AI 中文总结
研究在氮化硅微腔中实现电可调Friedrich-Wintgen BIC，利用其调控四波混频过程，提升参量增益、降低阈值，实现双光子波包与器件阈值动力学的控制。
AI 中文摘要
本工作在理论和实验上研究可重构集成光子结构中的连续谱束缚态（BICs），重点关注自发四波混频。我们考虑一种配置，其中仅闲频光模式调谐至BIC条件，结果表明抑制该单模式的辐射损耗会显著重塑整体非线性动力学。我们在干涉耦合的氮化硅微腔中实现了电可调的Friedrich-Wintgen BICs，其品质因数Q>10^6。尽管该BIC无法通过线性激发获得，但它可通过四波混频布居，并通过其辐射光子对进行读出。在低增益 regime 中，我们研究了产生的光子对的光谱、关联和相干性特性，揭示了信号-闲频关联中的独特特征，且提取的信号相干时间接近暗态闲频光的固有损耗限制寿命。在高增益 regime 中，使参与光学参量放大的一个模式成为BIC，可将参量增益提高12 dB，并将振荡阈值降低1.6 dB。这些结果确立了BIC作为模式选择性寿命工程的工具，可实现对双光子波包和集成参量器件的阈值动力学的控制。
英文摘要
In this work we theoretically and experimentally investigate bound states in the continuum (BICs) in a reconfigurable integrated photonic structure, focusing on spontaneous four-wave mixing. We consider a configuration in which only one mode, the idler, is tuned to the BIC condition, and show that suppressing the radiative loss of this single mode profoundly reshapes the overall nonlinear dynamics. In particularly, we realize electrically tunable Friedrich-Wintgen BICs with Q > 10^6 in an interferometrically coupled silicon-nitride microresonator. Although inaccessible through linear excitation, the BIC is populated by four-wave mixing and read out through its radiative photon partner. In the low-gain regime, we investigate the spectral, correlation, and coherence properties of the generated photon pairs, revealing distinctive signatures in the signal-idler correlations and an extracted signal whose coherence time approaches the intrinsic-loss-limited lifetime of the dark idler. In the high-gain regime, making one mode participating in optical parametric amplification a BIC enhances the parametric gain by 12 dB and lowers the oscillation threshold by 1.6 dB. These results establish BICs as a tool for mode-selective lifetime engineering, enabling control over both biphoton wavepackets and the threshold dynamics of integrated parametric devices.
