6/22/2023 0 Comments Spectrometer resolution calculator![]() This XUV spectrometer uses a slit that is imaged by a curved reflective grating. In this comparison, the highest resolution is obtained by the XUV spectrometer from McPherson (model 251MX). The resolution can be strongly increased 18–20 compared to the transmission grating spectrometer. ![]() 17 An overview of XUV spectrometers that operate in this wavelength range is shown in Table I. Additionally, diffraction from the support mesh and the low diffraction efficiency of the transmission grating hampered high-quality XCT measurements. Accordingly, higher modulation frequencies and thus deeper lying nanostructures cannot be revealed by XCT using this XUV spectrometer. In our previous XCT setup, a transmission grating spectrometer 16 was used that provides a resolution of Δ E > 0.4 eV. This is equivalent to a resolving power of R = λ/Δ λ = E/Δ E ∼ 600 at 20 nm. To detect a layer buried 1000 nm below the surface, a spectrometer resolution of Δ E ∼ 0.1 eV over the entire spectral bandwidth is required. The modulations of the spectral reflectivity are analyzed with an XUV spectrometer. In XCT, a broad-band XUV beam is reflected at a layered sample. ![]() For frequency-domain XCT, the efficiency of the spectrometer is essential because of the small scattering cross sections in the XUV while the resolution directly corresponds to the maximum depth at which structures can be detected beneath the sample’s surface. 9–11 It extends Optical Coherence Tomography (OCT) 12 into the XUV utilizing the short coherence length of broadband XUV radiation. 8 The instrument described here has been developed for XUV Coherence Tomography (XCT), a method which has been introduced recently for non-invasive cross-sectional imaging of nanostructures. For example, XUV spectroscopy has been applied to investigate warm dense hydrogen using Thomson scattering, 6 multi-electron photoionization cross sections, 7 and strong-field laser-atom interactions. In most of the scientific applications, XUV spectrometers with high detection efficiency and resolution are required. The advent of extreme ultraviolet (XUV) sources such as free-electron lasers (FLASH 1 FERMI 2) or laser-driven high harmonic (HHG) sources 3–5 has opened new applications and opportunities in basic research and applied science.
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