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Reflectance vs Wavelength (Just Glass)
Posted 14 mars 2024, 22:25 UTC−4 Ray Optics Version 6.0 4 Replies
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Hello,
I experimented with analyzing how reflectance (%) changes with wavelength for just a glass layer, intending to align my findings with the graphs presented in "Introduction to Optics" (Third Edition) by Frank L. Pedrotti, Leno M. Pedrotti, and Leno S. Pedrotti - a screenshot of one such graph is attached. Attached are the .mph file and a screenshot from the study.
My inquiry is about the discrepancy observed in the reflectance plots. Despite knowing that the refractive index changes with wavelength, the plots show a nearly constant reflectance around 4% across various wavelengths, appearing as a straight line. Why do these plots not showcase the expected variation due to the refractive index's dependence on wavelength?
Please advise.
Kind regards, Collins Kariuki.
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The refractive indeces in your model are obviously constant and do not depend on the wavelength.
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
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The refractive indeces in your model are obviously constant and do not depend on the wavelength.
Thank you for the assistance! Could you guide me on how to configure my model so that the refractive indices vary with wavelength?
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You must provide this data to the model. You can define a function n(lambda) e.g. as an interpolation function. You need a respective table, that may be provided by the glass manufacturer or in the literature. This wavelength dependent index is called dispersion. The function can be complex if losses are taken into account.
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Please login with a confirmed email address before reporting spam
You must provide this data to the model. You can define a function n(lambda) e.g. as an interpolation function. You need a respective table, that may be provided by the glass manufacturer or in the literature. This wavelength dependent index is called dispersion. The function can be complex if losses are taken into account.
This solution was effective. I discovered that COMSOL includes various materials with predefined interpolation functions, like the Corning HPFS 7980 Fused Silica. As a result, I'm now able to produce a reflectance (%) versus wavelength (nm) plot that accurately reflects dependence on wavelength. Thank you very much.