Inner surface profile measurement of a cylindrical object by an oblique incidence and multiple-wavelength interferometer

将准直线光束以斜入射角射入内径和长度分别为3mm和3mm的流体动力轴承的内表面。分别为5mm。选择从内表面向指定方向反射的光，得到相位分布与内表面轮廓成正比的光场。该光场通过可调谐外腔激光二极管与多波长干涉仪中的参考光场进行干涉。可测量内表面深度约为5μm的凹槽形状，误差小于0。3μm。

A collimated line beam is incident at an oblique incident angle into an inner surface of a hydrodynamic bearing whose inner diameter and length are 3 mm and 3. 5 mm, respectively. Lights reflected in specified directions from the inner surface are selected to obtain an optical field whose phase distribution is proportional to the inner surface profile. This optical field interferes with a reference optical field in a multiple-wavelength interferometer using a tunable external cavity laser diode. Shapes of grooves with depth of about 5μm on the inner surface can be measured with an error less than 0. 3μm.