Innovative education networking aimed at multimedia tools for geometrical optics learning

We present a purposeful initiative to open new grounds for teaching Geometrical Optics. It is based on the creation of an innovative education networking involving academic staff from three Spanish universities linked together around Optics. Nowadays, students demand online resources such as innovative multimedia tools for complementing the understanding of their studies. Geometrical Optics relies on basics of light phenomena like reflection and refraction and the use of simple optical elements such as mirrors, prisms, lenses, and fibers. The mathematical treatment is simple and the equations are not too complicated. But from our long time experience in teaching to undergraduate students, we realize that important concepts are missed by these students because they do not work ray tracing as they should do. Moreover, Geometrical Optics laboratory is crucial by providing many short Optics experiments and thus stimulating students interest in the study of such a topic. Multimedia applications help teachers to cover those student demands. In that sense, our educational networking shares and develops online materials based on 1) video-tutorials of laboratory experiences and of ray tracing exercises, 2) different online platforms for student self-examinations and 3) computer assisted geometrical optics exercises. That will result in interesting educational synergies and promote student autonomy for learning Optics.

Ultrathin high-index metasurfaces for shaping focused beams

The volume size of a converging wave, which plays a relevant role in image resolution, is governed by the wavelength of the radiation and the numerical aperture (NA) of the wavefront. We designed an ultrathin (λ/8 width) curved metasurface that is able to transform a focused field into a high-NA optical architecture, thus boosting the transverse and (mainly) on-axis resolution. The elements of the metasurface are metal-insulator subwavelength gratings exhibiting extreme anisotropy with ultrahigh index of refraction for TM polarization. Our results can be applied to nanolithography and optical microscopy.

Notebook on geography, navigation, mensuration, and other subjects, ca. 1723-1743

This heavily illustrated notebook contains entries on the following topics, among others: geography; mensuration; navigation and the history of navigation; "the use of Gunter's Scale in plain sailing;" compasses; quadrants and their use; "the refraction of the stars observed by the famous Tycho Brahe;" the latitude and longitude of coasts in America, Europe, and Africa; oceans and islands; mountains and "burning mountains" (volcanoes); rivers and lakes; forests and deserts; maps and sea charts; and the uses of geometry and other measurements by carpenters, joiners, painters, glaziers, masons, and bricklayers. Many pages contain navigational problems and their detailed solutions, as well as chronologies of global exploration and lists of all known rivers, mountains, and other geographic features across the world, many with vivid descriptions. The last pages of the notebook contain entries made in December of 1743 regarding celestial measurements Prince took in Stratford, Connecticut, where he was staying with his brother.

Tight-Binding Approximations in 1D and 2D Coupled-Cavity Photonic Crystal Structures

Light confinement and controlling an optical field has numerous applications in the field of telecommunications for optical signals processing. When the wavelength of the electromagnetic field is on the order of the period of a photonic microstructure, the field undergoes reflection, refraction, and coherent scattering. This produces photonic bandgaps, forbidden frequency regions or spectral stop bands where light cannot exist. Dielectric perturbations that break the perfect periodicity of these structures produce what is analogous to an impurity state in the bandgap of a semiconductor. The defect modes that exist at discrete frequencies within the photonic bandgap are spatially localized about the cavity-defects in the photonic crystal. In this thesis the properties of two tight-binding approximations (TBAs) are investigated in one-dimensional and two-dimensional coupled-cavity photonic crystal structures We require an efficient and simple approach that ensures the continuity of the electromagnetic field across dielectric interfaces in complex structures. In this thesis we develop \textrm{E} -- and \textrm{D} --TBAs to calculate the modes in finite 1D and 2D two-defect coupled-cavity photonic crystal structures. In the \textrm{E} -- and \textrm{D} --TBAs we expand the coupled-cavity \overrightarrow{E} --modes in terms of the individual \overrightarrow{E} -- and \overrightarrow{D} --modes, respectively. We investigate the dependence of the defect modes, their frequencies and quality factors on the relative placement of the defects in the photonic crystal structures. We then elucidate the differences between the two TBA formulations, and describe the conditions under which these formulations may be more robust when encountering a dielectric perturbation. Our 1D analysis showed that the 1D modes were sensitive to the structure geometry. The antisymmetric \textrm{D} mode amplitudes show that the \textrm{D} --TBA did not capture the correct (tangential \overrightarrow{E} --field) boundary conditions. However, the \textrm{D} --TBA did not yield significantly poorer results compared to the \textrm{E} --TBA. Our 2D analysis reveals that the \textrm{E} -- and \textrm{D} --TBAs produced nearly identical mode profiles for every structure. Plots of the relative difference between the \textrm{E} and \textrm{D} mode amplitudes show that the \textrm{D} --TBA did capture the correct (normal \overrightarrow{E} --field) boundary conditions. We found that the 2D TBA CC mode calculations were 125-150 times faster than an FDTD calculation for the same two-defect PCS. Notwithstanding this efficiency, the appropriateness of either TBA was found to depend on the geometry of the structure and the mode(s), i.e. whether or not the mode has a large normal or tangential component.

