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DOE OSTI2013

SPIDER: probing the early Universe with a suborbital polarimeter

We evaluate the ability of SPIDER, a balloon-borne polarimeter, to detect a divergence-free polarization pattern (B-modes) in the cosmic microwave background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the SPIDER instrument is significantly below the amplitude of an interesting cosmological signal with r = 0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the SPIDER field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all SPIDER frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the ''Southern Hole.'' We show that two ∼ 20-day flights of the SPIDER instrument can constrain the amplitude of the B-mode signal to r < 0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2014

Landscape Characterization and Representativeness Analysis for Understanding Sampling Network Coverage

Sampling networks rarely conform to spatial and temporal ideals, often comprised of network sampling points which are unevenly distributed and located in less than ideal locations due to access constraints, budget limitations, or political conflict. Quantifying the global, regional, and temporal representativeness of these networks by quantifying the coverage of network infrastructure highlights the capabilities and limitations of the data collected, facilitates upscaling and downscaling for modeling purposes, and improves the planning efforts for future infrastructure investment under current conditions and future modeled scenarios. The work presented here utilizes multivariate spatiotemporal clustering analysis and representativeness analysis for quantitative landscape characterization and assessment of the Fluxnet, RAINFOR, and ForestGEO networks. Results include ecoregions that highlight patterns of bioclimatic, topographic, and edaphic variables and quantitative representativeness maps of individual and combined networks.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2019

The Plant Ontology Facilitates Comparisons of Plant Development Stages Across Species

The Plant Ontology (PO) is a community resource consisting of standardized terms, definitions, and logical relations describing plant structures and development stages, augmented by a large database of annotations from genomic and phenomic studies. This paper describes the structure of the ontology and the design principles we used in constructing PO terms for plant development stages. It also provides details of the methodology and rationale behind our revision and expansion of the PO to cover development stages for all plants, particularly the land plants (bryophytes through angiosperms). As a case study to illustrate the general approach, we examine variation in gene expression across embryo development stages in Arabidopsis and maize, demonstrating how the PO can be used to compare patterns of expression across stages and in developmentally different species. Although many genes appear to be active throughout embryo development, we identified a small set of uniquely expressed genes for each stage of embryo development and also between the two species. Evaluating the different sets of genes expressed during embryo development in Arabidopsis or maize may inform future studies of the divergent developmental pathways observed in monocotyledonous versus dicotyledonous species. The PO and its annotation database (http://www.planteome.org) make plant data for any species more discoverable and accessible through common formats, thus providing support for applications in plant pathology, image analysis, and comparative development and evolution.

Plant Sciences↗

DOE OSTI2021

Sculpting the Plasmonic Responses of Nanoparticles by Directed Electron Beam Irradiation

Spatial confinement of matter in functional nanostructures has propelled these systems to the forefront of nanoscience, both as a playground for exotic physics and quantum phenomena and in multiple applications including plasmonics, optoelectronics, and sensing. In parallel, the emergence of monochromated electron energy loss spectroscopy (EELS) has enabled exploration of local nanoplasmonic functionalities within single nanoparticles and the collective response of nanoparticle assemblies, providing deep insight into associated mechanisms. However, modern synthesis processes for plasmonic nanostructures are often limited in the types of accessible geometry, and materials and are limited to spatial precisions on the order of tens of nm, precluding the direct exploration of critical aspects of the structure-property relationships. Here, the atomic-sized probe of the scanning transmission electron microscope is used to perform precise sculpting and design nanoparticle configurations. Using low-loss EELS, dynamic analyses of the evolution of the plasmonic response are provided. It is shown that within self-assembled systems of nanoparticles, individual nanoparticles can be selectively removed, reshaped, or patterned with nanometer-level resolution, effectively modifying the plasmonic response in both space and energy. This process significantly increases the scope for design possibilities and presents opportunities for unique structure development, which are ultimately the key for nanophotonic design.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2017

A novel immunofluorescence method to visualize microtubules in the antiparallel overlaps of microtubule-plus ends in the anaphase and telophase midzone

