Design and implementation of a LIDAR imaging system

Light Detection and Ranging (LIDAR) is a valuable tool for collecting information along the coastline, which is also referred to as the littoral zone. Data collected in this area is useful for the study and analysis of algae growth, water depths, and identifying objects in shallow waters. A LIDAR system typically consists of a pulsed LASER, a light collection device, and a sensor. Currently at RIT we have an airborne imager called the Modular Imaging Spectrometer Instrument (MISI). MISI is a passive system and currently obtains data in the visible and infrared regions of the electromagnetic spectrum. My objective was to analyze the MISI optical path to determine whether or not a LIDAR could be incorporated into it, and if not, then to design a separate system. This research was conducted by creating several analyses of possible systems using an optical software package called Optical Software for Layout and Optimization (OSLO)

Sustainable Poetry: Four American Ecopoets

Focusing on the work of A.R. Ammons, Wendell Berry, W.S. Merwin, and Gary Snyder, author Leonard Scigaj shows that just as a sustainable society does not depreciate its resource base, so a sustainable poetry does not restrict interest to language. Over the past thirty years many poets have shown an increasing sensitivity to ecological thinking. But critics trained in poststructuralist language theory often fail to explore the substance of ecopoetry. Scigaj is the first to define ecopoetry as separate and distinct from nature or environmental poetry, marked by its concern with balancing the interests of human beings with the needs of nature. Just as science learned that the earth was not the center of the universe, ecopoetry insists on the recognition that humans are not at the center of the natural world. The first book to treat the US’s four foremost ecopoets as ecopoets. -- Choice Scigaj uses his examination of contemporary ecological poetry to mount a direct assault on the way literary theory has been conducted over the past twenty years. -- Interdisciplinary Studies in Literature and Environment Will join John Elder\u27s Imagining the Earth as the most important contribution to date to the study of contemporary ecopoetry. -- Lawrence Buell A rich context for our understading the work and persons of A.R. Ammons, Wendell Berry, W.S. Merwin, and Gary Snyder, four outstanding American poets. -- Psychological Reports Anyone who things that nature poetry is a leftover mode from a bygone era, or that all nature poets are alike, needs to read this book before we have no nature left. -- Virginia Quarterly Review Urges readers to distinguish between two kinds of poetry in order to set the stage for an epic intellectual and aesthetic battle. -- Western American Literaturehttps://uknowledge.uky.edu/upk_english_language_and_literature_north_america/1001/thumbnail.jp

High ferroelectric polarization in c-oriented BaTiO3 epitaxial thin films on SrTiO3/Si(001)

Scigaj, M. et al.The integration of epitaxial BaTiO3 films on silicon, combining c-orientation, surface flatness, and high ferroelectric polarization is of main interest towards its use in memory devices. This combination of properties has been only achieved so far by using yttria-stabilized zirconia buffer layers. Here, the all-perovskite BaTiO3/LaNiO3/SrTiO3 heterostructure is grown monolithically on Si(001). The BaTiO3 films are epitaxial and c-oriented and present low surface roughness and high remnant ferroelectric polarization around 6 μC/cm2. This result paves the way towards the fabrication of lead-free BaTiO3 ferroelectric memories on silicon platforms.ICMAB-CSIC authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015-0496) and the MAT2014-56063-C2-1-R project, and from Generalitat de Catalunya (2014 SGR 734). Work at Oak Ridge National Laboratory was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. C. H. Chao acknowledges the NSC-CSIC 2014 Summer Program in Spain for Taiwanese PhD students. I. Fina acknowledges Juan de la Cierva – Incorporación postdoctoral fellowship (IJCI-2014-19102) from the Spanish Ministry of Economy and Competitiveness of Spanish Government. INL gratefully acknowledges the European commission and the national French research agency (ANR) for funding, through the projects SITOGA (FP7-ICT-2013-11-619456), TIPS (H2020‐ICT‐02-2014‐1-644453), ANR HIRIS and ANR DIAMWAFEL. INL also acknowledges P. Regreny, C. Botella and J.-B. Goure for MBE technical assistance.Peer reviewe

Yttria-stabilized zirconia/SrTiO_(3) oxide heteroepitaxial interface with symmetry discontinuity

