93 research outputs found
Photographic Facial Soft Tissue Analysis by Means of Linear and Angular Measurements in an Adolescent Persian Population.
To obtain objective average measurements of the profile and frontal facial soft tissue to be used as a guide for aesthetic treatment goals. Methods and Materials : This observational study included 110 females and 130 males high school students aged 16-18 years. None of the subjects had any facial deformities. All of them and their parents gave consent to take part in this study. In each case, two standard photographs of profile and frontal views were taken 27 landmarks were digitized on photographs. The mean, standard deviation, and range for a total of 43 facial indices were calculated digitally by computer software. The Student's t-test was used to compare males and females. Results : The ratio between the lower and middle facial thirds was one to one, but the height of the upper facial third was proportionally smaller than the other two-thirds in both sexes. Boys had greater nasal length, depth, and prominence than girls with statistically significant differences. Both upper and lower lips were more prominent in girls than in boys. All measurements of the chin showed sexual dimorphism characterized by greater chin height and prominence and deeper mentolabial sulcus. Boys had greater facial dimensions than girls. Mouth width, nasal base width, and intercanthal distance were significantly greater in boys. Conclusion : The labial, nasal, and chin areas showed sexual dimorphism in most of the parameters used in this study. Boys had larger faces, greater facial heights, longer nasal, labial, and chin lengths, and greater nasal, labial, and chin prominence
Optical response of supported gold nanodisks
It is shown that the ellipsometric spectra of short range ordered
planar arrays of gold nanodisks supported on glass substrates can be
described by modeling the nanostructured arrays as uniaxial homogeneous
layers with dielectric functions of the Lorentz type. However, appreciable
deviations from experimental data are observed in calculated spectra of
irradiance measurements. A qualitative and quantitative description of all
measured spectra is obtained with a uniaxial effective medium dielectric
function in which the nanodisks are modeled as oblate spheroids. Dynamic
depolarization factors in the long-wavelength approximation and interaction
with the substrate are considered. Similar results are obtained calculating the
optical spectra using the island-film theory. Nevertheless, a small in-plane
anisotropy and quadrupolar coupling effects reveal a very complex optical
response of the nanostructured arrays
Feeling Torn When Everything Seems Right: Semantic Incongruence Causes Felt Ambivalence
The co-occurrence of positive and negative attributes of an attitude object typically accounts for less than a quarter of the variance in felt ambivalence toward these objects, rendering this evaluative incongruence insufficient for explaining felt ambivalence. The present research tested whether another type of incongruence, semantic incongruence, also causes felt ambivalence. Semantic incongruence arises from inconsistencies in the descriptive content of attitude objects’ attributes (e.g., attributes that are not mutually supportive), independent of these attributes’ valences. Experiment 1 manipulated evaluative and semantic incongruence using valence norms and semantic norms. Both of these norm-based manipulations independently predicted felt ambivalence, and, in Experiment 2, they even did so over and above self-based incongruence (i.e., participants’ idiosyncratic perceptions of evaluative and semantic incongruence). Experiments 3a and 3b revealed that aversive dissonant feelings play a role in the effects of evaluative incongruence, but not semantic incongruence, on felt ambivalence
A bimetallic nanoantenna for directional colour routing
Recent progress in nanophotonics includes demonstrations of meta-materials displaying negative refraction at optical frequencies, directional single photon sources, plasmonic analogies of electromagnetically induced transparency and spectacular Fano resonances. The physics behind these intriguing effects is to a large extent governed by the same single parameter—optical phase. Here we describe a nanophotonic structure built from pairs of closely spaced gold and silver disks that show phase accumulation through material-dependent plasmon resonances. The bimetallic dimers show exotic optical properties, in particular scattering of red and blue light in opposite directions, in spite of being as compact as ∼λ3/100. These spectral and spatial photon-sorting nanodevices can be fabricated on a wafer scale and offer a versatile platform for manipulating optical response through polarization, choice of materials and geometrical parameters, thereby opening possibilities for a wide range of practical applications
Magnetoplasmonic design rules for active magneto-optics
Light polarization rotators and non-reciprocal optical isolators are
essential building blocks in photonics technology. These macroscopic passive
