| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus for measuring surface irregularities with a sensitivity of nanometer to sub-nanometer, where no crosstalk exists with less optical loss. SOLUTION: An orthogonal 2-frequency laser beam is split into two optical light paths using an order difference of a photoacoustic member. The advancing direction of the beam on the light path is split with a Rochon prism to obtain four light fluxes, while multiplexed so that two light fluxes of the light paths coincide, to generate three light fluxes. The three light fluxes are used to constitute a sharing heterodyne interferometer which uses three points. COPYRIGHT: (C)2004,JPO
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