THz Electron Paramagnetic Resonance / THz Spectroscopy at BESSY II

Abstract

The THz beamline at BESSY II employs high power broadband femto- to picosecond long THz pulses for magneto-optical THz and FIR studies. A newly designed set-up exploits the unique properties of ultrashort THz pulses generated by laser-energy modulation of electron bunches in the storage ring or alternatively from compressed electron bunches. Experiments from 0.15 to 5 THz (~ 5 – 150 cm-1) may be conducted at a user station equipped with a fully evacuated high resolution FTIR spectrometer (0.0063 cm-1), lHe cooled bolometer detectors, a THz TDS set-up and different sample environments, including a superconducting high field magnet (+11 T - 11T) with variable temperature insert (1.5 K – 300 K), a sample cryostat and a THz attenuated total reflection chamber.  Main applications are Frequency Domain Fourier transform THz-Electron Paramagnetic Resonance (FD-FT THz-EPR), THz-FTIR spectroscopy and optical pump - THz probe time domain spectroscopy (TDS), with sub-ps time resolution.