Abstract
The reflectance spectra of solid and liquids can be complicated since they depend not only on absorption, but also on the refraction, reflection, and scattering of light, all of which are wavelength dependent. The physical form and morphological effects associated with solid and liquid samples are thus known to affect their reflectance spectra in a non-linear fashion, particularly in the infrared. Measuring the optical constants n(ν) and k(ν) represents an alternative approach, allowing one to model these many effects and thus requiring fewer laboratory measurements. In this paper an overview is presented of the protocols used to measure the n/k optical constants, particularly for liquids. For the liquids, a multiple path length measurements approach is employed, and in this paper we demonstrate the method to determine the complex optical constants n(ν) and k(ν) of squalene. The resultant calculated spectra of 1 µm and 100 µm thick layers of squalene on an aluminum substrate as derived from the experimental n(ν) and k(ν) values are shown to demonstrate such effects. The public availability of the n(ν)/k(ν) data as well as solids hemispherical reflectance data are also discussed.
© 2019 SPIE, ICO, IEEE, OSA
PDF ArticleMore Like This
Tanya L. Myers, Tracy J. Baker, Oliva Primera-Pedrozo, Russell G. Tonkyn, and Timothy J. Johnson
EM3E.4 Optics and Photonics for Sensing the Environment (ES) 2023
Kelly A. Peterson, Timothy J. Johnson, Bruce E. Bernacki, Charmayne E. Lonergan, and Tanya L. Myers
LM3B.3 Laser Applications to Chemical, Security and Environmental Analysis (LACSEA) 2022
Enrico Baria, Simone Morselli, Suresh Anand, Riccardo Fantechi, A. Sebastianelli, Mauro Gacci, Sergio Serni, Riccardo Cicchi, and Francesco S. Pavone
11073_4 European Conference on Biomedical Optics (ECBO) 2019