近日，中国科学院大学的樊仲维及其研究小组与美国加州大学的Tenio Popmintchev等人合作并取得一项新进展。经过不懈努力，他们研制出用于EUV-软X射线应用的高效、无像差离面光栅光谱仪和单色仪。相关研究成果已于2024年1月8日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队成功开发了一种新型的平场、双光成像EUV软X射线光谱仪和单色仪。通过精心设计，该仪器实现了前所未有的超过60%的吞吐量效率，并且在一个不使用可变线间距光栅的系统中达到了极高的光谱分辨率λ/Δλ>200。该仪器的光学系统利用锥形衍射几何结构的优势，在多维参数空间中进行了全局优化，以确保在宽光谱范围内的最佳成像性能。

同时，它在第一、第二和第三衍射级保持了圆形和椭圆偏振状态。该研究还分析了仪器的性能，发现其时间色散极小，脉冲宽度尾对尾限制在80fs以内，FWHM值为29fs。这使得超快光谱和飞秒精度的泵浦探测研究成为可能。

此外，该光谱仪具备一种特殊的能力，能够轻松地将单一光栅转换为横跨EUV-软X射线光谱区域的单色仪，而不会引入任何像差。这一特性使得相干衍射成像应用能够在宽光谱范围内以高度单色光进行，同时将光子损失降至最低，并扩展到软X射线区域。这一创新技术为复杂纳米和生物系统的最先进成像提供了强有力的支持，具有显著增强的时空分辨率，低至纳米飞秒级别。

附：英文原文

Title: Highly efficient and aberration-free off-plane grating spectrometer and monochromator for EUV—soft X-ray applications

Author: Li, Jie, Li, Kui, Zhang, Xiaoshi, Popmintchev, Dimitar, Xu, Hao, Wang, Yutong, Li, Ruixuan, Zhang, Guangyin, Tang, Jiyue, Niu, Jin, Ma, Yongjun, Meng, Runyu, Ke, Changjun, Qiu, Jisi, Ma, Yunfeng, Popmintchev, Tenio, Fan, Zhongwei

Issue&Volume: 2024-01-08

Abstract: We demonstrate a novel flat-field, dual-optic imaging EUV—soft X-ray spectrometer and monochromator that attains an unprecedented throughput efficiency exceeding 60% by design, along with a superb spectral resolution of λ/Δλ>200 accomplished without employing variable line spacing gratings. Exploiting the benefits of the conical diffraction geometry, the optical system is globally optimized in multidimensional parameter space to guarantee optimal imaging performance over a broad spectral range while maintaining circular and elliptical polarization states at the first, second, and third diffraction orders. Moreover, our analysis indicates minimal temporal dispersion, with pulse broadening confined within 80fs tail-to-tail and an FWHM value of 29fs, which enables ultrafast spectroscopic and pump-probe studies with femtosecond accuracy. Furthermore, the spectrometer can be effortlessly transformed into a monochromator spanning the EUV—soft X-ray spectral region using a single grating with an aberration-free spatial profile. Such capability allows coherent diffractive imaging applications to be conducted with highly monochromatic light in a broad spectral range and extended to the soft X-ray region with minimal photon loss, thus facilitating state-of-the-art imaging of intricate nano- and bio-systems, with a significantly enhanced spatiotemporal resolution, down to the nanometer–femtosecond level.

DOI: 10.1038/s41377-023-01342-9

Source: https://www.nature.com/articles/s41377-023-01342-9