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The paper presents transmission and reflection properties of multilayered chiro-ferrite mediums-based structure under the π/4 oblique angle of incidence of the electromagnetic (EM) wave. The spectral characteristics of bi-layer periodic structure revealed its possible usage as optical filter under the choice of suitable parameters. In particular, the chiro-ferrite structure under consideration can act as band-stop filter without the usage of defects in the configuration. Furthermore, in the case of TM-polarized wave, the structure exhibited strong filtering properties.

The paper deals with scattering of electromagnetic (EM) waves by perfectly magnetic conducting (PMC) cylinder coated with chiro-ferrite medium under the assumption of oblique angle of incidence wave with perpendicular polarization (transverse electric; TE). An on-demand (in respect of orientation) kind of conducting sheath helix structure is assumed to exist at the outer surface of cylinder. The effects of sheath helix orientation, along with the material parameters, such as chirality admittance and gyrotropy, on the echo width as well as the magnitude and phase of the electric and magnetic fields are investigated. Control on the anisotropic property remains greatly useful in obtaining the required optical response from the scatterer — the feature which would find fabulous sensing related applications.

A new process for simultaneous generation and positioning of microdroplets within a single step named oblique interface shearing (OIS) is reported based on the observation that liquid microdroplets generated by vibrating a thin capillary across the air-liquid interface at an oblique angle exhibit notable lateral displacements. An analytical model is established to describe the lateral droplet displacement induced by the Stokes drift effect. The dependency of the lateral displacement on typical operating parameters allows for on-demand droplet positioning while they are produced. The efficacy of the process is validated through delivering microdroplets with the same size to different positions as well as size-dependent positioning of these microdroplets.

Recent studies have demonstrated that extended imaging depth can be achieved using dual-axis optical coherence tomography (DA-OCT). By illuminating and collecting at an oblique angle, multiple forward scattered photons from large probing depths are preferentially detected. However, the mechanism behind the enhancement of imaging depth needs further illumination. Here, the signal of a DA-OCT system is studied using a Monte Carlo simulation. We modeled light transport in tissue and recorded the spatial and angular distribution of photons exiting the tissue surface. Results indicate that the spatial separation and offset angle created by the non-telecentric scanning configuration promote the collection of more deeply propagating photons than conventional on-axis OCT.

Advanced materials interfaces 5(18), 1800530 (2018). doi:10.1002/admi.201800530, This work reports a thorough characterization analysis of various porous thin film multilayers by means of grazing‐incidence small‐angle X‐ray scattering (GISAXS). Alternated TiO2/SiO2 nanocolumnar layers deposited at oblique angles are fabricated in slanted, chiral, and zig‐zag configurations by rotating azimuthally the substrate from one layer to the next. Multilayer systems formed by the stacking of 3 and 15 alternant thin films of these two oxides are morphologically characterized by scanning electron microscopy (SEM) and structurally by GISAXS. This technique has provided a means to determine various vertical and lateral correlation lengths and to assess the anisotropic electron density distribution along the structural elements existing in the multilayers. This information can be systematically used to account for the actual arrangement of nanostructural elements in multilayer systems., Published by Wiley-VCH, Weinheim

In this work we analyze a phenomenon that takes place when growing magnetron sputtered porous/compact multilayer systems by alternating the oblique angle and the classical configuration geometries. We show that the compact layers develop numerous fissures rooted in the porous structures of the film below, in a phenomenon that amplifies when increasing the number of stacked layers. We demonstrate that these fissures emerge during growth due to the high roughness of the porous layers and the coarsening of a discontinuous interfacial region. To minimize this phenomenon, we have grown thin interlayers between porous and compact films under the impingement of energetic plasma ions, responsible for smoothing out the interfaces and inhibiting the formation of structural fissures. This method has been tested in practical situations for compact TiO/porous SiO multilayer systems, although it can be extrapolated to other materials and conditions., Authors acknowledge the University of Seville (VPPI-US), the Junta de Andalucía (TEP8067, TEP5283 and P12–2265MO) and the Ministry of Economy and Competitiveness of Spain (MAT2013-42900-P, MAT2013-40852-R, MAT2016-79866-R, MAT2015-69035-REDC) for financial support.

