| 摘要 |
PROBLEM TO BE SOLVED: To improve the resolution of a low-coherent interference measuring instrument in the depth direction of samples. SOLUTION: Low-coherent light L emitted front a light source device 10 is split into a signal light Ls and a reference light Lr separately advancing along two different optical paths and a slight frequency differenceΔf is produced between the signal light Ls and reference light Lr by means of AOMs 25a and 25b. Then the signal light Ls is made incident to a sample 15 through a movable mirror 27 and a variable magnification optical system 30 and the intensity of the interference light between the reflected light Ls' of the signal light Ls from a prescribed surface of the sample 15 and the reference light Lr is detected by means of a photodetector 28. At the time of measuring the intensity of the interference light, a conjugate relation is established between the prescribed surface of the sample 15 and the optical system 30 and another relation, f2 , is established between the focal distances f1 and f2 of the optical system 30 on the sample 15 side and mirror 27 side.
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