Opt Lett. 2018 May 15;43(10):2320-2323. doi: 10.1364/OL.43.002320.
Precise control of the dispersion landscape is of crucial importance if optical fibers are to be successfully used for the generation of three-photon states of light-the inverse of third-harmonic generation (THG). Here we report gas-tuning of intermodal phase-matched THG in sub-micron-diameter tapered optical fiber. By adjusting the pressure of the surrounding argon gas up to 50 bars, intermodally phase-matched third-harmonic light can be generated for pump wavelengths within a 15 nm range around 1.38 μm. We also measure the infrared fluorescence generated in the fiber when pumped in the visible and estimate that the accidental coincidence rate in this signal is lower than the predicted detection rate of photon triplets.
如果要成功地将光纤用于产生三光子态（三次谐波产生的逆过程），则精确控制色散景观至关重要。在这里，我们报告了亚微米直径锥形光纤中模式间相位匹配的三谐波产生的气体调谐。通过将周围氩气的压力调节至 50 巴，可以在 1.38μm 附近的 15nm 泵浦波长范围内产生模式间相位匹配的三次谐波光。我们还测量了在可见光激发下光纤中产生的红外荧光，并估计该信号中的偶然符合率低于预测的三重态光子检测率。
