THz-Beamline

Coherent THz dipole radiation for THz spectroscopy & THz EPR

Science drivers for the THz beamline

Station data
Temperature range	1.6 - 300 K
Pressure range	For details contact the station scientist.
More details	THz spectroscopy & THz EPR
Beamline data
Segment	H11
Location (Pillar)	12.1
Source	Dipole D112 (2nd after slicing undulators)
Monochromator	FTIR-Spectrometer IFS125 HR (Bruker Optics) and VERTEX 70
Energy range	5 1/cm 10000 1/cm
Energy resolution	0.0063 1/cm
Flux	5 mW / mm^2
Polarisation	variable
Divergence horizontal	60 mrad
Divergence vertical	15 mrad
Focus size (hor. x vert.)	> 0.3 x 0.3 mm
User endstation	not possible
Distance Focus/last valve	900 mm
Height Focus/floor level	1200 mm
Beam availability	24h/d
Phone	+4930 8062 13170

Optical layout and schematic of the instrumental set-up at the THz beamline. THz radiation extracted from the storage ring may be readily directed towards three different detection schemes.

The THz beamline exploits intense coherent synchrotron radiation (CSR, [1-2]) as emitted from special storage ring modes, for the study of magneto optical phenomena in the energy range from 3 to 150 cm^-1. A dedicated THz electron paramagnetic resonance (THz-EPR) facility combines a broad range of excitation and detection schemes with extreme sample environments (in particular high magnetic fields and low temperatures). Research topics are related to manipulation and detection of high spin states in e.g., proteins, single molecule magnets, energy materials and materials relevant for future information technologies.

The THz beamline extracts CSR from the 2° dipole source (D112) after the slicing section at an acceptance of 60 mrad (h) x 15 mrad (v). A true optical transmission line transports CSR as emitted by ultra-short bunches in the low a mode (pulse length: < 10 ps, spectral range: 3-50 cm^-1)[1] and laser-induced by Femtoslicing [2] ( pulse length: ~ 200 fs, spectral range: 20-150 cm^-1), respectively. Complementary, FIR-UV-VIS cw radiation and 1 mJ of synchronized fs laser pulses (800 or 400 nm) are available at the experiment. Sample environments include a superconducting magnet (Oxford Spectromag, -11 T to +11 T) equipped with a variable temperature insert (1.5 K-200 K), and an optical cryostat (Oxford Optistat, T = 1.5 K- 300 K). THz detection is achieved either with a high resolution FTIR-spectrometer (Bruker IFS 125-HR, min. bandwidth: 0.0063 cm^-1) in combination with ultra-sensitive liquid helium cooled Si- or InSb – bolometers or fast Schottky diode THz detectors (ACST, time resolution 250 ps). Alternatively, transient THz signals may be directly detected via a time domain (TD) THz set-up. This dedicated TD THz scheme allows for a cross-correlation of THz pulses from the storage ring with the synchronized external fs-laser source (optical pump – THz probe).

References / Latest Publications

[1] M. Abo-Bakr, et al. Phys. Rev. Lett., 2003, 90, 094801.

[2] K. Holldack, et al. Phys. Rev. Lett., 2006, 96, 054801.

[3] A. Schnegg, et al. Phys. Chem. Chem. Phys., 2009, 11, 6820.

[4] K. S. Pedersen, et al. Chem. Commun., 2011, 47, 6918

[5] J. Dreiser, et al. Chem. Eur. J.,2011, 17, 7492.

[6] A. P. Forshaw, et al. Inorg. Chem., 2013, 52, 144.

[7] J. Dreiser, et al. Chem. Eur. J., 2013, 19, 3693.

[8] J. Nehrkorn, et al., Mol. Phys.,2013, 111 (18-19), 2696.

[9] N. E. Massa ,et al. J. Phys.: Condensed Matter, 2013, 25,235603.