Walter K. Kahn

  • Citations Per Year
Learn More
This paper describes a novel approach to the application of conformal mapping to capacitance evaluation. A particular structure composed of an array of identical lines and located below a conductive plate is studied. Results show the application of conformal mapping can reduce computing time when using three-dimensional electrostatic modeling and it can be(More)
A simple theory is developed for optical resonators, in which the mirrors are each composed of two planes forming a nearly straight dihedral angle and an equivalent beam-waveguide comprising a sequence of narrow angle prisms. Geometric optical considerations yield the variation of the intensity within the resonator in a manner analogous to (although not(More)
In stable resonators any given initially paraxial rays remain close to the axis of the structure and are, in fact, confined within well-defined contours-the envelope of the ray system. Previously, envelopes of rays in empty resonators had been found and their form identified with the variation of the spot size. This geometric optical approach is extended to(More)
A technique, firmly based on a development from ray optics, is presented for calculating the loss due to the finite sizes of curved mirrors when these form an unstable optical resonator. If paraxial rays launched within such a resonator are confined near the resonator axis, the resonator is termed stable; otherwise it is termed unstable, and is known to(More)
Fluid flow measurement capabilities of a traveling wave laser oscillator (or ring laser) are assessed theoretically and experimentally. The feasibility of this alternative optical technique for measuring gas flow profiles without insertion of a mechanical probe is examined. Measurements are reported for a range of Reynolds numbers including both laminar and(More)
A unified network approach to the analysis of infinite regular arrays of antennas is presented. The periodically repeated constituent of the array is itself regarded as a sub-array, the subarray taking a variety of particular forms. With the appropriate choice of sub-array, the same formulation yields as special cases the uniform linear, planar, and(More)
This letter outlines a geometrical construction for the virtual centers of unstable spherical mirror F.P. resona­ tors. Geometrical constructions that interrelate the pa­ rameters, phase curvature, and spot size of Gaussian beams were presented by Deschamps and Mast in 1964 and applied by them to determine the properties of stable optical resonators.(More)
A specialized coupler formed by two identical multimode graded-index slab fibers is described. This special coupler can be used to examine the tilt or the roughness of a surface through the reflected beam. It may also find applications as a mode filter, an alignment sensor, or a feed component of an optical monopulse tracking radar. Coupled-mode theory is(More)
The oscillations about the fiber axis that generally accompany a beam injected eccentrically into a gradient-index fiber can be substantially suppressed. It is shown how the constraint of Liouville's theorem, which was thought to preclude this effect, is satisfied inma system of two coupled fibers. The length of the coupled-fiber section required for(More)