我們研究了分子吸收與量子光傳播之間的交互作用，重點聚焦於單光子 層級下的快光（fast-light）現象。從量子觀點出發，我們推導了吸收 譜線的形成機制，並在符合因果律的條件下，模擬了由反常色散所引起 的脈衝前移效應。 在實驗方面，透過自發參數下轉換（SPDC）所產生的單光子脈衝，其頻 譜被調整至與乙炔分子的吸收線對齊，成功觀察到不違反因果律的可測 負群延遲（negative group delay）。 作為前置步驟，我們亦分析了 SPDC 雙光子訊號的訊噪比（SNR），以確 定最佳操作條件。此外，本研究也指出，快光效應可望藉由有效負折射 率提升光學陀螺儀的靈敏度。;We investigate the interaction between molecular absorption and quantum light propagation, focusing on the fast-light phenomenon at the single-photon level. From a quantum perspective, we derived the formation mechanism of absorption lines and simulated pulse advancement induced by anomalous dispersion under causality. Experimentally, single-photon pulses generated via spontaneous parametric down conversion(SPDC) were spectrally aligned with an acetylene absorption line, enabling the observation of measurable negative group de lays without violating causality. As a preparatory step, the signal-to-noise ratio (SNR) of SPDC biphotons was analyzed to determine the optimal operating regime. The potential application of fast light in enhancing optical gyroscope sensitivity via an effective negative refractive index is also highlighted.
