# A microrod optical-frequency reference in the ambient environment

## TL;DR

This paper demonstrates an ultrahigh-Q solid-silica microrod resonator operating in ambient conditions, achieving thermal-noise-limited laser stabilization and generating stable optical and microwave signals, paving the way for compact low-noise frequency sources.

## Contribution

It introduces a robust, ambient-condition microrod resonator with ultra-high Q supporting low-noise laser stabilization and signal generation, advancing miniature optical frequency references.

## Key findings

- Achieved thermal-noise-limited laser fractional frequency stability of 3×10^{-13}
- Linewidth of the stabilized laser is 62 Hz
- Generated stable optical and microwave signals using fiber photonics

## Abstract

We present an ultrahigh-$Q$, solid-silica microrod resonator operated under ambient conditions that supports laser-fractional-frequency stabilization to the thermal-noise limit of $3 \times 10^{-13}$ and a linewidth of 62 Hz. We characterize the technical-noise mechanisms for laser stabilization, which contribute significantly less than thermal noise. With fiber photonics, we generate optical and microwave reference signals provided by the microrod modes and the free-spectral range, respectively. Our results suggest the future physical considerations for a miniature, low noise, and robust optical-frequency source.