Si surfaces evolving durin... more In this work we analyze GISAXS measurements of the structure factor of Si surfaces evolving during 1 keV Ar+ ion bombardment. Using newly-developed methods sensitive to the full range of experimentally-available wavenumbers q, we extract the linear amplification rate R(q) governing surface stability over a range of wavenumbers 4-5 times larger than has previously been obtained. Comparing with theoretical models also retaining full wavenumber-dependence, we find an excellent fit of the experimental data over the full range of irradiation angles and wavenumbers. Moreover, the fitted parameter values represent experimental evaluation of the magnitudes of most physical mechanisms currently believed to be important to the pattern-formation process. In all cases, the extracted values agree well with direct observations or atomistic simulations of the same quantities, suggesting that GISAXS analysis may allow more powerful comparison between experiment and theory than had previously been t...

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Research paper thumbnail of Designing steep, sharp patterns on uniformly ion-bombarded surfaces

Proceedings of the National Academy of Sciences of the United States of America, Oct 11, 2016

We propose and experimentally test a method to fabricate patterns of steep, sharp features on sur... more We propose and experimentally test a method to fabricate patterns of steep, sharp features on surfaces, by exploiting the nonlinear dynamics of uniformly ion-bombarded surfaces. We show via theory, simulation, and experiment that the steepest parts of the surface evolve as one-dimensional curves that move in the normal direction at constant velocity. The curves are a special solution to the nonlinear equations that arises spontaneously whenever the initial patterning on the surface contains slopes larger than a critical value; mathematically they are traveling waves (shocks) that have the special property of being undercompressive. We derive the evolution equation for the curves by considering long-wavelength perturbations to the one-dimensional traveling wave, using the unusual boundary conditions required for an undercompressive shock, and we show this equation accurately describes the evolution of shapes on surfaces, both in simulations and in experiments. Because evolving a coll...

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Research paper thumbnail of Organic Field-Effect Transistors

Optical Science and Engineering, 2007

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Research paper thumbnail of Model-independent test of the truncated crater function theory of surface morphology evolution during ion bombardment

Physical Review B, 2014

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Research paper thumbnail of Nanoscale surface pattern formation kinetics on germanium irradiated by Kr+ions

Physical Review B, 2012

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Research paper thumbnail of Nanoscale topographic pattern formation on Kr+-bombarded germanium surfaces

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2013

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Research paper thumbnail of The effects of polydispersity on the morphology of polystyrene-polyferrocenyldimethylsilane block copolymer thin films

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Research paper thumbnail of Magnetic reversal phenomena in pseudo-spin-valve films with perpendicular anisotropy

Journal of Applied Physics, 2007

Perpendicular pseudo-spin-valve films with structure Ti∕CoCrPt∕Ti∕CoCrPt were fabricated by UHV s... more Perpendicular pseudo-spin-valve films with structure Ti∕CoCrPt∕Ti∕CoCrPt were fabricated by UHV sputtering. The Ti serves both as a seed layer, to promote a perpendicular c-axis orientation, and as a spacer between the magnetic layers. The films show characteristic two-step switching with a wide plateau corresponding to antiparallel alignments of the magnetic layers. For a 5nm Ti∕5nm CoCrPt∕5nm Ti∕20nm CoCrPt, antiparallel alignment exists between 70 and 345Oe. Minor loops demonstrate switching of the thin layer, in addition to time-dependent magnetization reversal attributed to creep in the magnetization as a result of growth of reversed domains. Magnetic force microscopy and time-dependent magnetization measurements suggest that the domain propagation field is lower than the field necessary for domain nucleation.

