Affiliation:
1. National Institute of Metrology
Abstract
In the field of precision measurement and metrology, a vertical laser
is a valuable measurement tool. Its applications include, but are not
limited to, the measurement of vertical displacement and attitude in
the Kibble balance and joule balance for kilogram realization. A
vacuum compatible, vertical-laser alignment method based on an oil
mirror and air-spaced doublets is proposed to measure and compensate
the vertical deviation angle of the laser beams. Dimethyl silicone oil
was selected as the natural direction reference, and the air-spaced
doublets were designed as the focusing elements to make the deviation
angle correspond to a distance of spots. The corresponding alignment
system is vacuum compatible, nonmagnetic, and can be miniaturized. In
addition to the mass traceability in the realization of a kilogram,
this system can also be applied to the gravity measurements of outer
space planets in the field of aerospace science. The off-axis error,
which is the highly influential systematic error of the alignment
system, is suppressed by replacing the plano-convex lens with a
combined optical element—“air-spaced doublets+aperture.” The
performance of the alignment system has been investigated by
experiments. The Type B uncertainty of the alignment system was
evaluated to be 19.19 µrad.
Funder
National Natural Science Foundation of
China
Natural Science Foundation of Zhejiang
Province
National Key Research and Development
Program of China
Open Project of the Key Laboratory for
the Electrical Quantum Standard of SAMR
Subject
Atomic and Molecular Physics, and Optics,Engineering (miscellaneous),Electrical and Electronic Engineering