We present a comprehensive optical study of the narrow gap FeSb<Subscript>2</Subscript> semiconductor. From the optical reflectivity, measured from the far infrared up to the ultraviolet spectral range, we extract the complete absorption spectrum, represented by the real part σ<Subscript>1</Subscript>(ω) of the complex optical...</subscript></subscript>

Optical experiments are reported for the metallic state of the linear chain compound (TMTSF)<Subscript>2</Subscript>ClO<Subscript>4</Subscript>. For the electric field polarized both along the highly (a) and intermediately (b′) conducting directions, a zero energy (ZE) mode and a finite energy mode (FE) are observed. The large anisotropy...</subscript></subscript>