Kotsina Nikoleta, Belli Federico, Gao Shou-Fei, Wang Ying-Ying, Wang Pu, Travers John C, Townsend Dave
Institute of Photonics & Quantum Sciences , Heriot-Watt University , Edinburgh EH14 4AS , U.K.
Beijing Engineering Research Centre of Laser Technology, Institute of Laser Engineering , Beijing University of Technology , 100124 Beijing , China.
J Phys Chem Lett. 2019 Feb 21;10(4):715-720. doi: 10.1021/acs.jpclett.8b03777. Epub 2019 Feb 1.
We demonstrate, for the first time, the application of rare-gas-filled hollow-core photonic crystal fibers (HC-PCFs) as tunable ultraviolet light sources in femtosecond pump-probe spectroscopy. A critical requirement here is excellent output stability over extended periods of data acquisition, and we show this can be readily achieved. The time-resolved photoelectron imaging technique reveals nonadiabatic dynamical processes operating on three distinct time scales in the styrene molecule following excitation over the 242-258 nm region. These include ultrafast (<100 fs) internal conversion between the S(ππ*) and S(ππ*) electronic states and subsequent intramolecular vibrational energy redistribution within S(ππ*). Compact, cost-effective, and highly efficient benchtop HC-PCF sources have huge potential to open up many exciting new avenues for ultrafast spectroscopy in the ultraviolet and vacuum ultraviolet spectral regions. We anticipate that our initial validation of this approach will generate important impetus in this area.
我们首次展示了充稀有气体的空心光子晶体光纤（HC - PCF）在飞秒泵浦 - 探测光谱中作为可调谐紫外光源的应用。这里的一个关键要求是在长时间数据采集过程中具有出色的输出稳定性，我们表明这很容易实现。时间分辨光电子成像技术揭示了在242 - 258纳米区域激发后，苯乙烯分子中在三个不同时间尺度上运行的非绝热动力学过程。这些过程包括S(ππ*)和S(ππ*)电子态之间的超快（<100飞秒）内转换以及随后S(ππ*)内的分子内振动能量重新分布。紧凑、经济高效且高效的台式HC - PCF光源具有巨大潜力，可为紫外和真空紫外光谱区域的超快光谱学开辟许多令人兴奋的新途径。我们预计我们对这种方法的初步验证将在该领域产生重要推动作用。
