Open AccessNovel laser datum system for nanometric profilometry for large optical surfaces
Author(s) -
Hyunjo Yang,
Sug Whan Kim,
David D. Walker
Publication year - 2003
Publication title -
optics express
Language(s) - Danish
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.11.000624
Subject(s) - optics , profilometer , laser , geodetic datum , repeatability , interferometry , materials science , compensation (psychology) , photodiode , tilt (camera) , physics , surface finish , geology , geodesy , mechanical engineering , psychology , chemistry , engineering , chromatography , psychoanalysis , composite material
We report a new laser datum system for precision point-by-point profilometry of large curved optical surfaces. The laser datum is sensed by a nulling quadrant photodiode mounted in a flexural system with hybrid actuators, which also carries interferometer reference optics for vertical and horizontal displacement measurement. The flexure characteristics such as cross-talk and hysteresis were investigated. The optimum environmental conditions for the active position-control were studied, and closed-loop control was modeled. The experimental results for compensation accuracy showed a repeatability of +/- 4 nm rms, the compensation accuracy of 10 nm (vertical channel) and 20 nm (horizontal channel).