How to calculate refractive index from reflectance values

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Discussion Overview

The discussion focuses on calculating the refractive index, extinction coefficient, and absorption coefficient from reflectance data, as well as exploring the relationship between transparency and refractive index. The scope includes theoretical and practical aspects of optics and materials science.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant inquires about methods to calculate refractive index and related coefficients from reflectance data, and questions the relationship between transparency and refractive index.
  • Another participant suggests that calculating the refractive index depends on additional factors, including the phase change upon reflection, which cannot be determined from intensity measurements alone.
  • A third participant notes that the extinction and absorption coefficients are closely related, but emphasizes that transparency also depends on the material's thickness.
  • A later reply asks for guidance on calculating the phase shift from measured reflectance data, indicating a need for a detailed explanation of the dispersion relation formula.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of calculating refractive index solely from reflectance data, with some emphasizing the necessity of phase information. The discussion remains unresolved regarding the specific methodologies and relationships discussed.

Contextual Notes

Limitations include the dependence on phase information for accurate calculations and the potential complexity of the dispersion relation formula, which remains unsolved for one participant.

Mythili
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Greetings.
how to calculate the refractive index, extinction coefficient, absorption coefficient values from the reflectance data. And also suggest me how to measure the transparency of glass. Is there any relation between transparency and refractive index

Thanks in advance
 
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Not possible using only intensity measurements to my knowledge - you need to know the phase change upon reflection as amplitude to calculate the complex (i.e. refraction + absorption) refractive index.

Extinction and absorption coefficient are basically the same thing, transparency additionally depends on the thickness of the material you are looking at. Absorption coefficient is related to the imaginary component of the refractive index.

Claude.
 
Hi,
do you know how i can calculate the phase shift of measured reflectance data? I find the dispersion relation formula but I can´t solve it.
A step by step description will really help.

thanks
chris
 

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