| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the effect of fringe noise by simple constitution and to also effectively arrange a reference cell in the min. space at the min. cost. SOLUTION: The photodetection surfaces 12a, 15a of photodetectors 12, 15 are arranged so as to be inclined at a predetermined angle with respect to optical axes C1, C2. A reference cell 16 in which an object to be measured is sealed is provided in the light path of the laser beam reflected by the photodetection surface 12a of the photodetector 12 and a photodetector 17 measuring the intensity of the laser beam passed through the reference cell 16 is provided.</p> |
