光誘起相転移を用いたプラズモニック構造・光導波路による超高速全光変調器

去年，实现了三个关键目标。首先，完成了独特的微泵探针光谱设置。该装置具有将超短激光脉冲注入光子集成电路并测量其时间分辨响应的能力。使用空间滤波系统，该装置还可以隔离从光子集成电路的特定元件输出的信号。其次，研究了VO 2薄膜在超短激光脉冲激发下的回复动力学。发现了一个中等通量区域，其中VO 2经历了完整的绝缘体-金属过渡，同时仍然表现出亚ns恢复，从而首次验证了VO 2具有以GHz速度调制的潜力。最后，研究了NbO 2薄膜在超短激光脉冲激发下的光致调制特性，并详细分析了这种响应的唯象起源。有人发现，NbO 2有可能被调制在太赫兹的速度给予适当的管理散热。在此基础上，编写了两篇期刊文章。其中一篇发表于2019年12月（J. Kenji Clark et al.，Phys. Rev. Res. 1，033168（2019）），另一个目前正在ACS Photonics进行审查。

In the previous year, three key objectives were achieved. First, a unique micro-pump probe spectroscopy setup was completed. The setup has the capability of injecting ultrashort laser pulses into photonic integrated circuits and measuring their time-resolved response. Using a spatial filtering system, the setup can also isolate signals output from specific elements of a photonic integrated circuit. Second, the recovery dynamics of VO2 thin films after excitation by an ultrashort laser pulse were studied. A mid-fluence region where VO2 undergoes a full insulator-metal transition while still exhibiting sub-ns recovery was discovered, thus verifying for the first time that VO2 has the potential to be modulated at GHz speeds. Finally, the photo-induced modulation of NbO2 thin films after excitation by an ultrashort laser pulse was studied and the phenomenological origins of the response was examined in detail. It was found that NbO2 has the potential to be modulated at up to THz speeds given proper management of heat dissipation. Based on this work two journal articles were compiled. One was published in December of 2019 (J. Kenji Clark et al., Phys. Rev. Res. 1, 033168 (2019)) and the other is currently under review in ACS Photonics.