title: Mode-locked laser autocollimator with an expanded measurement range.
abstract: A mode-locked laser is employed as the light source of a laser autocollimator, instead of the conventionally employed single-wavelength laser, for an expanded range of tilt angle measurement. A group of the spatially separated diffracted beams from a diffraction grating are focused by a collimator objective to form an array of light spots on the focal plane of the collimator objective where a light position-sensing photodiode is located for detecting the linear displacement of the light spot array corresponding to the tilt angle of the reflector. A prototype mode-locked femtosecond laser autocollimator is designed and constructed for achieving a measurement range of 11000 arc-seconds.
authors.forename: Yuan-Liu
authors.initials: YL
authors.lastname: Chen
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Kudo
authors.forename: So
authors.initials: S
authors.lastname: Ito
authors.forename: Wei
authors.initials: W
authors.lastname: Gao