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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.


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Journal ArticleDOI
TL;DR: In this paper, a formulation for investigating the intensity distribution of Fresnel diffraction by a circular aperture illuminated with partially coherent light was developed for the normal axis to the aperture in the diffraction field when the spatially mutual coherence function of the illumination over the aperture takes three different forms.
Abstract: A formulation is developed for investigating the intensity distribution of Fresnel diffraction by a circular aperture illuminated with partially coherent light. The theory formulated is applied to obtain the intensity distribution along the normal axis to the aperture in the Fresnel diffraction field when the spatially mutual coherence function of the illumination over the aperture takes three different forms. It is shown that the Fresnel diffraction is largely influenced by the coherence condition across the diffracting aperture.

15 citations

Journal ArticleDOI
TL;DR: An integrated optical-disk pickup that uses a focusing grating coupler with a numerical aperture of 0.45 was developed, and the readout signal on an International Standards Organization -formatted 90-mm optical disk was detected by the pickup.
Abstract: An integrated optical-disk pickup that uses a focusing grating coupler with a numerical aperture of 0.45 (a focal length of 1.0 mm and an aperture of 1.0 mm × 0.8 mm) was developed, and the readout signal on an International Standards Organization (ISO) -formatted 90-mm optical disk was detected by the pickup. The signal-amplitude ratio of the minimum-limit data pattern to the maximum was 0.53 on the innermost track. It meets the requirement on the signal resolution for optical-disk storage devices.

15 citations

Journal Article
TL;DR: The central focal masking technique is convenient and effective for determining the refractive index of a microfragment by the immersion method and for distinguishing between minerals in an immersion mount.
Abstract: The central focal masking ("dispersion staining") technique is convenient and effective for determining the refractive index of a microfragment by the immersion method and for distinguishing between minerals in an immersion mount For most microscopes the only modification needed is the installation of a small opaque dot at or near the focal point of the medium power objective White light illumination, stopped down to the angular aperture of the opaque dot, produced a dark field on which the image of the fragment is outlined in diagnostic dispersion color Precision of refractive index determination by this technique, about + or -0001 under routine controlled conditions, is similar to that of the conventional Becke line technique using monochromatic yellow illumination However, it has the advantages that (1) near the match the direction and approximate amount of mismatch may be inferred from the dispersion color of the image alone without the need for manipulation of the focus, (2) at the match the microfragment is clearly visible, and (3) results are obtainable even in the presence of an appreciable amount of inclusions or specific absorption (body color) in the fragment--Modified journal abstract

15 citations

Journal ArticleDOI
TL;DR: In this article, the second-order statistics of time-averaged speckle were investigated for the case of speckles formed in the Fraunhofer plane when an aperture was moved over the surface of a uniformly illuminated diffuse object.

15 citations

Journal ArticleDOI
01 Aug 1956

15 citations


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