Progress in the development of critical-angle transmission gratings

Heilmann, Ralf K.; Bruccoleri, Alex R.; Mukherjee, Pran; Schattenburg, Mark L.

doi:10.1117/12.926827

Cited by 6 publications

(7 citation statements)

References 20 publications

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“…Current methods used to produce X-ray diffractive optics include top-down methods involving patterning of a thick resist mould 6,7 , pattern transfer into a substrate using deep reactive ion etching [8][9][10] , anisotropic Si wet etch 11,12 , multiple patterning techniques 13 , multilayer Laue lens, various multilayer-sliced zone plate techniques 14 , lithographic stacking 15 and mechanical stacking 16 . Advantages and tradeoffs exist with each method.…”

mentioning

confidence: 99%

Ultra-high aspect ratio high-resolution nanofabrication for hard X-ray diffractive optics

2014

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Although diffractive optics have played a major role in nanoscale soft X-ray imaging, highresolution and high-efficiency diffractive optics have largely been unavailable for hard X-rays where many scientific, technological and biomedical applications exist. This is owing to the long-standing challenge of fabricating ultra-high aspect ratio high-resolution dense nanostructures. Here we report significant progress in ultra-high aspect ratio nanofabrication of high-resolution, dense silicon nanostructures using vertical directionality controlled metalassisted chemical etching. The resulting structures have very smooth sidewalls and can be used to pattern arbitrary features, not limited to linear or circular. We focus on the application of X-ray zone plate fabrication for high-efficiency, high-resolution diffractive optics, and demonstrate the process with linear, circular, and spiral zone plates. X-ray measurements demonstrate high efficiency in the critical outer layers. This method has broad applications including patterning for thermoelectric materials, battery anodes and sensors among others.

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confidence: 99%

Ultra-high aspect ratio high-resolution nanofabrication for hard X-ray diffractive optics

2014

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“…Over the last 2-3 years we developed masks, pattern transfer and etch recipes for the simultaneous vertical etching of CAT gratings and L1 supports, as well as for the L2 support mesh, first on bulk silicon and separate SOI wafers, and then combined on a single SOI wafer. [24][25][26][27] Thus DRIE on the front and back sides of SOI wafers can be used to fabricate large-area, freestanding CAT grating membranes with minimal support structures.…”

Section: Overviewmentioning

confidence: 99%

Fabrication of large-area and low mass critical-angle x-ray transmission gratings

et al. 2014

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Soft x-ray spectroscopy of celestial sources with high resolving power R = E/∆E and large collecting area addresses important science listed in the Astro2010 Decadal Survey New Worlds New Horizons, such as the growth of the large scale structure of the universe and its interaction with active galactic nuclei, the kinematics of galactic outflows, as well as coronal emission from stars and other topics. Numerous studies have shown that a transmission grating spectrometer based on lightweight critical-angle transmission (CAT) gratings can deliver R = 3000-5000 and large collecting area with high efficiency and minimal resource requirements, providing spectroscopic figures of merit at least an order of magnitude better than grating spectrometers on Chandra and XMM-Newton, as well as future calorimeter-based missions. The recently developed CAT gratings combine the advantages of transmission gratings (low mass, relaxed figure and alignment tolerances) and blazed reflection gratings (high broad band diffraction efficiency, utilization of higher diffraction orders). Their working principle based on blazing through reflection off the smooth, ultra-high aspect ratio grating bar sidewalls has previously been demonstrated on small samples with x rays. For larger gratings (area greater than 1 inch square) we developed a fabrication process for grating membranes with a hierarchy of integrated low-obscuration supports. The fabrication involves a combination of advanced lithography and highly anisotropic dry and wet etching techniques. We report on the latest fabrication results of free-standing, large-area CAT gratings with polished sidewalls and preliminary x-ray tests.

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“…Progress on the development and manufacturing of the CAT gratings is given by Heilmann et al in this volume and a series of papers stretching back many years. 14,15 For our ray-trace simulations, we use CAT grating efficiences that are predicted from numerical simulations and that match the efficiences measured for CAT gratings in the laboratory. The numbers include the effect of cross-dispersion from L1 support structures, dispersion and blockage by the hexagonal L2 supports and any coverage by grating frames.…”

Section: Cat Gratingsmentioning

confidence: 99%

“…all global CCD misalignments use the same photons. Figures 12,13,and 14 show some examples of the results. In the figures, A eff is given summed over all dispersed orders that fall on a CCD (bottom row) and R is the average resolving power, where the resolving power from individual orders is averaged weighted by the number of photons in that particular order (top row).…”

Section: Alignment Tolerancesmentioning

confidence: 99%

Arcus x-ray telescope performance and alignment

Günther,

Cheimetz,

Miller

et al. 2023

UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXIII

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Arcus is a concept for a probe class mission to deliver high-resolution FUV and X-ray spectroscopy. For Xrays, it combines cost-effective silicon pore optics (SPO) with high-throughput critical-angle transmission (CAT) gratings to achieve R > 3000 in a bandpass from 12-50 Å. We show in detail how the X-ray and the UV spectrographs (XRS and UVS) on Arcus will be aligned to each other. For XRS we present ray-tracing studies to derive performance characteristics such as the spectral resolving power and effective area, study the effect of misalignments on the performance, and conclude that most tolerances can be achieved with mechanical means alone. We also present an estimate of the expected on-orbit background.

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Progress in the development of critical-angle transmission gratings

Cited by 6 publications

References 20 publications

Ultra-high aspect ratio high-resolution nanofabrication for hard X-ray diffractive optics

Ultra-high aspect ratio high-resolution nanofabrication for hard X-ray diffractive optics

Fabrication of large-area and low mass critical-angle x-ray transmission gratings

Arcus x-ray telescope performance and alignment

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