Center for Neuroscience and Biomedical Engineering, The University of Electro-Communications.
Department of Electrophysics, National Chiao Tung University.
Proc Jpn Acad Ser B Phys Biol Sci. 2021;97(5):236-260. doi: 10.2183/pjab.97.014.
Ultrashort visible-near infrared (NIR) pulse generation and its applications to ultrafast spectroscopy are discussed. Femtosecond pulses of around 800 nm from a Ti:sapphire laser are used as a pump of an optical parametric amplifier (OPA) in a non-collinear configuration to generate ultrashort visible (500-780 nm) pulses and deep-ultraviolet (DUV, 259-282 nm) pulses. The visible-NIR pulses and DUV pulses were compressed to 3.9 fs and 10.4 fs, respectively, and used to elucidate various ultrafast dynamics in condensed matter with a sub-10 fs resolution by pump-probe measurements. We have also developed a 128-channel lock-in amplifier. The combined system of the world-shortest visible pulse from the OPA and the lock-in amplifier with the world-largest channel-number can clarify the sub-10 fs-dynamics in condensed matter. This system clarified structural changes in an excited state, reaction intermediate, and a transition state. This is possible even during molecular vibration and reactions via a real-time-resolved vibronic spectrum, which provides molecular structural change information. Also, ultrafast dynamics in exotic materials like carbon nanotubes, topological insulators, and novel solar battery systems have been clarified. Furthermore, the carrier-envelope phase in the ultrashort pulse has been controlled and measured.
超短可见-近红外（NIR）脉冲的产生及其在超快光谱学中的应用。飞秒脉冲约 800nm 的钛宝石激光器作为一个泵浦光参量放大器（OPA）的非共线配置产生超短可见光（500-780nm）脉冲和深紫外（DUV，259-282nm）脉冲。可见-NIR 脉冲和 DUV 脉冲被压缩到 3.9fs 和 10.4fs，分别用于通过泵浦探测测量以亚 10fs 的分辨率阐明凝聚态中的各种超快动力学。我们还开发了一个 128 通道锁相放大器。OPA 的世界最短可见光脉冲和具有世界上最大通道数的锁相放大器的组合系统可以阐明凝聚态中的亚 10fs 动力学。该系统阐明了激发态、反应中间体和过渡态的结构变化。这是可能的，即使在分子振动和反应过程中，通过实时分辨的振子光谱，提供分子结构变化信息。此外，还阐明了碳纳米管、拓扑绝缘体和新型太阳能电池系统等奇异材料中的超快动力学。此外，还控制和测量了超短脉冲中的载波包络相位。
