近日，北京航空航天大学的余霞及其研究团队取得一项新进展。经过不懈努力，他们利用正交激光维持等离子体研制出明亮紧凑超宽带光源。相关研究成果已于2024年9月26日在国际知名学术期刊《光：科学与应用》上发表。

本文提出一种创新的正交线性扫描投影（LSP）方法，旨在突破转换效率的局限性。在将吸收的激光功率高效转换为紫外（UV）辐射的驱动下，研究人员利用超过100W的泵浦激光，实现了紫外光谱辐亮度超过210 mW/(mm²·sr·nm)的紧凑型宽带光源（250–1650nm）。通过二维折射率模型的绘制，研究人员报道了一项重要的概念进展：正交设计消除了负透镜效应对激光功率密度的影响。

实验结果明确表明，他们成功获得了一个亮度高、结构紧凑的紫外-可见光-近红外（UV-VIS-NIR）光源，其热损失可忽略不计，且转换效率据他们所知为最高。使用所提出的超宽带光源，光谱单像素成像的对比度噪声比（CNR）显著提高了4dB。通过建立泵浦光学设计与等离子体吸收之间的定量联系，本研究展示了一款结合了卓越转换效率和前所未有的亮度的紧凑型宽带光源，这对于高速检测与光谱分析应用至关重要。

据悉，激光持续等离子体(LSP)光源具有高亮度和宽带频谱覆盖的特点，在科学和工业的各个领域都有着强大的应用前景。然而，低转换效率的根本极限限制了这种宽带光源的系统紧凑性和广泛应用。

附：英文原文

Title: Bright compact ultrabroadband source by orthogonal laser-sustained plasma

Author: Shi, Zhaojiang, Yang, Shichao, Hu, He, Lei, Haodong, Yang, Zhaohua, Yu, Xia

Issue&Volume: 2024-09-26

Abstract: Laser-sustained plasma (LSP) source featuring high brightness and broadband spectral coverage is found to be powerful in various fields of scientific and industrial applications. However, the fundamental limit of low conversion efficiency constrains the system compactness and widespread applications of such broadband light sources. In this paper, we propose an innovative orthogonal LSP to break through the conversion efficiency limitation. Driven by the elevated conversion efficiency from absorbed laser power to ultraviolet (UV) emission, a compact broadband source (250–1650nm) with UV spectral radiance exceeding 210 mW/(mm²·sr·nm) is achieved with >100W pump laser. With the plot of a two-dimensional refractive index model, we report an important conceptual advance that the orthogonal design eliminates the influence of the negative lensing effect on laser power density. Experimental results unambiguously demonstrate that we achieve a bright compact UV-VIS-NIR source with negligible thermal loss and the highest conversion efficiency to our knowledge. Significant enhancement of 4dB contrast-to-noise ratio (CNR) in spectral single-pixel imaging has been demonstrated using the proposed ultrabroadband source. By establishing the quantitative link between pumping optics design and plasma absorption, this work presents a compact broadband source that combines superior conversion efficiency and unprecedented brightness, which is essential to high-speed inspection and spectroscopy applications.

DOI: 10.1038/s41377-024-01602-2

Source: https://www.nature.com/articles/s41377-024-01602-2