Abstract

Humidity is the most problematic parameter for the accurate determination of the refractive index of air. Besides the fact that the humidity measurement can be limiting, the existing empirical equations for the refractive index of moist air are either restricted to $20°\mathrm{C}$ or are based on insufficient knowledge of the refractivity of water vapor. To overcome this problem, a new kind of measurement method for the refractivity of water vapor is suggested that is based on the accurate measurement of the absolute length of a step length by interferometry under vacuum conditions and subsequent measurements at different well-defined absolute water vapor pressures.

© 2006 Optical Society of America

Water-vapor isotope ratio measurements in air with a quantum-cascade laser spectrometer

L. Joly, V. Zéninari, B. Parvitte, D. Courtois, and G. Durry
Opt. Lett. 31(2) 143-145 (2006)

Refractive Indices of Water Vapor and Carbon Dioxide at Low Pressure

Kenneth B. Newbound
J. Opt. Soc. Am. 39(10) 835-840 (1949)

High-accuracy displacement interferometry refin air

W. Tyler Estler
Appl. Opt. 24(6) 808-815 (1985)

Direct determination of the refractive index and thickness of a biolayer based on coupled waveguide-surface plasmon resonance mode

F.-C. Chien and S.-J. Chen
Opt. Lett. 31(2) 187-189 (2006)

Simultaneous diode-laser-based in situ measurement of liquid water content and oxygen mole fraction in dense water mist environments

Andrew R. Awtry, James W. Fleming, and Volker Ebert
Opt. Lett. 31(7) 900-902 (2006)