Abstract

The relationship between thermal conductivity and optical absorption has been investigated for over 60 samples of CVD diamond grown in 10 different laboratories. A simple and inexpensive apparatus is described to enable accurate and quick measurement of the optical absorption coefficient α averaged over the visible spectrum. The thermal conductivities κ_‖ and κ_⊥ (with heat flow either parallel or perpendicular to the plane of the sample) were measured by methods described previously -- steady state and laser flash, respectively. The observed correlation between κ_‖ or κ_⊥ and α can be used to obtain estimates of κ_‖ or κ_⊥ (within uncertainties of ~ ± 3 Wcm^-1 K^-1) from a measurement of the optical absorption.