On the use of conical reflectors in laser displacement interferometry
A laser interferometer with 90/spl deg/ conical reflectors was tested. Reflectors with a conic section of 90/spl deg/ in the meridional plane are of interest in a number of applications, including laser displacement interferometry, especially for measurements in submicrometre range, laser spectroscopy, and multi-pass optical cells.
Design of a multipass optical cell based on the use of shifted corner cubes and right-angle prisms.
A design of a multipass optical cell is proposed. This design is based on the use of corner-cube retroreflectors arranged opposite to parallel axes, an incident beam that enters off the plane that contains the axes of the retroreflectors, and right-angle prisms to return to the cell the beam that left it after several reflections. This design allows the light beam to pass through the cell many times so that the beam paths fill the cell volume tightly and homogeneously.
A new method of near field analysis
The problem of the accurate determination of the total electromagnetic field produced by a current distribution on a circular disc type aperture is examined. For comparison of the near and Fresnel region solutions, an exact Maxwellian integral is used as the starting point. Aperture and space coordinates are separated by the use of Bessel function addition theorems, allowing the field to be expressed as a sum of terms containing radial and angular integrals. The radial integrals involve only the disc (aperture) distribution and coordinates while the angular integrals involve only the elevation angle. The distance from origin appears implicitly in the series coefficients. These integrals are suitable for high speed computations and have been evaluated for a number of cases. The results are compared with the small angle and general Fresnel formula values for various observation angles, distances from the aperture, and aperture distributions.