Showing papers on "Physical optics published in 1986"

Electromagnetic Principles of Integrated Optics

Abstract: Using optics to present electromagnetic theory, Electromagnetic Principles of Integrated Optics is a radical departure from other texts and a unified and comprehensive introduction to the field of integrated optics. All the fundamental concepts and principles of guided wave optics are developed from Maxwell's equations. From this perspective, the study of the slab and rectangular dielectric waveguide replaces that of the parallel plate and rectangular mentalic waveguide, the optical fiber that of the coaxial transmission line, radiation losses that of conduction losses, and aperture diffraction that of antenna radiation. This complete guide gives you clear coverage of 2- and 3-dimensional optical waveguides, optical fibers, prism and dielectric waveguide couplers, waveguide filters, grating reflectors and optical spectrum analyzers. You will find new approaches to topics such as dielectric waveguides, radiation modes and WKB theory. Electromagnetic Principles of Integrated Optics is carefully structured so that all material is developed from first principles. Sophisticated concepts such as the Goos-Haenchen shift, radiation modes, Bragg scattering of guided modes and optical fiber mode theory have a firm foundation and are made easily understandable. Problems and worked-out examples reinforce the material and are good for self-study. For reference, as a problem-solver, or for self-study. The book provides many of the concepts and mathematical tools necessary to analyze realworld guided wave optics problems.

Foundations of a Lie algebraic theory of geometrical optics

Abstract: We present the foundations of a new Lie algebraic method of characterizing optical systems and computing their aberrations. This method represents the action of each separate element of a compound optical system —including all departures from paraxial optics— by a certain operator. The operators can then be concatenated in the same order as the optical elements and, following well-defined rules, we obtain a resultant operator that characterizes the entire system. These include standard aligned optical systems with spherical or aspherical lenses, models of fibers with polynomial z-dependent index profile, and also sharp interfaces between such elements. They are given explicitly to third aberration order.

Seeing the Light: Optics in Nature, Photography, Color, Vision, and Holography

Abstract: Fundamental Properties of Light. Principles of Geometrical Optics. Mirrors and Lenses. The Camera and Photography. The Human Eye and Vision I: Producing the Image. Optical Instruments. The Human Eye and Vision II: Processing the Image. Binocular Vision and the Perception of Depth. Color. Color Perception Mechanisms. Color Photography. Wave Optics. Scattering and Polarization. Holography. Light in Modern Physics. Mathematical Appendixes. References. Index.

Elimination of infinities in equivalent edge currents, Part II: Physical optics components

Abstract: A solution finite for all directions of illumination and observation is derived for the physical optics (PO) components of equivalent edge currents. The solution is based on the uniform asymptotic theory of endpoint evaluation of integrals. An extension taking into account the variation of the surface metric with the distance from the edge is presented, and a similar extension for including slope diffraction is indicated. The expressions derived complement the results of our previous work on elimination of infinities from the fringe components of equivalent currents.

The physical optics fields of an aperture on a perfectly conducting screen in terms of line integrals

Abstract: The physical optics fields due to an aperture on a perfectly conducting screen are expressed in terms of line integrals over the boundary of the aperture. These line-integral representations have the same properties as the ones in terms of surface integrals over the aperture; in particular, they admit arbitrary, source distributions, and are continuous everywhere in the source-free half-space, including the geometric optics shadow boundary.

Prediction of the Fresnel region field of a compact antenna test range with serrated edges

Abstract: The performance of antenna systems is always influenced by diffraction effects. Diffraction problems may be analysed using physical optics or geometrical theory of diffraction. Here, the Fresnel field of a rectangular aperture with serrated edges is analysed using physical optics. The method can be applied very succesfully in compact antenna test range design for a fast prediction of the test-zone field performance.

The SAR Image of Short Gravity Waves On a Long Gravity Wave

Abstract: A SAR imaging model appropriate to oceanographic applications is derived, unifying fundamental models of hydrodynamics, rough surface scattering, and SAR imaging of time-variant scenes. The sea surface is a sinusoidal long gravity wave upon which short gravity waves propagate and are modified by the long wave in accordance with a recent theory of Phillips; the electromagnetic scattering is described by the two-scale approximation appropriate to long wave and short wave ensembles that are, respectively, smoothly varying and not too rough with respect to the radar wavelength. The resulting model, accurate to first order in the long wave slope, for the first time fundamentally characterizes the nonlinear hydrodynamic and scattering interactions of the long and short waves and their effect, along with temporal variation, on the SAR image. Of particular importance, the long wave enters (among other ways) as a phasemodulated waveform that, when filtered by the SAR system, can be, for large-amplitude long waves, the principal determinant of the image nature. The numerical analysis of the model is discussed and an approximation describing the image of a delimited scene area is derived and exemplified. (1) When the small waves are a range-directed ensemble and the long wave is azimuth directed, the latter’s temporal variation “blurs,” in azimuth, the image due, primarily, to the SAR system’s narrowband filtering of the aforementioned phase- modulated waveform and, secondarily, the nonlinear hydrodynamic interaction; it is shown that this “blurring” is, at higher long wave amplitudes, due to a quadratic phase error proportional to the phase velocity of the long wave. That part of the short wave ensemble allowed influential by SAR system (wavenumber) filtering is approximately nondispersive during the SAR azimuth integration time, its concerted effect being a rigid azimuth image translation, proportional to the short wave’s mean phase velocity. (2) More briefly treated, when the long wave is ranged directed and the short wave ensemble is simply a single range-directed sinusoid (“Bragg-matched”), the image is solely range variant and its nature is primarily determined by the aforementioned narrowband filtering effect, the secondary effects of nonlinear hydrodynamics and physical optics (i.e., surface slope) being evident. Therefore, the present model, as thus far elaborated, contradicts predictions of models based on the SAR response to a point scatterer in motion in accordance with the “orbital motion” of the long wave: e.g., no “azimuth bunching” attributed to such motion is observed.

