# 946-nm Nd:YAG digital-locked laser at $1.1\times10^{-16}$ in 1 s and transfer-locked to a cryogenic silicon cavity

## TL;DR

This paper reports a highly stable 946 nm Nd:YAG laser achieving a fractional frequency instability of 1.1×10⁻¹⁶ at 1 second, utilizing digital electronics and transfer-locking to a cryogenic silicon cavity for enhanced stability.

## Contribution

It introduces a digital-locked Nd:YAG laser system at 946 nm with record stability, and demonstrates transfer-locking to a cryogenic silicon cavity for further stability improvement.

## Key findings

- Achieved fractional frequency instability of 1.1×10⁻¹⁶ at 1 s.
- Replaced analog components with FPGA-based digital electronics.
- Transferred stability from a cryogenic silicon cavity to the laser.

## Abstract

We present a Nd:YAG ultra-stable laser system operating at 946 nm and demonstrate a fractional frequency instability of $1.1\times10^{-16}$ at 1 s by pre-stabilizing it to a 30 cm-long ULE cavity at room temperature. All key analog components have been replaced by FPGA-based digital electronics. To reach an instability below the $10^{-16}$ level, we transfer the stability of a 1542 nm laser stabilized to a cryogenic silicon cavity exhibiting a fractional frequency instability of $4\times10^{-17}$ at 1 s to the laser at 946 nm.