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Articles 61 - 90 of 145
Full-Text Articles in Electrical and Electronics
Polarization Properties Of Corner-Cube Retroreflectors: Theory And Experiment, Jian Liu, R. M.A. Azzam
Polarization Properties Of Corner-Cube Retroreflectors: Theory And Experiment, Jian Liu, R. M.A. Azzam
Electrical Engineering Faculty Publications
Polarization properties of the corner-cube retroreflector are discussed theoretically by use of ray tracing and analytical geometry. The Jones matrices and eigenpolarizations of the six propagation trips of the corner-cube retroreflector are derived. An experiment is also set up for the determination of the linear eigenpolarizations and the output states of polarization for incident linearly polarized light. The experimental results are consistent with theoretical expectations.
Infrared Quarter-Wave Reflection Retarders Designed With High-Spatial-Frequency Dielectric Surface-Relief Gratings On A Gold Substrate At Oblique Incidence, Jian Liu, Rasheed M.A. Azzam
Infrared Quarter-Wave Reflection Retarders Designed With High-Spatial-Frequency Dielectric Surface-Relief Gratings On A Gold Substrate At Oblique Incidence, Jian Liu, Rasheed M.A. Azzam
Electrical Engineering Faculty Publications
One- and two-dimensional high-spatial-frequency dielectric surface-relief gratings on a Au substrate are used to design a high-reflectance quarter-wave retarder at 70° angle of incidence and 10.6-μm light wavelength. The equivalent homogeneous anisotropic layer model is used. It is shown that equal and high reflectances (>98.5%) for the p and the spolarizations and quarter-wave retardation can be achieved with two-dimensional ZnS surface-relief gratings. Sensitivities to changes of incidence angle, light wavelength, grating filling factor, and grating layer thickness are considered.
Determination Of The Refractive Index And Thickness Of Transparent Pellicles By Use Of The Polarization-Independent Absentee-Layer Condition, Y. Cui, R. M.A. Azzam
Determination Of The Refractive Index And Thickness Of Transparent Pellicles By Use Of The Polarization-Independent Absentee-Layer Condition, Y. Cui, R. M.A. Azzam
Electrical Engineering Faculty Publications
The refractive index and the thickness of a transparent pellicle are determined when the pellicle is placed between two vertical crossed polarizers and rotated in the horizontal plane. The transmission axes of the polarizers are neither parallel nor perpendicular to the plane of incidence. The light transmitted through the crossed polarizers reaches a minimum when the pellicle satisfies the absentee-layer condition. The refractive index and the film thickness are obtained from the pellicle orientation angles under such a condition.
Applications Of The Normal-Incidence Rotating-Sample Ellipsometer To High- And Low-Spatial-Frequency Gratings, Y. Cui, R. M.A. Azzam
Applications Of The Normal-Incidence Rotating-Sample Ellipsometer To High- And Low-Spatial-Frequency Gratings, Y. Cui, R. M.A. Azzam
Electrical Engineering Faculty Publications
The normal-incidence rotating-sample ellipsometer is an instrument that can be used to characterize grating surfaces from the measured ratio ρof complex reflection coefficients ry/rx of light polarized perpendicular and parallel to the grating groove direction. Experimental results at different wavelengths for different gratings with spatial frequencies from 150 to 5880 grooves/mm are presented. The groove depth of the 5880-grooves/mm gold-coated grating can be estimated from the measured ρ and rigorous grating theory.
Extreme Ultraviolet Polarizing Optics Using Bare And Aluminum-Coated Silicon Carbide, R. M.A. Azzam, A. M. Kan’An
Extreme Ultraviolet Polarizing Optics Using Bare And Aluminum-Coated Silicon Carbide, R. M.A. Azzam, A. M. Kan’An
Electrical Engineering Faculty Publications
A deformable three-reflection system that uses a bare silicon carbide substrate can function as an in-line, high-throughput (>30%), 90° phase shifter in the 50–100 nm spectral range. For a given extreme ultraviolet wavelength, an aluminum thin film can be deposited on the silicon carbide substrate to suppress the parallel (p) or perpendicular (s) polarization on single reflection or to introduce quarter-wave retardation and equal reflectances for incident p- and s-polarized light.