Cell division, in which duplicated chromosomes are separated into two daughter cells, is the most dynamic event during cell proliferation. Chromosome movement is powered mainly by microtubules, which vary in morphology and are organized into characteristic structures according to mitotic progression. During the later stages of mitosis, antiparallel microtubules form the spindle midzone, and the irregular formation of the midzone often leads to failure of cytokinesis, giving rise to the unequal segregation of chromosomes. However, it is difficult to analyze the morphology of these microtubules because microtubules in the antiparallel overlaps of microtubule-plus ends in the midzone are embedded in highly electron-dense matrices, impeding the access of anti-tubulin antibodies to their epitopes during immunofluorescence staining. Here, we developed a novel method to visualize selectively antiparallel microtubule overlaps in the midzone. When cells are air-dried before fixation, aligned α-tubulin staining is observed and colocalized with PRC1 in the center of the midzone of anaphase and telophase cells, suggesting that antiparallel microtubule overlaps can be visualized by this method. In air-dried cells, mCherry-α-tubulin fluorescence and β-tubulin staining show almost the same pattern as α-tubulin staining in the midzone, suggesting that the selective visualization of antiparallel microtubule overlaps in air-dried cells is not attributed to an alteration of the antigenicity of α-tubulin. Taxol treatment extends the microtubule filaments of the midzone in air-dried cells, and nocodazole treatment conversely decreases the number of microtubules, suggesting that unstable microtubules are depolymerized during the air-drying method. It is of note that the air-drying method enables the detection of the disruption of the midzone and premature midzone formation upon Aurora B and Plk1 inhibition, respectively. These results suggest that the air-drying method is suitable for visualizing microtubules in the antiparallel overlaps of microtubule-plus ends of the midzone and for detecting their effects on midzone formation. - Highlights: • A novel method to visualize antiparallel microtubule overlaps is developed. • Unstable microtubules are depolymerized during an air-drying method. • This method can detect the effect of compounds on antiparallel microtubule overlaps.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2011

Data Intensive Architecture for Scalable Cyber Analytics

Cyber analysts are tasked with the identification and mitigation of network exploits and threats. These compromises are difficult to identify due to the characteristics of cyber communication, the volume of traffic, and the duration of possible attack. In this paper, we describe a prototype implementation designed to provide cyber analysts an environment where they can interactively explore a month’s worth of cyber security data. This prototype utilized On-Line Analytical Processing (OLAP) techniques to present a data cube to the analysts. The cube provides a summary of the data, allowing trends to be easily identified as well as the ability to easily pull up the original records comprising an event of interest. The cube was built using SQL Server Analysis Services (SSAS), with the interface to the cube provided by Tableau. This software infrastructure was supported by a novel hardware architecture comprising a Netezza TwinFin® for the underlying data warehouse and a cube server with a FusionIO drive hosting the data cube. We evaluated this environment on a month’s worth of artificial, but realistic, data using multiple queries provided by our cyber analysts. As our results indicate, OLAP technology has progressed to the point where it is in a unique position to provide novel insights to cyber analysts, as long as it is supported by an appropriate data intensive architecture.

Olsen, Bryan K.↗

DOE OSTI2021

Improving I/O Performance for Exascale Applications through Online Data Layout Reorganization

The applications being developed within the U.S. Exascale Computing Project (ECP) to run on imminent Exascale computers will generate scientific results with unprecedented fidelity and record turn-around time. Many of these codes are based on particle-mesh methods and use advanced algorithms, especially dynamic load-balancing and mesh-refinement, to achieve high performance on Exascale machines. Yet, as such algorithms improve parallel application efficiency, they raise new challenges for I/O logic due to their irregular and dynamic data distributions. Thus, while the enormous data rates of Exascale simulations already challenge existing file system write strategies, the need for efficient read and processing of generated data introduces additional constraints on the data layout strategies that can be used when writing data to secondary storage. We review these I/O challenges and introduce two online data layout reorganization approaches for achieving good tradeoffs between read and write performance. We demonstrate the benefits of using these two approaches for the ECP particle-in-cell simulation WarpX, which serves as a motif for a large class of important Exascale applications. Here, we show that by understanding application I/O patterns and carefully designing data layouts we can increase read performance by more than 80 percent.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2016

