1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Relating absorbance wavelengths and refractive index

  1. Jul 12, 2013 #1
    Dear All,
    thank you for your attention. I am a Biologist and I was wondering if it is possible to translate absorbance λ values into a refractive index value? I found out about the sellmeier equation however it appears to require coefficients that have to be experimentally determined.

    Is there a way around using these coefficients? I just need to know if it is possible or not and pointed in the right direction.
    Thank you for your time.
  2. jcsd
  3. Jul 12, 2013 #2

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Absorption can be treated as an imaginary component of the refractive index, n = n' + in'', where n' is the real component and is used in, for example, Snell's law. If you have n''(λ), the absorption, you can calculate the real component via Kramers-Kronig relations (the real part is the Hilbert transform of the imaginary part and vice-versa), but the details will depend on the units associated with your absorption measurement.

    The Sellmeier equation is an empirical dispersion relation for the real part of the refractive index, and is unrelated to your question.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook