Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants

Near-field infrared spectroscopy by elastic scattering of light from a probe tip resolves optical contrasts in materials at dramatically sub-wavelength scales across a broad energy range, with the demonstrated capacity for chemical identification at the nanoscale. However, current models of probe-sample near-field interactions still cannot provide a sufficiently quantitatively interpretation of measured near-field contrasts, especially in the case of materials supporting strong surface phonons. We present a model of near-field spectroscopy derived from basic principles and verified by finite-element simulations, demonstrating superb predictive agreement both with tunable quantum cascade laser near-field spectroscopy of SiO$_2$ thin films and with newly presented nanoscale Fourier transform infrared (nanoFTIR) spectroscopy of crystalline SiC. We discuss the role of probe geometry, field retardation, and surface mode dispersion in shaping the measured near-field response. This treatment enables a route to quantitatively determine nano-resolved optical constants, as we demonstrate by inverting newly presented nanoFTIR spectra of an SiO$_2$ thin film into the frequency dependent dielectric function of its mid-infrared optical phonon. Our formalism further enables tip-enhanced spectroscopy as a potent diagnostic tool for quantitative nano-scale spectroscopy.Comment: 19 pages, 9 figure

Adaptations of Frank Miller's Graphic Novels: Possible Ways of Translating Comics into Film

(CS) Komiksové filmy jsou nezanedbatelnou součástí současné kinematografie, ze svých předloh však často přebírají pouze postavy či základní dějovou linku. Tato práce ukazuje, že do filmové adaptace je možné vnést také jiné prvky původního díla, a to takové, které by se na první pohled mohly zdát z prvního média do druhého nepřenositelné. Jako vzorek byly použity filmové adaptace grafických románů Franka Millera, především filmy 300 a Sin City. Práce sleduje, jak se ve filmových adaptacích odráží jednotlivé prvky typické pro komiks (např. panely a jejich rozvržení, styl kresby, narativní struktura, scénář a lettering) a čím jsou tyto doplněny (např. hudba, zvuk, pohyb, casting). Komparativní analýzou filmů a jejich předloh zjišťujeme, jak věrné adaptace opravdu jsou, ale snažíme se též poukázat na to, jak rozdílné mohou být přístupy tvůrců filmů k předlohám. Cílem je také ukázat, které ze zmíněných prvků lze do filmové řeči přenést a jakými způsoby, a se kterými je to naopak obtížnější, ve druhém případě poté odhalit, jsou-li tyto ztráty něčím kompenzovány.(ENG) Comic book movies are a significant part of contemporary cinema, however, they often take only the characters or the basic plot line from their source material. This thesis is intended to show that other elements of the original can also be brought into a film adaptation, ones that at first glance might seem non-transferable from one media to another. Film adaptations of Frank Miller's graphic novels will serve as a sample, focusing primarily on the films 300 and Sin City. The thesis looks at how the film adaptations reflect the various elements typical of comics (e.g. panels and their layout, drawing style, narrative structure, script and lettering) and what these are complemented by (e.g. music, sound, movement, casting). Through comparative analysis of both films, their prequels, and other adaptations, we want to determine how faithful the adaptations really are, but also to highlight how different the filmmakers' approaches to the source material can be. The aim is also to show which of the elements mentioned above can be transferred into film language and in what ways, and which are more difficult to translate, and in the latter case to reveal if these losses are compensated.Katedra filmových studiíFilm Studies DepartmentFilozofická fakultaFaculty of Art

J/\psi-dissociation by a color electric flux tube

We adress the question of how a $c-\bar{c}$-state (a $J/\psi$) can be dissociated by the strong color electric fields when moving through a color electric flux tube. The color electric flux tube and the dissociation of the heavy quarkonia state are both described within the Friedberg-Lee color dielectric model. We speculate on the importance of such an effect with respect to the observed $J/\psi$-suppression in ultrarelativistic heavy ion collisions.Comment: 19 pages, 6 PostScript figures included, LaTe

¿MÁS CIENTÍFICOS, MÁS CIENCIA?: CARACTERIZACIÓN HISTÓRICO-CUANTITATIVA DE LA COMUNIDAD CIENTÍFICA EN CHILE, 1960-1990

El artículo identifica y caracteriza a la comunidad científica chilena entre 1960 y 1990, principalmente proveniente de las ciencias naturales, matemáticas y exactas, mediante la recopilación y análisis de estadísticas elaboradas en la época. Se describen aspectos como el volumen y género de los científicos, las disciplinas que contaban con mayor desarrollo, así como las universidades y ubicación geográfica donde se concentraba la investigación científica. El período coincide con la institucionalización de políticas científicas por medio de la fundación de la Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, 1967) y el Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT, 1981)

Graphene terahertz modulators by ionic liquid gating

Graphene based THz modulators are promising due to the conical band structure and high carrier mobility of graphene. Here, we tune the Fermi level of graphene via electrical gating with the help of ionic liquid to control the THz transmittance. It is found that, in the THz range, both the absorbance and reflectance of the device increase proportionately to the available density of states due to intraband transitions. Compact, stable, and repeatable THz transmittance modulation up to 93% (or 99%) for a single (or stacked) device has been demonstrated in a broad frequency range from 0.1 to 2.5 THz, with an applied voltage of only 3 V at room temperature

Detection of High Energy Ionizing Radiation using Deeply Depleted Graphene-Oxide-Semiconductor Junctions

Graphene's linear bandstructure and two-dimensional density of states provide an implicit advantage for sensing charge. Here, these advantages are leveraged in a deeply depleted graphene-oxide-semiconductor (D2GOS) junction detector architecture to sense carriers created by ionizing radiation. Specifically, the room temperature response of the silicon-based D2GOS junction is analyzed during irradiation with 20 MeV Si4+ ions. Detection was demonstrated for doses ranging from 12-1200 ions with device functionality maintained with no substantive degradation. To understand the device response, D2GOS pixels were characterized post-irradiation via a combination of electrical characterization, Raman spectroscopy, and photocurrent mapping. This combined characterization methodology underscores the lack of discernible damage caused by irradiation to the graphene while highlighting the nature of interactions between the incident ions and the silicon absorber.Comment: 15 pages, 4 figure