Low-temperature atomic layer deposition of TiO{sub 2} thin layers for the processing of memristive devices

Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO{sub 2} thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO{sub 2} thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO{sub 2} thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2025

Spatial quantum-interference landscapes of multi-site-controlled quantum dots coupled to extended photonic cavity modes

Abstract A compact platform to integrate emitters in a cavity-like support is to embed quantum dots (QDs) in a photonic crystal (PhC) structure, making them promising candidates for integrated quantum photonic circuits. The emission properties of QDs can be modified by tailored photonic structures, relying on the Purcell effect or strong light-matter interactions. However, the effects of photonic states on spatial features of exciton emissions in these systems are rarely explored. Such effect is difficult to access due to random positions of self-assembled QDs in PhC structures, and the fact that quantum well excitons’ wavefunctions resemble photonic states in a conventional distributed Bragg reflector cavity system. In this work, we instead observe a spatial signature of exciton emission using site-controlled QDs embedded in PhC cavities. In particular, we observe the detuning-dependent spatial repulsion of the QD exciton emissions by polarized imaging of the micro-photoluminescence, dependent on the controlled QD’s position in a spatially extended photonic pattern. The observed effect arises due to the quantum interference between QD decay channel in a spatially-extended cavity mode. Our findings suggest that integration of site-controlled QDs in tailored photonic structures can enable spatially distributed single-photon sources and photon switches.

Physics↗

DOE OSTI2023

The extended ‘stellar halo’ of the Ursa Minor dwarf galaxy

Stellar candidates in the Ursa Minor (UMi) dwarf galaxy have been found using a new Bayesian algorithm applied to Gaia EDR3 data. Five of these targets are located in the extreme outskirts of UMi, from ∼5 to 12 elliptical half-light radii (r h ), where r h (UMi) = 17.32 ± 0.11 arcmin, and have been observed with the high-resolution Gemini Remote Access to CFHT ESPaDOnS Spectrograph at the Gemini North telescope. Precise radial velocities (σ RV < 2 km s −1 ) and metallicities (σ [Fe/H] < 0.2 dex) confirm their memberships of UMi. Detailed analysis of the brightest and outermost star (Target 1, at ∼12r h ), yields precision chemical abundances for the α (Mg, Ca, and Ti), odd-Z (Na, K, and Sc), Fe-peak (Fe, Ni, and Cr), and neutron-capture (Ba) elements. With data from the literature and APOGEE data release 17, we find the chemical patterns in UMi are consistent with an outside-in star-formation history that includes yields from core-collapse supernovae, asymptotic giant branch stars, and Type Ia supernovae. Evidence for a knee in the [α/Fe] ratios near [Fe/H] ∼ −2.1 indicates a low star-formation efficiency similar to that in other dwarf galaxies. Detailed analysis of the surface number density profile shows evidence that UMi’s outskirts have been populated by tidal effects, likely as a result of completing multiple orbits around the Galaxy.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2020

Power of halometry

Astrometric weak gravitational lensing is a powerful probe of the distribution of matter on sub-Galactic scales, which harbor important information about the fundamental nature of dark matter. Here we propose a novel method that utilizes angular power spectra to search for the correlated pattern of apparent motions of celestial objects induced from time-dependent lensing by a population of Galactic subhalos. Application of this method to upcoming astrometric datasets will allow for the direct measurement of the properties of Galactic substructure, with implications for the underlying particle physics. We show that, with near-future astrometric observations, it may be possible to statistically detect populations of cold dark matter subhalos, compact objects, as well as density fluctuations sourced by scalar field dark matter. Currently unconstrained parameter space will already be accessible using upcoming data from the ongoing Gaia mission.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2023

Operation of Dual-T-Type Modular Multilevel Converter for Uninterrupted Power Supply Under Bridge Failures

