The effect due to imperfect optical surface of test mass in laser interferometry absolute gravimeters*

The laser wavefront is an important parameter in absolute gravimeters based on laser interferometry. It has been researched that wavefront curvature of the laser will induce a bias in laser interferometry absolute gravimeters, however, the influence induced by the surface imperfection of optical elements has not been studied. The effect induced by imperfect optical elements coupled with transverse motion and rotation of the test mass is analyzed theoretically in this work. Simulation results state that this effect introduced by imperfect corner cube whose surface quality is λ /6 can bring a systematic error up to 1.3 μ Gal (1 μ Gal = 1 × 10 −8 m s −2 ) in a laser interferometry absolute gravimeters with typical parameters, which is large enough to be considered in μ Gal level absolute gravimeters.