| 摘要 |
The linear slope range of the axial response curve of confocal imaging is utilized to obtain nanometer depth resolution, a sample which is at the top of a piezo-electric translator (PZT) 6, using a highly spatial-coherent light source, high numerical aperture focusing devices, a pinhole, and an optical detector to produce the axial response of confocal imaging Before the measurement, the calibration of height and resolution must be done by fitting the linear slope range of the axial response curve to a straight fitting line. While measuring surface profiles, the sample height is first finely adjusted to the linear slope range, and a two-dimensional scanning is then performed on the plane vertical to the detecting light beam. The signal of optical detector which represents the variation of the surface height, is then recorded. In this way, a three-dimensional image of the sample surface profile can be obtained with nanometer depth resolution. As the system does not require any feed-back control circuit to lock the position of the sample to be detected, it operates in open-loop and has the ability of real-time image display.
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