The diffraction correction for absolute gravimeters

摘要

The inherent curvature of the wavefronts in the laser beams used in most absolute gravimeters introduces a systematic reduction in the measured gravity value. This error depends strongly on the diameter of the laser beam, but is typically of the order of 1-5 μGal. This paper describes the origin of this reduction, and provides a correction based on the laser beam diameter as well as a practical method to measure the beam's diameter.