Huang Yibo, Lu Yao, Li Wei, Xu Xitan, Jiang Xinda, Ma Ruobin, Chen Lu, Ruan Ningjuan, Wu Qiang, Xu Jingjun
The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, TEDA Applied Physics Institute and School of Physics, Nankai University, Tianjin, 300071, China.
Shenzhen Research Institute of Nankai University, Shenzhen, 518083, Guangdong, China.
Light Sci Appl. 2024 Aug 23;13(1):212. doi: 10.1038/s41377-024-01509-y.
Optical Kerr effect, in which input light intensity linearly alters the refractive index, has enabled the generation of optical solitons, supercontinuum spectra, and frequency combs, playing vital roles in the on-chip devices, fiber communications, and quantum manipulations. Especially, terahertz Kerr effect, featuring fascinating prospects in future high-rate computing, artificial intelligence, and cloud-based technologies, encounters a great challenge due to the rather low power density and feeble Kerr response. Here, we demonstrate a giant terahertz frequency Kerr nonlinearity mediated by stimulated phonon polaritons. Under the influences of the giant Kerr nonlinearity, the power-dependent refractive index change would result in a frequency shift in the microcavity, which was experimentally demonstrated via the measurement of the resonant mode of a chip-scale lithium niobate Fabry-Pérot microcavity. Attributed to the existence of stimulated phonon polaritons, the nonlinear coefficient extracted from the frequency shifts is orders of magnitude larger than that of visible and infrared light, which is also theoretically demonstrated by nonlinear Huang equations. This work opens an avenue for many rich and fruitful terahertz Kerr effect based physical, chemical, and biological systems that have terahertz fingerprints.
光学克尔效应，即输入光强度线性改变折射率，已实现了光学孤子、超连续谱和频率梳的产生，在片上器件、光纤通信和量子操纵中发挥着至关重要的作用。特别是，太赫兹克尔效应在未来高速计算、人工智能和基于云的技术中具有迷人的前景，但由于功率密度相当低且克尔响应微弱，面临着巨大挑战。在此，我们展示了一种由受激声子极化激元介导的巨大太赫兹频率克尔非线性。在巨大克尔非线性的影响下，与功率相关的折射率变化将导致微腔中的频率偏移，这通过测量芯片级铌酸锂法布里 - 珀罗微腔的共振模式在实验上得到了证实。由于受激声子极化激元的存在，从频率偏移中提取的非线性系数比可见光和红外光的非线性系数大几个数量级，这也通过非线性黄方程在理论上得到了证明。这项工作为许多基于太赫兹克尔效应的、具有太赫兹指纹的丰富多样的物理、化学和生物系统开辟了一条途径。
