Complex refractive index measurements for BaF2 and CaF2 via single-angle infrared reflectance spectroscopy
Abstract
We have re-investigated the optical constants n and k for the homologous series of inorganic salts barium fluoride (BaF2) and calcium fluoride (CaF2) using a single-angle near-normal incidence reflectance device in combination with a calibrated Fourier transform infrared (FTIR) spectrometer. Our results are in good qualitative agreement with most previous works. However, certain features of the previously published data near the reststrahlen band exhibit distinct differences in spectral characteristics. Notably, our measurements of BaF2 do not include a spectral feature in the ∼250 cm-1 reststrahlen band that was previously published. Additionally, CaF2 exhibits a distinct wavelength shift relative to the model derived from previously published data. We confirmed our results with recently published works that use significantly more modern instrumentation and data reduction techniques.
- Publication:
-
Optical Materials
- Pub Date:
- October 2017
- DOI:
- 10.1016/j.optmat.2017.06.052
- Bibcode:
- 2017OptMa..72..743K
- Keywords:
-
- Fourier transform infrared spectroscopy;
- Barium fluoride;
- Calcium fluoride;
- Complex optical constants;
- Kramers-Kronig transform;
- Single-angle reflectance