An ultra-stable cryogenic sapphire cavity laser with an instability of $1.9\times 10^{-16}$ based on a low vibration level cryostat

Abstract

Cryogenic ultra-stable lasers have extremely low thermal noise limits and frequency drifts, but they are more seriously affected by vibration noise from cryostats. Main material candidates for cryogenic ultra-stable cavities include silicon and sapphire. Although sapphire has many excellent properties at low temperature, the development of sapphire-based cavities is less advanced than that of silicon-based. Using a homemade cryogenic sapphire cavity, we develop an ultra-stable laser source with a frequency instability of $1.9\times 10^{-16}$. This is the best frequency instability level among similar systems using cryogenic sapphire cavities reported so far. Low vibration performance of the cryostat is demonstrated with a two-stage vibration isolation, and the vibration suppression is further improved by different mixing ratio of the gas-liquid helium. With this technique, vibrations at frequencies higher than tens of hertz are greatly suppressed.

4 pages, 4 figures

References in corpus (3)

• An ${}^{27}$Al${}^{+}$ quantum-logic clock with systematic uncertainty below $10^{-18}$
• An ultrastable silicon cavity in a continuously operating closed-cycle cryostat at 4 K
• A simplified cryogenic optical resonator apparatus providing ultra-low frequency drift

Cited by in corpus (1)

• A laser with instability reaching $4\times 10^{-17}$ based on a 10-cm-long silicon cavity at sub-5-K temperatures