Single-Layer-Coated Surfaces With Linearized Reflectance Versus Angle Of Incidence: Application To Passive And Active Silicon Rotation Sensors, R. M.A. Azzam, M. M. K. Howlader, T. Y. Georgiou
Single-Layer-Coated Surfaces With Linearized Reflectance Versus Angle Of Incidence: Application To Passive And Active Silicon Rotation Sensors, R. M.A. Azzam, M. M. K. Howlader, T. Y. Georgiou
Electrical Engineering Faculty Publications
A transparent or absorbing substrate can be coated with a transparent thin film to produce a linear reflectanceversus- angle-of-incidence response over a certain range of angles. Linearization at and near normal incidence is a special case that leads to a maximally flat response for p-polarized, s-polarized, or unpolarized light. For midrange and high-range linearization with moderate and high slopes, respectively, the best results are obtained when the incident light is s polarized. Application to a Si substrate that is coated with a SiO2 film leads to novel passive and active reflection rotation sensors. Experimental results and an error analysis …
Maximum Rate Of Change Of The Differential Reflection Phase Shift With Respect To The Angle Of Incidence For Light Reflection At The Surface Of An Absorbing Medium: Èrratum, R. M.A. Azzam, A. M. El-Saba
Maximum Rate Of Change Of The Differential Reflection Phase Shift With Respect To The Angle Of Incidence For Light Reflection At The Surface Of An Absorbing Medium: Èrratum, R. M.A. Azzam, A. M. El-Saba
Electrical Engineering Faculty Publications
No abstract provided.
Polarized Light Reflectometer, R. M.A. Azzam
Polarized Light Reflectometer, R. M.A. Azzam
Electrical Engineering Faculty Publications
The modulated reflected and nonreflected light fluxes, measured as the azimuth of incident linearly polarized light is varied, yield the absolute reflectances Rp, and Rs, of a dielectric or semiconductor surface. Application to a reflective Si detector determines the refractive index and thickness of a SiO2 film on the detector surface.
Direct Relation Between Fresnel's Interface Reflection Coefficients For The Parallel And Perpendicular Polarizations: Erratum 2, R. M.A. Azzam
Direct Relation Between Fresnel's Interface Reflection Coefficients For The Parallel And Perpendicular Polarizations: Erratum 2, R. M.A. Azzam
Electrical Engineering Faculty Publications
The record is set straight concerning two equations that determine the reflection phase shifts at a single interface from the intensity reflectances forp- and s-polarized light at one angle of incidence. These equations appeared previously in this journal [J. Opt. Soc. Am. 69, 1007 (1979); erratum, J. Opt. Soc. Am. 70, 261 (1980)].
Field Tests Of The Dolphin--A Remotely Operated Survey Vehicle, M T. Kalcic, Edit J. Kaminsky
Field Tests Of The Dolphin--A Remotely Operated Survey Vehicle, M T. Kalcic, Edit J. Kaminsky
Electrical Engineering Faculty Publications
No abstract provided.
