Sur les propriétés optiques du tellure dans le spectre visible

Abstract

Spectral dispersion curves of reflectances in air and in oil are given for the synthetic tellurium. From 420 to 800 nm, the reflectance in air varies from 70 % to 62 % (extraordinary ray Re), and from 60 % to 53 % (R₀). A large difference between values of R₀ measured on two different faces (10.0) and (00.1) allowed to suppose either a modifiation of the surface state or an effect of the rotatory power (?). The calculation of the optical constants, from reflectance values against two immersion media, leads to very unreliable values. Vickers microhardness numbers, measured on the face (00. 1) for 5 and 25 g loads, are respectively 68 and 117. The very big deformation of indentations made on the face (10.0) shows that this face is much more fragile than the basal face.