Topic
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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Patent•
20 Apr 1998
TL;DR: In this article, a large (10's of meters) aperture space telescope including two separate spacecraft, an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece, was used to estimate the positions of the two spacecraft.
Abstract: A large (10's of meters) aperture space telescope including two separate spacecraft—an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass “aiming” at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.
32 citations
TL;DR: The experiments reveal a surprisingly simple structure for the diffraction pattern and its dependence on the orbital angular momentum index of the incident beam when the aperture size is small compared to the beam radius.
Abstract: Far field diffraction of Laguerre–Gauss vortex (LGV) beams of different angular momentum index by a circular aperture placed at different locations with respect to incident beam waist is studied experimentally. The experiments reveal a surprisingly simple structure for the diffraction pattern and its dependence on the orbital angular momentum index of the incident beam when the aperture size is small compared to the beam radius.
32 citations
TL;DR: Using nonparaxial vector diffraction theory derived using the Hertz vector formalism, integral expressions for the electric and magnetic field components of light within and beyond an apertured plane are obtained for an incident plane wave.
Abstract: Using nonparaxial vector diffraction theory derived using the Hertz vector formalism, integral expressions for the electric and magnetic field components of light within and beyond an apertured plane are obtained for an incident plane wave. For linearly polarized light incident on a circular aperture, the integrals for the field components and for the Poynting vector are numerically evaluated. By further two-dimensional integration of a Poynting vector component, the total transmission of a circular aperture is determined as a function of the aperture radius to wavelength ratio. The validity of using Kirchhoff boundary conditions in the aperture plane is also examined in detail.
32 citations
Patent•
27 Mar 2002TL;DR: A projection optical system that projects an image on a first side onto a second plane through a plurality of lenses includes the following elements in order from the first side to the second plane: a first lens group that has a negative refractive power, a second lens group with a positive.
Abstract: A projection optical system that projects an image on a first side onto a second plane through a plurality of lenses includes the following elements in order from the first side to the second plane: a first lens group that has a negative refractive power, a second lens group that has a positive refractive power, a third lens group that has a negative refractive power, a fourth lens group that has an aperture stop in the optical path, and a fifth lens group that has a positive refractive power. A clear aperture of a lens surface or an outer diameter of a lens in the projection optical system has a relative maximum in the second lens group, a relative minimum in the third lens group, and a relative maximum in the third-fifth lens groups, and has only one significant minimum between the first side and the second plane.
32 citations
Patent•
24 Jul 2013TL;DR: A partitioned aperture wavefront imaging system as mentioned in this paper is an imaging system consisting of a partitioned array of 2 or more off-axis lenses symmetrically distributed about an optical axis, and adapted to produce simultaneously at the camera plane at least two images of an object, or intermediate image of an image, presented at the entrance plane.
Abstract: A partitioned aperture wavefront imaging system includes an imaging system comprising a partitioned aperture lens array positioned at the aperture plane or Fourier plane between the entrance plane and camera plane of an imaging system. The partitioned aperture lens array can include 2 or more off-axis lenses symmetrically distributed about an optical axis, and adapted to produce simultaneously at the camera plane at least two images of an object, or intermediate image of an object, presented at the entrance plane. Preferably, the partitioned aperture lens array includes from 3 to 5 off-axis lenses and produces 3 to 5 images at the camera plane from which phase and amplitude information about the light field can be determined. The partitioned aperture wavefront imaging system provides enough information about the light field presented at the entrance plane to enable reconstruction of the light field at other planes relative to the entrance plane.
32 citations