References:

1.Timmermans, J., Physico-Chemical Constants of Pure Organic Compounds (Elsevier, New York, 1950).

2.Hauf, W. and Grigull, U., Optical Methods in Heat Transfer (Academic Press, New York, 1970).

3.Lusty, M. E. and Dunn, M. H., Appl. Phys. B 44, 193 (1987).

4.International Critical Tables of Numerical Data, Physics and Chemistry and Technology, Vol. VII, Washburn, E. W., Ed., (McGraw-Hill, New York, 1930).

5.Kaye, G. W. and Laby, T. H., Tables of Physical and Chemical Constants (Longman Group, London, 1986).

5.4.2 Inorganic Liquids

Reference:

Wohlfarth, C. and Wohlfarth, B., Landolt-Börnstein, Numerical Data and Functional Relationships in Science and Technology, New Series, III/38A, Martienssen, W., Ed. (Springer-Verlag, Heidelberg, 1996). The index of refraction at other temperatures and wavelengths may be found in this reference.

© 2003 by CRC Press LLC

5.4.3 Calibration Liquids

The six liquids below are available in highly pure form and their index of refraction has been accurately measured as a function of wavelength and temperature. They are therefore useful for calibration of refractometers. The estimated uncertainties in the values are:

Further details are given in the references below. This table is reprinted from Reference 1 by permission of the Intemational Union of Pure and Applied Chemistry.

References:

1.Marsh, K. N., Ed., Recommended Reference Materials for the Realization of Physicochemical Properties (Blackwell Scientific Publications, Oxford, 1987).

2.Tilton, L. W., J. Opt. Soc. Am. 32, 71 (1941).

© 2003 by CRC Press LLC

5.4.4 Abnormal Dispersion Liquids

Chromatic aberrations in complex lens systems can be corrected by combining lenses made of materials having different refractive indices and dispersions. When the partial dispersion of a material (refractive index for a pair of wavelengths) is plotted versus its Abbe number, most materials lie along a straight line, the so-called “normal” line. (Plots of relative dispersions showing the deviation of various glass types from the normal curve are included in most optical glass catalogs.) To correct for the secondary spectrum in apochromatic lens system (one corrected for three wavelengths), at least one of the materials must have an abnormal dispersion, that is, one lying off the normal line.

The wavelength dependence of the refractive index of a material can be described by the Buchdahl equation N(ω) = N0 + ν1ω + ν2ω2 + . . . νjωj , where N0 is the refractive index

at the wavelengths λ, ν1, ν2, . . . characterize the dispersion, and ω is the chromatic coordinate ω = (λ − λ0/[1 + 5/2(λ − λ0)]. The dispersive power of a material in this model is

given by

where n is the order of the Buchdahl dispersion equation. The dispersion coefficients η are defined by ηi = νi/(N0 – 1). Below is a plot of the primary and secondary dispersion properties of 178 Schott optical glasses and 300 Cargille optical liquids (courtesy of R. D. Sigler).

References:

1.Sigler, R. D., Apochromatic color correction using liquid lenses, Appl. Opt. 29, 2451 (1990).

2.Petrova, M. V., Petrovskii, G. T., Tolstoi, M. N., and Volynkin, V. M., Abnormal dispersion liquids, Opt. Eng. 31, 664 (1992).

© 2003 by CRC Press LLC