Poletto Luca, Nicolosi Piergiorgio, Tondello Giuseppe
Istituto Nazionale per la Fisica della Materia, Department of Electronics and Informatics, University of Padova, Italy.
Appl Opt. 2002 Jan 1;41(1):172-81. doi: 10.1364/ao.41.000172.
The design of a stigmatic spectroscopic system for diagnostics of laser-produced plasmas in the 2.5-40-nm region is presented. The system consists of a grazing-incidence toroidal mirror that focuses the radiation emitted by a laser-produced plasma onto the entrance slit of a spectrograph. The latter has a grazing-incidence spherical variable-line-spaced grating with flat-field properties coupled to a spherical focusing mirror that compensates for the astigmatism. The mirror is crossed with respect to the grating; i.e., it is mounted with its tangential plane coincident with the equatorial plane of the grating. The spectrum is acquired by an extreme-UV- (EUV-) enhanced CCD detector with high quantum efficiency. This stigmatic design also has spectral and spatial resolution capability for extended sources: The spectral resolution is also preserved for off-plane points, whereas the spatial resolution decreases for points far from the optical axis. The expected performance is presented and compared with that of a stigmatic design with a plane variable-line-spaced grating illuminated in converging light.
本文介绍了一种用于诊断2.5 - 40纳米区域激光产生等离子体的像散光谱系统的设计。该系统由一个掠入射环形镜组成，它将激光产生等离子体发出的辐射聚焦到光谱仪的入射狭缝上。光谱仪有一个具有平场特性的掠入射球面可变线间距光栅，与一个补偿像散的球面聚焦镜相连。该镜子相对于光栅交叉安装；即其切平面与光栅的赤道平面重合。光谱由具有高量子效率的极紫外（EUV）增强型电荷耦合器件（CCD）探测器采集。这种消像散设计对扩展光源也具有光谱和空间分辨率能力：对于离轴点，光谱分辨率得以保留，而对于远离光轴的点，空间分辨率会降低。文中给出了预期性能，并与在会聚光中照明的平面可变线间距光栅的消像散设计的性能进行了比较。
