High performance passive vibration isolation system for optical tables using six-degree-of-freedom viscous damping combined with steel springs

TL;DR

This paper presents a low-cost, passive vibration isolation system for optical tables that uses steel springs and viscous damping, outperforming existing systems in the 1-10 Hz range.

Contribution

The authors developed a simple, adaptable, and cost-effective passive vibration isolation system using steel springs and viscous damping, achieving superior performance in low-frequency vibration isolation.

Findings

Outperforms state-of-the-art systems in 1-10 Hz range

Achieves fundamental resonance frequency of 0.5 Hz

Can be adapted to various loads and dimensions

Abstract

Mechanical vibrations in buildings are ubiquitous. Such vibrations limit the performance of sensitive instruments used, for example, for high-precision manufacturing, nanofabrication, metrology, medical systems, or microscopy. For improved precision, instruments and optical tables need to be isolated from mechanical vibrations. However, common active or passive vibration isolation systems often perform poorly when low-frequency vibration isolation is required or are expensive. Furthermore, a simple solution such as suspension from common bungee cords may require high ceilings. Here we developed a vibration isolation system that uses steel springs to suspend an optical table from a common-height ceiling. The system was designed for a fundamental resonance frequency of 0.5 Hz. Resonances and vibrations were efficiently damped in all translational and rotational degrees of freedom of the optical table by spheres, which were mounted underneath the table and immersed in a highly viscous silicone oil. Our low-cost, passive system outperformed several state-of-the-art passive and active systems in particular in the frequency range between 1-10 Hz. We attribute this performance to a minimal coupling between the degrees of freedom and the truly three dimensional viscous damping combined with a nonlinear hydrodynamic finite-size effect. Furthermore, the system can be adapted to different loads, resonance frequencies, and dimensions. In the long term, the excellent performance of the system will allow high-precision measurements for many different instruments.