| 摘要 |
An apparatus and method for measuring the space (36) between a transparent member (12) such as a disk, and a reflective member (14) such as a slider, by detecting a change of polarization of a reflected light beam. The apparatus (10) includes a light source (20) that emits a light beam which is circularly polarized, directed onto the disk (12) and reflected off of the interface between the disk (12) and the slider (14). The reflected light beam is split into four separately polarized beams by a beam splitter/polarizer assembly (42, 50, 52) and the varying intensities measured by photodetectors (70, 72). Stokes parameters are computed from signals from the photodetectors (70, 72). Ellipsometric parameters delta and psi are computed from the Stokes parameters. The thickness of the space (36) and the complex index of refraction (n and k) of the slider (14) are computed from the delta and psi parameters.
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