抄録
In most of the conventional microinterferometers, a fringe spacing obtained by a reflecting light-beam from a test surface expresses λ/2 in difference of the height where λ is the wavelength of a used light source. So it is difficult to measure a precise finishing surface effectively in a conventional microinterferometers. Because the relative fringe shift in ordinary interferometer is too small to measure them. A microinterferometer in which the Michelson's interferometer is combined with the Fizeau type multi-reflection mechanism is developed. And by using the microinterferometer which enhances the interferometric sensitivity according to the method of "multi-reflection optical path difference", it becomes possible to measure a finer surface. A laser beam with high luminance and good coherency was employed as the light source. In case that light-beam is repeatedly reflected n-times at multi-reflection part, the measuring unit is expected to decrease to λ/2n. (n is natural number.) It is experimentally ascertained to obtain n-times sensitivity compared with the conventional types. This method is especially useful in measuring thickness of thin metallic film and precisely finished surfaces. And it is found that an effective result of the increasing interferometric sensitivity can be expected.
