近日，美国威斯康星大学麦迪逊分校Uwe Bergmann团队研究了阿秒内壳层激光米波长。这一研究成果于2025年6月11日发表在《自然》杂志上。

自激光器发明以来，人们在光学领域探索了非线性效应，如丝状化、拉比循环和集体发射，从而带来了广泛的科学和工业应用。X射线自由电子激光器（XFEL）因其具有奥斯特罗姆尺度空间分辨率和元素特异性的优点，将许多光学技术扩展到了X射线。一个例子是XFEL驱动的内壳Kα₁（2p_3/2 → 1s_1/2）从氖到铜的元素中的X射线激光，已被用于非线性光谱学和新型X射线激光源的开发。

研究组表明，在铜和锰元素的Kα₁激光发射过程中，当使用高强度（>10¹⁹ W cm^-2）X射线自由电子激光（XFEL）驱动时，可在1.5–2.1埃波长范围内产生与光学波段类似的强激光效应。根据时间XFEL泵浦脉冲子结构，产生的X射线脉冲（约10⁶-10⁸个光子）可以表现出强烈的空间不均匀性和光谱分裂、不均匀性以及展宽。三维Maxwell–Bloch计算表明，观察到的空间不均匀性是由X射线丝状化引起的，宽光谱特征是由亚飞秒拉比循环驱动的。该模拟表明，这些X射线脉冲的脉冲长度可以小于100 阿秒和相干特性为量子X射线光学应用提供了机会。 

附：英文原文

Title: Attosecond inner-shell lasing at ngstrm wavelengths

Author: Linker, Thomas M., Halavanau, Aliaksei, Kroll, Thomas, Benediktovitch, Andrei, Zhang, Yu, Michine, Yurina, Chuchurka, Stasis, Abhari, Zain, Ronchetti, Daniele, Fransson, Thomas, Weninger, Clemens, Fuller, Franklin D., Aquila, Andy, Alonso-Mori, Roberto, Boutet, Sbastien, Guetg, Marc W., Marinelli, Agostino, Lutman, Alberto A., Yabashi, Makina, Inoue, Ichiro, Osaka, Taito, Yamada, Jumpei, Inubushi, Yuichi, Yamaguchi, Gota, Hara, Toru, Babu, Ganguli, Salpekar, Devashish, Sayed, Farheen N., Ajayan, Pulickel M., Kern, Jan, Yano, Junko, Yachandra, Vittal K., Kling, Matthias F., Pellegrini, Claudio, Yoneda, Hitoki, Rohringer, Nina, Bergmann, Uwe

Issue&Volume: 2025-06-11

Abstract: Since the invention of the laser, nonlinear effects such as filamentation1, Rabi cycling2,3 and collective emission4 have been explored in the optical regime, leading to a wide range of scientific and industrial applications5,6,7,8. X-ray free-electron lasers (XFELs) have extended many optical techniques to X-rays for their advantages of ngstrm-scale spatial resolution and elemental specificity9. An example is XFEL-driven inner-shell Kα1 (2p3/2→1s1/2) X-ray lasing in elements ranging from neon to copper, which has been used for nonlinear spectroscopy and development of new X-ray laser sources10,11,12,13,14,15,16. Here we show that strong lasing effects similar to those in the optical regime can occur at 1.5–2.1 wavelengths during high-intensity (>1019Wcm2) XFEL-driven Kα1 lasing of copper and manganese. Depending on the temporal XFEL pump pulse substructure, the resulting X-ray pulses (about 106108 photons) can exhibit strong spatial inhomogeneities and spectral splitting, inhomogeneities and broadening. Three-dimensional Maxwell–Bloch calculations17 show that the observed spatial inhomogeneities result from X-ray filamentation and that the broad spectral features are driven by sub-femtosecond Rabi cycling. Our simulations indicate that these X-ray pulses can have pulse lengths of less than 100attoseconds and coherence properties that provide opportunities for quantum X-ray optics applications.

DOI: 10.1038/s41586-025-09105-9

Source: https://www.nature.com/articles/s41586-025-09105-9