Izumi Kiwamu, Sigg Daniel, Barsotti Lisa
Opt Lett. 2014 Sep 15;39(18):5285-8. doi: 10.1364/OL.39.005285.
High finesse optical cavities are an essential tool in modern precision laser interferometry. The incident laser field is often controlled and stabilized with an active feedback system such that the field resonates in the cavity. The Pound-Drever-Hall reflection locking technique is a convenient way to derive a suitable error signal. However, it only gives a strong signal within the cavity linewidth. This poses a problem for locking an ultra-narrow linewidth cavity. We present a novel technique for acquiring lock by utilizing an additional weak control signal, but with a much larger capture range. We numerically show that this technique can be applied to the laser frequency stabilization system used in the Laser Interferometric Gravitational-wave Observatory (LIGO), which has a linewidth of 0.8 Hz. This new technique will allow us to robustly and repeatedly lock the LIGO laser frequency to the common mode of the interferometer.
高精细度光学腔是现代精密激光干涉测量中的一项重要工具。入射激光场通常通过有源反馈系统进行控制和稳定，以使该场在腔内产生共振。庞德 - 德雷弗 - 霍尔反射锁定技术是获得合适误差信号的一种便捷方法。然而，它仅在腔线宽范围内给出强信号。这给锁定超窄线宽腔带来了问题。我们提出了一种通过利用额外的弱控制信号来实现锁定的新技术，但捕获范围要大得多。我们通过数值模拟表明，该技术可应用于激光干涉引力波天文台（LIGO）所使用的激光频率稳定系统，其线宽为0.8赫兹。这项新技术将使我们能够稳健且重复地将LIGO激光频率锁定到干涉仪的共模上。
