Fresnel Effects Research Articles

Nonlinear optical response of a gold surface in the visible range: A study by two-color sum-frequency generation spectroscopy. I. Experimental determination

We experimentally determine the effective nonlinear second-order susceptibility of gold over the visible spectral range. To reach that goal, we probe by vibrational two-color sum-frequency generation spectroscopy the methyl stretching region of a dodecanethiol self-assembled monolayer adsorbed on a gold film. The sum-frequency generation spectra show a remarkable shape reversal when the visible probe wavelength is tuned from 435 to 705 nm. After correcting from Fresnel effects, the methyl stretching vibrations serve as an internal reference, allowing to extract the dispersion of the absolute phase and relative amplitude of the effective nonlinear optical response of gold in the visible range.

Rapid optical determination of topological insulator nanoplate thickness and oxidation

The stability of 2D antimony telluride (Sb2Te3) nanoplates in ambient conditions is elucidated. These materials exhibit an anisotropic oxidation mode, and CVD synthesized samples oxidize at a much faster rate than exfoliated samples investigated in previous studies. Optical measurement techniques are introduced to rapidly measure the oxidation modes and thickness of 2D materials. Auger characterization were conducted to confirm that oxygen replaces tellurium as opposed to antimony under ambient conditions. No surface morphology evolution was detected in AFM before and after exposure to air. These techniques were employed to determine the origin of the thickness dependent color change effect in Sb2Te3. It is concluded that this effect is a combination of refractive index change due to oxidation and Fresnel effects.

Multi-scale rendering of scratched materials using a structured SV-BRDF model

We introduce a Spatially-Varying BRDF model tailored to the multi-scale rendering of scratched materials such as metals, plastics or finished woods. Our approach takes advantage of the regular structure of scratch distributions to achieve high performance without compromising visual quality. We provide users with controls over the profile, micro-BRDF, density and orientation of scratches, while updating our material model at interactive rates. The BRDF for a single scratch is simulated using an optimized 2D ray-tracer and compactly stored in a three-component 2D texture. In contrast to existing models, our approach takes into account all interreflections inside a scratch, including Fresnel effects. At render time, the SV-BRDF for the scratch distribution under a pixel or ray footprint is obtained by linear combination of individual scratch BRDFs. We show how to evaluate it using both importance and light sampling, in direct and global illumination settings.

A parametric reflectance approximation for rendering Japanese lacquerware and Maki-e

This paper proposes a reflectance distribution model that is able to express complex reflections from materials such as Japanese lacquerware and Maki-e to produce highly realistic computer graphics. Our method improves the Ward model for materials with anisotropic reflection, and uses the approximate coefficients calculated from measured reflectance distribution data to reconstruct the actual reflectance. Our research derives a Gaussian distribution summation method and a modified Fresnel reflectance approximation function from measured reflectance data. Our Fresnel reflectance approximation function adds parameters to Schlick's approximation function to control the whole curve and extinction component, and is thus closer to the actual Fresnel reflectance. Based on these functions, a decision process is developed for the approximation coefficients, and this makes it possible to easily reconstruct the actual reflectance. The reconstructed reflectance distributions obtained using these coefficients are compared with measured reflectance data using the L2 norm of the difference. In addition, reconstructed Fresnel reflection effects are compared with those from actual sample materials. Using these coefficient values, this paper shows a sample of simulated Maki-e images under two different lighting environments.

Curvature dependence of semiclassical corrections to ray optics: How Goos-Hänchen shift and Fresnel filtering deviate from the planar case result

Ray optics is a useful tool even in the regime where, actually, full wave calculations would be appropriate. However, wave-inspired adjustments are needed to ensure the accuracy of ray-based predictions. Here, we investigate these semiclassical corrections to the ray picture —the Goos-Hänchen shift and the Fresnel filtering effect— for the reflection of light beams at curved, rather than planar, interfaces. We present analytical and numerical results that highlight the role of boundary curvature and show clear deviations from the planar case. The Goos-Hänchen shift is decreased at convexely curved interfaces present in optical microcavities and microlasers compared to the planar case, and increased for concave curvature. In contrast, the Fresnel filtering effect is increased by both kinds of curvature. For a straightforward explanation of these findings we introduce an intuitive picture that explicitly takes curvature into account and that allows for a qualitative understanding of the beam shift behaviour.

