B16-Test Beamline
Optics
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Yixiao
Ma
,
Jiali
Wu
,
Xinyi
Liu
,
Qiushi
Huang
,
Xiaohao
Dong
,
Weizheng
Lei
,
Hongchang
Wang
,
Wenbin
Li
,
Andrey
Sokolov
,
Zhe
Zhang
,
Zhong
Zhang
,
Zhanshan
Wang
Diamond Proposal Number(s):
[21446]
Abstract: The internal layer structure and optical performance of coating for X-ray free-electron laser (XFEL) applications were studied. Surface morphology analysis shows that the layer growth at 5 mTorr replicates the substrate morphology at low and mid frequencies but adds slight high-frequency roughness, with the RMS value increasing from 0.13 to 0.33 nm. To investigate the internal physical and chemical structure of , angle-resolved X-ray photoelectron spectroscopy (ARXPS) and depth profiling were performed. Together with soft X-ray (SXR) and hard X-ray (HXR) reflectivity measurements and the fitted results, a three-sublayer model with different composition and density was built for the 50 nm coating. The developed coating was further deposited on a 600 mm length mirror with a thickness variation of 0.7 nm (peak-to-valley). The radius of curvature changed slightly from 181 km before coating to 128 km after coating, and the slope errors were maintained at around 0.07 µrad, indicating a high-performance and large-size coating for the XFEL.
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Apr 2026
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[34842]
Abstract: The development of high-performance infrared (IR) nonlinear optical (NLO) crystals is fundamentally challenged by the conflicting requirements for a large NLO coefficient, a high laser damage threshold (LDT), and a broad IR transparency range. We establish a structure–property relationship governing nonlinear optical response in diamond-like compounds, namely, a sixth-power scaling relation between the NLO coefficient dijk and average flexibility index F, i.e., dijk ∝ F6. Based on this relation, a multiple flexible-group synergistic polarization strategy is proposed, which successfully guided the discovery of an exceptional IR NLO crystal, Cd2In3Si2P7 (CISP). CISP exhibits the largest recorded SHG effect (8.8 × AgGaS2 (AGS) and 2.5 × ZnGeP2 (ZGP) @ 2050 nm) among reported pnictide NLO crystals, high NLO coefficients (d22 and d23 = 137.6 and 89.3 pm/V @ 1500 nm, respectively), a high LDT (10.3 × AGS), a moderate birefringence (0.098 @ 2050 nm), and a broad IR transmission range (0.62–18.0 μm). The outstanding comprehensive performances underscore its significant potential as a promising IR NLO material. This work not only provides a strategy for the design of IR NLO crystals but also introduces a straightforward yet powerful descriptor for understanding the structure–property correlation in polarizable functional materials.
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Apr 2026
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B16-Test Beamline
Optics
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Yuanze
Xu
,
Vishal
Dhamgaye
,
Hongchang
Wang
,
Oliver
Fox
,
Futing
Yi
,
Ming
Li
,
Weiwei
Zhang
,
Junliang
Yang
,
David
Laundy
,
Dongni
Zhang
,
Kawal
Sawhney
,
Jing
Liu
,
He
Lin
Diamond Proposal Number(s):
[34816]
Open Access
Abstract: A novel aberration-free X-ray compound refractive kinoform lens design based on the Cartesian oval curve is presented, designated as the OVAL-OK (OVAL Overlap Kinoform) lens. Material infilling of the kinoform step structure maintains focal spot dimensions while reducing focal intensity and reproducibility of structures. A SU-8 OVAL-OK lens fabricated through X-ray lithography achieved vertical focal sizes of 70.8 nm (knife-edge scanning) and 56 nm (wavefront propagation analysis) under 15 keV X-ray illumination, using a 120 μm × 200 μm (horizontal × vertical) aperture and 40.8 mm working distance. The lens exhibits a horizontal structural depth of 170 μm and a minimum feature size of 5 μm. The observed discrepancy between direct knife-edge measurements and wavefront-derived values is attributable to the combined effects of geometric, diffraction, coherence, instrumental instability, etc. These results demonstrate the potential for achieving sub-50 nm 2D focusing in future iterations through enhanced structural depth and expanded aperture dimensions.
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Apr 2026
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B23-Circular Dichroism
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Diamond Proposal Number(s):
[17621]
Open Access
Abstract: Nonreciprocal chiroptical properties in thin films of chiral organic materials have gained remarkable attention in recent years. Originating from the presence of two-dimensional (2D) chiral structures, these properties manifest as an inversion of the handedness of circularly polarized light preferentially transmitted or emitted from opposite faces of the same sample. Here, we provide a comprehensive overview of the most recent advances in this area, discussing representative systems based on organic small molecules, organic polymers, and hybrid organic–inorganic composites, with particular emphasis on elucidating structure–property relationships. Finally, we survey emerging technological applications enabled by nonreciprocal chiroptical responses. By outlining current challenges and open questions, this review aims to stimulate further discussion and inspire new investigations in this rapidly emerging field.
