| 摘要 |
A method and means for measuring and/or determining characteristics of a material by analyzing the characteristics of an energy beam incident upon and affected by the sample. Polarized radiant energy reflected and/or transmitted by the material sample is analyzed to infer optical properties such as index of refraction, and physical properties such as material thickness. The invention is not subject to the disadvantages of prior art measuring systems, in that absolute detected light values are not used, measurement of varying wavelengths of light are not necessary, surface defects contribute a balanced effect in the calculations so as to effectively cancel out, highly accurate angular measuring devices are not needed, precision nulling instruments are avoided, system parameter drift effects upon the measurement is avoided, inter alia. According to the invention, a method and means are provided for measuring an optical property of a thin material sample having a transmission efficiency of greater than zero for an impinging beam of radiant energy. A source beam of radiant energy at a given wavelength and of varying polarization direction is provided, and the polarization-varying beam is directed onto an entry surface of the thin material sample at a predetermined angle with respect thereto. The beam leaving the sample is analyzed to determine the relative amplitudes of first and second polarized components thereof. The optical property of the sample is determined from a mathematical model equating the optical property to a relationship between said wavelength of the source beam, the predetermined angle, and the results of detecting and analyzing the beam exiting the sample.
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