Scattering by multiple perfectly conducting cylinders buried in a lossy half space

The analytical solution for scattering of electromagnetic wave by an arbitrary configuration of parallel infinite cylinders buried in a lossy half space is presented in this paper. The cylinders are perfectly conducting and the incident wave is arbitrarily polarized that propagates in the plane perpendicular to the axes of the cylinders. The formulation accounts for the Fresnel effect at the half space interface, absorption of electromagnetic wave by the lossy medium, and near-field interaction between the cylinders. Near-field and far-field formulas are derived for the electric and magnetic fields and Poynting vector of radiation emerging from the half space. Numerical results are shown for scattering by two different configurations of perfectly conducting cylinders buried in a lossy half space.

Scattering by a radially stratified infinite cylinder buried in an absorbing half-space

This paper presents a theoretical treatment of scattering by a radially stratified infinite cylinder buried in an absorbing, i.e., lossy, half-space. The permeability and refractive index of the host medium and cylinder layers are generally complex. The half-space is irradiated by an arbitrarily polarized plane wave that propagates in the plane perpendicular to the axis of the cylinder. The theoretical formulation rigorously accounts for the Fresnel effect at the half-space interface, interaction of the cylinder with scattered waves that are reflected from the interface, and attenuation of the propagating waves by the host medium. Analytical formulas are derived for the electric and magnetic fields and Poynting vector of the scattered waves emerging from the half-space. Numerical results on backscattering are shown for the cases of a homogeneous and a hollow cylinder buried at various depths in an absorbing half-space.

On the Role of Fresnel Factors in Sum-Frequency Generation Spectroscopy of Metal–Water and Metal-Oxide–Water Interfaces

We performed sum-frequency generation (SFG) spectroscopic measurements on water in contact with supported thin metal and metal-oxide films. We employed an internal reflection configuration and varied the angles of incidence of the visible and infrared beams and measured the SFG signals using different polarization combinations. While SFG is a surface-specific vibrational spectroscopy, the shape of the SFG spectra can be fully accounted for by the bulk response of the materials through the frequency-dependent enhancement of the local incident infrared fields at the interface, i.e., Fresnel effects. We find that the dispersion of the refractive index of the bulk water phase leads to a strong enhancement of the electric field at the interface at specific infrared frequencies. These local, frequency-dependent fields act on the frequency-independent, nonresonant SFG response of the electrons at the surfaces of the metal or metal-oxide films. As a result, the measured SFG spectra closely follow this infrared fr...

Optimizing textured structures possessing both optical gradient and diffraction properties to increase the extraction efficiency of light-emitting diodes

The external quantum efficiency of a light-emitting diode (LED) is strictly limited by total internal reflection and Fresnel reflection effects. In this study, we sought to optimize light extraction by monitoring the shape effects of four kinds of periodic textured structures (nanorod, inverted rod, pyramid, inverted pyramid) on the surface of gallium nitride (GaN)-based LEDs. We employed the three-dimensional rigorous coupled waves approach to calculate the direct emissions at different incident angles on the various textured structures, and then determined an optimized structure that would improve the extraction efficiency of LEDs. The optical gradient of the inverted pyramid structure could decrease not only the Fresnel reflection at incident angles less than the critical angle but also the total internal reflection at incident angles greater than the critical angle. Many inverted pyramid structures at the GaN–air interface, with various sizes and periods, provided enhancement factors of greater than 150%.

Directional waveguide coupling from a wavelength-scale deformed microdisk laser

We demonstrate uni-directional evanescent coupling of lasing emission from a wavelength-scale deformed microdisk to a waveguide. This is attributed to the Goos-Hänchen shift and Fresnel filtering effect that result in a spatial separation of the clockwise (CW) and counter-clockwise (CCW) propagating ray orbits. By placing the waveguide tangentially at different locations to the cavity boundary, we may selectively couple the CW (CCW) wave out, leaving the CCW (CW) wave inside the cavity, which also reduces the spatial hole burning effect. The device geometry is optimized with a full-wave simulation tool, and the lasing behavior and directional coupling are confirmed experimentally.

