Complex refractive indices in the TeraHertz domain of samples from atmospheric aerosol sources

oral session Spectroscopy/Gas phase spectroscopy 1International audienceWe report the TeraHertz (THz) characterization of calcium carbonate (CaCO3) particles, one of the major components of desert dust, to determine the real and imaginary parts of their complex refractive indices. The optical characterization is done by TeraHertz Time Domain Spectroscopy (THz-TDS) technique. CaCO3 powders are diluted with High Density PolyEthylene (PE) at different concentrations (0.1% to 75% of CaCO3) and compressed in pellets. Time-traces are then fitted using the Fit@TDS algorithm developed by Photonic TeraHertz group members, and the complex refractive indices are extracted. We support the optical characterization by a morphological characterization by Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX) analysis after resuspension of particles and filtration on a polycarbonate 0.2 µm pore filter