近日，德国马克斯·玻恩非线性光学和短脉冲光谱学研究所Tamas Nagy团队研究了可调谐短周期真空紫外脉冲的时间特性。这一研究成果发表在2025年10月8日出版的《自然—光子学》杂志上。
在过去的几十年里，超快激光器的发展已经彻底改变了他们洞察光与物质相互作用的能力。从可见光到中红外光谱范围内的少周期光强度的出现，以及阿秒极紫外线和x射线技术，提供了在自然时间尺度上直接观察和控制物质超快电子动力学的可能性；然而，对深紫外（4-6 eV，对应波长300-200纳米）与真空紫外（6-12 eV，对应波长200-100纳米）光谱区域的数飞秒光源进行时间表征仍极具挑战性。
研究组通过基于稀有气体双光子电离的频率分辨光学开关技术，完整表征了在毛细管内通过孤子自压缩过程中共振色散波发射产生的160-190纳米波段、微焦耳能量级真空紫外脉冲的时间波形。原位测量表明，在多数情况下这些脉冲持续时间短于3飞秒。该研究成果为利用真空紫外脉冲研究众多原子与分子的超快电子动力学及价电子激发过程开辟了新途径，其时间分辨率达到了使用真空紫外脉冲时迄今无法实现的水平。
附：英文原文
Title: Temporal characterization of tunable few-cycle vacuum ultraviolet pulses
Author: Andrade, Jos R. C., Kretschmar, Martin, Danylo, Rostyslav, Carlstrm, Stefanos, Witting, Tobias, Mermillod-Blondin, Alexandre, Patchkovskii, Serguei, Ivanov, Misha Yu, Vrakking, Marc J. J., Rouze, Arnaud, Nagy, Tamas
Issue&Volume: 2025-10-08
Abstract: In the past few decades, the development of ultrafast lasers has revolutionized our ability to gain insight into light–matter interactions. The emergence of few-cycle light sources operating from the visible to the mid-infrared spectral range—as well as attosecond extreme ultraviolet and X-ray technologies—provide the possibility to directly observe and control ultrafast electron dynamics in matter on their natural timescale; however, the temporal characterization of few-femtosecond sources in the deep ultraviolet (4–6eV, 300–200nm) and the vacuum ultraviolet (VUV; 6–12eV, 200–100nm) spectral regions is challenging. Here we fully characterize the temporal shape of microjoule-energy VUV pulses tuned between 160 and 190nm generated via resonant dispersive wave emission during soliton self-compression in a capillary using frequency-resolved optical gating based on two-photon photoionization in noble gases. The in situ measurements reveal that in most of the cases the pulses are shorter than 3fs. These findings pave the way toward investigating ultrafast electron dynamics and valence excitation of a large class of atoms and molecules with a time-resolution that has been hitherto inaccessible when using VUV pulses.
DOI: 10.1038/s41566-025-01770-6
Source: https://www.nature.com/articles/s41566-025-01770-6