Dual-T-type modular multilevel converter (DTMMC) is an alternative to the existing uninterrupted power supply (UPS) due to its advantage in flexible leg reusing, multiple power ports, and high operating efficiency. Here, in this article, a DTMMC-UPS, which has series configurations on both input/output ac sides, obtains high-voltage grid/load accessing interfaces is presented. In the described system, the fact that copies of T-type legs are employed makes semiconductor failure common to happen. Moreover, both the coupling between rectifier and inverter conversions and the confliction between intercell and inner-cell voltage balancing make fault-tolerant control a tough issue. In this article, the switch fault types are first clarified and diagnosed by the different impacts on normal operation. An improved voltage vector modulation is then deduced to facilitate the planning of proper primary switching patterns, to achieve rectifier side normal operation. The secondary alternated level-shifted pulsed-width modulation (LS-PWM) is also modified to achieve inverter side normal operation. The experiment results are supplied to verify the validity of the modulation-coordinated fault toleration strategy.

42 ENGINEERING↗

DOE OSTI2013

The Use of Geomorphometrics for Geologic Site Characterization

The Problem: Developing an accurate geologic site characterization is difficult for denied-access sites. A good understanding of the geology (both in terms of the rock types and the fracture networks) is required for event evaluation (e.g., modulation of seismic signals from the source), planning of treaty monitoring sensors (fracture play a key role in the gas migration pathways), and evaluation of containment strategies. The Hypothesis: Quantitative analysis of terrain characteristics provides a way to relate the topography (easily obtained at high resolution) to surface geology. The Method: Integration of Terrain Complexity Index (TCI, derived from surface roughness) with drainage patterns and texture to produce a "predicted" geologic map. The viability of this method was evaluated by applying the algorithm to an area of know geology (Area 15 at the Nevada Test Site - NNSS). A 10-meter digital elevation model (DEM) was used for this evaluation. The Application: We have demonstrated the utility of this method by developing an improved surface geologic map for the North Korean Test Site using a 5-meter DEM. Why Now: Improved geologic characterization of potential nuclear test sites in a number of countries is needed for a number of Nonproliferation objectives. What's Needed Next: 1) A more robust and automated interpretation algorithm for the drainage analysis aspect; 2) improved data fusion of the TCI with drainage patterns; and 3) evaluation of the potential for fracture mapping in granite using a very high resolution DEM at the NNSS site (a 1-meter DEM in on order).

58 GEOSCIENCES↗

DOE OSTI2024

Land cover and space use influence coyote carnivory: evidence from stable-isotope analysis

For many species, the relationship between space use and diet composition is complex, with individuals adopting varying space use strategies such as territoriality to facilitate resource acquisition. Coyotes ( Canis latrans ) exhibit two disparate types of space use; defending mutually exclusive territories (residents) or moving nomadically across landscapes (transients). Resident coyotes have increased access to familiar food resources, thus improved foraging opportunities to compensate for the energetic costs of defending territories. Conversely, transients do not defend territories and are able to redirect energetic costs of territorial defense towards extensive movements in search of mates and breeding opportunities. These differences in space use attributed to different behavioral strategies likely influence foraging and ultimately diet composition, but these relationships have not been well studied. We investigated diet composition of resident and transient coyotes in the southeastern United States by pairing individual space use patterns with analysis of stable carbon (δ 13 C) and nitrogen (δ 15 N) isotope values to assess diet. During 2016–2017, we monitored 41 coyotes (26 residents, 15 transients) with GPS radio-collars along the Savannah River area in the southeastern United States. We observed a canopy effect on δ 13 C values and little anthropogenic food in coyote diets, suggesting 13 C enrichment is likely more influenced by reduced canopy cover than consumption of human foods. We also observed other land cover effects, such as agricultural cover and road density, on δ 15 N values as well as reduced space used by coyotes, suggesting that cover types and localized, resident-like space use can influence the degree of carnivory in coyotes. Finally, diets and niche space did not differ between resident and transient coyotes despite differences observed in the proportional contribution of potential food sources to their diets. Although our stable isotope mixing models detected differences between the diets of resident and transient coyotes, both relied mostly on mammalian prey (52.8%, SD = 15.9 for residents, 42.0%, SD = 15.6 for transients). Resident coyotes consumed more game birds (21.3%, SD = 11.6 vs 13.7%, SD = 8.8) and less fruit (10.5%, SD = 6.9 vs 21.3%, SD = 10.7) and insects (7.2%, SD = 4.7 vs 14.3%, SD = 8.5) than did transients. Our findings indicate that coyote populations fall on a feeding continuum of omnivory to carnivory in which variability in feeding strategies is influenced by land cover characteristics and space use behaviors.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2014

