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Applied Optics

Applied Optics


  • Vol. 38, Iss. 30 — Oct. 20, 1999
  • pp: 6439–6446

Frequency dependence in a liquid’s complex refractive index measured with infrared spectroradiometry

Walt McKeown  »View Author Affiliations

Applied Optics, Vol. 38, Issue 30, pp. 6439-6446 (1999)

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A laboratory measurement of wavelength dependence in the real n(λ) and the imaginary k(λ) parts of a liquid’s complex refractive index is presented. A known heat flow through the liquid–gas interface is generated while a high-resolution infrared radiance spectrum is taken simultaneously. Wavelength variations of the absorption coefficient allow the emerging radiation to sense subsurface temperature gradients. This technique is valid only at intervals at which the absorption coefficient is sufficiently low to allow subsurface temperatures to be measured. Knowledge of a liquid’s thermal conductivity, specific heat, and light transmission speed is required. Measurement error depends on radiance measurement error and the minimization of atmospheric parameters.

© 1999 Optical Society of America

OCIS Codes
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(240.6490) Optics at surfaces : Spectroscopy, surface
(300.2140) Spectroscopy : Emission

Original Manuscript: February 1, 1999
Revised Manuscript: May 10, 1999
Published: October 20, 1999

Walt McKeown, "Frequency dependence in a liquid’s complex refractive index measured with infrared spectroradiometry," Appl. Opt. 38, 6439-6446 (1999)

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