Photopolarimeter Based On Planar Grating Diffraction, R. M.A. Azzam, K. A. Giardina
Photopolarimeter Based On Planar Grating Diffraction, R. M.A. Azzam, K. A. Giardina
Electrical Engineering Faculty Publications
A division-of-amplitude photopolarimeter (DOAP) is described that employs a diffraction grating in the conventional spectrometer orientation with the grating grooves normal to the plane of incidence. Four coplanar diffracted orders are used for polarimetric analysis to determine all four Stokes parameters of incident light simultaneously and virtually instantaneously (with the speed being determined solely by the photodetectors and their associated electronics); a fifth order is used for alignment by autocollimation or by use of a position-sensing quadrant detector. To sensitize the instrument for the +45° and -45° azimuths of incident linearly polarized light and for the handedness of incident circular …
Acoustical Boundary Location Through Texture Analysis Of Multibeam Bathymetric Sonar Data, Herb Barad, Andrews B. Martinez, Brian S. Bourgeois, Edit J. Kaminsky
Acoustical Boundary Location Through Texture Analysis Of Multibeam Bathymetric Sonar Data, Herb Barad, Andrews B. Martinez, Brian S. Bourgeois, Edit J. Kaminsky
Electrical Engineering Faculty Publications
Texture analysis is performed on multibeam sonar signal returns discriminated angularity by beamforming. A collection of fourteen texture features are computed via co-occurrence matrices and data reduction is then performed using a principal components transformation. Acoustical boundaries (boundaries between regions with homogeneous acoustical properties) are evident from the features. Results indicate that seafloor bottom characteristics can be extracted from these texture features.
Limaçon Of Pascal Locus Of The Complex Refractive Indices Of Interfaces With Maximally Flat Reflectance-Versus-Angle Curves For Incident Unpolarized Light, R. M.A. Azzam
Electrical Engineering Faculty Publications
For an interface between two isotropic media the power reflectance Rv (ø) is an even function, Rv (ø) = Rv (--), of the angle of incidence ø; hence all the odd derivatives, Rv(n) = dn Rv /døn (n odd), are identically 0 at ø = 0, independent of the incident polarization v. When the incident light is unpolarized (v = u), the second derivative, Ru(2), is also 0 at ø = 0, so that the flatness of the Ru -versus-ø curve …
Division-Of-Amplitude Photopolarimeter Based On Conical Diffraction From A Metallic Grating, R. M.A. Azzam
Division-Of-Amplitude Photopolarimeter Based On Conical Diffraction From A Metallic Grating, R. M.A. Azzam
Electrical Engineering Faculty Publications
A new photopolarimeter that employs polarization-dependent conical diffraction of light by a metallic grating for the simultaneous measurement of the four Stokes parameters of light is described.
Achieving A Given Reflectance For Unpolarized Light By Controlling The Incidence Angle And The Thickness Of A Transparent Thin Film On An Absorbing Substrate: Application To Energy Equipartition In The Four-Detector Photopolarimeter, R. M.A. Azzam, Kurt A. Giardina
Achieving A Given Reflectance For Unpolarized Light By Controlling The Incidence Angle And The Thickness Of A Transparent Thin Film On An Absorbing Substrate: Application To Energy Equipartition In The Four-Detector Photopolarimeter, R. M.A. Azzam, Kurt A. Giardina
Electrical Engineering Faculty Publications
At a given wavelength λ we determine all possible solution pairs (ϕ, ζ) of the incidence angle ϕ and the thickness ζ of a transparent thin film on an absorbing substrate that achieve a given unpolarized light reflectance Ru. The trajectory of the point that represents a solution pair in the ζ, ϕ plane depends on the optical properties of the film and substrate and on whether Ru is greater than or less than the normal-incidence reflectance -R0 of the bare substrate. When Ru > - R0, the specified reflectance is achieved over a …
Principal Linear Polarization States Of An Optical System, R. M.A. Azzam