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Research paper thumbnail of Sawtooth structure formation under nonlinear-regime ion bombardment

Journal of Physics: Condensed Matter

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Research paper thumbnail of Tunable infrared spectral imaging system

Electro-Optical and Infrared Systems: Technology and Applications XVII, 2020

Bookmarks Related papers MentionsView impact

Research paper thumbnail of 30‐4: Electroholographic Display Based on a Horizontal Array of Edge‐Emitting Surface Acoustic Wave Modulators

SID Symposium Digest of Technical Papers, 2021

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nanoscale Pattern Self-Organization Under Ion Bombardment

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Faraday effect in polycrystalline Mn-doped InSb for LWIR applications

Optical Materials Express, 2021

The Faraday rotation (FR) in Mn-doped InSb (Mn-InSb) depends on extremely low doping of Mn into t... more The Faraday rotation (FR) in Mn-doped InSb (Mn-InSb) depends on extremely low doping of Mn into the InSb lattice. The polycrystalline Mn-InSb was prepared by direct alloying of InSb and Mn2Sb, followed by slow cooling of the melt. X-ray diffraction confirms the incorporation of Mn into the In sites, whereas the non-uniform precipitation of MnSb micro-nanoprecipitates was observed via SEM images. The FR of Mn-InSb was measured at room temperature in the 8 to 12 µm spectral range and compared to commercially-available undoped InSb as well as Te-doped InSb (Te-InSb) references and found to be about 1.27 - 1.35 times stronger than that of Te-InSb measured under the same conditions.

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Research paper thumbnail of Gravity Waves : The Kelvin Wedge and Related Problems

Gravity waves in water present many interesting phenomena that are not immediately intuitive. Cer... more Gravity waves in water present many interesting phenomena that are not immediately intuitive. Certain applied mathematics and physics concepts that arise throughout the study of gravity waves, such as the method of stationary phase, can be used to analyze and explain a variety of situations. This paper discusses some of the basic mathematical concepts of wave analysis, and then applies these concepts to gravity waves in water. In particular, this paper works through the derivation of the angle that confines the wake behind a moving boat on deep water, known as the Kelvin wedge. Behavior of the waves near the border of this wake is also discussed. Finally, an overview is given of two related wedge problems.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dynamic Light Scattering Study of Polymer Chain Dimensions

The long, string-like nature of polymers causes them to take on a variety of complex, coiled conf... more The long, string-like nature of polymers causes them to take on a variety of complex, coiled conformations. The conformations of polymers in solution depend on three characteristics: 1) the chain flexibility (some chains are stiff like piano wires, others are flexible like silk thread, depending on bond stiffness), 2) interactions between monomers in the chains (attractive or repulsive), and 3) interactions between monomers and the solvent. These conformations can be modeled using random walk statistics. An ideal random walk denotes a path of successive steps in which the direction of each step is uncorrelated with or independent of the previous steps: steps forward and backward, left and right, up and down are all equally probable (Figure 1). In the ideal random walk, the root mean squared (rms) end-to-end distance characterizes the average spacial dimension traversed. Given a step length of l, the rms end-to-end distance is shown to be

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Magneto-Optical Properties of InSb for Spectral Filtering in the Far-Infrared

arXiv: Optics, 2020

We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determin... more We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determined for a range of carrier concentrations near 101710^{17}1017 cm−3cm^{-3}cm−3 in the lambda\lambdalambda = 8 mu\mumum - 12 mu\mumum far-infrared regime. The absorption coefficient was measured and a figure of merit calculated for each sample. From these measurements, we calculated the carrier effective mass and illustrate the variation of the figure of merit with wavelength. A method for creating a tunable bandpass filter via the Faraday rotation is discussed along with preliminary results from a prototype device.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Magneto-optical properties of InSb for infrared spectral filtering

Journal of Applied Physics, 2021

We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determin... more We present measurements of the Faraday effect in n-type InSb. The Verdet coefficient was determined for a range of carrier concentrations near 1017 cm−3 in the λ=8–12μm long-wave infrared regime. The absorption coefficient was measured and a figure of merit was calculated for each sample. From these measurements, we calculated the carrier effective mass and illustrated the variation of the figure of merit with the wavelength. A method for creating a tunable bandpass filter via the Faraday rotation is discussed along with preliminary results from a prototype device.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Surface-emitting electroholographic SAW modulator

