| 摘要 |
<p>PURPOSE:To accurately measure the voltage of an object body by an electrooptic material which is affected by the voltage of the object body and an electrooptic material for compensating a phase difference due to natural double refraction. CONSTITUTION:A light beam from a polarizer 54 is incident on the electrooptic material 21 through a beam splitter 56. The polarization state of the incident light incident on the material 21 changes with the phase difference due to the natural double refraction and the light is incident on the electrooptic material 22 from the material 21. The materials 21 and 22 are equal in length in the optical axis direction to each other, so the polarization state of the incident light incident on the material 22 changes according to the phase difference due to the natural double refraction, but changes in the opposite direction from it in the material 21, so their polarization states cancel each other. The polarization state when the incident light reaches a reflecting mirror 24 has only a change corresponding to the variation in the refractive index of the material 22 based upon the voltage at the specific part of the object body, so the voltage of the object body is accurately detected.</p> |