Principal Linear Polarization States Of An Optical System, R. M.A. Azzam
Electrical Engineering Faculty Publications
The constraint on the Jones matrix of an optical system such that there exist two linear polarization states at its input that are mapped onto two corresponding linear states at its output is derived. These principal linear polarization (PLP) states, which characterize a broad range of systems, are also found in terms of the Jones matrix elements. Special cases when the PLP states are orthogonal, collapse onto one state, or become infinite in number are indicated. For a deterministic or nondeterministic optical system described by a Mueller matrix, the existence of two PLP states places a constraint on only 3 …
Transmission Ellipsometry On Transparent Unbacked Or Embedded Thin Films With Application To Soap Films In Air, R. M.A. Azzam
Transmission Ellipsometry On Transparent Unbacked Or Embedded Thin Films With Application To Soap Films In Air, R. M.A. Azzam
Electrical Engineering Faculty Publications
The ratio ρt = Tp/Ts of the complex amplitude transmission coefficients for the p and s polarizations of a transparent unbacked or embedded thin film is examined as a function of the film thickness-to-wavelength ratio d/λ and the angle of incidence Φ for a given film refractive index N. The maximum value of the differential transmission phase shift (or retardance), Δt = argρt, is determined, for given N and Φ, by a simple geometrical construction that involves the iso-Φ circle locus of ρt in the complex plane. The …
Instrument Matrix Of The Four-Detector Photopolarimeter: Physical Meaning Of Its Rows And Columns And Constraints On Its Elements, R. M.A. Azzam
Instrument Matrix Of The Four-Detector Photopolarimeter: Physical Meaning Of Its Rows And Columns And Constraints On Its Elements, R. M.A. Azzam
Electrical Engineering Faculty Publications
The four-detector photopolarimeter (FDP) is an arrangement of four photodetectors for measuring the state of polarization of light. The output current vector I of the FDP is related to the input Stokes vector S by I = AS, where A is the instrument matrix. The rows of A can be viewed as projection operators that determine the output currents of the detectors. This leads to the recognition of four special totally polarized input states, each of which maximizes the output of one detector. The associated four orthogonal states produce minimum signals. Because each detector is absorptive and its output is …
Contours Of Constant Pseudo-Brewster Angle In The Complex Є Plane And An Analytical Method For The Determination Of Optical Constants, R. M.A. Azzam, Ericson E. Ugbo
Contours Of Constant Pseudo-Brewster Angle In The Complex Є Plane And An Analytical Method For The Determination Of Optical Constants, R. M.A. Azzam, Ericson E. Ugbo
Electrical Engineering Faculty Publications
The locus of all points in the complex plane of the dielectric function є[єr + jєi = |є| exp(jθ)], that represent all possible interfaces characterized by the same pseudo-Brewster angle θpB of minimum p reflectance, is derived in the polar form: |є| = l cos(ζ/3), where l = 2(tan2ΦpB)k, ζ = arccos(- cosθ cos2ΦpB/k3), and k = (1 - 2/3 sin2ΦpB)½. Families of iso-ΦpB contours for (I) 0° ≤ ΦpB ≤ …
Accurate Calibration Of The Four-Detector Photopolarimeter With Imperfect Polarizing Optical Elements, R. M.A. Azzam, Ali G. Lopez
Accurate Calibration Of The Four-Detector Photopolarimeter With Imperfect Polarizing Optical Elements, R. M.A. Azzam, Ali G. Lopez
Electrical Engineering Faculty Publications
The first three columns of the instrument matrix A of the four-detector photopolarimeter (FDP) are determined by Fourier analysis of the output current vector I(P) as a function of the azimuth angle P of the incident linearly polarized light. Therefore 12 of the 16 elements of A are measured free of the imperfections of the (absent) quarter-wave retarder (QWR). The effect of angular beam deviation by the polarizer is compensated for by taking the average, (1/2) [I(P) + I(P + 180°)], of the FDP output at 180°-apart, optically equivalent, angular positions of the polarizer. The remaining fourth column of A …