Coherent and incoherent grating reconstruction

Abstract: Recent progress in coherent and incoherent optical inverse-scattering problems is reviewed with emphasis on the construction of grating-groove profiles from known or desired diffraction efficiencies and the detection of phase gratings hidden by diffusers using optical correlation techniques. Retrieval and synthesis problems and the role of coherence are described. The coherent grating-profile reconstruction is revisited in terms of the full mathematical description of our previous procedure. The crucial role of prior phase information for uniqueness of the reconstruction is elucidated. The theoretical prediction and experimental verification of a provoking coherence effect are presented: The signature of a hidden phase grating can be seen in the far-zone coherence function but not in the far-zone intensity for a certain range of ratios of the diffuser correlation length to the grating period.

Diffractive corrections to the high‐frequency Kirchhoff approximation

Abstract: Diffractive corrections to the physical optics solution for the scattering of high‐frequency sound by a random rough pressure release surface are derived. The correction terms are obtained by applying the composite‐roughness theory to an expansion of the scattering integral. Results are presented for a three‐dimensional rough surface and are compared with those obtained using a conventional composite‐roughness approach.

Canonical transforms for paraxial wave optics

Abstract: Paraxial geometric optics in N dimensions is well known to be described by the inhomogeneous symplectic group I2N ∧ Sp(2N, ℜ). This applies to wave optics when we choose a particular (ray) representation of this group, corresponding to a true representation of its central extension and twofold cover \(\tilde \Gamma _N = W_N ^ \wedge Mp(2N,\Re )\). for wave optics, the representation distinguished by Nature is the oscillator one. There applies the theory of canonical integral transforms built in quantum mechanics. We translate the treatament of coherent states and other wave packets to lens and pupil systems. Some remarks are added on various topics, including a fundamental euclidean algebra and group for metaxial optics.

Energy transport in optical systems with partially coherent light.

Abstract: The propagation of a generalized radiance through optical systems is considered under the customary assumptions of physical optics (paraxial propagation in a uniform medium and amplitude transmission functions associated with optical elements). It is shown that in specular optical systems that consist of homogeneous media separated by spherical surfaces, the generalized radiance remains invariant along each paraxial ray regardless of the state of coherence of the wavefield. It is further demonstrated that with nonspecular optical systems it is more convenient to use, in place of the generalized radiance, a closely related physical-optics quantity known as the Wigner (distribution) function. As an application, we analyze the energy transport through an optical device that has been employed to produce highly directional, partially coherent beams.

Cross polarization in dual reflector antennas--A PO and PTD analysis

Abstract: A physical optics (PO) and physical theory of diffraction (PTD) analysis of symmetric and offset dual reflector antennas is performed. It is shown that in most cases PO gives sufficient accuracy, but the PTD correction can be of importance to determine the depolarization, especially if the subreflector edge taper is low.

New Stigmatic XUV Plane Gratings Spectrometers

Abstract: In this paper we describe new types of VUV monochromators using only plane type V holographic gratings. New design rules using physical optics associated with the phase balancing method are suggested to achieve super resolution.

Comparison of three cross-polarisation prediction methods for reflector antennas

Abstract: Three analysis methods for reflector antennas, the spherical near-field geometric theory of diffraction (SNFGTD), the moment method (MM) and physical optics (PO) are compared. In the SNFGTD method, the far field from the antenna is found by a spherical near-field transformation (SNF) of the tangential electric near field on a sphere surrounding the antenna once this has been found using the geometrical theory of diffraction (GTD). SNFGTD and MM agree very well, whereas PO differs with respect to the cross-polar pattern. Some discrepancies between SNFGTD and MM are shown to be related to inaccuracies in the GTD diffraction coefficients close to the reflection boundary.

