Christiansen effect
Encyclopedia
The Christiansen effect is named after the Danish physicist Christian Christiansen
the effect of this filter is based on the various dispersions of two different media.
A Christiansen filter is a narrow bandpass
or monochromatic optical filter
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
and carbon disulfide
. The wavelength of operation can be varied by changing the percentage of the two components of the liquid mixture, or by varying the temperature.
Christian Christiansen
Christian Christiansen was a Danish physicist.Christiansen first taught at the local polytechnical school. In 1886 he was appointed to a chair for physics at the University of Copenhagen....
the effect of this filter is based on the various dispersions of two different media.
A Christiansen filter is a narrow bandpass
Narrowband
In radio, narrowband describes a channel in which the bandwidth of the message does not significantly exceed the channel's coherence bandwidth. It is a common misconception that narrowband refers to a channel which occupies only a "small" amount of space on the radio spectrum.The opposite of...
or monochromatic optical filter
Filter (optics)
Optical filters are devices which selectively transmit light of different wavelengths, usually implemented as plane glass or plastic devices in the optical path which are either dyed in the mass or have interference coatings....
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
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
and carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...
. The wavelength of operation can be varied by changing the percentage of the two components of the liquid mixture, or by varying the temperature.