Analytical Determination Of The Complex Dielectric Function Of An Absorbing Medium From Two Angles Of Incidence Of Minimum Parallel Reflectance, R. M.A. Azzam
Electrical Engineering Faculty Publications
The real and imaginary parts of the complex dielectric function (or complex refractive index) of an opaque substrate or a thick film can be determined from two pseudo-Brewster angles measured in two transparent incidence media of different refractive indices. This two-angle method is simple in that it involves no photometric or polarimetric analysis and in that the solution for the optical properties in terms of the measured angles is explicit, analytical, and direct (i.e. noniterative). The two-angle method is demonstrated for an opaque TiN film on a Cleartran ZnS substrate as a specific example. The effect of angle-of-incidence errors on …
Maximum Rate Of Change Of The Differential Reflection Phase Shift With Respect To The Angle Of Incidence For Light Reflection At The Surface Of An Absorbing Medium, R. M.A. Azzam, A. M. El-Saba
Maximum Rate Of Change Of The Differential Reflection Phase Shift With Respect To The Angle Of Incidence For Light Reflection At The Surface Of An Absorbing Medium, R. M.A. Azzam, A. M. El-Saba
Electrical Engineering Faculty Publications
The differential reflection phase shift, Δ = δp - δs, associated with the external reflection of monochromatic light at the surface of an absorbing medium is a monotonically decreasing function of the angle of incidence ø which is determined by the complex dielectric function ε. A new special angle of incidence, denoted by øΔ′max, is defined at which the slope Δ′ = ∂Δ/∂ø of the Δ-ø curve is maximum negative, Δ′max, and a transcendental equation is derived that determines this angle. øΔ′max differs from the principal angle øp at which Δ …
Reflectance Of An Absorbing Substrate For Incident Light Of Arbitrary Polarization: Appearance Of A Secondary Maximum At Oblique Incidence, R. M.A. Azzam, A. M. El-Saba
Reflectance Of An Absorbing Substrate For Incident Light Of Arbitrary Polarization: Appearance Of A Secondary Maximum At Oblique Incidence, R. M.A. Azzam, A. M. El-Saba
Electrical Engineering Faculty Publications
The reflectance of an absorbing substrate Rθ(ɸ) is considered as a function of the angle of incidence ϕ and an incident polarization parameter θ, where cos2θ and sin2θ give the power fractions of incident radiation that are p-and s-polarized, respectively. Taking GaAs as an example, we find that at certain wavelengths (e.g., 0.248 and 0.620 µm), the Rθ vs ɸ curve becomes oscillatory in a narrow range of θ > 45° with an unexpected secondary maximum appearing at oblique incidence. The extrema of the function Rθ(ɸ) are determined numerically, and their angular …
Division-Of-Wave-Front Thin-Film Beam Splitter For Generating Binary Patterns Of Orthogonal Elliptical Polarization States, R. M.A. Azzam
Division-Of-Wave-Front Thin-Film Beam Splitter For Generating Binary Patterns Of Orthogonal Elliptical Polarization States, R. M.A. Azzam
Electrical Engineering Faculty Publications
A division-of-wave-front thin-film beam splitter is described that reflects monochromatic light at oblique incidence with orthogonal elliptical polarization states. It consists of a metallic substrate partially covered with a transparent thin film that inverts the ratio ρ of the complex p and s reflection coefficients at the principal angle of the metal. Any pattern of coated and uncoated areas of the substrate is imprinted upon the reflected wave front as a corresponding two-dimensional spatial binary polarization pattern. A specific design is given that uses a Au substrate at a wavelength of 632.8 nm. The effects of small errors in the …
Thin-Film Devices For Polarized Light- Introduction, R. M.A. Azzam, William H. Southwell
Thin-Film Devices For Polarized Light- Introduction, R. M.A. Azzam, William H. Southwell
Electrical Engineering Faculty Publications
No abstract provided.
