Lépaisseurindice

Lépaisseurindice is a term encountered mainly in niche or informal French technical writing. It combines the words épaisseur (thickness) and indice (index) and is not a standard entry in major dictionaries or widely adopted in formal standards. In practice, its meaning depends on context and may be used as a neologism to describe a relationship between thickness and an index value.

Two common interpretations recur in technical discussions. The first is optical thickness, also called optical path length, defined as the product of thickness d and refractive index n (nd). This quantity has the dimension of length and plays a central role in thin-film interference, anti-reflection coatings, and multilayer optics. For example, a film with n = 1.5 and d = 200 nm has an optical thickness of 300 nm.

The second interpretation treats lépaisseurindice as a dimensionless thickness ratio, defined as d divided by a characteristic scale or index value i used in a specific model. In such contexts, the term signals that thickness is being compared to an index-related reference to enable scaling or non-dimensional analysis.

Measurement and reporting practices vary. When optical thickness is relevant, researchers often report nd along with or instead of separate n and d. Ellipsometry, spectroscopic reflectometry, and profilometry are common methods to determine thickness and refractive index, while clear documentation is essential when applying a term like lépaisseurindice.

See also: optical thickness, refractive index, thin-film interference, ellipsometry, profilometry.