Large Aperture Optical System Research Articles

Electronic speckle pattern interferometric system based on a speckle reference beam

A new electronic speckle pattern interferometric (ESPI) technique is introduced. The technique is based on a reference beam combined with a large aperture optical system. The basic principles are described and compared with conventional ESPI setups. The new interferometer is easy to adjust, it is invulnerable to dust and scratches on the optical components, and is very compact. It is well-suited for practical engineering applications. Light sensitivity and fringe quality are comparable with the conventional ESPI features. Superior fringe pattern can be obtained by use of a new speckle reduction technique to be described.

The design and construction of a large aperture optical system using holographic and interferometric testing techniques

In the design and construction of a large aperture optical system problems were encountered in figuring the optical elements and in mounting them to achieve mechanical stability. The various optical tests which were used to help overcome these problems on a system comprising refracting, reflecting, and Mangin elements are described. Test plates, star tests, OTF, Twyman-Green, and holographic techniques were all used at some stage, and the application for which each was used and the reasons why it was considered the most suitable technique are discussed.

An optical system designed for image processing

In some cases it is possible to radically modify the character of an optical system to make it highly compatible with image processing. One such case is discussed in this paper. A large-aperture optical system may be operated as a multi-element interferometer such that a posteriori image processing can yield images that are free from the usual distortions of atmospheric “seeing”. Most significantly, the image corrections can be accomplished without any knowledge of the point-spread function of the atmosphere.

Design of a Wavefront Shearing Interferometer Useful for Testing Large Aperture Optical Systems

The construction of a Drew type variable shear wavefront shearing interferometer, useful for testing optical systems of large aperture and short focal length, is described. The mechanical arangement, used for adjustment of the mirrors and the dividing plate, and a novel arrangement to achieve white light compensation easily, are described. Sheared interferograms of some lenses are shown.

Intensity Distribution near the Focus of a Large Aperture Optical System

A general expression for the light disturbance near the focus of a large aperture optical system is obtained from the Kirchhoff integration. On reversal of the sign of the aberration function, the light intensity at a point symmetrical to an original point about an axis (y-axis), perpendicular to the meridian plane and passing through the Gaussian image point, is the same as that of the original one. The intensity distribution on the y-axis is expressed in a form, I=I(γ_1^cγ_3^d…,γ_2^eγ_4^f…), c+d+…=even, e+f+…=even, where γ1, γ3,… are comatic aberration terms and γ2, γ4,… are astigmatic terms. This equation holds at the Gaussian image point, too. Aberrations of the same type, comatic or astigmatic, must be corrected one another in order to minimize the decrement of the intensity at the Gaussian image point.