A vibration-insensitive optical cavity and absolute determination of its ultrahigh stability

TL;DR

This paper evaluates the stability of a vibration-insensitive optical cavity using the three-cornered-hat method, demonstrating its ultrahigh stability and absolute frequency accuracy without vibration isolation.

Contribution

It introduces a vibration-insensitive cavity design and provides the first absolute stability measurement of such a cavity without vibration isolation.

Findings

Vibration-insensitive cavity achieves 1.4×10⁻¹⁵ Allan deviation at 1 s.

Beat note linewidths of ~1 Hz between cavities.

Absolute frequency uncertainty of 0.44 Hz.

Abstract

We use the three-cornered-hat method to evaluate the absolute frequency stabilities of three different ultrastable reference cavities, one of which has a vibration-insensitive design that does not even require vibration isolation. An Nd:YAG laser and a diode laser are implemented as light sources. We observe $\sim1$ Hz beat note linewidths between all three cavities. The measurement demonstrates that the vibration-insensitive cavity has a good frequency stability over the entire measurement time from 100 $\mu$s to 200 s. An absolute, correlation-removed Allan deviation of $1.4\times10^{-15}$ at 1 s of this cavity is obtained, giving a frequency uncertainty of only 0.44 Hz.