Li Bohan, Yuan Zhiquan, Williams James, Jin Warren, Beckert Adrian, Xie Tian, Guo Joel, Feshali Avi, Paniccia Mario, Faraon Andrei, Bowers John, Marandi Alireza, Vahala Kerry
T. J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, CA, USA.
Department of Electrical Engineering, California Institute of Technology, Pasadena, CA, USA.
Nature. 2025 Mar;639(8056):922-927. doi: 10.1038/s41586-025-08662-3. Epub 2025 Mar 19.
Entangled photon pairs from spontaneous parametric down-conversion (SPDC) are central to many quantum applications. SPDC is typically performed in non-centrosymmetric systems with an inherent second-order nonlinearity (χ). We demonstrate strong narrowband SPDC with an on-chip rate of 0.8 million pairs per second in SiN. SiN is the pre-eminent material for photonic integration and also exhibits the lowest waveguide loss (which is essential for integrated quantum circuits). However, being amorphous, silicon nitride lacks an intrinsic χ, which limits its role in photonic quantum devices. We enabled SPDC in SiN by combining strong light-field enhancement inside a high optical Q-factor microcavity with an optically induced space-charge field. We present narrowband photon pairs with a high spectral brightness. The quantum nature of the down-converted photon pairs is verified through coincidence measurements. This light source, based on SiN integrated photonics technology, unlocks new avenues for quantum systems on a chip.
来自自发参量下转换（SPDC）的纠缠光子对是许多量子应用的核心。SPDC通常在具有固有二阶非线性（χ）的非中心对称系统中进行。我们展示了在SiN中每秒080万对的片上速率的强窄带SPDC。SiN是光子集成的卓越材料，并且还表现出最低的波导损耗（这对于集成量子电路至关重要）。然而，由于是非晶态，氮化硅缺乏固有χ，这限制了其在光子量子器件中的作用。我们通过将高光Q因子微腔内的强光场增强与光感应空间电荷场相结合，在SiN中实现了SPDC。我们展示了具有高光谱亮度的窄带光子对。通过符合测量验证了下转换光子对的量子性质。这种基于SiN集成光子技术的光源为片上量子系统开辟了新途径。
