HIGH OPTICAL TRANSPARENCY AND GOOD ADHESION OF DIAMOND FILMS DEPOSITED ON FUSED-SILICA WINDOWS WITH A SURFACE-WAVE SUSTAINED PLASMA

We utilized a microwave plasma reactor based on a surface-wave-sustain ed discharge for uniform coating of fused silica windows with polycrys talline diamond films. Grain size and average roughness as small as 30 and 2.2 nm, respectively, were obtained, resulting in a uniform loss of transparency of only 10% over the 190-800-nm band for as-deposited 1.5-mu m-thick coatings. A pretreatment procedure provides a film coat ing with a surface resistance to scratching that is approximately a fa ctor of 2 higher than that of bare fused silica. (C) 1997 Optical Soci ety of America.