Design of a lidar receiver with fiber-optic output.

Design considerations for a coaxial lidar receiver are examined, including details of coupling to an optical fiber for transfer of return light to a remote detector box. Attention is concentrated on the influence of fiber position on return-light capture efficiency and dynamic range of the return signal. The effect of a central obstruction on short-range signals is included. The analysis is augmented with simulations of lidar receiver performance.

Computing uses of the optical tunnel.

An optical tunnel configuration can perform crossover operations applicable to optical digital computing.

Fine structure of an image facsimile synthesized with a Gaussian spot.

A TV picture or any other line-scan image facsimile is anisotropic. Its intensity varies continuously along a sweep, and its resolution capability in this direction can be described by a modulation transfer function (MTF). In the orthogonal direction the facsimile's fine structure is discontinuous, and only discrete spatial frequencies can be reproduced. Such a system can be characterized by its MTF in the sweep direction and the ratio of its sweep interval and spot diameter. If the spot has a rotationally symmetric Gaussian intensitydistribution, the fine structure of the facsimile can be described in terms of the Gaussian spot profile. With a compatible relay-lens design, the optimum spot diameter for a CRT-to-film recording system is less than that for a directly viewed display.

The modulation transfer function of an optical system with a rotationally symmetric circle of confusion.

The relationship between an optical system's circle of confusion and the quality of the image it forms is not specified by any universally accepted criterion. However, a simple geometric theory helps place the problem in perspective. As a first-order approximation, the circle of confusion is considered to be a uniformly illuminated disk. Then the illumination at a point in the image is the average of the illumination which would occur in the geometric image within an aperture of finite diameter centered at this point in the image plane. If the circle of confusion has a more complex radial illumination distribution, the image-forming process can be considered as the combined operation of a number of concentric averaging apertures of varying radii. If the circle of confusion has a Gaussian radial illumination distribution, a solution for the modulation transfer function can be obtained in closed form.