Application Of Geometrical Optics Research Articles

Improving the energy characteristics of a solar photoelectric station of spherical and cylindrical surface shapes for the power supply of remote rural areas and agricultural enterprises

One of the actual tasks of generating electricity is to increase the energy efficiency of solar photoelectric stations (SPS) in uneven lighting. The purpose of the work is to study the energy characteristics of the SPS under uneven lighting to improve the energy efficiency of solar power plants, including those for agro–industrial enterprises located and operating in remote rural areas, on sloping lands, mountainous and foothill terrain, where the efficiency of the SPS can be higher than on the plain due to a higher level of illumination. The methods of mathematical analysis with application of geometric optics, photoelectric conversion methods and construction physics in solar engineering are used. Analytical calculations were carried out to clarify the design parameters of the SPS that are made in the form of a sphere and a cylinder. The article presents the results of theoretical studies of the electrical characteristics of SPS made in the form of a sphere and a cylinder under uneven illumination of solar photoelectric modules (SPM). The relationship of electrical power and the number of SPS in the SPS is determined by the methods of mathematical statistics. As a result of studies of the electrical characteristics of SPS in uneven lighting, the following results were obtained: for SPS in the form of a sphere, small-area SPS have energy efficiency 32% more than large-area SPS; for SPS in the form of a cylinder of small-area SPS, energy efficiency increases by 19% compared to large-area SPS. The relationship between electrical power and the number of SPS was determined using the coefficient of determination, which is equal to: for a spherical surface - 36.2%, for a cylindrical one - 26.6%.

Iteration Path-Length Error Correction Approach to Subreflector Shaping for Distortion Compensation of Large Reflector Antenna

At the stage of structural optimization, the subreflector structure should be designed such that it compensates for the residual error or relaxes the accuracy requirement of the main reflector to a certain extent. However, there is no fast and effective means to shape the subreflector during the structural optimization process. This communication is based on the application of geometrical optics (GO)/physical optics (PO) analysis to shape a subreflector for antenna distortion compensation. Thus, a method performing an iterative approximation to the GO/PO analysis is proposed. Unlike GO shaping or optimization, the proposed method is not formulated by simultaneous nonlinear ordinary differential equations. Therefore, the main contribution of this communication is that the method does not entail computationally intensive calculation and optimization, and thus, it does not require a large amount of time to complete the calculation. The proposed method is very suitable for a large reflector antenna with a small-amplitude deformation and smoothly varying errors such that the shaped subreflector does not have a significant effect on the amplitude of the main reflector’s electric field. An example with regard to the symmetric system is presented. The obtained results demonstrate that the proposed method is effective.

Two approaches to the problem of ray seismic tomography

Approximation of nonlinear geophysical medium as a linear one substantiates a transition to geometrical seismics based on geometric optics. Conditions, necessary and sufficient for application of geometrical optics bring possibility of linearization the eikonal equation and produce two approaches in the problems of seismic tomography: a classical Lavrentyev— Romanov linearization and the Taylor approximation.

On optical depth profiling using confocal Raman spectroscopy

Until 2006 the performance of confocal Raman spectroscopy depth profiling was typically described and modeled through the application of geometrical optics, including refraction at the surface, to explain the degree of resolution and the precise form of the depth profile obtained from transparent and semicrystalline materials. Consequently a range of techniques, physical and analytical, was suggested to avoid the errors thus encountered in order to improve the practice of Raman spectroscopy, if not the understanding of the underlying mechanisms. These approaches were completely unsuccessful in accounting for the precise form of the depth profile, the fact that spectra obtained from laminated samples always contain characteristic peaks from all materials present both well above and below the focal point and that spectra can be obtained when focused some 40 mum above the sample surface. This paper provides further evidence that the physical processes underlying Raman spectroscopy are better modeled and explained through the concept of an extended illuminated volume contributing to the final Raman spectrum and modeled through a photon scattering approach rather than a point focus ray optics approach. The power of this numerical model lies in its ability to incorporate, simultaneously, the effects of degree of refraction at the surface (whether using a dry or oil objective lens), the degree of attenuation due to scatter by the bulk of the material, the Raman scattering efficiency of the material, and surface roughness effects. Through this we are now able to explain why even removing surface aberration and refraction effects through the use of oil immersion objective lenses cannot reliably ensure that the material sampled is only that at or close to the point of focus of the laser. Furthermore we show that the precise form of the depth profile is affected by the degree of flatness of the surface of the sample. Perhaps surprisingly, we show that the degree of flatness of the material surface is, in fact, more important than obtaining a precise refractive index match between the immersion oil and the material when seeking a high-quality depth profile or Raman spectrum from within a transparent or semicrystalline material, contrary to accepted norms that samples for interrogation by Raman spectroscopy require little preparation.

Propagation of a Gaussian pulse through an optical fiber: applicability of geometrical optics

Propagation of a Gaussian pulse through an optical fiber: applicability of geometrical optics

Comments on "The analysis of deployable umbrella parabolic reflectors"

In a recent paper (see abstr. B28664 of 1972), Ingerson and Wong show, using geometrical relations, that the entire deployable reflector can be thought of as being made up of an infinite number of parabolas. They give an expression for the focal length of this infinite collection of parabolas and then state incorrectly that `The infinite collection of parabolas has a continuous distribution of foci. Thus, if a primary feed is placed in focus for one parabola, it is out of focus for the rest of the collection'. This statement is evidently the result of improper application of geometrical optics (surface normals are not taken into account) and provides a wrong physical picture of the focusing and the axial defocusing in the umbrella parabolic reflectors

Rays and modes in optical fibres

Difficulties have recently been noted in the application of geometric optics to modal propagation and cutoff in optical fibres. It is shown here that geometric optics is adequate, provided that it treats collectively the congruence of modal rays.

Removing a restriction on the applicability of geometrical optics

Removing a restriction on the applicability of geometrical optics