Technique for in situ measurement of free spectral range and transverse mode spacing of optical cavities.
Technique for in situ measurement of free spectral range and transverse mode spacing of optical cavities.
复制标题
光腔自由光谱范围和横模间距的原位测量技术。
DOI：
10.1364/ao.51.006571
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发表时间：
2012
期刊：
影响因子：
1.9
通讯作者：
R. Adhikari
中科院分区：
文献类型：
--
作者：
A. Stochino;K. Arai;R. Adhikari
长度和g因子是表征光学腔的基本参数。我们开发了一种技术来测量这些参数，在现场确定的基本模式和空间模式的光学腔的谐振之间的频率间隔。将两束激光注入腔中，通过锁相环扫描它们的相对频率，同时将腔锁定到任一激光器。通过测量它们在透射过程中拍音的振幅，揭示了腔体的纵模和横模的共振及其间距。这种方法被证明是特别有用的复杂的光学系统，包括非常长的和/或耦合的光学腔，如在引力波干涉仪。本文介绍了这项技术及其在40 m长引力波干涉仪原型耦合腔中的应用结果。
Length and g-factor are fundamental parameters that characterize optical cavities. We developed a technique to measure these parameters in situ by determining the frequency spacing between the resonances of fundamental and spatial modes of an optical cavity. Two laser beams are injected into the cavity, and their relative frequency is scanned by a phase-lock loop, while the cavity is locked to either laser. The measurement of the amplitude of their beat note in transmission reveals the resonances of the longitudinal and the transverse modes of the cavity and their spacing. This method proves particularly useful to characterize complex optical systems, including very long and/or coupled optical cavities, as in gravitational-wave interferometers. This technique and the results of its application to the coupled cavities of a 40 m-long gravitational-wave interferometer prototype are presented here.