Thermal conductivity and heat flow measurements from cruise Planet69, 4-21 August 1969, Norwegian Sea

This is a report about a joint scientific venture of German and Norwegian Institutes in an area between Latitude = 66°45' N and 68°30' N and Longitude 1.0° E to 7°30' W. The chief scientist's report gives an outline of the cruise. The preliminary contributions by the scientists deal with results of gravity at sea, magnetic and geothermic measurements, the seismic shooting, results of continuous seismic reflection work, some refraction seismic results and with the observations of the ship's weather station.

(Table 1) Physical properties of sediments at DSDP Holes 79-545 and 79-547A

Laboratory measurements of the acoustic and physical properties of deep-sea sediments and rocks are important for the interpretation of seismic reflection and refraction data and estimation of in situ physical property values. Furthermore, the results of such measurements can be used to design geoacoustic models of the upper oceanic crust that can relate the physical properties of deep-sea sediments to lithology, depth of burial, and diagenetic effects (Hamilton, 1980; Milholland et al., 1980). The purpose of this paper is to report the results of laboratory measurements of wet-bulk density, compressionalwave velocity, and velocity anisotropy on sediments cored during DSDP Leg 79. The sample suite consists of 11 calcareous claystones and clay-rich chalks recovered between 370 to 720 m sub-bottom at Holes 545 and 547A.

Analysis of coastal sediment transport processes from Wrightsville Beach to Fort Fisher, North Carolina /

A comprehensive engineering analysis of the coastal sediment transport processes along a 42-kilometer segment of the North Carolina shoreline from Wrightsville Beach to Fort Fisher is presented. Included in the analysis is an interpretation of the littoral processes, longshore transport, and the behavior and success of beach nourishment projects at Wrightsville Beach and Carolina Beach, North Carolina. The historical position of the MLW, MSL, and MHW contours, relative to a fixed base line, is plotted for the period between 1964 and 1975. An equivalent volumetric erosion or accretion between successive surveys is determined by multiplying the average excursion distance of the contours by a constant of proportionality. The plots of excursion distance versus time for the MLW, MSL, and MHW contours also show the time response of the beach fills. This response is described by a mathematical function. The alongshore components of wave-induced energy flux are also determined within the study area through wave refraction analysis. This information, together with the information on volumetric change, is used in a sediment budget analysis to determine the coefficient of alongshore sediment transport and the inlet trapping characteristics. (Author).

A numerical model for predicting shoreline changes /

A mathematical model for long-term, three-dimensional shoreline evolution is developed. The combined effects of variations of sea level; wave refraction and diffraction; loss of sand by density currents during storms, by rip currents, and by wind; bluff erosion and berm accretion; effects of manmade structures such as long groin or navigational structures; and beach nourishment are all taken into account. A computer program is developed with various subroutines which permit modification as the state-of-the-art progresses. The program is applied to a test case at Holland Harbor, Michigan. (Author).

Interaction of waves and currents /

This report presents an overview of wave-current interacion, including comprehensive review of references to significant U.S. and foreign literature available through December 1981. Specific topics under review are the effects of horizontally and vertically varying currents on waves, wave refraction by currents, dissipation and turbulence, small- and medium-scale currents, caustics and focusing, and wave breaking. The results of the review are then examined for engineering applications. The most appropriate general-purpose computer program to include wave-current interaction is the Dutch Rijkswaterstaat program CREDIZ, which is based on a parabolic wave equation. Further applications include wave and current forces on structures and possibly sediment transport. The report concludes with a brief state-of-the-art review of wave-current interaction and a list of topics needing further research and development.

Untersuchungen über die astronomische Refraktion.

Mode of access: Internet.

Voyage de la Louisiane, fait par ordre du roy en l'année mil sept cent vingt : dans lequel sont traitées diverses matieres de physique, astronomie, géographie [et] marine : L'on y a joint les Observations sur la réfraction ... Divers voyages faits pour la correction de la carte de la côte de Provence et des Reflexions sur quelques points du sistème de M. Newton /

Las h. plegadas: "Observations de la variation de l'aiguille aimantée, faites pendant le voyage des Vaisseaux du Roy le Toulouse & le Henry à la Louisiane, dans l'année 1720" (p. 238). "Table pour la comparaison de la variation observée dans le voïage de la Louisiane en 1720 ..." (p. 244). El resto de las h. pleg. acompañan las "Observations sur la refraction, faites à Marseille", con paginación propia.

Ueber die wirkung der astronomischen strahlenbrechung auf beobachtungen mit dem kreismikrometer ...

Inaug.--diss.--Göttingen.

Recueil d'observations astronomiques, d'opérations trigonométriques et de mesures barométriques, faites pendant le cours d'un voyage aux régions équinoxiales du Nouveau continent, depuis 1799 jusqu'en 1803,

Mode of access: Internet.

Dioptrik, oder, Anleitung zur Verfertigung der Fernröhre /

Plate printed on double leaves.

Recherches sur les réfractions extraordinaires qui ont lieu près de l'horizon,

Mode of access: Internet.