When investigating nickel (Ni) thin films deposited by using an oblique angle deposition (OAD) technique, we find a strong correlation between the structural, electrical, and optical properties. The microstructure of the Ni thin-films is largely influenced by the deposition angle of the OAD technique. By increasing the deposition angle, we find that the sheet resistance of the Ni thin-films increases superlinearly and that the optical reflectance of the films increases. These results are explained by the degree of formation of a columnar nanostructure during OAD deposition.

SiO2 nanocolumns as spacers are introduced into plasmonic antireflective structure by oblique angle deposition. The deposition angles determine the morphology of SiO2 and the size distributions of Ag particles, which results in different reflections.

CuIn 0.8 Ga 0.2 Se 2 (CIGS) is a chalcogenide semiconducting material used as absorbing layer in photovoltaic cell. In the present study, CIGS thin films were deposited on bare soda lime glass substrate by RF magnetron sputtering at various oblique angles. The structural, surface morphological, film surface roughness, optical, and electrical properties of CIGS thin films were studied at various oblique angles. Films were characterised by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Atomic force microscopy (AFM), UV-Vis-NIR spectrophotometer and four probe method. XRD revealed that all the deposited thin films were polycrystalline with preferred peak intensity along (112) plane. The film deposited at 0° (target- substrate parallel) exhibited larger crystallite size (28 nm) with low dislocation density (1.2×10 15 lines m -2 ). The film surface at this angle was more compact and uniform in comparison to the films deposited at other deposition angles. The optical data revealed that the film exhibits more transparency (23%) at higher oblique angle (60°). The optical band gap of developed film was found to be 1.33 eV at 60° while 1.14 eV at 0°. Slanting morphology was observed at higher oblique angle. The electrical resistivity was following an increasing trend with rise in oblique angle.

Plasmonics based on localized surface plasmon resonance (LSPR) has found many exciting applications recently. Those applications usually require a good morphological and structural control of metallic nanostructures. Oblique angle deposition (OAD) has been demonstrated as a powerful technique for various plasmonic applications due to its advantages in controlling the size, shape, and composition of metallic nanostructures. In this review, we focus on the fabrication of metallic nanostructures by OAD and their applications in plasmonics. After a brief introduction to OAD technique, recent progress of applying OAD in fabricating noble metallic nanostructures for LSPR sensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, metal-enhanced fluorescence, and metamaterials, and their corresponding properties are reviewed. The future requirements for OAD plasmonics applications are also discussed.

To determine the individual values of the two strain components by separate principal strains, a theoretical model of strain separation by oblique incidence with a new luminescent photoelastic coating configuration is presented. Considering the non-strain related refraction effect included in the total optical response at oblique incidence, the small incidence angle technique for simplifying the post-processing complexity is given. To affirm the validity of this strain separation method based on small oblique angles, the signal-to-noise ratio for providing sufficient signal intensity has been theoretically analyzed.

Silicon solar cell modules, where the EVA layer is replaced by an air gap, are able to produce the same electric power as standard modules with EVA only if their anti-reflective properties are enhanced. We propose a method to do this by exploiting the fact that, on Si surfaces textured with random pyramids, light incident from near normal angle always hits at least two pyramidal faces before being reflected back toward the sun. If these two faces are covered with an anti-reflective coating (ARC) made of one and the same material but with two different thicknesses, the coating acts as a double ARC. Such a coating can be produced by depositing the SiN x layer from an oblique angle,optimally from 14.7°. Our detailed raytracing analysis predicts that J sc can then be improved by 0.2 mA/cm 2 for normal incident sunlight and AM1.5 g standard illumination, and is improved for all angles within a cone with an apex angle of approximately 64°. Furthermore, the coating can be optimized for modules in vertical mounting, where a Jsc gain of 0.1 mA/cm2 is predicted for an angle of incidence of 40°.

