Electron spin resonance (ESR) spectroscopy is based on the detection of resonance absorption of electromagnetic radiation corresponding to transitions between electron spin energy levels split by internal effects (e.g., crystal-ﬁeld anisotropy, exchange interactions etc.) and/or by an applied magnetic ﬁeld. The strength of such interactions in magnetic materials can vary from tens of millikelvin to hundreds of kelvin (which corresponds to a frequency range from tens of megahertz to tens of terahertz). That is why extending the frequency range of ESR techniques towards 1 THz (and beyond) appears to be one of the central issues in modern ESR spectroscopy.
Edinburgh Instruments have installed a FIRL100 CO2 far infrared (THz) laser system at Dresden High Magnetic Field Laboratory (HLD) at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The laser will be used for the multi-frequency pulsed-field (up to 70 T) ESR spectroscopy of strongly-correlated magnets, including low-dimensional and frustrated spin systems, high-Tc superconductors and related compounds, multiferroics etc.
Edinburgh Instruments hope that their FIRL-100 will help the Dresden High Magnetic Field Laboratory extend the frequency range of ESR techniques towards 1 THz.