A revolutionary soft X-ray scanning transmission microscope at the Swiss Light Source
In the hidden universe of nanoscale structures—where materials exhibit exotic magnetic behaviors, polymers arrange in intricate patterns, and environmental particles reveal toxic secrets—conventional microscopes fall tragically short.
PolLux is a revolutionary soft X-ray scanning transmission microscope (STXM) at the Swiss Light Source (SLS), designed to map chemistry, magnetism, and structure with unprecedented precision.
PolLux's unique combination of capabilities enables breakthroughs across multiple scientific disciplines.
PolLux exploits a fundamental principle: when soft X-rays (200–1,600 eV) strike matter, their absorption spectra act as a "chemical fingerprint." By tuning X-ray energy to specific atomic transitions (e.g., carbon K-edge at 284 eV), researchers identify molecular composition, bond orientation, and even magnetic states.
Unique to PolLux is its use of circularly polarized light, enabling real-time imaging of magnetic phenomena like skyrmions—nanoscale spin structures crucial for next-gen computing 1 8 .
Unlike optical microscopes, PolLux uses Fresnel zone plates—concentric rings of metal—to focus X-rays into a nanometer-scale beam. As samples raster-scan through this beam, detectors measure transmitted X-rays, generating hyperspectral maps.
Recent upgrades achieved <20 nm resolution, revealing features 10,000x smaller than a human hair 1 6 .
| Parameter | Specification | Scientific Impact |
|---|---|---|
| Energy Range | 200–1,600 eV | Covers K/L-edges of C, O, Fe, Co, Ni |
| Spatial Resolution | <40 nm (currently ~20 nm) | Resolves viruses, magnetic domains |
| Polarization Modes | Linear, Circular (R/L) | Probes chirality and magnetic textures |
| Sample Environment | Vacuum to 1 atm (He/inert gas) | Studies hydrated or reactive materials |
Table 1: Comprehensive technical specifications of PolLux 1 2 6 .
In 2025, an international team used PolLux to solve a persistent puzzle: how do magnetic skyrmions—whirlpool-like spin structures—maintain stability in three dimensions? These entities could revolutionize data storage but collapse under conventional imaging.
| Component | Details |
|---|---|
| Sample | FeGe nanomembrane (70 nm thick) |
| X-ray Energy | 706 eV (Fe L₃-edge) |
| Polarization | Rapid-switch circular (left/right) |
| Technique | Soft X-ray laminography |
| Spatial Resolution | 30 nm (in-plane); 50 nm (depth) |
Table 2: Detailed parameters of the skyrmion imaging experiment 2 8 .
3D visualization of magnetic skyrmion structures revealed by PolLux's advanced imaging capabilities.
Nanofabricated lenses focus X-rays. Current versions achieve <20 nm spots, with future upgrades targeting 10 nm 1 .
Higher-Order Suppressor (HOS) Mirrors filter out stray high-energy photons, ensuring spectral purity 5 .
Electron-beam steering allows sub-second polarization switching—critical for dynamic magnetic studies 1 .
| Reagent/Tool | Function |
|---|---|
| Circular Polarized X-rays | Switchable helicity probes magnetic chirality |
| NEXAFS Spectroscopy | Measures bond-specific absorption edges |
| TEY-STXM Detector | Surface-sensitive electron yield imaging |
| Inert Gas Chamber | Enables studies of air-sensitive nanomaterials |
Table 3: Key components that enable PolLux's advanced capabilities 1 2 5 .
PolLux analyzed aerosol particles from urban air, identifying toxic heavy metals (e.g., lead) bound to organic residues. This revealed how pollutants evade lung clearance 4 .
Using TEY-STXM, researchers confirmed homogeneous doping in organic solar cell nanoparticles. This ensured efficient charge transport, boosting device efficiency by 15% 2 .
Studies of superconducting cuprates mapped oxygen vacancy distributions, linking defects to quantum coherence loss 7 .
With the SLS 2.0 upgrade (2025), PolLux now delivers brighter beams, enabling multi-modal imaging (fluorescence + absorption) and faster nanoscale dynamics. The first post-upgrade user call is open for November 2025 beamtime 3 .
"Our next goal is 10 nm resolution—seeing single molecules in action."
PolLux transcends traditional microscopy, merging chemistry, magnetism, and topology into a single vision. From stabilizing quantum states to tracking environmental toxins, it epitomizes how synchrotron science transforms abstract principles into tangible solutions. As it enters its SLS 2.0 era, this facility remains a beacon of what happens when human ingenuity illuminates the invisible.
Proposal deadlines for PolLux beamtime are August 20, 2025 (12:00 CET). Details: PSI Call Portal .