We show that yttria-stabilized zirconia (YSZ) films deposited on structurally dissimilar SrTiO_(3)(110) substrates exhibit two-dimensional layer-by-layer growth. We observed that, up to a thickness of about 15 nm, the square (001) basal plane of the cubic YSZ grows epitaxially on the rectangular (110) crystallographic plane of SrTiO3 substrates, with [110]YSZ(001)//[001]SrTiO_(3)(110) epitaxial relationship. Thus, the heterointerface presents symmetry discontinuity between the YSZ(001) film and the lower surface symmetry SrTiO_(3)(110) substrate. Beyond this specific case, we envisage similar approaches to develop other innovative oxide interfaces showing similar crystal symmetry discontinuities

Conducting interfaces between amorphous oxide layers and SrTiO3(110) and SrTiO3(111)

Interfaces between (110) and (111)SrTiO3 (STO) single crystalline substrates and amorphous oxide layers, LaAlO3 (a-LAO), Y:ZrO2 (a-YSZ), and SrTiO3 (a-STO) become conducting above a critical thickness tc. Here we show that tc for a-LAO is not depending on the substrate orientation, i.e. tc (a-LAO/(110)STO) ~ tc(a-LAO/(111)STO) interfaces, whereas it strongly depends on the composition of the amorphous oxide: tc(a-LAO/(110)STO) < tc(a-YSZ/(110)STO) < tc(a-STO/(110)STO). It is concluded that the formation of oxygen vacancies in amorphous-type interfaces is mainly determined by the oxygen affinity of the deposited metal ions, rather than orientational-dependent enthalpy vacancy formation and diffusion. Scanning transmission microscopy characterization of amorphous and crystalline LAO/STO(110) interfaces shows much higher amount of oxygen vacancies in the former, providing experimental evidence of the distinct mechanism of conduction in these interfaces

Untangling Electrostatic and Strain Effects on the Polarization of Ferroelectric Superlattices

Khestanova, Ekaterina et al.The polarization of ferroelectric superlattices is determined by both electrical boundary conditions at the ferroelectric/paraelectric interfaces and lattice strain. The combined infl uence of both factors offers new opportunities to tune ferroelectricity. However, the experimental investigation of their individual impact has been elusive because of their complex interplay. Here, a simple growth strategy has permitted to disentangle both contributions by an independent control of strain in symmetric superlattices. It is found that fully strained short-period superlattices display a large polarization whereas a pronounced reduction is observed for longer multilayer periods. This observation indicates that the electrostatic boundary mainly governs the ferroelectric properties of the multilayers whereas the effects of strain are relatively minor.Financial support by the Spanish Government [Projects MAT2014- 56063-C2-1-R and MAT2013-41506 ] and Generalitat de Catalunya ( 2014-SGR-734 and 2014-SGR-672 ) is acknowledged. ICMAB-CSIC authors acknowledge fi nancial support from the Spanish Ministry of Economy and Competitiveness , through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV- 2015-0496 ). I.F. acknowledges Juan de la Cierva – Incorporación postdoctoral fellowship (IJCI-2014- 19102) from the Spanish Ministry of Economy and Competitiveness. The transmission electron microscopy works were conducted in the Laboratorio de Microscopias Avanzadas at Instituto de Nanociencia de Aragón (Universidad de Zaragoza). The authors acknowledge the LMA-INA for offering access to their instruments and expertise. The authors thank Massimiliano Stengel for useful discussions.Peer reviewe

Competition between polar and nonpolar lattice distortions in oxide quantum wells: new critical thickness at polar interfaces

Two basic lattice distortions permeate the structural phase diagram of oxide perovskites: antiferrodistortive (AFD) rotations and tilts of the oxygen octahedral network and polar ferroelectric modes. With some notable exceptions, these two order parameters rarely coexist in a bulk crystal, and understanding their competition is a lively area of active research. Here we demonstrate, by using the LaAlO₃/SrTiO₃ system as a test case, that quantum confinement can be a viable tool to shift the balance between AFD and polar modes and selectively stabilize one of the two phases. By combining scanning transmission electron microscopy (STEM) and first-principles-based models, we find a crossover between a bulklike LaAlO₃ structure where AFD rotations prevail, to a strongly polar state with no AFD tilts at a thickness of approximately three unit cells; therefore, in addition to the celebrated electronic reconstruction, our work unveils a second critical thickness, related not to the electronic properties but to the structural ones. We discuss the implications of these findings, both for the specifics of the LaAlO₃/SrTiO₃ system and for the general quest towards nanoscale control of material properties