| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique capable of measuring an absolute distance between a reference surface and a surface to be tested in a wide range with high accuracy. <P>SOLUTION: A measurement device 1 for measuring an absolute distance between a reference surface RS and a surface TS to be tested includes: a wavelength reference element including a gas cell 112 for enclosing more than one kind of gas each having absorption lines different from each other; a phase detection part 122 for detecting an interference signal of first light reflected by the reference surface RS and second light reflected by the surface TS to be tested to detect a phase corresponding to an optical path length between the reference surface RS and the surface TS to be tested; and a processing part 128 for setting wavelengths of light emitted from the light source 102 to each of a plurality of wavelengths different from each other which are corresponding to a plurality of absorption lines different from each other by using the wavelength reference element, controlling the phase detection part 122 to detect a phase corresponding to the optical path length between the reference surface RS and the surface TS to be tested as to each of the plurality of wavelengths different from each other and performing processing to determine the absolute distance. <P>COPYRIGHT: (C)2012,JPO&INPIT |
