High Resolution Molecular Spectroscopy in the THz Region Using Synchrotron Radiation

Our team exploits the synchrotron radiation extracted by the AILES beamline of SOLEIL synchrotron facility to study different molecular physics problematics in the far-IR and THz spectral ranges. The existing experimental configuration of the beamline, with a high-resolution Bruker interferometer, allows the rotationally resolved spectra of a large number of molecules to be obtained. These absorption spectra cover a broad spectral range (typically between 1 and 30 THz, i.e., 30 and 900 cm
^-1
) but are limited in terms of spectral resolution to 30 MHz (0.001 cm
^-1
) by the ultimate optical path difference provided by the interferometer. To push the resolution limit further, we are developing a new spectrometer allowing to record sub-MHz resolution absorption spectra using heterodyne mixing of the synchrotron radiation with a THz molecular laser.