Monochromateur multicouche X-UV à bande passante étroite et faible fond continu

Benbalagh, Rabah; André, Jean‐Michel; Barchewitz, R.; Ravet, M. F.; Delmotte, Franck; Bridou, Françoise; Julie, G; Bosseboeuf, Alain; Laval, R.; Remond, C.; Soullié, G.; Troussel, P.; Fialin, Michel

doi:10.1051/jp4:20020238

Cited by 7 publications

(18 citation statements)

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“…As can be seen in figure 3.3, the agreement between our numerical solution and the previous results of ref. [63] are in excellent agreement. …”

Section: Numerical Solutionsupporting

confidence: 77%

“…(3.39) in section 3.3) are well below the periods used in refs. [12,63]. Figure 3.4 shows the comparison of our numerical and analytic solutions for the same ML and Γ-ratio as used in figure 3.3, but with a reduced grating period D of 300 nm.…”

Section: Higher Diffraction Order Efficienciesmentioning

confidence: 99%

“…To test the validity of the CWA derived in this section, we compared the calculated 0 th order reflectivity curves with other works [5,12,63]. We therefore .…”

Section: Numerical Solutionmentioning

confidence: 99%

“…Although Reactive Ion Etching (RIE) has been used to etch ML mirrors, this approach generally suffers from a lack of directional etching, resulting in poor critical-dimension (CD) control and a limitation on ML stack heights that can be etched [63,71]. Furthermore, these processes showed strong dependence of the etch results on the grating structure.…”

Section: Fabrication Of Gratings In W/si Multilayer Mirrors 41 Intromentioning

confidence: 99%

“…At present, several rigorous approaches such as modal theory or integral method are used to simulate LMGs [54][55][56][57], in particular in the SXR region [11,12,[58][59][60][61][62][63]. However, the modal theory is poorly suited for LMGs with non-rectangular groove shapes or for smooth interfaces between neighboring materials.…”

Section: Introductionmentioning

confidence: 99%

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Single-order lamellar multilayer gratings

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Cover: 3D artist impression of a Lamellar Multilayer Grating (LMG). A Transmission Electron Microscope image of an actual LMG is shown on the rear. The grating was etched into a 400 bi-layer W/Si multilayer mirror with a total stack height H of 1 μm and a tungsten layer thickness of only 3 atoms. The grating had a period D of 300 nm and a lamel width ΓD of 75 nm. In comparison to the TEM image on the rear, the red and green layers in the artist impression correspond to tungsten and silicon, respectively. The bi-layer period in the artist impression is overestimated by a factor of 10 for visibility. SummaryA major challenge in the soft x-ray (SXR) and eXtreme UltraViolet (XUV) spectral ranges is the ability to manipulate the incident radiation using optical elements. By patterning conventional multilayer mirrors with nanoscale structures, novel optical elements with a variety of optical properties can be obtained. In this work, the design, fabrication and characterization of Lamellar Multilayer Gratings (LMG) was investigated. Such LMGs are a particular form of the general class of Bragg-Fresnel optics which combine Fresnel optics with Bragg reflection to provide unique dispersive and focusing optics. In particular, LMGs can be used to improve the spectral resolution of x-ray fluorescence techniques.A Coupled Waves Approach (CWA) was derived to simulate the optical performance, in terms of resolution and reflectivity, of LMGs. This CWA allowed to study the physical principles behind LMGs and resulted in the identification of an optimal LMG operating regime. In this regime, the incident beam is reflected in a single diffraction order and is hence referred to as the singleorder regime. Such single-order LMGs were fabricated using UV-NanoImprint Lithography and Bosch Deep Reactive Ion Etching, a process chosen to enable rapid practical development. Single-order operation was experimentally demonstrated and showed an improvement in spectral resolution of a factor of 3.8 with regard to conventional multilayer mirrors. Singe-order excitation of higher diffraction orders was also measured and analyzed.Single-order operation often requires multilayer stacks and grating structures that cannot be fabricated with sufficient accuracy using current technologies. As this invalidates the semi-infinite multilayer approximation, we investigated the optical performance of LMGs with finite multilayer stacks. We determined the ratio between the absorber thickness and bi-layer period of the multilayer stack can be used to further tailor LMG optical performance to maximize bandwidth reduction or minimize peak reflectivity loss. We also investigated various degradation processes that could limit the lifetime of LMGs, which is important for the applicability of such elements. Oxidation of tungsten and silicon as well as changes to the sidewall composition were clearly seen. However, SXR reflectivity remained stable to within measurement accuracy for an extended storage period of 18 months in a 1 atm air environment. The possibility of ...

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“…As can be seen in figure 3.3, the agreement between our numerical solution and the previous results of ref. [63] are in excellent agreement. …”

Section: Numerical Solutionsupporting

confidence: 77%

Section: Higher Diffraction Order Efficienciesmentioning

confidence: 99%

“…To test the validity of the CWA derived in this section, we compared the calculated 0 th order reflectivity curves with other works [5,12,63]. We therefore .…”

Section: Numerical Solutionmentioning

confidence: 99%

Section: Fabrication Of Gratings In W/si Multilayer Mirrors 41 Intromentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Single-order lamellar multilayer gratings

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An etched multilayer as a dispersive element in a curved‐crystal spectrometer: implementation and performance

et al. 2012

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Etched multilayers obtained by forming a laminar grating pattern within interferential multilayer mirrors are used in the soft x-ray range to improve the spectral resolution of wavelength dispersive spectrometers equipped with periodic multilayers. We describe the fabrication process of such an etched multilayer dispersive element, its characterizationthrough reflectivity measurement and simulations, and its implementation in a high-resolution Johann-type spectrometer. The specially designed patterning of a Mo/B 4 C multilayer is found fruitful in the range of the C K emission as the diffraction pattern narrows by a factor 4 with respect to the non-etched structure.This dispersive element with an improved spectral resolution was successfully implemented for electronic structure study with an improved spectral resolution by x-ray emission spectroscopy. As first results we present the distinction between the chemical states of carbon atoms in various compounds, such as graphite, SiC and B 4 C, bythe different shape of their C K emission band.

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