The plasmonic property of Ag patchy particles fabricated using a colloid monolayer and oblique angle deposition shows significant variations due to the multidomain nature of the monolayer. A swinging oblique angle deposition method is proposed to create uniform patchy particles. Both numerical calculations and experiment show that when the swinging angle is larger than 90°, the resulting plasmonic patchy particles have similar morphology and demonstrate uniform optical response that does not depend on the monolayer domain orientation. These uniform patchy plasmonic particles have great potential for plasmonic-based applications.

The oriented Co80Ir20 soft magnetic thin films with adjustable in-plane uniaxial anisotropy field and strong negative magnetocrystalline anisotropy ( $$K_{\text{u}}^{\text{grain}}$$ ) were fabricated by magnetron sputtering. The oblique angle dependence of the static and high-frequency properties for the oriented Co80Ir20 soft magnetic films was systematically investigated. The results suggest that the in-plane uniaxial anisotropy field (H u) can be adjusted by changing the oblique angle, while the total out-of-plane anisotropy field remains invariable. With the increase in the oblique angle, the value of H u varies from 80 to 310 Oe. As a result, the natural resonance frequency (f r) significantly increases from 4.6 to 7.9 GHz.

Oblique angle ion etching at incidences of 30° and 75° from surface normal were used to produce sharp tipped topographical features on Ti6Al4V alloy. The 30° etching resulted in a random distribution of needles raising ~ 4 μm from the base surface, while needles from the 75° etching laid closer to the surface. The cellular response of these surfaces was evaluated by a weeklong culture of hFOB 1.19 cells. It was shown that the features of the 30° etch prevented cells from spreading while cells on the 75° etched surface displayed preferential elongation in the direction of the needles.

A well-aligned composition-graded CuSi nanorod array structure has been fabricated by a simple oblique angle codeposition technique in a physical vapor deposition system. The Cu and Si graded compo...

Oval shape footballs used in American and Canadian football are similar in size, shape and weight to those used in Rugby League, Rugby Union and Australian Rules, all being about 28 cm long, 60 cm in circumference and weighing about 410 g. A generic football fitting that description was filmed with a video camera at 100 fps (frames per second) to determine its bounce properties. Compared with a spherical ball, the bounce of an oval shaped football is less predictable since the normal reaction force can act ahead of or behind the centre of the ball, depending on its alignment on impact with the ground. Projected at an oblique angle without spin or with backspin, a football usually bounces backward if the top end points backward on impact. Projected with topspin, a football usually bounces forward, but it can sometimes bounce to a much larger height than usual, or roll for a short distance before it bounces. The coefficient of restitution was found to be greater than unity in some cases. Another surprise wa...

This work presents a new automatic high-order shimming method that maps the B(0) field using a group of parallel columns. We found that a pair of four columns in two separate slices could determine an optimal correction field comprising the spherical harmonic terms up to the third-order. The technique of multiple stimulated echoes was incorporated into the method, allowing the use of at least eight shots to accomplish field mapping. The shim currents were first determined in the logic frame by assuming that the slices were in axial planes, and then uniquely converted into the physical frame where the slices could be at any oblique angle, by using a spherical harmonics rotation transformation. This method thus works regardless of slice orientation. It was demonstrated on a 3T scanner equipped with a complete set of second-order harmonic shim coils. Both phantom and in vivo experiments showed that this newly introduced high-order shimming method is an effective and efficient way to reduce field inhomogeneity for a region of imaging slices.

This paper investigates the application of a novel frequency selective surface (FSS) reflector for 4×2 dipole array antenna to reduce radar cross section (RCS) out of operating band. The proposed FSS adopting a regular hexagon quasi-fractal structure has good bandstop characteristic. By replacing the metal reflector with this bandstop FSS sheet, the in-band radiation performance of the proposed array antenna is preserved, while the out-of-band backward RCS is significantly reduced. Due to the good angle stability of the given FSS, the monostatic RCS peaks at oblique angle ( = 60°, ϕ = 0°) are also controlled. The measured results demonstrate the feasibility of antenna RCS reduction by this method.

