Optical properties of Sr14-xCaxCu24O41 and Sr0.73CuO2

The optical reflectivity as a function of temperature of the title compound s has been measured over a broad spectral range from 4 meV up to 12 eV. On the one hand, our findings suggest a very anisotropic dynamics of the charg e excitation spectrum when measuring along or perpendicular to the ladders in Sr14-xCaxCu24O41. On the other hand, the investigation of Sr0.73CuO2 all ows us to study the electrodynamics of hole doped CuO2 chains alone without complications arising from the presence of Cu2O3 ladders in Sr14-xCaxCu24O 41. (C) 1999 Published by Elsevier Science B.V. All rights reserved.