optical flat

Fetched 2026-10-26 (cache).

Synonyms: optical flint

Antonyms: optical flint

Related words from Datamuse; suggestions, not definitions.

Noun

1. {{lb|en|optics}} A disk of high-quality [[quartz]] [[glass]] having at least one side [[ground]] and [[polished]] with a [[deviation]] in [[flatness]] less than 50 [[nanometer]]s all over, and a [[surface quality]] of 5 [[microfinish]] or less; used, in an [[interferometer]], to measure the flatness of other surfaces.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.