| 摘要 |
PURPOSE:To improve sensitivity and resolutions of photometry, by canceling scattered light directly by interference at sampling to avoid saturation of a detector. CONSTITUTION:A beam sampler 30 extracts laser light 31 from output laser light 3 of a light source 1. The laser light 31 is divided in two with a beam splitter 25 just as scattered light 9 through lenses 32 and 33 and reflection mirrors 44 and 45 and reflected with a fixed flat mirror 26 and a mobile flat mirror 27 to interfere with each other on the splitter 25. The interference light output thus obtained is detected with a photodiode 34 and an optical path difference signal 36 obtained after amplified 35 is inputted into a gate circuit 37. Then, when an output of the signal 36 is at its minimum, directly scattered light out of the scattered light 9 cancels each other by interference to remove signals of the directly scattered light from output signals of a photoelectric multiplier 18. Thus, at a point where the signal 36 reaches its minimum, the circuit 37 outputs a sampling signal 46 to sample and hold 39 an output signal 20. The resulting sampled and hold signal 40 has a sharp peak and a computer 50 converts the signal 40 into a spectrum by Fourier transform.
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