A5083956747- Photonic and Optical Devices
- Optical Coatings and Gratings
- Photonic Crystals and Applications
- Advanced X-ray Imaging Techniques
- Advanced Electron Microscopy Techniques and Applications
- Plasmonic and Surface Plasmon Research
- X-ray Spectroscopy and Fluorescence Analysis
- Metamaterials and Metasurfaces Applications
- Advanced Fiber Laser Technologies
- Near-Field Optical Microscopy
- Surface Roughness and Optical Measurements
- Particle Accelerators and Free-Electron Lasers
- Photorefractive and Nonlinear Optics
- Molecular Junctions and Nanostructures
- Laser-Plasma Interactions and Diagnostics
- Graphene research and applications
- Nanowire Synthesis and Applications
- Laser Material Processing Techniques
- Nanofabrication and Lithography Techniques
- Quantum optics and atomic interactions
- Semiconductor Lasers and Optical Devices
- Crystallography and Radiation Phenomena
- Orbital Angular Momentum in Optics
- Physics of Superconductivity and Magnetism
- Laser-Matter Interactions and Applications
University of Eastern Finland
2008-2024
Finland University
2016-2024
Paul Scherrer Institute
2011-2017
FinnMedi (Finland)
2016
Japan Synchrotron Radiation Research Institute
2016
SPring-8
2016
Swiss Light Source
2014
Joensuu Science Park
2008
X-ray ptychography is a scanning variant of coherent diffractive imaging with the ability to image large fields view at high resolution. It further allows non-isolated specimens and can produce quantitative mapping electron density distribution in 3D when combined computed tomography. The method does not require lenses, which makes it dose efficient suitable multi-keV X-rays, where photon counting, pixelated detectors are available. Here we present first highly resolved ptychographic...
The Materials Science beamline at the Swiss Light Source has been operational since 2001. In late 2010, original wiggler source was replaced with a novel insertion device, which allows unprecedented access to high photon energies from an undulator installed in medium-energy storage ring. order best exploit increased brilliance of this new source, entire front-end and optics had be redesigned. work, upgrade is described detail. tone didactic, it hoped reader can adapt concepts ideas his or her needs.
The smaller pixel size and high frame rate of next-generation photon counting detectors opens new opportunities for the application X-ray coherent diffractive imaging (CDI). In this manuscript we demonstrate fast image acquisition ptychography using an Eiger detector. We achieve above 25,000 resolution elements per second, or effective dwell time 40 μs element, when a 500 μm × 290 region integrated electronic circuit with 41 nm resolution. further present scheme sharing information between...
Ptychographic coherent X-ray diffractive imaging (PCDI) has been combined with nano-focus diffraction to study the structure and density distribution of unstained unsliced bacterial cells, using a hard beam 6.2 keV photon energy, focused about 90 nm by Fresnel zone plate lens.While PCDI provides images bacteria quantitative contrast in real space resolution well below size at sample, spatially resolved small angle scattering same (cellular nano-diffraction) structural information highest...
We report a method for achieving advanced photon diagnostics of x-ray free-electron lasers (XFELs) under quasi-noninvasive condition by using beam-splitting scheme. Here, we used transmission grating to generate multiple branches beams. One the two primary diffracted (+1st-order) is utilized spectral measurement in dispersive scheme, while other (-1st-order) dedicated arrival timing between XFEL and optical laser pulses. The transmitted beam (0th-order) guided an experimental station. To...
High-efficiency nanofocusing of hard X-rays using stacked multilevel Fresnel zone plates with a smallest width 200 nm is demonstrated. The approach to approximate the ideal parabolic lens profile two-, three-, four- and six-level plates. By stacking binary three-level an additional plate, number levels in optical transmission function was doubled, resulting profiles, respectively. Efficiencies up 53.7% focusing were experimentally obtained 6.5 keV photons compact alignment apparatus based on...
The fabrication of high aspect ratio metallic nanostructures is crucial for the production efficient diffractive X-ray optics in hard range. We present a novel method to increase their structure height via double-sided patterning support membrane. In transmission, two Fresnel zone plates on sides substrate will act as single plate with added height. presented 30 nm smallest width offer up 9.9% focusing efficiency at 9 keV, that results factor improvement over previously demonstrated...
Nonlinear metamaterials show potential for realizing flat nonlinear optical devices but are generally lacking in terms of achievable conversion efficiencies. Recent work has focused on enhancing processes by utilizing high quality factor resonances, such as collective responses known surface lattice resonances (SLRs) taking place periodic metal nanoparticle arrays. Here, we investigate how the dispersive nature SLRs affects SLR-supporting metasurfaces. Particularly, measure second-harmonic...
We have developed an on-line spectrometer for hard x-ray free-electron laser (XFEL) radiation based on a nanostructured diamond diffraction grating and bent crystal analyzer.Our method provides high spectral resolution, interferes negligibly with the XFEL beam, can withstand intense pulses at repetition rates of >100 Hz.The is capable providing shot-to-shot information normalization data obtained in scientific experiments optimization accelerator operation parameters.We demonstrated these...
