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Angular aperture

About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, low sidelobe aperture distributions for both blocked and unblocked circular apertures are investigated for both peak sidelobe levels and wide-angle sidelobe level.
Abstract: Low sidelobe aperture distributions are investigated for both blocked and unblocked circular apertures. Both peak sidelobe levels and wide-angle sidelobe levels are considered. For unblocked apertures, Taylor's circular aperture synthesis technique is generalized to provide control over the wide angle sidelobe decay rate. These distributions are compared to a wide variety of alternative distributions in terms of the beamwidth, aperture efficiency, and radiated power distributions achieved for a given peak sidelobe level. A comparison is also made between the sidelobe envelopes achieved by four different distributions with a fixed beamwidth. For centrally blocked apertures, it is shown that wide angle sidelobes can be reduced by employing aperture distributions with a hole in the blocked central area.

23 citations

Journal ArticleDOI
Abstract: Stitching interferometry is an attractive method for measuring optics with large apertures. However, existing stitching algorithms are not suitable for measuring cylindrical optics, because the misalignment aberrations in cylindrical interferometry are more complicated than those in plane, spherical and aspherical measurements. This paper presents a stitching algorithm for measuring cylindrical optics with large angular apertures. With it, we use five aberrations (i.e. piston, tilt, tip, defocus and twist) to describe the possible misalignments of the tested cylindrical surface and to build the cylindrical stitching model. Using this model allows us to calculate the relative misalignment aberrations of subapertures from their overlapped areas, so that the full aperture map of a cylindrical surface is obtained by compensating for these misalignment aberrations. In experiment, a cylindrical lens with an angular aperture over 150° is measured, thus demonstrating the feasibility and validity of the proposed method.

23 citations

Patent
04 Nov 1988
TL;DR: In this paper, a laser light scattering and spectroscopic detector is presented which includes a probe comprising an optical fiber coupled to a graded index microlens, and the angular aperture and divergence of the probe are designed specifically to satisfy the scattering volume and coherence requirements.
Abstract: A laser light scattering and spectroscopic detector is provided which includes a probe comprising an optical fiber coupled to a graded index microlens. The angular aperture and the divergence of the probe are designed specifically to satisfy the scattering volume and coherence requirements for laser light scattering and spectroscopic measurements. The detector includes a housing which defines an elongate cell therein and a selected number of detector ports extending at various angles with respect to the cell. A method is provided for detecting scattered light which includes the steps of positioning the probe inside or outside the scattering medium at a selected angle with respect to the laser beam.

23 citations

Journal ArticleDOI
TL;DR: Replacement of the central exit aperture of a conventional Fabry-Perot (F.P.) photoelectric interferometer with a multiple annulus exit plate provides a substantial gain in luminosity while maintaining resolving power in the study of extended sources of radiation.
Abstract: Replacement of the central exit aperture of a conventional Fabry-Perot (F.P.) photoelectric interferometer with a multiple annulus exit plate provides a substantial gain in luminosity while maintaining resolving power in the study of extended sources of radiation. The design, fabrication, assembly, and testing of multiple aperture exit plates (MAEPs) which pass 6 interference orders via a central aperture and five concentric annular openings are described. The measured luminosity gains and inferred aperture finesses of MAEPs used with 150- and 100-mm aperture F.P.s are quite close to the design values of 6 and 14.5, respectively.

23 citations

Journal ArticleDOI
TL;DR: A versatile three-parameter (3-P) elliptical aperture distribution, which encompasses many of the existing circular aperture distributions, is presented in this paper, where characteristics of the 3-P distributions such as the edge taper, the taper efficiency, the aperture power, the closed-form far fields, the sidelobe levels, the beamwidth and beam efficiency are analyzed.
Abstract: A versatile three-parameter (3-P) elliptical aperture distribution, which encompasses many of the existing circular aperture distributions, is presented. Characteristics of the 3-P distributions such as the edge taper, the taper efficiency, the aperture power, the closed-form far fields, the sidelobe levels, the beamwidth and beam efficiency are analyzed. Also derived is an asymptotic form of the far-field, based on which the far-angle features of the 3-P distributions such as the far-field envelope, the decay rate, and the positions of nulls are determined. Examples are presented to illustrate the improvements resulting from the enlarged parameter space for aperture models obtainable from the 3-P distributions. Issues concerning the total power associated with an aperture distribution are studied and the inadequacy of some commonly used approximation is demonstrated. >

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
20224
20217
20207
20195
201811