devices are commonly based on magneto-optical Faraday and Kerr polarization
rotation. Magnetoplasmonics - the combination of magnetism and plasmonics - is
a promising route to bring these devices to the nanoscale. We introduce design
rules for highly tunable active magnetoplasmonic elements in which we can
tailor the amplitude and sign of the Kerr response over a broad spectral range
3D optical Yagi–Uda nanoantenna array
Future photonic circuits with the capability of high-speed data processing at optical frequencies will rely on the implementation of efficient emitters and detectors on the nanoscale. Towards this goal, bridging the size mismatch between optical radiation and subwavelength emitters or detectors by optical nanoantennas is a subject of current research in the field of plasmonics. Here we introduce an array of three-dimensional optical Yagi–Uda antennas, fabricated using top-down fabrication techniques combined with layer-by-layer processing. We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension. Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity. Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths
Magnetic hot spots in closely spaced thick gold nanorings
This document is the Accepted Manuscript version of a Published Work that appeared in final form in
Nano Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/page/policy/articlesonrequest/index.htmlLigh-matter interaction at optical frequencies is mostly mediated by the electric component of the
electromagnetic field, with the magnetic component usually being considered negligible. Recently, it has been shown that properly engineered metallic nanostructures can provide a magnetic response at optical frequencies originated from real or virtual flows of electric current in the structure. In this work,
we demonstrate a magnetic plasmonic mode which emerges in closely spaced thick gold nanorings. The plasmonic resonance obtains a magnetic dipole character by sufficiently increasing the height of the nanorings. Numerical simulations show that a virtual current loop appears at resonance for sufficiently thick nanorings, resulting in a strong concentration of the magnetic field in the gap region (magnetic hot spot). We find that there is an optimum thickness that provides the maximum magnetic intensity
enhancement (over 200-fold enhancement) and give an explanation of this observation. This strong magnetic resonance, observed both experimentally and theoretically, can be used to build new metamaterials and resonant loop nanoantennas at optical frequencies.This work has been supported by Spanish Government and European Union (EU) funds under contracts CSD2008-00066 and TEC2011-28664-C02-02 and Universitat Politecnica de Valencia (program INNOVA 2011). The authors extend special thanks to Mr. J. Ross Aitken for his contribution to this work.Lorente Crespo, M.; Wang, L.; Ortuño Molinero, R.; García Meca, C.; Ekinci, Y.; Martínez Abietar, AJ. (2013). Magnetic hot spots in closely spaced thick gold nanorings. Nano Letters. 13(6):2654-2661. https://doi.org/10.1021/nl400798sS2654266113
Absorption Enhancement in Lossy Transition Metal Elements of Plasmonic Nanosandwiches
Combination of catalytically active transition metals and surface plasmons offers a promising way to drive chemical reactions by converting incident visible light into energetic electron-hole pairs acting as a mediator. In such a reaction enhancement scheme, the conversion efficiency is dependent on light absorption in the metal. Hence, increasing absorption in the plasmonic structure is expected to increase generation of electron-hole pairs and, consequently, the reaction rate. Furthermore, the abundance of energetic electrons might facilitate new reaction pathways. In this work we discuss optical properties of homo- and heterometallic plasmonic nanosandwiches consisting of two parallel disks made of gold and palladium. We show how near-field coupling between the sandwich elements can be used to enhance absorption in one of them. The limits of this enhancement are investigated using finite-difference time-domain simulations. Physical insight is gained through a simple coupled dipole analysis of the nanostructure. For small palladium disks (compared to the gold disk), total absorption enhancement integrated over the near visible solar AM 1.5 spectrum is 8-fold, while for large palladium disks, similar in size to the gold one, it exceeds three
Quinine doped hybrid sol-gel coatings for wave guiding and optical applications
Pure and quinine doped silica coatings have been prepared over sodalime glasses. The coatings were consolidated at low temperature (range 60-180 A degrees C) preserving optical activity of quinine molecule. We designed a device to test the guiding properties of the coatings. We confirmed with this device that light injected in pure silica coatings is guided over distances of meters while quinine presence induces isotropic photoluminescence. With the combined use of both type of coatings, it is possible to design light guiding devices and illuminate regions in glass elements without electronic circuits
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