Lim Jinkang, Liang Wei, Savchenkov Anatoliy A, Matsko Andrey B, Maleki Lute, Wong Chee Wei
1Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory, University of California, Los Angeles, CA 90095 USA.
2OEwaves Inc., 465 North Halstead Street, Suite 140, Pasadena, CA 91107 USA.
Light Sci Appl. 2019 Jan 3;8:1. doi: 10.1038/s41377-018-0109-7. eCollection 2019.
The thermal stability of monolithic optical microresonators is essential for many mesoscopic photonic applications such as ultrastable laser oscillators, photonic microwave clocks, and precision navigation and sensing. Their fundamental performance is largely bounded by thermal instability. Sensitive thermal monitoring can be achieved by utilizing cross-polarized dual-mode beat frequency metrology, determined by the polarization-dependent thermorefractivity of a single-crystal microresonator, wherein the heterodyne radio-frequency beat pins down the optical mode volume temperature for precision stabilization. Here, we investigate the correlation between the dual-mode beat frequency and the resonator temperature with time and the associated spectral noise of the dual-mode beat frequency in a single-crystal ultrahigh- MgF resonator to illustrate that dual-mode frequency metrology can potentially be utilized for resonator temperature stabilization reaching the fundamental thermal noise limit in a realistic system. We show a resonator long-term temperature stability of 8.53 μK after stabilization and unveil various sources that hinder the stability from reaching sub-μK in the current system, an important step towards compact precision navigation, sensing, and frequency reference architectures.
对于许多介观光子应用，如超稳定激光振荡器、光子微波时钟以及精密导航与传感而言，单片光学微谐振器的热稳定性至关重要。其基本性能在很大程度上受热不稳定性的限制。利用交叉极化双模拍频计量可实现灵敏的热监测，该计量由单晶微谐振器的偏振相关热折射性决定，其中外差射频拍频可确定光学模式体积温度以实现精确稳定。在此，我们研究了单晶超高MgF谐振器中双模拍频与谐振器温度随时间的相关性以及双模拍频的相关光谱噪声，以说明双模频率计量在实际系统中有可能用于使谐振器温度稳定至基本热噪声极限。我们展示了稳定后谐振器的长期温度稳定性为8.53 μK，并揭示了当前系统中阻碍稳定性达到亚微开尔文的各种因素，这是迈向紧凑型精密导航、传感和频率参考架构的重要一步。
