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.
MEASUREMENT OF THE GRAVITATIONAL CONSTANT USING THE ATTRACTION BETWEEN TWO FREELY FALLING DISCS: A PROPOSAL
The constant of gravitation, G, is the least well-known of the physical constants. A new, independent method of measurement, estimated as having a potential uncertainty at least as small as that achieved by existing methods, would be useful for an improvement in G determination. This experiment is based on the measurement of the relative motion of two freely falling test bodies (discs), caused by their gravitational attraction. The uncertainties are analyzed for two parallel tungsten discs with masses of about 30 kg. The use of test bodies with an incorporated optical system of multipass two-beam interferometers, as well as of multibeam interferometers, is proposed to measure their relative displacement. The estimations were made for laboratory experiment with free fall duration of 0.714 s. In this case, the relative displacement to be measured is about 0.1 μm. These estimates show that relative uncertainties lower than 5 × 10-5 can be obtained in G measurement in a single drop of the test bodies. The pro...
Study of Light Deviation Errors in Triple Mirrors and Tetrahedral Prisms
In this study, a procedure based upon vector analysis methods is outlined for the tracing of optical rays through triple-mirror and tetrahedral prism retrodirective reflectors. This procedure is utilized to determine the light deviation errors of such reflectors in terms of the errors in the three dihedral angles between the reflecting surfaces. It is shown that if the dihedral angles of a given reflector are in error by a tolerance amount ±θ, the resulting deviation errors of that reflector will not exceed 3.26θ for a triple mirror or 3.26 Nθ for a tetrahedral prism of refractive index N.Experimental verifications of the theoretical relationships developed in this study are described. The procedures which are used in this verification are applicable to “in-process” and final inspection operations during the manufacture of prismatic retrodirective reflectors of moderate precision.