Laserlab-Europe
MBI - XUV spectroscopy of magnetic material

A) Beamline for spectroscopy of magnetic materials in the extreme ultraviolet spectral range

The extreme ultraviolet radiation (XUV) is generated in a standard gas (Ar, Ne, He) target. After a reflective XUV/IR beamsplitter the XUV light is focused by a toroidal mirror and circularly polarized by a 4-mirror reflective polarizer. We record a reference spectrum by diffracting the first order of a reflection grating by a in vacuum CCD camera. The 0 order is refocused by a second toroidal mirror onto the sampleto a spot size of approximately 100 µm FWHM. The transmitted or reflected light is collected by a flat field grating and collected by a second CCD camera. The two camera are synchronized and allow accurate and low noise measurements with an RMS ~ 1E-4. The sample environment includes an electromagnet to apply an external magnetic field of approximately  300 mT and a closed cycle, low vibration croystat for temperatures between ~10 K and 700 K.

Alternatively the polarization of the XUV beam can be controlled by a bi-circular pump field.

For a detailed overview please refer to a recent publication in Review of Scientific Instruments:

https://doi.org/10.1063/5.0013928
 

 

B) Beamline for coherent imaging and small angle scattering

By removing the switching mirror unit (SMU) the XUV beam is sent into a flexible vacuum chamber equipped with different monochromatizing focusing optics precise sample stages and a 4k in vacuum CCD camera.

Laser-based light source parameters

Coherent Legend Elite Duo

Source type
Ultrafast Ti:Sapphire amlifier with pulse energy of 1 x 3 mJ and 1 x 1.5 mJ at 3 KHz with two separate compressors. Energy stability of < 0.5% rms.
For optical excitation there is currently the option to use the output from a optical parametric amplfier for accessing wavelength from 190 nm to 15 µm. Note that for extreme wavelength the pulse energy drops to approximately 1 µJ.
Photon energy range / wavelength range
800 [nm]
Peak Photon energy / central wavelenght
800 [nm]
Photon energy / wavelength fluctuations
5 * 10-1 [%, RMS]
Spectral Bandwidth FWHM / %
750 - 850 [nm]
Beam shape
Gaussian
Pulse duration FWHM
25 * 10-15 [s]
Polarisation
Linear Horizontal, Linear Vertical, Circular
Pulse repetition rate
3000 [Hz]
Maximum pulse energy
4.5 [mJ]
Peak power
1 * 1011 [W]
Beam diameter
8 [mm]
Endstations or Setup

XUV spectrometer

Diffractometer
theta scan available, 2theta only selected angles between 0 and 90 degrees
Spectrometer
Hitachi Aberration-Corrected Concave Gratings for Flat-Field Spectrographs
Grazing incidence typ
lambda range: 11- 62 nm
sample - spectrometer: 350 mm
spectrometer - detector: 469 mm

https://www.hitachi-hightech.com/products/images/9797/ana-grating_05.pdf
Base Pressure
1 * 10-8 [mbar]
Detectors Available
Endstation Operative
Yes

Sample

Sample Type
Crystal, Amorphous
Other Sample Type
for transmission on XUV transparent membrane, i.e. SiN etc.
Required Sample Size
X = 200 [um], Y = 200 [um]

Manipulator or Sample stage

Positioning Precision
X = 10 [nm], Y = 10 [nm], Z = 10 [nm]
Range Of Movement
X = 2.5 [mm], Y = 2.5 [mm], Z = 2.5 [mm]

Sample Environment

Pressure (min)
1 * 10-8 [mbar]
Pressure (Max)
1 * 10-6 [mbar]
Temperature
10 - 700 [K]

Magnetic Fields

AC Fields
electromagnet with < 100 ms switching time, out of plane, in plane
Max AC Field
3 * 10-1 [T]
DC Fields
permanent magntes
Max DC Field
5 * 10-1 [T]
Detectors

CCD Camera

Type
CCD cameras greateyes GE 1024 256 BI UV1
Description
Architecture: Full-frame, AIMO
Type: Back-illuminated, enhanced process
AR Coating: No coating
Pixel Format: 1024 × 256
Image Area: 26.6mm × 6.7mm
Pixel Size: 26µm × 26µm
Full-Well Capacity: 500.000e -
Max. Dynamic Range: 125.000:1
Dark Current: 0.0005 eˉ/pixel/sec at -80°C
Camera features:
Flange: Vacuum flange ISO-F DN63
Read Noise at 500kHz: min 2.4eˉ rms, typical 4eˉ rms
Pixel Frequency: 250kHz – 3.0Mhz
ADC Resolution: 16 bit
CCD Sensor Cooling: -70°C to 20°C, forced air, water cooling
Interface: USB 2.0
Power Supply: 110-240VAC, max. 1A
Dimensions: 61mm × 89mm × 136mm
Pixel Size
X = 26 [um], Y = 26 [um]
Array Size
X = 1024 [pixel], Y = 256 [pixel]
Thickness
-1 [um]
Passive or Active (Electronics)
Active
Output Readout Software
labview

Detection

Detected Particle
Electron
contacts
Clemens von Korff Schmising
Bastian Pfau
Techniques
Absorption
  • Time-resolved studies
  • XMCD
Diffraction
  • Time-resolved studies
Emission or Reflection
  • Polarimetry
  • Reflectrometry
  • Time-resolved studies
Imaging
  • X-ray holography
Scattering
  • Coherent scattering
  • Magnetic scattering
  • Time-resolved scattering
Disciplines
Material Sciences
  • Knowledge based multifunctional materials
  • Other - Material Sciences
control/Data analysis
Control Software Type
  • labview, spec
Data Output Type
  • dat
Data Output Format
  • h5, dat
Softwares For Data Analysis
  • matlab, phython