Optics Express, 2019

We report the design and operation of a surface-emitting surface acoustic wave (SAW) acousto-opti... more We report the design and operation of a surface-emitting surface acoustic wave (SAW) acousto-optical modulator which behaves as a cm-scale linear hologram in response to an applied electronic waveform. The modulator is formed by an optical waveguide, transducer, and out-coupling surface grating on a 1 mm-thick lithium niobate substrate. We demonstrate the ability to load and illuminate a 9-region linear hologram into the modulator's 8 mm-long interaction region using applied waveforms of 280–320 MHz. To the best of the authors’ knowledge, this is the first demonstration of a monolithically-integrated, surface-emitting SAW modulator fabricated using lithographic techniques. Applications include practical implementations of a holographic display.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Simulation of redistributive and erosive effects in a-Si under Ar+ irradiation

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Distinguishing physical mechanisms using GISAXS experiments and linear theory: the importance of high wavenumbers

Scientific reports, Jan 17, 2017

In this work we analyze GISAXS measurements of the structure factor of Si surfaces evolving durin... more In this work we analyze GISAXS measurements of the structure factor of Si surfaces evolving during 1 keV Ar+ ion bombardment. Using newly-developed methods sensitive to the full range of experimentally-available wavenumbers q, we extract the linear amplification rate R(q) governing surface stability over a range of wavenumbers 4-5 times larger than has previously been obtained. Comparing with theoretical models also retaining full wavenumber-dependence, we find an excellent fit of the experimental data over the full range of irradiation angles and wavenumbers. Moreover, the fitted parameter values represent experimental evaluation of the magnitudes of most physical mechanisms currently believed to be important to the pattern-formation process. In all cases, the extracted values agree well with direct observations or atomistic simulations of the same quantities, suggesting that GISAXS analysis may allow more powerful comparison between experiment and theory than had previously been t...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Designing steep, sharp patterns on uniformly ion-bombarded surfaces

Proceedings of the National Academy of Sciences of the United States of America, Oct 11, 2016

We propose and experimentally test a method to fabricate patterns of steep, sharp features on sur... more We propose and experimentally test a method to fabricate patterns of steep, sharp features on surfaces, by exploiting the nonlinear dynamics of uniformly ion-bombarded surfaces. We show via theory, simulation, and experiment that the steepest parts of the surface evolve as one-dimensional curves that move in the normal direction at constant velocity. The curves are a special solution to the nonlinear equations that arises spontaneously whenever the initial patterning on the surface contains slopes larger than a critical value; mathematically they are traveling waves (shocks) that have the special property of being undercompressive. We derive the evolution equation for the curves by considering long-wavelength perturbations to the one-dimensional traveling wave, using the unusual boundary conditions required for an undercompressive shock, and we show this equation accurately describes the evolution of shapes on surfaces, both in simulations and in experiments. Because evolving a coll...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Organic Field-Effect Transistors

Optical Science and Engineering, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Model-independent test of the truncated crater function theory of surface morphology evolution during ion bombardment

Physical Review B, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nanoscale surface pattern formation kinetics on germanium irradiated by Kr+ions

Physical Review B, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nanoscale topographic pattern formation on Kr+-bombarded germanium surfaces

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The effects of polydispersity on the morphology of polystyrene-polyferrocenyldimethylsilane block copolymer thin films

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Magnetic reversal phenomena in pseudo-spin-valve films with perpendicular anisotropy

Journal of Applied Physics, 2007

Perpendicular pseudo-spin-valve films with structure Ti∕CoCrPt∕Ti∕CoCrPt were fabricated by UHV s... more Perpendicular pseudo-spin-valve films with structure Ti∕CoCrPt∕Ti∕CoCrPt were fabricated by UHV sputtering. The Ti serves both as a seed layer, to promote a perpendicular c-axis orientation, and as a spacer between the magnetic layers. The films show characteristic two-step switching with a wide plateau corresponding to antiparallel alignments of the magnetic layers. For a 5nm Ti∕5nm CoCrPt∕5nm Ti∕20nm CoCrPt, antiparallel alignment exists between 70 and 345Oe. Minor loops demonstrate switching of the thin layer, in addition to time-dependent magnetization reversal attributed to creep in the magnetization as a result of growth of reversed domains. Magnetic force microscopy and time-dependent magnetization measurements suggest that the domain propagation field is lower than the field necessary for domain nucleation.

Bookmarks Related papers MentionsView impact