AI 中文总结
研究针对地面引力波探测器光束管散射光噪声估计问题，利用改进解析传递因子，考虑多种因素将散射光场微扰转换为等效应变噪声，通过不同配置验证，为散射光噪声估计提供更完整框架。
AI 中文摘要
散射光是当前地面引力波探测器中的一个相关噪声源，也是下一代天文台关键的设计关注点。光束管散射光估计通常将光学传播模拟与解析耦合相结合，而这种方法不能完全将干涉仪的频率相关光机械响应传播到应变读出。在这项工作中，我们使用改进的解析传递因子将法布里 - 珀罗臂腔中的散射光场微扰转换为等效应变噪声，始终包括辐射压力耦合、信号提取动力学、微观失谐和零差读出角度。该形式主义保留了散射场的完整幅度和相位正交内容，包括在衍射和背散射噪声中出现的交叉项。对于衍射，我们还确定了与挡板运动的线性化耦合有效的区域，避免不必要的相位缠绕。使用代表性的LIGO、宇宙探测器（CE）和爱因斯坦望远镜 - 低频（ET - LF）配置，我们表明在相位主导区域中可以恢复传统估计，但当辐射压力耦合、正交相关性或失谐信号提取变得重要时可能会有所不同。特别是，由于失谐信号提取腔导致，修订后的ET - LF估计相对于以前的光束管噪声预算有很大变化。这些结果为当前和未来引力波探测器的散射光噪声估计提供了一个更完整的框架。
英文摘要
Scattered light is a relevant noise source in current ground-based gravitational-wave detectors and a critical design concern for next-generation observatories. Beamtube scattered light estimates usually combine optical propagation simulations with analytical couplings that do not fully propagate the frequency-dependent optomechanical response of the interferometer to the strain readout. In this work, we use improved analytical transfer factors to convert scattered-light field perturbations in the Fabry--Pérot arm cavities into equivalent strain noise, consistently including radiation-pressure coupling, signal-extraction dynamics, microscopic detunings, and the homodyne readout angle. The formalism keeps the full amplitude and phase quadrature content of the scattered field, including the cross terms that arise in both diffraction and backscattering noise. For diffraction, we also identify the regime in which the linearized coupling to baffle motion is valid, avoiding unnecessary phase wrapping. Using representative LIGO, Cosmic Explorer (CE), and Einstein Telescope - Low Frequency (ET-LF) configurations, we show that legacy estimates are recovered in phase dominated regimes, but can differ when radiation-pressure coupling, quadrature correlations, or detuned signal extraction become important. In particular, the revised ET-LF estimate changes substantially with respect to previous beamtube noise budgets due to the detuned signal extraction cavity. These results provide a more complete framework for scattered light noise estimations for present and future gravitational-wave detectors.
