| 摘要 |
1,210,272. Investigating polarized light. ETAT FRANCAIS, REPRESENTED BY THE MINIST’RE DES ARM•ES, DELEGATION MINISTERIELLE POUR L'ARMEMENT, DIRECTION TECHNIQUE DES CONSTRUCTIONS NAVALES. Sept.26, 1968 [Sept.28, 1967], No.45869/68. Heading G1A. In a method and apparatus for determining the phase retardation of the component beams of polarized light and their spacial orientation wherein the light is applied to a photo-multiplier through a rotating analyser, A.C. and D.C. components in the photo-multiplier output are separated, the D.C. component is fed back to maintain the photomultiplier output constant, and the phase difference between the A.C. and a reference signal from the rotating analyzer is measured together with the amplitude of the A.C., the former being a measure of the spacial orientation and the latter of the phase retardation. The output of photo-multiplier 30, Fig. 4 is separated by a filter bank 2 and the D.C. on line II after comparison with a reference voltage in a comparator 4 is used to control the photomultiplier high voltage generator 6 and may be applied to a ratiometer 7' to produce with the rectified A.C. a direct reading of ellipticity in a meter 11. The phase of the A. C. is compared in a comparator 7 with a reference A.C. produced in a unit 9 by light passing through the rotating analyzer and falling on a photo-cell. A mathematical analysis is given and the use of the apparatus in conjunctionwith a laser source providing circularly polarized monochromatic light in two or three dimensional photo-elasticity investigations is referred to. To determine the proper direction of polarization a swivelling quarter wave plate may be placed between the emerging light and the rotating analyzer and the phase of the A.C. indicates the sense of polarization. |
