A multiplexed high-resolution imaging spectrometer for resonant inelastic soft X-ray scattering spectroscopy

Abstract

The optical design of a two-dimensional imaging soft X-ray spectrometer is described. A monochromator will produce a dispersed spectrum in a narrow vertical illuminated stripe (∼2 µm wide by ∼2 mm tall) on a sample. The spectrometer will use inelastically scattered X-rays to image the extended field on the sample in the incident photon energy direction (vertical), resolving the incident photon energy. At the same time it will image and disperse the scattered photons in the orthogonal (horizontal) direction, resolving the scattered photon energy. The principal challenge is to design a system that images from the flat-field illumination of the sample to the flat field of the detector and to achieve sufficiently high spectral resolution. This spectrometer provides a completely parallel resonant inelastic X-ray scattering measurement at high spectral resolution (∼30,000) over the energy bandwidth (∼5 eV) of a soft X-ray absorption resonance.

Extending resonant inelastic X-ray scattering to the extreme ultraviolet

“…Resolving these widths and the larger feature widths in the SrCuO 2 spectrum illustrates the femtosecond time scale on which local multiplet excitations can persist and interact meaningfully with the surrounding many-body environment. Several upcoming soft X-ray spectrometers are anticipated to reveal momentum dispersion in the critically important "thermal1" resolution regime (δE ∼ k B T near or below room temperature) [50][51][52][53][54][55], and superior energy resolution can also now be achieved with with hard X-rays [56,57] for certain specific cases such as the iridium L-edge.…”

Large area nanoimprint enables ultra-precise x-ray diffraction gratings

“…They are the heart of soft x-ray monochromators and spectrographs [1][2][3][4] utilized at the synchrotrons. Groove placement precision is a key characteristic of x-ray diffraction gratings for high-resolution applications such as Resonant Inelastic X-ray Scattering (RIXS).…”

“…However, the precision requirements are often beyond the manufacturer capabilities and the grating specifications have to be relaxed which affects the design and performance of spectrometers or monochromators. The next generation of ultrahigh resolution x-ray instrumentation [3,10,11] requires much higher groove placement accuracy and better groove density distribution control. In this work we suggest an alternative way of making ultra-precise x-ray gratings, which overcomes the traditional grating fabrication techniques.…”

Variable line spacing diffraction grating fabricated by direct write lithography for synchrotron beamline applications

“…Although traditional manufacturing methods are capable of meeting some of the needs, new optical designs are often limited by the availability of gratings. For example: advanced spectroscopy techniques such as Resonant Inelastic X-ray Scattering (RIXS) [1] require gratings with extreme resolving power and efficiency [2,3]. In lower resolution RIXS, with application in energy sciences, the need is for gratings with extremely large aperture, driving the development of gratings with highly curved grooves for aberration correction.…”