anomalous dispersion: meaning, definition, pronunciation and examples
Rare/Very LowTechnical/Scientific
Quick answer
What does “anomalous dispersion” mean?
A phenomenon in optics and physics where the refractive index of a material decreases with increasing wavelength, contrary to normal behavior.
Audio
Pronunciation
Definition
Meaning and Definition
A phenomenon in optics and physics where the refractive index of a material decreases with increasing wavelength, contrary to normal behavior.
Specifically, the region of the electromagnetic spectrum where a material's refractive index increases rapidly with wavelength near an absorption band. It also refers more generally to any deviation from the expected pattern of variation, such as in statistical data or wave propagation.
Dialectal Variation
British vs American Usage
Differences
No lexical differences. Minor potential differences in hyphenation in compound adjectives (e.g., 'anomalous-dispersion region' slightly more common in AmE, 'anomalous dispersion region' in BrE).
Connotations
Identical, purely technical.
Frequency
Equally rare in both varieties. Used almost exclusively within the same scientific discourse communities.
Grammar
How to Use “anomalous dispersion” in a Sentence
The [material/substance] exhibits/undergoes anomalous dispersion.Anomalous dispersion is observed/characterized by [description].The region of anomalous dispersion is near [specific wavelength/absorption line].Vocabulary
Collocations
Examples
Examples of “anomalous dispersion” in a Sentence
verb
British English
- The medium anomalously disperses the light.
- The material began to anomalously disperse the signal.
American English
- The substance anomalously disperses the light.
- The fiber is designed to anomalously disperse pulses.
adverb
British English
- The light propagated anomalously dispersively.
- The pulse spread anomalously.
American English
- The light propagated anomalously dispersively.
- The pulse spread anomalously.
adjective
British English
- The anomalous-dispersion region was mapped.
- An anomalous-dispersion fibre is key to the experiment.
American English
- The anomalous dispersion region was mapped.
- An anomalous dispersion fiber is key to the experiment.
Usage
Meaning in Context
Business
Never used.
Academic
Core usage. Found in physics, optics, and materials science textbooks, papers, and lectures.
Everyday
Never used.
Technical
Core usage in optical engineering, laser physics, spectroscopy, and photonics research.
Vocabulary
Synonyms of “anomalous dispersion”
Neutral
Weak
Vocabulary
Antonyms of “anomalous dispersion”
Watch out
Common Mistakes When Using “anomalous dispersion”
- Confusing it with 'anomalous diffraction'.
- Using it as an adjective alone (e.g., 'an anomalous dispersion glass' is better phrased as 'a glass exhibiting anomalous dispersion').
- Misspelling as 'anomolous dispersion'.
- Mispronouncing 'dispersion' with /z/ instead of /ʒ/ in AmE.
FAQ
Frequently Asked Questions
Normal dispersion is the common case where refractive index decreases with increasing wavelength (red bends less). Anomalous dispersion is the less common case where refractive index increases with increasing wavelength, occurring near absorption bands.
Almost never in everyday language. It may appear in highly technical analogies in fields like statistics or signal processing, but its home domain is optics and wave physics.
Typically not with a simple glass prism for visible light, as the effect is strong near absorption bands, which for common glass lie outside the visible spectrum. It requires specific materials and measurement near their absorption lines.
It comes from Greek 'anōmalos' meaning 'uneven, irregular' (a- 'not' + homalos 'even'). The spelling 'anomolous' is a common error, but the correct form retains the 'a' from the root.
Anomalous dispersion is usually technical/scientific in register.
Anomalous dispersion: in British English it is pronounced /əˈnɒmələs dɪˈspɜːʃən/, and in American English it is pronounced /əˈnɑːmələs dɪˈspɜːrʒən/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of a rainbow (normal dispersion) where red bends less than violet. Now imagine the rainbow is 'anomalous' and the colours are in reverse order near a dark band (absorption line). A-NOM-alous = A Notable Optical Misbehaviour.
Conceptual Metaphor
DEFAULT/VIOLATION: It is 'normal' for a prism to spread light predictably; 'anomalous dispersion' is the violation of that predictable rule.
Practice
Quiz
In which field is the term 'anomalous dispersion' primarily used?