download report - Sapienza

Scientific Report 2007-2009
Laboratories and Facilities of the Department of Physics
L5. Infrared Spectroscopy Lab
The Infrared Spectroscopy (IRS) laboratory is working in the
Sapienza Dept. of Physics since the end of the 1960’s, when the
first Fourier-transform Michelson interferometers appeared on the
market. It was established by late Professor Salvatore Cunsolo,
who had collaborated with Professor H. P. Gush to the development
of one of such devices, during a sabbatical year at the
University of British Columbia (Canada). That instrument after
became the prototype of a performant series of interferometers
produced by Bomem, a spin-off of British Columbia.
Today, the IRS laboratory (permanent staff P. Calvani, S.
Lupi, P. Maselli and A. Nucara) is focused on the spectroscopy
of solids characterized by strong electron-electron correlation
and/or electron-phonon interaction. Among them, there are
novel superconductors like the high-T c cuprates , the FeAs compounds,
and metallic diamond. Also the colossal-resistance manganites,
the vanadium oxides, the charge-ordered systems and the
multiferroics have been widely investigated in the last years in a
Figure 1: The Bruker 66V interferometer equipped with
a liquid helium cryostat and with an infrared microscope.
wide range of temperature and pressures. In those systems infrared spectroscopy, with its high spectral resolution and low
perturbation, allows one to identify the low-energy excitations which are relevant to the electrodynamics of the solid, and
to its phase transitions. Finally, an increasing activity is in progress in the domain of biophyisics. Immobilized enzymes
(Lipase) on nanostructured polymers are being studied by Infrared spectroscopy, to understand the enhancement of their
activity in such conditions. Another investigation concerns the study of proteins presnt in food, to find imprints of their
different bio-availability by the human metabolism is related to easily identifiable spectral features.
The IRS Lab also routinely performs tests on infrared windows, filters, sources and detectors, as well as simulations and
calculations, aimed at the development of new infrared sources, especially those synchrotron-based and the Fee-Electron
Lasers (FEL). Presently the IRS group, in addition to the laboratory at the Dept. of Physics in Rome, manages an
experimental station on the infrared beamline SISSI at ELETTRA (Trieste) and another one on the beamline SINBAD
at DAFNE (Frascati). Moreover, the group collaborates to the exploitation of Terahertz coherent radiation from the FEL
SPARC (Frascati). In this context, new activities started recently at the IRS Lab, concerning the applications of the
metamaterials and of nanostructured materials - like Quantum Wells - to THz spectroscopy.
The IRS laboratory in Rome is instead devoted to spectroscopy
with conventional black-body sources. Therein, we can perform
virtually any kind of infrared/visible spectrum (transmittance,
reflectance, diffuse reflectance, Attenuated Total Reflectance, Infrared
Microspectroscopy) from the sub-Terahertz range to the
Ultraviolet. To this aim, one can use two Michelson interferometers
(a Bomem DA3 and a Bruker 66 V, shown in Fig. 1) coupled
to nitrogen- and helium-cooled detectors, or a monochromator
coupled to a CCD camera. These instruments are equipped
with cryogenics for taking spectra down to 10 K, and with an
optical oven which can heat the samples up to 550 K. The laboratory
is also equipped with diamond anvil cells for collecting
infrared spectra up to 20 GPa (200 Kbar) and with the necessary
high-pressure technology. Finally, a small chemical laboratory
is present for the treatment of solid samples and powders. It includes
a system for polishing and washing the crystals, an oven, a
diamond-wire saw for cutting the crystals, microscopes and other
minor instrumentation.
Figure 2: The remotely controlled set-up for highprecision
reflectance measurements on small single crystals,
mounted in the sample chamber of the Bomem DA3
interferometer.
http://www.phys.uniroma1.it/gr/irs/
Related research activities: C6, C46.
Sapienza Università di Roma 179 Dipartimento di Fisica