Search results for "Angle of incidence"
showing 10 items of 12 documents
Study of the angular acceptance of surface plasmon Bragg mirrors
2007
Surface plasmon based photonic devices are promising candidates for highly integrated optics. A surface plasmon (SP) is basically an electromagnetic wave confined in the interface between a metal and a dielectric, and is due to the interaction of the electromagnetic field with the surface bounded electron charges in the metal. A SP can propagate along the interface where it is confined (the propagation length being tens of micrometers in the visible range), but its associated electromagnetic field decreases exponentially in the perpendicular direction, in such a way that this vertical confinement makes SP very attractive for the design of optical devices in coplanar geometry. An important e…
Some considerations on the transmissivity of trirefringent metamaterials
2016
Nonlocal effects in metal–dielectric (MD) periodic nanostructures may typically be observed when the plasmonic particles and gaps are on the scale of a few tens of nanometers, enabling under certain conditions (succinctly for epsilon near zero) a collimated beam to split into three refracted signals. We developed a method for precisely evaluating the categorized transmissivity in an air/trirefringent metamaterial interface, which uses a fast one-dimensional Fourier transform and finite element solvers of Maxwell’s equations. In periodic arrays of MD nanofilms, it is proved a tunable transmissivity switch of the multirefracted beams under varying angle of incidence and wavelength, while keep…
Incident angle effect on heavy ion induced reverse leakage current in SiC Schottky diodes
2016
Heavy-ion induced degradation in the reverse leakage current of SiC Schottky power diodes shows distinct dependence on the angle of incidence. TCAD simulations have been used to study the physical mechanisms involved.
Near-Field Distribution of Optical Transmission of Periodic Subwavelength Holes in a Metal Film
2000
Recent experimental discovery of the enhanced optical transmission through metal films with periodic subwavelength holes has given rise to a considerable interest in the optical properties of such structures due to their possible numerous applications in optics and optoelectronics as well as rich physics behind the phenomenon of the transmission enhancement [1–4]. The transmission of a subwavelength aperture is very low and proportional to the fourth power of the ratio of its diameter and light wavelength. However, if a metal film is perforated with a periodic array of such holes, the optical transmission can be significantly enhanced [1]. Being normalized to the total area of the illuminat…
Local excitation of surface plasmon polaritons at discontinuities of a metal film: Theoretical analysis and optical near-field measurements
2002
Nonresonant excitation of surface plasmon polaritons at discontinuities of a gold film is numerically studied and experimentally observed with scanning near-field optical microscopy. It is shown that surface polaritons can be effectively launched at the edges of a metal film illuminated at an angle of incidence greater than the resonant angle of surface polariton excitation. The electromagnetic near-field distribution over a thin metal film exhibits significantly different features under resonant and nonresonant excitations due to different surface polariton excitation mechanisms. In the latter case the field distribution is determined by the interference of the excitation light and surface…
Energy- and angle-dependent threshold photoemission magnetic circular dichroism from an ultrathin Co/Pt(111) film
2010
Threshold photoemission magnetic circular dichroism (TPMCD) in one-photon photoemission (1PPE) and two-photon photoemission (2PPE) is measured at an ultrathin Co film grown on Pt(111). Energy-dependent measurements reveal maximum asymmetries directly at the photoemission threshold (1.90% for 1PPE and 11.7% for 2PPE) which weakly decrease with increasing photon energy. The measured TPMCD asymmetries are discussed in two excitation models on the basis of spin-resolved band-structure calculations. For the model of direct band-to-band transitions in other k directions than the direction of observation (Gamma-L) ab initio calculations for 1PPE and 2PPE are performed. The theory is in reasonable …
Calibration of the XRT-SOLARB flat mirror samples at the XACT Facility of INAF-OAPA
2004
The X-Ray Telescope (XRT) experiment on-board the Japanese satellite SOLAR-B (launch in 2006) is equipped with a modified Wolter I grazing incidence X-ray telescope (focal length 2700 mm) to image the full Sun at ~ 1.5" angular resolution onto a 2048 x 2048 back illuminated CCD focal plane detector. The X-ray telescope consisting of one single reflecting shell is coated with ion beam sputtered Iridium over a binding layer of Chromium to provide nearly 5 square centimetres effective area at 60 A. We present preliminary results of X-ray calibrations of the XRT flat mirror samples performed at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF-OAPA. We describe the instrumenta…
Calibration of the Lunar Orbital X-ray Fluorescence Imaging Spectrometer (LOXIA) of Chang'E-1 satellite at INAF-OAPA
2007
The Lunar Orbital X-ray Fluorescence Imaging Spectrometer (LOXIA) designed and constructed at the Institute of High Energy Physics of the Chinese Academy of Sciences to perform chemical composition analysis of the Moon surface will operate on-board the Chang'E-1 mission, the first Chinese lunar spacecraft to be launched in 2007. We report the main results of the calibration measurements that we have performed using the X-ray beamline of the XACT facility of INAFOsservatorio Astronomico di Palermo G.S. Vaiana to determine the quantum efficiency of the XRS detector in the soft X-rays as a function of photon energy and angle of incidence.
Multimodal reflectivity of CRIGF filters: First experimental observation and modelling
2015
International audience; Cavity Resonator Integrated Guided-mode Resonance Filter (CRIGF) are a new class of filtering reflectors whose selected wavelength and spectral width are independent of the angle of incidence unlike GMRF. These particular properties allow both compactness and a high angular acceptance. However, ours studies show that CRIGFs offer simultaneously spectral and modal filtering and we evidence high-spatial-order reflected modes. In this paper, we will present characterization of the spectral and spatial profile that demonstrates the existence of these high-order modes. In addition, we will present a model based on the physical understanding of implied phenomena to explain…
Compact dielectric reflective elements II Multichannel filter of closely spaced spectral bands
1994
The optical design of an interference wedge filter providing the simultaneous separation of a number of closely spaced spectral bands is studied. Multiple reflections of the incident collimated beam within the wedge are initiated, each of them characterized by a different angle of incidence and consequently by specific spectral parameters of the transmitted band. Model calculations based on the measured angular dependences of filter transmission parameters have been performed. The design is proposed for applications in optical communications (wavelength division demultiplexing), analytical spectroscopy (minipolychromators), color analysis, and similar areas.