• The Exeter time-resolved magnetism (EXTREMAG) facility is an EPSRC funded ultrafast laser facility that is being developed in a dedicated, newly refurbished laboratory in the Department of Physics and Astronomy at the University of Exeter.
  • The EXTREMAG facility is designed to explore ultrafast magnetic processes on timescales down to 10s of femtosecond.  The proposed capability of EXTREMAG will allow samples to be probed at low temperatures, in high magnetic fields, and on length scales down to 100s of nanometers.
  • The EXTREMAG facility will make Exeter’s ultrafast optical expertise available to the UK and international community via a short form proposal mechanism.

The Free Space Lab B2 for THz spectroscopy and imaging, and all-optical pump-probe Kerr measurements, with low temperature and high magnetic field capability.  Laser beams will enter B2 from the adjacent laser enclosure via the ports on the wall (left). 


  • Use of high frequency measurement techniques in magnetism research has increased enormously because the fundamental timescales for resonance and relaxation lie in the sub-nanosecond regime.
  • Time-resolved magneto-optical measurement techniques offer a unique blend of high temporal and spatial resolution within table-top experiments.
  • EXTREMAG will be a dedicated facility for the time-resolved measurement of magnetic and spintronic materials and devices.

The user space of Microscopy Lab B3. The wide field Kerr microscope will be installed on the front half of the table, while time-resolved scanning Kerr microscopy (and later a 5 T MicrostatMO) will be installed on the rear half of the table. The laser enclosure is located behind the white screen (rear).

Users and benefits of EXTREMAG

  • There are approximately 200 permanent academic researchers in UK universities and national laboratories working in the field of magnetism.
  • The EXTREMAG facility will be available to UK-based users initially, but will welcome international users as the facility develops.
  • Recent UK research highlights include the stabilization of novel magnetic textures such as droplets and skyrmions, manipulation of spin currents in antiferromagnets, and integration of magnetic materials with superconductors for exploitation of spin within quantum technologies.
  • EXTREMAG will benefit the UK magnetism community by providing improved understanding of nanoscale magnetism on ultrafast timescales.  This knowledge may then be exploited within information technology and non-volatile data storage for low-power computation, while advancing the understanding of permanent magnet materials will underpin the development of green energy technologies.

The optical table configuration of adjacent Labs B2 (left) and B3 (right). The laser enclosure is located at the far end of Lab B3 and will be the light source for the user space of both labs. Image courtesy of Peter Savage.  

Objectives of the EPSRC project

  • To procure a femtosecond laser system and measurement apparatus optimized for the study of magnetic and spintronic systems.
  • To appoint an experienced scientific officer to maintain the facility, configure the apparatus for different types of measurement, and support external users.
  • To install the equipment and demonstrate capability for magneto-optical pump-probe measurements, THz spectroscopy and microscopy, and time resolved Kerr microscopy, in a range of sample environments identified through consultation with external users.
  • To request and evaluate proposals for user experiments from the UK and beyond, allocate time at the facility according to scientific merit, and monitor their success
  • To promote the facility within the magnetism and spintronics community, publicise its achievements, and host a facility users meeting at the end of an initial 2 year period.