Nawata Kouji, Tokizane Yu, Takida Yuma, Minamide Hiroaki
Tera-Photonics Research Team, RIKEN Center for Advanced Photonics, RIKEN, Sendai, 980-0845, Japan.
Sci Rep. 2019 Jan 24;9(1):726. doi: 10.1038/s41598-018-37068-7.
Backward optical parametric oscillation has attracted attention for cavityless spectral narrowband generation based on perfect photon conversion. Few demonstrations have shown its potential from the aspect of nonlinear photonics; therefore, the mechanisms of momentum conservation among interacting light waves have been concealed by the restricted configuration under the phase-matching condition of periodically poled structures. Here, we unveil a tunable mechanism in the terahertz region by active control of the phase-matching condition. The tunability of backward terahertz-wave parametric oscillation is investigated using a quasi-collinear phase-matching model and its frequency range from the sub-terahertz to terahertz region is identified. Transform-limited terahertz-wave pulse is achieved simply by installing a device on the pump propagating line with no cavity. Moreover, the cascading terahertz-wave generation enhances the photon conversion efficiency, thus making nonlinear optics and its applications more promising. The results highlight new capabilities for using modern ferroelectric materials and encourage further research on nonlinear optics.
基于完美光子转换的无腔光谱窄带产生，使得后向光学参量振荡受到关注。从非线性光子学角度来看，鲜有实例展示其潜力；因此，在周期性极化结构的相位匹配条件下，受限的配置掩盖了相互作用光波之间的动量守恒机制。在此，我们通过主动控制相位匹配条件，揭示了太赫兹区域的一种可调谐机制。利用准共线相位匹配模型研究了后向太赫兹波参量振荡的可调谐性，并确定了其从亚太赫兹到太赫兹区域的频率范围。只需在无腔的泵浦传播线上安装一个装置，就能实现变换极限太赫兹波脉冲。此外，级联太赫兹波产生提高了光子转换效率，从而使非线性光学及其应用更具前景。这些结果凸显了使用现代铁电材料的新能力，并鼓励对非线性光学进行进一步研究。
