Multilayer-coated blazed grating with variable line spacing and a variable blaze angle

Diffraction gratings with two-orders-of-magnitude-enhanced dispersion rates for sub-meV resolution soft X-ray spectroscopy

“…1(a 1 )-1(a 2 )]. Although the Bragg reflectivity in this case is relatively low compared with the 80% to 90% reflectivity typical in the hard X-ray regime (because of high photoabsorption of the 930 eV photons), it is still larger than the typical diffraction gratings reflectivity of $ 5%, unless multilayer-coated blazed grating are used (Voronov et al, 2014(Voronov et al, , 2015. The angular dispersion rate is, however, zero in the case of symmetric diffraction.…”

“…1(b) and 2(a). Using equation 9, we estimate D > 20 mrad meV À1 for E = 930 eV, assuming È 0 < $ 60 mrad, 2 the values, which are two orders of magnitude larger than those possible using manmade diffraction gratings (Ghiringhelli et al, 2006;Strocov et al, 2010;Chaix et al, 2017;Brookes et al, 2018;Bisogni, 2019;Warwick et al, 2014;Chuang et al, 2017;Lai et al, 2014;Zhou, 2019;Dvorak et al, 2016;Voronov et al, 2014Voronov et al, , 2015.…”

“…Angular dispersion rate D measures the angular variation of the propagation direction of the diffracted photon with its energy. It is primarily determined by the smallness of the diffraction grating period, or equivalently by the large value of the groove density g. The maximum angular dispersion rates of the state-of-the-art diffraction gratings is in the range D ' 0.2-0.4 mrad meV À1 at E ' 1 keV, corresponding to a groove density of g ' 5-10 mm À1 (Michette, 1986;Ghiringhelli et al, 2006;Strocov et al, 2010;Chaix et al, 2017;Brookes et al, 2018;Bisogni, 2019;Warwick et al, 2014;Chuang et al, 2017;Lai et al, 2014;Zhou, 2019;Dvorak et al, 2016;Voronov et al, 2014Voronov et al, , 2015.…”

Innovative diffraction gratings for high-resolution resonant inelastic soft x-ray scattering spectroscopy

“…This would result in reduction of efficiency of peripheral parts of the grating and would be a limiting factor for a useful grating length. However, the local blaze angle of a VLS MBG grating is not constant due to staggered layer structure of the multilayer stack in the peripheral part of the MBG as was shown in [8]. In the center of the VLS grating (X = 0 mm) groove depth measured perpendicular to the blazed facets equals m × D ML (this condition provides the highest possible efficiency of the m th diffraction order), and multilayer interfaces of adjacent grooves are stitched perfectly forming a continuous layer structure.…”

Self-Calibration of a Large-Scale Variable-Line-Spacing Grating for an Absolute Optical Encoder by Differencing Spatially Shifted Phase Maps from a Fizeau Interferometer

“…With the employment of a planar VLS grating having grating pattern structures along the two orthogonal directions, in-plane absolute position measurement can be achieved [ 10 ]. However, instabilities in the mechanical manufacturing process or any distortion and imperfect wavefront control in the lithography process can result in unwanted pitch deviation of the planar VLS grating [ 12 , 13 ], which can influence its performance as the scale for two-dimensional absolute position measurement. Since the measurement range of the absolute optical encoder with the planar VLS grating is mainly determined by the scale size [ 14 ], a large-scale planar VLS grating is often employed.…”