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Apr 2026
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Metrology
Optics
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Open Access
Abstract: Advanced metrology methods are continually being developed and refined to meet the demanding quality standards of high-performance X-ray mirrors. Among these, interferometric techniques are the most widely used for measuring the height maps of optical surfaces. However, they often encounter limitations when applied to strongly curved or freeform surfaces, primarily due to high fringe density caused by steep slope. To address these challenges, we have developed a laser Speckle-based Curvature Optical Metrology instrument (SCOM) for measuring the two-dimensional surface curvature maps. This technique offers an alternative for characterizing complex optical surfaces by using a digital image correlation algorithm to extract curvature information from the speckle pattern, which effectively acts as a set of wavefront markers. We have demonstrated the effectiveness of this method for measuring strongly curved mirrors with a radius of curvature from 10 m down to 100 mm. Additionally, we have applied this technique to online deterministic figuring of optical surfaces, in-situ stress measurements during multilayer deposition processes, and the characterization of deformable mirrors. This technique shows great promise not only for high precision metrology of X-ray mirrors used in synchrotron radiation facilities, free-electron lasers, and space and astronomical observatories, but also for freeform optical components in advanced industrial applications.
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Apr 2026
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I09-Surface and Interface Structural Analysis
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O.
Tkach
,
S.
Fragkos
,
Deepnarayan
Biswas
,
J.
Liu
,
O.
Fedchenko
,
Y.
Lytvynenko
,
S.
Babenkov
,
D.
Zimmer
,
Q. L.
Nguyen
,
S.
Chernov
,
D.
Kutnyakhov
,
M.
Scholz
,
N.
Wind
,
A.
Gloskovskii
,
F.
Pressacco
,
J.
Dilling
,
L.
Bruckmeier
,
M.
Heber
,
L.
Wenthaus
,
G.
Brenner
,
D.
Puntel
,
P. E.
Majchrzak
,
D.
Liu
,
F.
Scholz
,
J. A.
Sobota
,
J. D.
Koralek
,
G.
Dakovski
,
A.
Mehta
,
N.
Sirica
,
M.
Hoesch
,
C.
Schlueter
,
L. V.
Odnodvorets
,
Y.
Mairesse
,
T.-L.
Lee
,
A.
Kunin
,
K.
Rossnagel
,
Z. X.
Shen
,
H. J.
Elmers
,
S.
Beaulieu
,
G.
Schönhense
Abstract: A new type of objective lens has recently been proposed for use in x-ray photoemission electron microscopes (XPEEMs) and momentum microscopes. Adding a ring electrode concentric with the extractor allows the field in the gap between the sample and the extractor to be shaped. Forming a lens field in this gap reduces the field strength at the sample by up to an order of magnitude. This mitigates the risk of field emission, particularly for cleaved samples with sharp edges. A retarding field can redirect all slow electrons, thus eliminating the primary contribution to the space-charge interaction. Here, we present the first experimental investigation of the new lens, examining its performance at photon energies ranging from the extreme ultraviolet (XUV) produced by a high-harmonic generation-based source to soft and hard x rays at two synchrotron facilities. The gap lens in a region without electrodes enables large working distances up to 23 mm. Reduced aberrations allow for larger fields of view in both k-space and real-space imaging, with resolutions comparable to those of conventional cathode lenses. However, field strengths are an order of magnitude smaller. The zero-field mode enables the study of 3D structured objects and is, therefore, beneficial for small cleaved samples as well as for operando devices involving top electrodes. The repeller mode reduces space-charge effects but results in a smaller k-field diameter. This reduction ranges from 10% at hard x-ray energies to 50% in the XUV range. The usable energy interval is also reduced by a factor of two. In time-of-flight XPEEM mode, the raw data show a resolution of 250 nm, which can be improved to better than 100 nm through data processing.
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Mar 2026
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Metrology
Optics
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Open Access
Abstract: High-performance synchrotron X-ray focusing mirrors require aspheric surfaces with nanoradian slope accuracy, which are challenging to provide for many manufacturers. Conventional grinding and polishing techniques typically introduce tooling marks to the surface during the fabrication process, and these marks can impose significant challenges for the deterministic figuring processes used as the final step in mirror fabrication, ultimately limiting the slope errors of the mirrors. To overcome this limitation, we present an alternative approach by using ion beam shaping to form an elliptical sub-microfocusing mirror from a flat mirror, followed by ion beam figuring to improve the remaining errors. Two mirrors fabricated using this approach achieved tangential slope errors below 200 nrad root mean squared (rms), in contrast to a conventionally pre-shaped mirror with identical ellipse parameters that was limited to > 500 nrad rms after ion beam figuring due to residual tooling marks. In X-ray focusing tests, the ion beam shaped mirrors are able to realise a spot size below 250 nm (full width half maximum), compared to 404 nm for the pre-shaped mirror. This demonstrates the excellent potential of ion beam shaping as a method for rapid, efficient and high-quality X-ray mirror fabrication.
