ONE-DIMENSIONAL SURFACE PROFILOMETER BASED ON THE HETERODYNE ANGLE DEVIATION INTERFEROMETRY

Ming-Hung Chiu ； Pei-Wei Gao

《技術學刊》 32卷3期 (2017/09) Pp. 197-203

摘要

We propose heterodyne angle deviation interferometry (HADI) to measure the surface profile in real time. A beam incident into a lens’ marginal and reflected from a sample and then finally passing through to the lens is parallel to the optic axis when the sample is just located on the focal plane. When the sample’s surface departs from the focal plane, the reflection beam deviates a small angle from the optic axis which is proportional to the defocus length. We use the common-path heterodyne interferometer (CPHI) with a surface plasmon resonance (SPR) angular sensor to measure the deviation angle by the phase presentation. From the phase difference to surface height transformation and scanning the surface, the one-dimensional surface profile is plotted. The measurable range is of ±2.5 mm with the lateral resolution of 10 μm and the best vertical resolution is of 12 nm.

關鍵字

first-order optics ； heterodyne interferometry ； surface plasmon resonance ； height measurements