Optical constants of ethylene glycol over an extremely wide spectral range

• The knowledge of optical constants n, k is required for many applications.
• For liquid ethylene glycol k is obtained over an extremely wide spectral range.
• We used the Kramers–Kronig theory and an ad hoc technique to calculate n from k.
• Limitations and tricks of this approach are discussed.

Besides providing insights into the fundamental properties of materials, the knowledge of optical constants is required for a large variety of applications. In this work, for the first time to the best of our knowledge, an extremely wide spectral range from 181 to ∼54,000 cm−1 has been explored for ethylene glycol in the liquid phase, and optical constants in the whole range have been given. The approach we propose can also be applied to different fluids.