Extrema Of The Magnitude And The Phase Of A Complex Function Of A Real Variable: Application To Attenuated Internal Reflection, R. M.A. Azzam
Extrema Of The Magnitude And The Phase Of A Complex Function Of A Real Variable: Application To Attenuated Internal Reflection, R. M.A. Azzam
Electrical Engineering Faculty Publications
Given a complex function F(ω) = |F(ω)|exp[jΔ(ω)] of a real argument ω, the extrema of its magnitude |F(ω)| and its phase Δ(ω), as functions of ω, are determined simultaneously by finding the roots of one common equation, Im[G(ω)] = 0, where G= (F′/F)2 and F′ = ∂F/∂ω. The extrema of |F| and Δ are associated with Re G < 0 and Re G > 0, respectively. This easy-to-prove theorem has a wide range of applications in physical optics. We consider attenuated internal reflection (AIR) as …
General Analysis And Optimization Of The Four-Detector Photopolarimeter, R. M.A. Azzam, I. M. Elminyawi, A. M. El-Saba
General Analysis And Optimization Of The Four-Detector Photopolarimeter, R. M.A. Azzam, I. M. Elminyawi, A. M. El-Saba
Electrical Engineering Faculty Publications
The four-detector photopolarimeter (FDP) is analyzed for an arbitrary spatial configuration and any reflection characteristics (ri, ψi, Δi) of the first three detectors. The instrument matrix A, which relates the output signal vector I to the input Stokes vector S by I = AS, and its determinant are derived explicitly. The essential condition that A be nonsingular (det A ≠ 0) is satisfied in general with uncoated absorbing detector surfaces, assuming that the plane of incidence (POI) is rotated between successive reflections by other than 90°. Therefore no special coatings on …
Constraint On The Optical Constants Of A Transparent Film On An Absorbing Substrate For Inversion Of The Ratio Of Complex P And S Reflection Coefficients At A Given Angle Of Incidence, R. M.A. Azzam, M. A. Habli
Constraint On The Optical Constants Of A Transparent Film On An Absorbing Substrate For Inversion Of The Ratio Of Complex P And S Reflection Coefficients At A Given Angle Of Incidence, R. M.A. Azzam, M. A. Habli
Electrical Engineering Faculty Publications
An absorbing substrate of complex refractive index n2-jk2 can be coated by a transparent thin film of refractive index n1 and normalized thickness ζ so that the ratio of complex reflection coefficients for the pand s polarizations of the film-covered substrate ρ is the inverse of that of the film-free substrate ρ¯ at a given angle of incidence φ. A pair of parallel (metallic) mirrors, one uncoated and the other coated with a ρ-inverting layer, causes a beam displacement without change of polarization and with a certain net reflectance (insertion loss) ℜ. In this …
Angular Sensitivity Of Brewster-Angle Reflection Polarizers: An Analytical Treatment, R. M.A. Azzam
Angular Sensitivity Of Brewster-Angle Reflection Polarizers: An Analytical Treatment, R. M.A. Azzam
Electrical Engineering Faculty Publications
The angular sensitivity of Brewster-angle reflection polarizers (BARP) is first studied approximately by determining the Taylor series expansion of the parallel reflectance Rp as a function of angle of incidence ø near the Brewster angle øB. Subsequently, exact and explicit equations are derived that determine the lower and upper limits, øl and øu, of the range of ø, that includes øB, over which Rp or the extinction ratioER is below a stated limit L. Examples are given of Ge and Si IR BARP for which øl and ø …
Antireflection Of An Absorbing Substrate By An Absorbing Thin Film At Normal Incidence, R. M.A. Azzam, E. Bu-Habib, J. Casset, G. Chassaing, P. Gravier
Antireflection Of An Absorbing Substrate By An Absorbing Thin Film At Normal Incidence, R. M.A. Azzam, E. Bu-Habib, J. Casset, G. Chassaing, P. Gravier
Electrical Engineering Faculty Publications
An absorbing substrate of complex refractive index n2 - jk2 at wavelength λ can be coated by an absorbing thin film of complex refractive index n1 - jk1 and thickness d to achieve zero reflection at normal incidence. For given n2,k2 multiple solutions (n1,k1,d/λ) are found that correspond to infinitely many distinct antireflection layers. This is demonstrated for a Si substrate at two wavelengths (6328 and 4420 Å). The response of these absorbing antireflection layers to changes of the angle of incidence from 0 …