Most investigations of Jaumann and circuit analog absorbers (CA absorbers) consider normal angle of incidence only. This paper expands our investigation to also include oblique angle of incidence as well as arbitrary polarization. Essentially two problems are encountered for oblique angle of incidence: An upward shift of the center frequency; and a mismatch that, in general, will vary with angle of incidence of the incident field. The new contribution given in this paper is that it considers ways to combat both of these dilemmas. Finally, comparison will be made with similar designs obtained by the genetic algorithm (GA) approach. It will be observed that the analytic approach, as used in this paper, in general leads to designs that are not only superior to the GA designs but also simpler, at least in the present case

Metamaterial emitters have previously been studied for controlling the angle and polarization of near-IR emissivity from a surface. Here, we investigate bianisotropic metamaterials that can be tailored to have custom angle-dependent emissivity polarization profiles in the near-IR. A genetic algorithm is employed to synthesize an electromagnetic band-gap metamaterial structure that transitions from linear polarization normal to the surface to circular polarization at a preselected oblique angle.

A novel surface angle measurement technique is described using an LPC for surface inclinations between 20° and 70°. The technique utilizes the Fresnel transmission equations and a similar experimental setup for measuring strain. Measurement of the optical Fresnel response is necessary for accurate strain measurements. Additionally, the oblique angle intensity responses between a luminescent and reflective photoelastic coating are compared. The LPC exhibits a considerably more diffuse emission characteristic than the RPC. At 30° and 60°, respectively, the LPC normalized intensity retains 88% and 49% compared to 25% and 4% for the RPC, enabling more accurate strain measurements at higher surface inclinations.

We have developed a method for measurement of internal stress in glass articles. The method uses Rayleigh-scattered light from a properly polarized laser beam propagating through glass at an oblique angle. This light is imaged with an electronic focal plane array camera. The method is similar to earlier published methods except for the inclusion of an externally controlled phase retarder. The phase retarder allows for the success of the method. The method is suitable for use on flat or curved glass and is applicable over a broad range of residual stresses. Experimental results are provided showing the in-plane stress throughout the thickness of a television glass sample.

FeNi thin films were fabricated by radio frequency magnetron sputtering on Si(1 1 1). Dynamic properties at remanence of the films were systematically investigated in a wide frequency range from 100 MHz to 5 GHz. The results show that both thickness of FeNi films and oblique angle have important effects on the magnetic properties of the films, the magnetic resonant frequency of the films can also be adjusted by the two factors. The in-plane uniaxial magnetic anisotropy field can be adjusted from 82 Oe to 220 Oe by increasing the oblique angle. As a consequence, the magnetic resonant frequency of the films increased from 2.7 GHz to 4.2 GHz.

It has long been known that the use of finely textured transparent conducting oxide layers substantially improves the performance of thin film amorphous silicon (a-Si:H) solar cells. Major efforts to understand the nature of this effect and to fully capture its potential have been made by researchers using advanced modeling techniques. In this work, modeling the oblique angle optical performance and use of an effective medium approximation to simulate microrough interfaces suggests that effective interface grading makes a significant contribution to optical enhancement.

We report on efforts to develop a theory to understand director oscillations that are generated when a linearly polarized light-wave falls on a homeotropically aligned nematic at a slightly oblique angle. The results of various approaches are compared with each other and to experimental results.

In this study, numerical approaches were applied to theoretically investigate the influence of process parameters, such as the incident angle and the deposition rate, on the nanostructural formation of thin films by oblique angle deposition (OAD). A continuum model was first developed, and the atomic diffusion, shadowing effect and steering effect were incorporated in the formation mechanisms of the surface morphology and nanostructure of the deposited films. A characteristic morphology of columnar nanorods corresponding to an OAD was well reproduced through this kinetic model. With the increase of the incident angle, the shadowing effect played a significant role in the columnar structures and the ratio of the surface area to volume was raised, implying a high level of voids in the nanostructures. When the deposition rate decreased, the porosity was notably suppressed due to the atomic diffusion in the growth process. These simulation results coincide well with many experimental observations. With the manipulation of the numerical simulations, the underlying mechanisms of the morphological formation during OAD were revealed, which also provided plentiful information to stimulate the process designs for manufacturing advanced materials.

