An accurate readout of low-power optical higher-order spatial modes is of increasing importance to the precision metrology community. Mode sensors are used to prevent mode mismatches from degrading quantum and thermal noise mitigation strategies. Direct mode analysis sensors (MODAN) are a promising technology for real-time monitoring of arbitrary higher-order modes. We demonstrate MODAN with photo-diode readout to mitigate the typically low dynamic range of CCDs. We look for asymmetries in the response of our sensor to break degeneracies in the relative alignment of the MODAN and photo-diode and consequently improve the dynamic range of the mode sensor. We provide a tolerance analysis and show methodology that can be applied for sensors beyond first order spatial modes.

中文翻译：

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高动态范围空间模式分解

低功率光学高阶空间模式的准确读数对精密计量界越来越重要。模式传感器用于防止模式不匹配降低量子和热噪声缓解策略的性能。直接模式分析传感器（MODAN）是一种用于实时监视任意高阶模式的有前途的技术。我们用光电二极管读出来演示MODAN，以减轻CCD通常的低动态范围。我们在传感器响应中寻找非对称性，以打破MODAN和光电二极管相对对准中的简并性，从而改善模式传感器的动态范围。我们提供了公差分析并展示了可应用于一阶空间模式以外的传感器的方法。