Effective optical constants {ital n} and {kappa} and extinction coefficient of silica aerogel
Abstract
In this work the normal reflectance, {ital R}, at a planar silica aerogel interface and the normal transmittance, {ital T}, of a silica aerogel slab were measured using a Fourier Transform Infrared Spectrometer. Two procedures were used to obtain the effective optical constants, i.e., the refractive index {ital n} and the absorption index {kappa}, of silica aerogel. One procedure determined {kappa} from the measured transmittance {ital T} and then determined {ital n} from the results for {kappa} and from the measured reflectance {ital R} using the Kramers-Kronig relation; the other procedure determined {ital n} and {kappa} of silica aerogel from {ital n} and {kappa} of fully dense silica glass by using the Clausius-Mossotti equation, Maxwell Garnett formula, and Bruggeman formula. The first procedure has a relatively large error due to the inaccuracy of the transmission and reflection measurements. The second procedure, especially the Clausius{endash}Mossotti equation, yields values of {ital n} that are consistent with experiments and may be used for the calculation of the effective optical constants and the extinction coefficient of silica aerogel. {copyright} {ital 1996 Materials Research Society.}
- Authors:
-
- Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)
- Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)
- Publication Date:
- Research Org.:
- Lawrence Berkeley National Laboratory
- OSTI Identifier:
- 279742
- DOE Contract Number:
- AC03-76SF00098
- Resource Type:
- Journal Article
- Journal Name:
- Journal of Materials Research
- Additional Journal Information:
- Journal Volume: 11; Journal Issue: 3; Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; GELS; OPTICAL PROPERTIES; SILICA; INFRARED RADIATION; KRAMERS-KRONIG CORRELATION; TRANSMISSION; EXTINCTION
Citation Formats
Zeng, J S, Greif, R, Stevens, P, Ayers, M, and Hunt, A. Effective optical constants {ital n} and {kappa} and extinction coefficient of silica aerogel. United States: N. p., 1996.
Web. doi:10.1557/JMR.1996.0083.
Zeng, J S, Greif, R, Stevens, P, Ayers, M, & Hunt, A. Effective optical constants {ital n} and {kappa} and extinction coefficient of silica aerogel. United States. https://doi.org/10.1557/JMR.1996.0083
Zeng, J S, Greif, R, Stevens, P, Ayers, M, and Hunt, A. Fri .
"Effective optical constants {ital n} and {kappa} and extinction coefficient of silica aerogel". United States. https://doi.org/10.1557/JMR.1996.0083.
@article{osti_279742,
title = {Effective optical constants {ital n} and {kappa} and extinction coefficient of silica aerogel},
author = {Zeng, J S and Greif, R and Stevens, P and Ayers, M and Hunt, A},
abstractNote = {In this work the normal reflectance, {ital R}, at a planar silica aerogel interface and the normal transmittance, {ital T}, of a silica aerogel slab were measured using a Fourier Transform Infrared Spectrometer. Two procedures were used to obtain the effective optical constants, i.e., the refractive index {ital n} and the absorption index {kappa}, of silica aerogel. One procedure determined {kappa} from the measured transmittance {ital T} and then determined {ital n} from the results for {kappa} and from the measured reflectance {ital R} using the Kramers-Kronig relation; the other procedure determined {ital n} and {kappa} of silica aerogel from {ital n} and {kappa} of fully dense silica glass by using the Clausius-Mossotti equation, Maxwell Garnett formula, and Bruggeman formula. The first procedure has a relatively large error due to the inaccuracy of the transmission and reflection measurements. The second procedure, especially the Clausius{endash}Mossotti equation, yields values of {ital n} that are consistent with experiments and may be used for the calculation of the effective optical constants and the extinction coefficient of silica aerogel. {copyright} {ital 1996 Materials Research Society.}},
doi = {10.1557/JMR.1996.0083},
url = {https://www.osti.gov/biblio/279742},
journal = {Journal of Materials Research},
number = 3,
volume = 11,
place = {United States},
year = {1996},
month = {3}
}
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