The time-averaged path independent J-integral for a stationary crack subjected to time-harmonic elastic waves is introduced. It can be determined from remote fields providing an alternative approach to compute the stress intensity factors. The J-integral is evaluated for a semi-infinite crack impinged by a plane sheer wave at an oblique angle.

We studied the effects of liquid crystal (LC) alignment characteristics on a SiOx thin films of various thicknesses deposited at an oblique angle of 45° by RF magnetic sputtering. A uniform LC alignment characteristic was achieved on the SiOx thin film, and the pretilt angle was about 90°. The thermal stability of the SiOx thin film was sustained until 200 °C. There was no difference in LC aligning capability owing to the thickness of SiOx thin film obliquely deposited at 45°. The vertical alignment liquid crystal display (VA-LCD) on the SiOx thin film deposited at the oblique angle of 45° by sputtering showed good electrooptical characteristics. These results suggest that a uniform homeotropic LC alignment can be achieved and a large VA-LCD can be produced by sputtering.

EUVL requires a high yield of low-defect density reflective mask blanks, one of the top two critical technology gaps for the commercialization of this technology. One of the major sources of mask blank defects is the top of the substrate due to substrate quality, cleaning residue, and handling- or storage-induced defects. SEMATECH’s current inspection tool, the Lasertec 7360, can detect defects down to 37 nm on quartz substrates in dense scan mode. Defects below 40 nm on these substrate are difficult to detect, which challenges the quantification and characterization, and hence the determination of defect sources. SEMATECH developed a thin film decoration technique to quantify sub-40 nm defects and analyze composition to pinpoint defect sources. The technique involves oblique angle deposition in an ion beam deposition system, which decorates the particle. The decoration of particles is optimized by depositing enough thin film so that defects can be detected by the Lasertec7360 and yet keeping the film thin enough to employ several metrology techniques to efficiently analyze defect composition. The challenges involved with the metrology of such embedded defects and the impact of oblique angle deposition will be discussed. A theoretical model of defect decoration that can successfully simulate the thin film deposition on top of the defects will be provided. The effect of angle, deposition rate, and deposition time to quantify the decoration effect will also be presented.

Oblique angle metal deposition has been combined with high aspect ratio imprinted structures to create wire grid polarizers (WGP’s) for use as polarization recyclers in liquid crystal displays. The process of oblique deposition was simulated to determine optimal feature profile and deposition geometry. The optical results for the oblique deposition WGP show contrast comparable to a conventionally etched WGP. The next steps to the fabrication of meter sized WGP are proposed.

Oblique angle metal deposition has been combined with high aspect ratio imprinted structures to create wire grid polarizers (WGP’s) for use as polarization recyclers in liquid crystal displays. The optical results for the oblique deposition WGP show contrast comparable to a conventionally etched WGP. In addition, the WGP showed improved spectral and spatial uniformity as compared to a multilayer reflective polarizer. The next steps to the fabrication of meter sized WGP are proposed.

A new instrument for automatic recordings of angular dependent transmittance through thin film samples is described. The output is a polar plot giving a schematic and convenient overview of the optical performance. The usefulness of the instrument and procedures was documented by measurements on an angular selective Cr film prepared by oblique angle evaporation.

Strongly angular‐selective thin Cr films were made by oblique angle evaporation. The optical transmittance could be quantitatively modeled by the Bruggeman effective medium theory applied to inclined structural units.

