| 摘要 |
PURPOSE:To execute a measurement with a high accuracy without being subjected to a measuring limit by magnitude of a speed, by detecting an interference frequency generated by making reflected light from two measuring points interfere. CONSTITUTION:Light emitted from a laser 1 is divided into two by a spectroscope 2, and one light and the other light are led to an optical fiber 4 and an optical fiber 4', respectively. Also, the light led to the fiber 4 is condensed by a projecting lens 5 and irradiated at an angle theta to a measuring point of an object 6 which is moving, and the light led to the fiber 4' is condensed by a projecting lens 5', and thereafter, irradiated at an angle theta to a measuring point of an object 6' which is moving. Subsequently, only one directional component from reflected light from each measuring point is photodetected at an angle phi (phinot equal to theta) through photodetecting lenses 7, 7', respectively, led to an optical coupler 9 through optical fibers 8, 8' and coupled, and led to an optical fiber 10. In the fiber 10, two lights interfere with each other, therefore, an intensity of an interference light is detected by a photodetector 11, also sent to a frequency detector 12, and an interference frequency is detected. |