WE-G-BRF-07: Non-Circular Scanning Trajectories with Varian Developer Mode

Purpose: Cone-beam CT (CBCT) in image-guide radiation therapy (IGRT) typicallyacquires scan data via the circular trajectory of the linearaccelerator's (linac) gantry rotation. Though this lends itself toanalytic reconstruction algorithms like FDK, iterative reconstructionalgorithms allow for a broader range of scanning trajectories. Weimplemented a non-circular scanning trajectory with Varian's TrueBeamDeveloper Mode and performed some preliminary reconstructions toverify the geometry. Methods: We used TrueBeam Developer Mode to program a new scanning trajectorythat increases the field of view (FOV) along the gantry rotation axiswithout moving the patient. This trajectory consisted of moving thegantry in a circle, then translating the source and detector along theaxial direction before acquiring another circular scan 19 cm away fromthe first. The linear portion of the trajectory includes an additional4.5 cm above and below the axial planes of the source's circularrotation. We scanned a calibration phantom consisting of a lucite tubewith a spiral pattern of CT spots and used the maximum-likelihoodalgorithm to iteratively reconstruct the CBCT volume. Results: With the TrueBeam trajectory definition, we acquired projection dataof the calibration phantom using the previously described trajectory.We obtained a scan of the treatment couch for log normalization byscanning with the same trajectory but without the phantom present.Using the nominal geometric parameters reported in the projectionheaders with our iterative reconstruction algorithm, we obtained acorrect reconstruction of the calibration phantom. Conclusion: The ability to implement new scanning trajectories with the TrueBeamDeveloper Mode enables us access to a new parameter space for imagingwith CBCT for IGRT. Previous simulations and simple dual circle scanshave shown iterative reconstruction with non-circular trajectories canincrease the axial FOV with CBCT. Use of Developer Mode allowsexperimentally testing these and other new scanning trajectories. Support was provided in part by the University of Chicago Research Computing Center, Varian Medical Systems, and NIH Grants 1RO1CA120540, T32EB002103, S10 RR021039 and P30 CA14599. The contents of this work are solely the responsibility of the authors and do not necessarily represent the official views of the supporting organizations.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2011

Review of Recent Literature Relevant to the Environmental Effects of Marine and Hydrokinetic Energy Devices, Task 2.1.3: Effects on Aquatic Organisms – Fiscal Year 2011 Progress Report Environmental Effects of Marine and Hydrokinetic Energy