Plasmonic metasurfaces exhibiting collective responses known as surface lattice resonances (SLRs) show potential for realizing flat photonic components wavelength-selective processes, including lasing and optical nonlinearities. However, postfabrication tuning of SLRs remains challenging, limiting the applicability SLR-based components. Here, we demonstrate how properties high quality factor are easily modified by breaking symmetry nanoparticle surroundings. We break changing refractive...
Control of light polarization is a key technology in modern photonics including application to optical manipulation quantum information. The requisite obtain large rotation isotropic media with small loss. We report on extraordinary activity planar dielectric on-waveguide photonic crystal structure, which has no in-plane birefringence and shows more than 25 degrees for transmitted light. demonstrate that the chiral crystal, coupling normally incident wave low-loss waveguide Fabry-Pérot...
We demonstrate that the dissolution of 10 nm metal nanoparticles localized in subsurface layer silicate glass by static electric field can be employed to alter optical density and surface profile glass–metal composite with spatial resolution 200 nm. The developed technique, which referred as imprinting (EFI), offers an attractive alternative conventional micro- nano-pattering techniques.
We present a spectrometer setup based on grating dispersion for hard x-ray free-electron lasers. This consists of focusing and charge-integrating microstrip detector. Measurement results acquired at Linac Coherent Light Source are presented, demonstrating noninvasive monitoring single-shot spectra with resolution 2.0×10(-4) ±0.3×10(-4) photon energy 6 keV more than 95% transmission the main beam.
Abstract X-ray Free Electron Lasers (FELs) can produce extremely intense and very short pulses, down to below 10 femtoseconds (fs). Among the key applications are ultrafast time-resolved studies of dynamics matter by observing responses fast excitation pulses in a pump-probe manner. Detectors with sufficient time resolution for these processes not available. Therefore, such experiments typically measure sample's full repeating multiple cycles at different delay times. This conventional...
Nanograting-based plasmonic sensors are widely regarded as promising platforms due to their real-time label-free detection and ease of integration. However, many reported grating structures too complicated fabricate, which limits application. We propose a 1D bilayer metallic with trapezoidal profile near-infrared sensor in the spectral interrogation. Trapezoidal gratings tend perform better than rectangular sensors, particularly they can detect at oblique incidence obtain higher performance....
We propose a simple, fast, and low-cost method for producing Au-coated black Si-based SERS-active substrates with proven enhancement factor of 106. Room temperature reactive ion etching silicon wafer followed by nanometer-thin gold sputtering allows the formation highly developed lace-type Si surface covered homogeneously distributed islands. The mosaic structure deposited use Au-uncovered domains Raman peak intensity normalization. fabricated SERS have prominent uniformity (with less than...
Tunability of properties is one the most important features 2D materials, among which graphene attracting attention due to wide variety its possible applications. Here, we demonstrated that carrier concentration in can be efficiently tuned by material dielectric substrate on it resides. To this end, fabricated samples CVD-grown transferred onto silicon wafers covered with alumina, titanium dioxide, and dioxide. We measured transmission spectra these using a time-domain terahertz spectrometer...
The authors demonstrate that a dielectric resonant waveguide grating can enhance optical second-harmonic generation by factor of 550 compared to similar flat surface. Their structure, which consists purely and thereby transparent materials, has low index silicon dioxide covered high titanium layer it is optimized for the fundamental wavelength 1064nm. Polarization dependence response suggests enhancement arises from favorable interaction mode its strong local field with inherent surface...
Beamline P11 at PETRA III is dedicated to structural investigations of biological samples. It provides two experimental stations, one for macromolecular crystallography and X-ray microscopy. The microscope will provide full field Zernike phase contrast scanning microscopy both in 2D tomographic mode. Full with a view 50 x μm<sup>2</sup> allow generate an overview the sample select regions interest later inspection element distribution by fluorescence diffraction Central part inhouse...
Zernike phase contrast microscopy is a well-established method for imaging specimens with low absorption contrast. It has been successfully implemented in full-field using visible light and X-rays. In Cowley's reciprocity principle connects scanning imaging. Even though the discussed by several authors over past thirty years, only recently it was experimentally verified X-ray microscopy. this paper, we investigate image formation particular detailed focus on origin of artifacts that are...
A nano-focusing module based on two linear Fresnel zone plates is presented.The are designed to generate a kinoform phase profile in tilted geometry, thus overcoming the efficiency limitations of binary diffractive structures.Adjustment tilt angle enables tuning setup for optimal over wide range photon energies, ranging from 5 20 keV.Diffraction more than 50% was measured full at 8 keV energy.A diffraction limited spot size 100 nm verified by ptychographic reconstruction lens with large...
Atomic layer deposited (ALD) thin films of Al2O3, SiO2, and TiO2 with thicknesses ranging from 0.25 nm to 10 were studied on inverse opal (IO) structures for their effect photocatalytic activity under ultraviolet A (UVA) excitation. 1 coating Al2O3 suppressed the significantly by more than 90% removing all water molecules surface. On contrary, SiO2 enhanced 112% increasing number surface whereas 3 reduced 87% as thicker prevented electron hole diffusion onto The highest enhancement up 226%...