Characterization of the long-term dimensional stability of a NEXCERA block using the optical resonator technique

TL;DR

This study measures the long-term dimensional stability of NEXCERA ceramic using optical resonator techniques, revealing its fractional length drift rate at room temperature, which is crucial for precision instrument applications.

Contribution

It provides the first precise measurement of NEXCERA's long-term length drift using an optical cavity, highlighting its stability characteristics.

Findings

Fractional length drift rate of -1.74×10⁻⁸ yr⁻¹ at room temperature

NEXCERA exhibits excellent dimensional stability suitable for precision instruments

Optical resonator technique effectively measures long-term material stability

Abstract

NEXCERA is a machinable and highly polishable ceramic with attractive properties for use in precision instruments, in particular because its coefficient of thermal expansion exhibits a zero crossing at room temperature. We performed an accurate measurement of the long-term drift of the length of a 12~cm long NEXCERA block by using it as a spacer of a high-finesse optical cavity. At room temperature, we found a fractional length drift rate $L^{-1}d\Delta L/dt=-1.74\times10^{-8}~\mathrm{yr}^{-1}$.