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Parallel rays coming into a parabolic mirror are focused at a point F. The vertex is V, and the axis of symmetry passes through V and F. For off-axis reflectors (with just the part of the paraboloid between the points P 1 and P 3), the receiver is still placed at the focus of the paraboloid, but it does not cast a shadow onto the reflector.
An off-axis optical system is an optical system in which the optical axis of the aperture is not coincident with the mechanical center of the aperture. The principal applications of off-axis optical systems are to avoid obstruction of the primary aperture by secondary optical elements, instrument packages, or sensors, and to provide ready access to instrument packages or sensors at the focus.
where the optic axis is presumed to lie in the z direction, and () is the sag—the z-component of the displacement of the surface from the vertex, at distance from the axis. The coefficients α i {\displaystyle \alpha _{i}} describe the deviation of the surface from the axially symmetric quadric surface specified by R {\displaystyle R} and κ ...
A Winston cone is a non-imaging light collector in the shape of an off-axis parabola of revolution [1] [2] with a reflective inner surface. It concentrates the light passing through a relatively large entrance aperture through a smaller exit aperture. [3]
Example of a particle collimator. A collimator is a device which narrows a beam of particles or waves. To narrow can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spatial cross section of the beam to become smaller (beam limiting device).
For example, (,) might represent a paraxial ray (i.e., a ray nearly parallel with the optic axis), and (,) might represent a marginal ray (i.e., a ray with the largest angle admitted by the system aperture). An optical imaging system for which this is true in for all rays is said to obey the Abbe sine condition.
By making the off-axis illumination (i.e., the light is illuminating the mask at an oblique angle), all the diffraction orders from the mask are tilted, which makes it more likely that the higher diffraction orders can make it through the projection lens and help form the image of the mask onto the wafer.
Main types of parabolic antennas. An offset dish antenna or off-axis dish antenna is a type of parabolic antenna.It is so called because the antenna feed is offset to the side of the reflector, in contrast to the common "front-feed" parabolic antenna where the feed antenna is suspended in front of the dish, on its axis.