Out-of-Band Response of Reflector Antennas

Abstract: The response of reflector antennas to out-of-band frequencies has been analyzed using physical optics. A simple approximate expression has been obtained for the effective aperture, and this expression yields both the receiving pattern and the frequency dependence of the on-axis gain. The theory has been compared with published out-of-band measurements, and the pattern agreement is good, but the measured gain falls below the theory. This discrepancy is caused by mismatch loss in the coax-to-waveguide adapter.

The variation of bistatic rough surface scattering cross section for a physical optics model

Abstract: The general behavior of a rough surface scattering cross section is examined as a function of incident and scattering angles, surface roughness, dielectric constant, and polarization for physical optics (PO) conditions. Quite distinct and complicated variations are observed. For some conditions, deep nulls occur in the normalized bistatic cross section \sigma \deg ; as a function of seatlering angle, while other parameter sets yield no such pattern. These results are analyzed and interpreted. The differences in the angular variation in \sigma \deg for different polarizations suggested that, for a given set of conditions, it would be possible to minimize the scattering from a rough surface. This topic is addressed in the second part of the paper. For the case of a given incident polarization, a technique is presented to optimize the bistatic observation of terrain scattering by using combinations of receiver polarization which vary as the scattering angles are changed.

Dedicated undulator monochromators

Abstract: In this paper we describe new types of VUV monochromators using only spherical or plane type V holographic gratings. New design rules using physical optics associated with the phase balancing method are suggested to achieve diffraction limited performances.

Analysis Of FEL Optical Systems With Grazing Incidence Mirrors

Abstract: The use of grazing incidence optics in resonators alleviates the problem of damage to the optical elements and permits higher powers in cavities of reasonable dimensions for a free electron laser (FEL). The design and manufacture of a grazing incidence beam expander for the Los Alamos FEL mock up has been completed. In this paper, we describe the analysis of a bare cavity, grazing incidence optical beam expander for an FEL system. Since the existing geometrical and physical optics codes were inadequate for such an analysis, the GLAD code was modified to include global coordinates, exact conic representation, raytracing, and exact aberration features to determine the alignment sensitivities of laser resonators. A resonator cavity has been manufactured and experimentally setup in the Optical Evaluation Laboratory at Los Alamos. Calculated performance is compared with the laboratory measurements obtained so far.

Physical optics analysis of four-reflector antenna

Abstract: A four-reflector physical optics analysis procedure is presented. Theoretical characteristics of the National Aeronautics and Space Administration/Jet Propulsion Laboratory (NASA/JPL) 64 m antennas computed from this procedure were found to be in excellent agreement with experimental observations. The S -band horn fields will subsequently be carried through all four reflectors (resulting in a transmission viewpoint of final antenna system beams) to account fully for all nearfield, cross polarization, and higher order mode generation effects caused by various intentional asymmetries in geometry. This appears to be the first time such a complete and rigorous analysis has been performed on such a complex antenna system. The analysis techniques presented are useful in many ongoing ground station antenna research and development efforts, including high-efficiency shaped reflector and beam waveguide feed designs and microwave metrology (holography) applied to large reflector surface measurements.

Convergence of physical optics integrals by Ludwig's technique

Abstract: The convergence properties of Ludwig's integration technique are investigated, when applied to physical optics (PO) analysis. It is demonstrated that the rate of convergence is sensitive to the choice of integration grid co-ordinate system. Examples of PO analysis applied to paraboloidal and ellipsoidal reflectors show the reduction in computation time achievable when using a cartesian integration grid rather than a polar grid.

GTD, physical optics, and jacobi-bessel diffraction analysis of beam waveguide elipsoids

Abstract: For certain applications of beam waveguides to large ground system antennas, the use of ellipsoid pairs in place of more conventional paraboloid pairs is appropriate. For example, in the application illustrated in Figure 1, the feed and maser system is rotated in azimuth with the antenna. In this case, the beam waveguide does not go directly to the axis of the main reflector but bypasses some in-place heavy machinery along this axis. In this configuration, ellipsoid pairs are more suitable because their convergent ray characteristic allows for a lower loss transmission and also because the three independent focii can be aligned in accordance with the rules discovered by Mizusawa and Kitsuregawa.l Thus aligned, the ellipsoid pair perfectly images the feed pattern according to geometrical optics (see Figure 2).

Physical optics analysis of a 4-reflector antenna, part 2

Abstract: Concern has been raised for the 64-m to 70-m antenna upgrade project that the 70-m system may experience greater S-band beam-pointing perturbations than the 64-m system The S-band perturbations are due to minor (higher order) mode generation, causing subtle cross-polarization fields affecting beam pointing direction, as described herein For the antennas in their present configuration (64 m), a slight S-band gain degradation of about 005 dB can be attributed to these effects Therefore, a full physical optics analysis was performed for the present-day 64-m system, as described herein The results were compared with past analyses and experimental observations in order to verify the algebra and computer code with the intent of deriving a valid analysis method for accurately analyzing the 70-m shaped dual reflector Cassegrainian antenna The results of the new analysis appear to be in excellent agreement with previous analyses and experimental data