Elkus Bradley S, Abdelsalam Kamal, Fathpour Sasan, Kumar Prem, Kanter Gregory S
Opt Express. 2020 Dec 21;28(26):39963-39975. doi: 10.1364/OE.411575.
We generate quantum-correlated photon pairs using cascaded : traveling-wave interactions for second-harmonic generation (SHG) and spontaneous parametric down-conversion (SPDC) in a single periodically-poled thin-film lithium-niobate (TFLN) waveguide. When pulse-pumped at 50 MHz, a 4-mm-long poled region with nearly 300%/Wcm SHG peak efficiency yields a generated photon-pair probability of 7±0.2 × 10 with corresponding coincidence-to-accidental ratio (CAR) of 13.6±0.7. The CAR is found to be limited by Stokes/anti-Stokes Raman-scattering noise generated primarily in the waveguide. A Raman peak of photon counts at 250 cm Stokes shift from the fundamental-pump wavenumber suggests most of the noise that limits the CAR originates within the lithium niobate material of the waveguide.
我们利用级联的行波相互作用在单个周期性极化的薄膜铌酸锂（TFLN）波导中产生用于二次谐波产生（SHG）和自发参量下转换（SPDC）的量子关联光子对。当以50 MHz的脉冲泵浦时，一个长度为4毫米、具有近300%/Wcm SHG峰值效率的极化区域产生的光子对概率为7±0.2 × 10，相应的符合与偶然比（CAR）为13.6±0.7。发现CAR受主要在波导中产生的斯托克斯/反斯托克斯拉曼散射噪声限制。在相对于基波泵浦波数250 cm斯托克斯频移处的光子计数拉曼峰表明，限制CAR的大部分噪声源自波导的铌酸锂材料内部。
