Charge dynamics in low-dimensional quantum

We compare our optical data collected for two families of low-dimensional correlated electron systems: the ladders and the organic Bechgaard salts. Our data display a remarkable optical anisotropy between the spectra along the three crystallographic axes, indicative of the lowdimensionality in the electronic band structure. Moreover, we optically identify a dimensionality crossover, induced by Ca doping in the ladders and by chemical pressure in the Bechgaard salts. An outlook on the ongoing research on carbon and MoS2 nanotubes, as novel one-dimensional quantum wires, is also addressed.