The Talbot effect is investigated for oblique angles of illumination. From the transfer function of free space assuming small diffraction angles we calculate the self-imaging condition for periodic diffractive elements. Additionally, aberrations are considered, which are of third order in spatial frequency. These aberrations originate from the asymmetric off-axis configuration and cause distortions of the self-images. We include experimental verifications of our considerations and suggest applications of the off-axis Talbot effect to planar optics.

A newly designed cylindrical optical micro-rotor which has slopes for trapping and rotation on its top is proposed. The cylindrical shape is effective in decreasing medium viscosity. Rotation is induced not only by a focused beam but also by a parallel (unfocused) beam. A ray-tracing method considering beam waist is employed for analyzing the radiation pressure exerted on the top and the bottom of the rotor. We theoretically demonstrate optical trapping and high speed rotation for various rotor shape parameters such as oblique angle, height and diameter.

It has been found that at the electrohydrodynamic convection in the hybrid aligned nematics the oblique rolls are formed. These patterns are not stationary. The dependencies of the threshold voltage, drift velocity of rolls and oblique angle on the frequency of the AC electric field have been measured.

This Letter reports a novel method for the simple fabrication of microlens arrays with a controlled shape and diameter on glass substrates. Multilayer stacks of silicon dioxide deposited by oblique angle deposition with hole mask patterns enable microlens formation. Precise control of mask height and distance, as well as oblique angle steps between deposited layers, supports the controllability of microlens geometry. The fabricated microlens arrays with designed geometry exhibit uniform optical properties.

Al-doped ZnO thin films were grown by rf-sputtering using the oblique angle deposition technique. The films are formed by tilted dense nanocolumns according to the substrate inclination during the growth. The film refractive index changed 16% due to the film nanocolumn tilt from 0° to 13.5°, which corresponded to substrate inclination from 0° to 75°, respectively. Band gap energy was found to diminish, which was associated to local redistribution of Al concentration x in the Al x Zn1−x O solid solution around the x 0.02 average.

The aim of this method is to determine the thickness of a transparent medium, close to the corneal thickness, using the angle at the first and second Purkinje images are aligned for a specific optical slit width. An optical slit is projected in an oblique angle relatively to the transparent medium, producing two different reflections in each medium surface (first and second Purkinje images). The slit is then moved until the first and second Purkinje images of the slit are aligned in such a way, that look as if they were a continuous slit. The slit width, the angle between the illumination and observation, and the medium index are used, then, to calculate the medium thickness. This method was implemented in a slit lamp and the central thicknesses (CT) of nine gas-permeable contact lenses (CL) were measured, with this method and a mechanical gauge and the results were compared. The mean CT difference ± standard deviation, between the two methods was 0.004 ± 0.008 mm with minimum and maximum absolute values of 0.002 and 0.019 mm. This technique showed good precision to measure the CT of CL and should be tried in human corneas.

On-lattice particle simulation is one of the most common types of Monte Carlo simulations used in studying the dynamics of film growth. We report the observation of a large artificial anisotropic growth rate variation owing to the fixed arrangement of particles in an on-lattice simulation of oblique angle deposition. This unexpectedly large anisotropy is not reported in previous literatures and substantially affects the simulation outcomes such as column angle and porosity, two of the most essential quantities in obliquely deposited nanostructures. The result of our finding is of interest to all on-lattice simulations in obliquely deposited films or nanostructures.

Soil roughness parameters have been traditionally retrieved using altimetric profiles acquired from profilometer devices. Measuring soil roughness using the technology called Terrestrial Laser Scanner (TLS) is an innovative method because of it is possible to get a three-dimensional surface more realistic than previous approaches. This paper shows a comparison between both techniques for different kind of soil roughness. A multilateral-based acquisition is proposed for TLS measurement. Analyses are made with profiles from the same soil samples acquired using a profilometer and a TLS. Profile-to-profile comparison got altimetric correlation between both devices and how soil roughness parameters are affected with. Results offer a straight relation (R=0.92 globlally) between both datasets. The oblique angle used by multilateral acquisition in TLS reports a smoother value than vertical acquisition by profilometer