Faraday laser pumped cesium beam clock

TL;DR

This paper presents a compact cesium beam clock using a Faraday laser as both pump and detection source, achieving high frequency stability and promising applications in timekeeping and quantum metrology.

Contribution

The work introduces a novel cesium beam clock utilizing a Faraday laser with narrow linewidth and high stability, demonstrating superior performance over existing systems.

Findings

Linewidth of Faraday laser is 2.5 kHz after MTS locking.

Fractional frequency stability reaches 1.8×10^{-12}/√τ for the laser.

Clock stability reaches 1.3×10^{-12}/√τ, comparable to hydrogen masers.

Abstract

We realize a high-performance compact optically pumped cesium beam clock using Faraday laser simultaneously as pumping and detection lasers. The Faraday laser, which is frequency stabilized by modulation transfer spectroscopy (MTS) technique, has narrow linewidth and superior frequency stability. Measured by optical heterodyne method between two identical systems, the linewidth of the Faraday laser is 2.5 kHz after MTS locking, and the fractional frequency stability of the Faraday laser is optimized to $1.8\times{10}^{-12}/\sqrt{\tau}$. Based on this high-performance Faraday laser, the cesium beam clock realizes a signal-to-noise ratio (SNR) in 1 Hz bandwidth of $39600$ when the cesium oven temperature is 130{\deg}C. Frequency-compared with Hydrogen maser, the fractional frequency stability of the Faraday laser pumped cesium beam clock can reach $1.3\times{10}^{-12}/\sqrt{\tau}$ and drops to $1.4\times{10}^{-14}$ at 10000 s when the cesium oven temperature is 110{\deg}C. %, which is the best reported result compared with other cesium beam clocks. This Faraday laser pumped cesium beam clock demonstrates its excellent performance, and its great potential in the fields of timekeeping, navigation, and communication. Meanwhile, the Faraday laser, as a high-performance optical frequency standard, can also contribute to the development of other applications in quantum metrology, precision measurement and atomic physics.