Practical and accurate calculations of Askaryan radiation

An in-depth characterization of coherent radio Cherenkov pulses from particle showers in dense dielectric media, referred to as the Askaryan effect, is presented. The time-domain calculation developed in this article is based on a form factor to account for the lateral dimensions of the shower. It is computationally efficient and able to reproduce the results of detailed particle shower simulations with high fidelity in most regions of practical interest including Fresnel effects due to the longitudinal development of the shower. In addition, an intuitive interpretation of the characteristics of the Askaryan pulse is provided. We expect our approach to benefit the analysis of radio pulses in experiments exploiting the radio technique.

Matting and compositing of transparent and refractive objects

This article introduces a new approach for matting and compositing transparent and refractive objects in photographs. The key to our work is an image-based matting model, termed the Attenuation-Refraction Matte (ARM), that encodes plausible refractive properties of a transparent object along with its observed specularities and transmissive properties. We show that an object's ARM can be extracted directly from a photograph using simple user markup. Once extracted, the ARM is used to paste the object onto a new background with a variety of effects, including compound compositing, Fresnel effect, scene depth, and even caustic shadows. User studies find our results favorable to those obtained with Photoshop as well as perceptually valid in most cases. Our approach allows photo editing of transparent and refractive objects in a manner that produces realistic effects previously only possible via 3D models or environment matting.

Disturbance Effects in Extreme Ultraviolet Interferometric Lithography Affecting Interference Fringes

We set up an extreme ultraviolet (EUV) interferometer lithography tool dedicated to the study of the photoresist properties at the EUV wavelength. Two coherent beams are recombined to generate a standing wave, which can be recorded in a photoresist. However, other physical phenomena are generated by the interferometer structure which can disturb the quality of interference fringes. The Fresnel effect is one of these phenomena which is fully detailed in this work. Accurate numerical models have been compared to experimental studies to quantify the reduction of the interference area by the Fresnel effect. Depending on the Fresnel number (NF), several advantageous conditions are presented in order to reduce the Fresnel disturbance on resist.

Performance of piezoelectric transducers in terms of amplitude and waveform

For seismic physical modeling, piezoelectric transducers (PETs) usually are used as sources and receivers. Their properties affect data significantly, especially if data are processed as seismic data: (1) Strong resonance at one frequency causes a ringy signal and a narrow frequency band; (2) the pronounced directionality effectively limits the offsets at which energy arrives; and (3) because the dimension of the [Formula: see text] transducer is larger than the wavelength [Formula: see text], the recorded waveform changes with offset. To reduce the pronounced directionality of the transducers at ultrasonic frequencies, we designed PETs that have a smaller effective diameter than do traditional ones. To test their applicability for laboratory seismic profiling, we tested their frequency sensitivity, their directionality, and the change of waveform as a function of offset caused by their size relative to the wavelengths. The experiments showed that the PETs produce their best-quality data at frequencies of [Formula: see text] and source-receiver offsets of [Formula: see text]. For these frequencies, the amplitudes decay to ringing-noise level at incidence angles of [Formula: see text]; for a reflector [Formula: see text] deep, that results in a [Formula: see text] source-receiver offset. For these frequencies and offsets, the spacious dimension of the PETs does not cause the waveform to change such that further processing is compromised. We also developed an analytic solution to the changing-waveform problem that predicts the temporal divergence of the signal as an additional resolution limit to the Fresnel effect; the loss of high frequencies is caused not by by attenuation alone, but also by the spacious dimension of the sensors.

Drawing the line between kinematics and dynamics in special relativity

Special relativity is preferable to those parts of Lorentz's classical ether theory it replaced because it shows that various phenomena that were given a dynamical explanation in Lorentz's theory are actually kinematical. In his book, Physical Relativity, Harvey Brown challenges this orthodox view. I defend it. The phenomena usually discussed in this context in the philosophical literature are length contraction and time dilation. I consider three other phenomena in the same class, each of which played a role in the early reception of special relativity in the physics literature: the Fresnel drag effect, the velocity dependence of electron mass, and the torques on a moving capacitor in the Trouton–Noble experiment. I offer historical sketches of how Lorentz's dynamical explanations of these phenomena came to be replaced by their now standard kinematical explanations. I then take up the philosophical challenge posed by the work of Harvey Brown and Oliver Pooley and clarify how those kinematical explanations work. In the process, I draw attention to the broader importance of the kinematics–dynamics distinction.

