title: Focus retrocollimated interferometry for focal-length measurements.
abstract: Focus retrocollimated interferometry is developed for the measurement of focal lengths of optical lenses and systems, and achievable accuracy is discussed. It is shown that this method can be used to measure both short and long focal lengths simply and with high accuracy.
authors.affiliation: State Key Laboratory for Applied Optics, Changchun Institute of Optics and Fine Mechanics and Physics, Academia Sinica, China. y.xiang@mail.china.com
authors.forename: Yang
authors.initials: Y
authors.lastname: Xiang