A literature search was conducted by using the Web of Science® Databases component of the ISI Web of KnowledgeSM to identify recent articles that would be useful to help assess the potential environmental effects of renewable energy development in the ocean, with emphasis on marine mammals, seabirds, and fish. Several relatively recent general review articles that included possible effects of marine renewable energy devices on marine mammals and seabirds were examined to begin the search process (e.g., Boehlert et al. 2008; Thompson et al. 2008; Simas et al. 2009). From these articles, several general topics of potential environmental effects on marine mammals, seabirds, and fish were derived. These topics were used as the primary search factors. Searches were conducted with reference to the potential effects of offshore wind farms and MHK devices on marine mammals, seabirds, and fish. Additional sources were identified by cross-checking the Web of Science databases for articles that cited the review articles. It also became clear that often the potential effects were offered as hypotheses that often were not supported by the presentation of appropriate documentation. Therefore, the search was refined and focused on trying to obtain the necessary information to support or challenge a proposed potential effect to a specific concern. One of the expressed concerns regarding MHK devices is that placing wave parks in coastal waters could compromise the migration patterns of whales. Disruption of the annual migration of the gray whale (Eschrichtius robustus), which swims at least 30,000 km on its round trip from breeding grounds in Baja California to feeding areas in the Bering Sea, is of particular concern. Among the hypothesized effects on the migrating gray whales are increased predation risk by constricting migration corridor to between array and shore or by forcing the whales to swim into deeper waters, increased metabolic energy costs and delays in reaching the destinations, and interrupting feeding by blocking access to benthic areas under arrays. The literature search focused on identifying published studies that could provide information to evaluate these concerns. The results were developed into a case study that evaluated the potential effects of the placement of wave parks in coastal waters along the migration route of the gray whale. Wave parks and other MHK arrays may have additional effects on gray whales and other marine mammals, including entanglement in mooring lines and interference with communications among other effects, that were not included in this case study. The case study results were rewritten into a simpler form that would be suitable for placement on a web blog

Kropp, Roy K.↗

DOE OSTI2022

Performance Monitoring Program: Developing Comparative Metrics for Fitness-for-Duty Programs

To comply with U.S. Nuclear Regulatory Commission (NRC) regulations, licensees and entities authorized under Title 10 of the Code of Federal Regulations (CFR) Part 26 Section 26.3 (§ 26.3) are required to have fitness-for-duty (FFD) programs. Under § 26.3, the expectation of these FFD programs is to provide reasonable assurance that individuals who are granted unescorted access to nuclear power reactor protected areas and Category I fuel cycle facility material control areas are trustworthy, will perform their tasks in a reliable manner, are not under the influence of any substance, legal or illegal, that may impair their ability to perform their duties, and are not mentally or physically impaired from any cause that can adversely affect their ability to safely and competently perform their duties. Pacific Northwest National Laboratory (PNNL) was tasked with developing a performance monitoring program to risk inform NRC inspection and policy regarding quantitative FFD performance data. To meet this need, PNNL developed methodologies that could be implemented within a performance monitoring program. Throughout this report, these methodologies are referred to as comparative metrics. The NRC provided PNNL with 2016–2019 data from annual reporting forms and single positive test forms provided by licensees and other entities. For most of the comparative metrics, the analyses required customized processing, such as creating filtering fields, adding data fields and summaries, and joining datasets. The comparative metrics developed include: random testing rate, random policy violation rate, pre-access policy violation rate, subversion attempt rate, and number of policy violations by labor category. The comparative metrics can be used for parsing and visualizing FFD program data and monitoring FFD performance at the labor category, facility, licensee, and industry levels to risk inform NRC inspection and policy with regard to the FFD data currently collected from licensees and other entities that implement Part 26 requirements. Furthermore, these developed comparative metrics allow a more in-depth look at the FFD programs for the industry to discern trends and patterns that may warrant changes at an industry level and to inform policy decisions. These analyses should be refreshed as new FFD data become available.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2018

Selective enhancement of Selényi rings induced by the cross-correlation between the interfaces of a two-dimensional randomly rough dielectric film

By the use of both perturbative and non-perturbative solutions of the reduced Rayleigh equation, we present a detailed study of the scattering of light from two-dimensional weakly rough dielectric films. It is shown that for several rough film configurations, Selényi interference rings exist in the diffusely scattered light. For film systems supported by dielectric substrates where only one of the two interfaces of the film is weakly rough and the other planar, Selényi interference rings are observed at angular positions that can be determined from simple phase arguments. For such single-rough-interface films, we find and explain by a single scattering model that the contrast in the interference patterns is better when the top interface of the film (the interface facing the incident light) is rough than when the bottom interface is rough. When both film interfaces are rough, Selényi interference rings exist but a potential cross-correlation of the two rough interfaces of the film can be used to selectively enhance some of the interference rings while others are attenuated and might even disappear. This feature may in principle be used in determining the correlation properties of interfaces of films that otherwise would be difficult to access.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