Physical optics

About: Physical optics is a research topic. Over the lifetime, 5342 publications have been published within this topic receiving 101388 citations. The topic is also known as: wave optics.

Doubly curved crystal point-focusing x-ray monochromators: geometrical and practical optics.

Abstract: The geometrical optics of symmetrical point-focusing x-ray monochromators made with elastically bent ideal monocrystalline wafers in the geometry employed by Despujols and Berreman are reinvestigated. Sharpness of focus is limited mainly by accuracy of curvature of the crystal wafer and by thermal diffuse scattering. Monochromaticity is limited by these factors and by source and crystal dimensions in the plane of reflection and rarely by the inherent width of the reflection band of the curved crystal. Two existing monochromators reflect about 2-3% of the incident CuKalpha(1) radiation.

Edge effects of truncated periodic surfaces of thin wire elements

Abstract: The effects of truncating a periodic structure of thin wire elements is examined. The structure is assumed to be infinite in extent along a single axis, enabling the analysis to be simplified via Floquet's currents on the infinite axis for plane wave incidence. The analysis of an infinite linear array of elements is thereby reduced to that of a single element. Scattered fields are presented for several truncated planar geometries and are compared to three approximate solutions that use unperturbed two-dimensionally infinite Floquet currents, diffraction from a strip, and a physical optics solution for a strip, respectively. >

On modeling the focus blur in image restoration

Abstract: The point spread function (PSF) of a defocused lens, in the continuous spatial coordinates, can be modeled using the principles of either geometrical optics or physical optics. The authors compare the PSFs and the corresponding optical transfer functions obtained on the basis of these two models under different amounts of blurs and different imaging sensor resolutions, in the discrete spatial domain. Different approximations for the discretization of the PSF are considered. The effect of using geometrical versus physical optics-based models on the quality of restored images is investigated experimentally in the case of images recorded by a charge-coupled device (CCD) camera. >

An SVD-based method for analyzing electromagnetic scattering from plates and faceted bodies using physical optics bases

Abstract: We propose a novel procedure to calculate the scattering from faceted bodies based on the use of universal bases that are obtained by applying the SVD procedure to PO-derived basis function. These bases, which are constructed totally bypassing any MoM-type approach, can be used for all angles of incidence and their use leads to a matrix whose dimensions are relatively small. Moreover, it can be shown that the matrix dimensions are weakly dependent upon the size of the facets of the scatterer. The method enables us to solve scattering problems in a computationally efficient and numerically rigorous manner, and yields good results both for 2D and 3D problems.

Planck pre-launch status: Low Frequency Instrument optics

Abstract: We describe the optical design and optimisation of the Low Frequency Instrument (LFI), one of two instruments onboard the Planck satellite, which will survey the cosmic microwave background with unprecedented accuracy. The LFI covers the 30–70 GHz frequency range with an array of cryogenic radiometers. Stringent optical requirements on angular resolution, sidelobes, main beam symmetry, polarization purity, and feed orientation have been achieved. The optimisation process was carried out by assuming an ideal telescope according to the Planck design and by using both physical optics and multi-reflector geometrical theory of diffraction. This extensive study led to the flight design of the feed horns, their characteristics, arrangement, and orientation, while taking into account the opto-mechanical constraints imposed by complex interfaces in the Planck focal surface.