Investigation on roughness of silver thin films inside silica capillaries for hollow waveguides

Using wet chemistry deposition, Ag thin films were successfully fabricated in silica capillaries, whose inner diameter was 0.53 mm. By means of atomic force microscopy (AFM), the metallisation process and roughness of the Ag thin films were analysed. It can be concluded that as the volume of AgNO3 solution increased, the silver deposition time increased, and the size of the Ag grains enlarged, resulting in an incremental increase in the surface roughness of the Ag thin films. IR transmission results show that the attenuation of the waveguides increases with an increase in the surface roughness of the Ag thin films and augments when the input power increases. 7 refs.