Prismatic imaging polarimeter calibration for the infrared spectral region

The calibration of a complete Stokes birefringent prismatic imaging polarimeter (BPIP) in the MWIR is demonstrated. The BPIP technique, originally developed by K. Oka, is implemented with a set of four Yttrium Vanadate (YVO(4)) crystal prisms. A mathematical model for the polarimeter is presented in which diattenuation due to Fresnel effects and dichroism in the crystal are included. An improved polarimetric calibration technique is introduced to remove the diattenuation effects, along with the relative radiometric calibration required for the BPIP operating with a thermal background and large detector offsets. Data demonstrating emission polarization are presented from various blackbodies, which are compared to data from our Fourier transform infrared spectropolarimeter.

A Study of Fresnel Scattered Fields for Ellipsoidal and Elliptic-Disk-Shaped Scatterers

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The study of scattered fields from nonspherical scatterers is becoming an important subject particularly in the area of theoretical modeling of microwave backscatter from vegetation. The generalized Rayleigh–Gans approximation has been widely used in the calculation of scattered fields from scatterers where at least one of its dimensions is comparably smaller than the wavelength. In such calculations, far-field approximations are used, which are not accurate when the observation points are in the Fresnel and near-field regions of the scatterer. Hence, the effects of Fresnel phase and amplitude corrections for the scattered field of circular disks, needles, and cylinders have been examined and shown to be significant in the calculation of closely spaced scatterers. However, the effects of Fresnel corrections in the scattered fields from general ellipsoids and elliptic disks have not yet been studied. In this paper, the scattered fields from general ellipsoids and elliptic disks are formulated based on the generalized Rayleigh–Gans approximation for cases with and without Fresnel corrections. Theoretical analysis shows that the Fresnel effects are important particularly at larger frequencies and at the null locations in the plots of the backscattering cross section. These effects become more important as the ellipticity of the scatterer increases. Comparisons with measurement data demonstrate that the calculated results with Fresnel corrections provide a better match compared with those without. </para>

Vectorial imaging of deep subwavelength mask features in high NA ArF lithography

As silicon processes scale toward the 45-nm node using conventional 0.25-magnification, the feature sizes on the photomask are below the ArF (193.3 nm) laser wavelength. At these scales, traditional scalar and paraxial approximations used for optical image modeling are no longer valid. Thick-mask and vector-based rigorous models are equired to account for mask topographic effects and large incident angles at the reticle plane in ultra-high numerical aperture (NA) systems. Experimental depolarization measurements through advanced optical reticles at 193 nm are compared to rigorous finite-difference timedomain vector-based electromagnetic simulations. The validated simulation model is extended to explore the impact of polarization purity, mask absorber profile, mask film properties, and Fresnel effects through the pellicle on the imaging process window and requirements for optical proximity correction (OPC) in immersion imaging. The model has shown that line-end pullback has a strong correlation with mask shadowing under TE-polarized off-axis illumination (OAI).

The Fresnel effect of a defocused biprism on the fringes in inelastic holography

We present energy filtered holography experiments on a thin foil of Al. By propagating the reduced density matrix of the probe electron through the microscope, we quantitatively predict the fringe contrast as a function of energy loss. Fringe contrast simulations include the effect of Fresnel fringes created at the edges of the defocused biprism, the effect of partial coherence in combination with inelastic scattering, and the effect of a finite energy distribution of the incoming beam.

Effects of Fresnel Corrections in the Scattered Field of General Ellipsoids

The study of the scattered field of non-spherical scatterers is becoming an important field, especially in the remote sensing of vegetation. In this study, the scattered field of general ellipsoidal scatterers is formulated based on the generalized Rayleigh-Gans approximation, in which at least one of the dimensions of the ellipsoid is comparably smaller than the wavelength. The scattered field is formulated for the case in which far field approximations are used, as well as for the case in which the Fresnel zone effects are included. Results show that when the Fresnel corrections axe considered, the calculated backscattering cross section gives a better match with measurement data compared to when far field approximations are used.