Compact, thermal-noise-limited optical cavity for diode laser stabilization at 1×10^−15

Abstract

We demonstrate phase and frequency stabilization of a diode laser at the thermal noise limit of a passive optical cavity. The system is compact and exploits a cavity design that reduces vibration sensitivity. The subhertz laser is characterized by comparison with a second independent system with similar fractional frequency stability $(1\times {10}^{-15}\mathrm{at}1\mathrm{s})$. The laser is further characterized by resolving a $2\mathrm{Hz}$ wide, ultranarrow optical clock transition in ultracold strontium.