AI 中文总结
本文计算光学参量振荡器输出场的频率分辨量子Fisher信息，揭示未监测损耗下临界增强仅线性增长，并给出最优工作点与零差读出策略，为耗散参量传感器提供设计指导。
AI 中文摘要
许多量子传感器从连续发射的场中推断参数，然而在存在未监测损耗的情况下，难以确定在可访问的输出中保留了多少临界增强。在本工作中，我们计算了用于腔失谐估计的稳态真空注入光学参量振荡器的全频率分辨输出量子Fisher信息（QFI）。我们表明，对于任意固定的非零未监测损耗，相关边带对的QFI在阈值附近随平均腔内光子数二次增长，但仅在一个随该光子数成反比变窄的光谱窗口内；因此，光谱积分输出QFI速率渐近地仅线性增长。我们确定了一个远失谐、近阈值的区域，在该区域中，仅监测输出渐近接近损耗对联合腔输出QFI施加的上限。我们进一步确定了使每个腔内光子的输出QFI速率最大化的工作点，并引入了一种频率分辨零差策略，该策略最大化可从单次记录中获得的Fisher信息。我们的结果建立了临界增强与输出场中可获得的计量信息之间的操作联系，同时为耗散参量传感器的设计和读出提供了具体指导。
英文摘要
Many quantum sensors infer parameters from continuously emitted fields, yet in the presence of unmonitored loss, it is difficult to determine how much critical enhancement survives in the accessible output. In this work, we calculate the full frequency-resolved output quantum Fisher information (QFI) of a stationary vacuum-seeded optical parametric oscillator for cavity-detuning estimation. We show that, for any fixed nonzero unmonitored loss, the QFI of correlated sideband pairs grows quadratically with the mean intracavity photon number near threshold, but only within a spectral window that narrows inversely with that number; consequently, the spectrum-integrated output QFI rate scales asymptotically only linearly. We identify a far-detuned, near-threshold regime in which the monitored output alone asymptotically approaches the loss-imposed upper bound on the joint cavity-output QFI. We further determine the operating points that maximize the output QFI rate per intracavity photon and introduce a frequency-resolved homodyne strategy that maximizes the Fisher information obtainable from a single record. Our results establish an operational connection between critical enhancement and metrological information accessible in the output field, while providing concrete guidance for the design and readout of dissipative parametric sensors.
Comments7 pages, 3 figures; 16-page Supplemental Material included
