Frequency-stabilization to 6x10^-16 via spectral-hole burning

TL;DR

This paper presents a two-stage laser stabilization method combining Fabry-Perot and spectral-hole burning techniques, achieving unprecedented fractional-frequency stability of 6x10^-16 over several seconds.

Contribution

It introduces a novel hybrid stabilization approach that significantly improves laser frequency stability beyond traditional Fabry-Perot cavities.

Findings

Achieved laser frequency stability of 6x10^-16 for 2-8 seconds.

Spectral holes in Eu3+:Y2SiO5 are more stable than Fabry-Perot cavities.

Demonstrated potential for ultra-stable laser applications.

Abstract

We demonstrate two-stage laser stabilization based on a combination of Fabry- Perot and spectral-hole burning techniques. The laser is first pre-stabilized by the Fabry-Perot cavity to a fractional-frequency stability of sigma_y(tau) < 10^-13. A pattern of spectral holes written in the absorption spectrum of Eu3+:Y2SiO5 serves to further stabilize the laser to sigma_y(tau) = 6x10^-16 for 2 s < tau < 8 s. Measurements characterizing the frequency sensitivity of Eu3+:Y2SiO5 spectral holes to environmental perturbations suggest that they can be more frequency stable than Fabry-Perot cavities.