本篇的研究目的在於，運用非古典時間相關光子對的糾纏特性，在充滿雜訊的環境中進行測量，透過實驗證明這種量子方法相對於古典方法的優勢，並將此量子方法用於測量目標物與偵測器的距離。實驗中使用的糾纏光子對是透過自發參數下轉換( Spontaneous Parametric Down Conversion, SPDC )所產生的。每對光子中的閒置( idler )光子會直接收集到偵測器中測量，而訊號( signal )光子則會發射到目標物再送到偵測器中測量，透過分析低反射率目標物反射的訊號光子及閒置光子間的量子時間相關性，能夠發現這種量子方法即使在充滿雜訊及高損耗的的環境下，仍然能提高訊號雜訊比( Signal-to-Noise Ratio, SNR )。為了衡量量子 SNR 相對於古典 SNR 的優勢，定義了量子增強因子( Quantum Enhancement Factor, QEF )，且透過實驗能得出 QEF 最高可達到約 7700 倍，並進一步將此量子方法用於測量目標物與偵測器間的距離，能夠得知其準確程度高並且還是很簡單的方法。這種量子方法在軍事應用方面具有潛力，為現代測距與偵測系統在面對複雜環境時提供一項具體且有效的解決方案。

The aim of this study is to utilize the entangled properties of non-classically time-correlated photon pairs to perform measurements in noisy environments, demonstrating through experiments the advantages of this quantum approach over traditional methods. This quantum technique is further applied to measure the distance between a target and a detector. The entangled photon pairs used in the experiment are generated via spontaneous parametric down-conversion (SPDC). In each pair, the idler photon is directly sent to the detector for measurement, while the signal photon is transmitted toward the target and then reflected back to the detector. By analyzing the quantum time correlation between the weakly reflected signal photon and its corresponding idler photon, it is shown that this quantum method can significantly enhance the signal-to-noise ratio (SNR) even under conditions of high noise and loss—achieving an improvement of up to 7700 times compared to classical techniques. Furthermore, applying this quantum method to free-space distance measurements demonstrates its exceptional accuracy. This approach holds great potential for military applications, offering a concrete and effective solution to the technical challenges faced by modern ranging and detection systems in complex environments.

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