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Feb 2026
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labSAXS-Offline SAXS and Sample Environment Development
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Ikechukwu D.
Nwosu
,
Lujo
Matasović
,
Tárcius N.
Ramos
,
Nguyen Le
Phuoc
,
Giacomo
Londi
,
Alexander J.
Gillett
,
Daniel T. W.
Toolan
,
Charles T.
Smith
,
George F. S.
Whitehead
,
Mireille
Blanchard-Desce
,
Jonathan
Daniel
,
Mikko
Linnolahti
,
Yoann
Olivier
,
Alexander S.
Romanov
Diamond Proposal Number(s):
[40538]
Open Access
Abstract: Advanced photonic materials showing two-photon absorption (2PA) have been widely explored to develop three-dimensional imaging, micro and nanofabrication, all-optical switching, lithography on a nanoscale and many other enabling technologies. These all require nonlinear absorption chromophores with intrinsic 2PA cross-sections and long-term photo- and thermal stability. Here, we disclose the very first example of the dipolar carbene-metal-amide (CMA) material showing a enhanced 2PA cross-section up to 105 GM. Overall molecular design considerations such as extended π-conjugation (to increase polarizability), minimizing the singlet-triplet energy gap (ΔEST), and using heavy metal atoms are the first design principles to obtain bright one- and two-photon excited thermally activated delayed fluorescence (TADF) material, showing one of the highest radiative rate of 2.18·106 s-1 across CMA materials. Bright red CMA 2P-TADF material shows excellent photostability (LT50 = 3 h) to 20 mW femtosecond pulsed laser excitation at 1000 nm, encouraging further CMA exploration for future applications in advanced photonic technologies requiring third-order nonlinear optical properties.
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Feb 2026
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B16-Test Beamline
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S.-X.
Wang
,
Z.-Q.
Zhao
,
X.-Y.
Wang
,
T.-J.
Li
,
Y.
Su
,
Y.
Uemura
,
F.
Alves Lima
,
A.
Khadiev
,
B.-H.
Wang
,
J. M.
Ablett
,
J.-P.
Rueff
,
H.-C.
Wang
,
O. J. L.
Fox
,
Wenbin
Li
,
L.-F.
Zhu
,
X.-C.
Huang
Diamond Proposal Number(s):
[31397]
Open Access
Abstract: X-ray cavity quantum optics with inner-shell transitions has been limited by the spectral overlap between resonant and continuum states. Here, we report the first experimental demonstration of cavity-controlled core-to-core resonant inelastic x-ray scattering (RIXS). We suppress the absorption-edge effects by monitoring the RIXS profile, thereby resolving the resonant state from the overlapping continuum. We observe distinct cavity-induced energy shifts and cavity-enhanced decay rates in the 2𝑝3𝑑 RIXS spectra of WSi2. These effects, manifesting as stretched or shifted profiles in the RIXS planes, enable novel spectroscopic applications via cavity-controlled core-hole states. Our results establish core-to-core RIXS as a powerful tool to manipulate inner-shell dynamics in x-ray cavities, offering new avenues for integrating quantum optical effects with x-ray spectroscopy.
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Feb 2026
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Optics
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Arindam
Majhi
,
Wadwan
Singhapong
,
Wai Jue
Tan
,
Andrey
Sokolov
,
Stefano
Agrestini
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Andrew C.
Walters
,
Chris
Bowen
,
Alexander J. G.
Lunt
,
Hongchang
Wang
,
Kawal J.
Sawhney
Open Access
Abstract: Laterally graded multilayer optics play an important role in advanced X-ray applications, enabling precise control of beam properties for spectroscopic and focusing techniques. The Multilayer Deposition System (MDS) at Diamond Light Source (DLS) has demonstrated its ability to fabricate highly precise laterally graded X-ray optics. Developing such optics is challenging due to stringent requirements for precise lateral thickness variations and sagittal uniformity, achieved through optimized substrate speed profiles and advanced mask design. This study presents a comprehensive investigation into the design, fabrication, and characterization of laterally graded multilayers. An adjustable mask design improves sagittal uniformity and reduces optimization times. The structural and optical performance of the multilayers is evaluated, confirming their suitability for synchrotron applications. Two types of laterally graded multilayers were developed: one with a constant lateral gradient (0.005 nm/mm) for O-K edge polarizers, achieving sagittal thickness variations of approximately 0.3–0.4% across an 80 mm substrate, and another featuring a strong variable gradient from 0.037 to 0.112 nm/mm, designed to match the elliptical periodicity profile. The constant gradient multilayer polarizer has been successfully implemented on the state-of-the-art I21 beamline at DLS, highlighting the MDS's role in producing next-generation X-ray optics that meet the stringent demands of synchrotron beamlines.
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Jan 2026
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