The Christiansen effect is named after the Danish physicist Christian Christiansen and describes the reduced scattering of multi-phase

microstructure Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material (such as metals, polymers ...

s at wavelengths where their refractive indices match. A Christiansen filter is a narrow bandpass or

monochromatic A monochrome or monochromatic image, object or color scheme, palette is composed of one color (or lightness, values of one color). Images using only Tint, shade and tone, shades of grey are called grayscale (typically digital) or Black and wh ...

optical

filter Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...

which consists of an optical cell which is stuffed with a crushed substance (e.g. glass) and a (mostly organic) liquid. The liquid is chosen according to the substance, so that the dispersion curves coincide at one wavelength. For this wavelength the filled optical cell behaves like a plane-parallel, homogeneous disk and allows transmission. All other wavelength ranges of the spectrum are reflected, scattered as well as refracted at the many interfaces between substance and liquid. A change of the transmission behavior of this dispersion filter can be achieved by variation of the liquid, the temperature or variation of the pressure. The fundamental consequence is the change of the refractive index of the liquid. A typical filter is composed of glass particles immersed in a mixture of

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...

and

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non ...

. The wavelength of operation can be varied by changing the percentage of the two components of the liquid mixture, or by varying the temperature.

Bibliography

* Christian Christiansen, „Untersuchungen über die optischen Eigenschaften von fein verteilten Körpern - Erste Mittheilung“ ��Studies on the optical properties of finely divided bodies - First part”br>''Annalen der Physik und Chemie (Leipzig)'', vol. 23
pp. 298-306, 1884 * Christian Christiansen, „Untersuchungen über die optischen Eigenschaften von fein verteilten Körpern - Zweite Mittheilung“ ��Studies on the optical properties of finely divided bodies - Second part”br>''Annalen der Physik und Chemie (Leipzig)'', vol. 24
pp. 439-446, 1885 *

Sir Chandrasekhara Venkata Raman Sir Chandrasekhara Venkata Raman (; 7 November 188821 November 1970) was an Indian physicist known for his work in the field of light scattering. Using a spectrograph that he developed, he and his student K. S. Krishnan discovered that when ...

, “The theory of the Christiansen experiment”, '' Proceedings of the Indian Academy of Sciences, Section A'', vol. 29, pp. 381-390, 1949 * V. I. Shelyubskii (В. И. Шелюбский), Новый нетод определения и контроля, однородности стекла ��A new method for determining and controlling the homogeneity of glass” Стекло и керамика '' lass and Ceramics', vol. 8, pp. 17-22, 1960 * Teruo Sakaino, Masayuki Yamane, Akio Makishima, and Satoru Inoue, “An improved method for measuring the homogeneity of glass by Shelyubskii's method”, ''Glass Technology'', vol. 19, pp. 69-74, 1978 * Roland Paul Heidrich, ''Experimentelle Homogenitätsuntersuchungen an technischen Gläsern mit dem Cristiansenfilter xperimental homogeneity studies on technical glasses using the Cristiansen filter', Thesis, Technische Universität Clausthal, 1999 * Roland Paul Heidrich, Günther Heinz Frischat
“Optimizing the Christiansen-Shelyubskii method and its comparison with industrial control methods for homogeneity determination of glasses”
''Glastechnische Berichte lass Science and Technology', vol. 72, no. 6, pp. 197-203, 1999 Optical filters de:Infrarotspektroskopie#Christiansen-Effekt