Uniaxial crystal and its ellipsometric measurement
Both thin and thick plates made of isotropic and anisotropic medium were studied. Although the multiple reflection phenomena in thin plate can be reduced by index matching technique, but the intensity fluctuation is still too large. A bulk quartz crystal was used as the sample for this PSA ellipsometer. Only one of the ellipsometric paramter φ were measured in this experiment. The difference between the ordinary and extraordinary refractive index of quartz crystal obtained from this measurement is well matched with the expected value, but there are some discrepancies between its intrinsic value. After examining the incident angle effect, we found that the rotating polarizer can cause significant error on incident angle. Using a numerical fitting technique, we calibrated the effective incident angle and produced a well fitted result. This provides us an on-line alignment technique for incident angle.
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