SEDL / STP / STP1028-EB / STP18571S

Admixture of SiO² to Suppress TiO² Crystallization

Sites, JR
Colorado State University, Fort Collins, CO

Postek, JS
Colorado State University, Fort Collins, CO

Robinson, RS
Colorado State University, Fort Collins, CO

Schemmel, TD
Colorado State University, Fort Collins, CO

She, CY
Colorado State University, Fort Collins, CO

Pages: 4    Published: Jan 1988

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Abstract

Crystallization of glassy TiO² films used in optical coatings can be a problem in high power applications and may be a major limitation to the laser damage threshold. An attempt to suppress such crystallization involved mixing small amounts of SiO² into TiO² during the ion-beam sputter deposition process. An admixture of 5% SiO² increased the crystallization onset temperature, determined by Raman spectroscopy, by approximately 150°C. The refractive index was relatively unaffected by the addition of 5% SiO², dropping from 2.42 to 2.38. Optical loss, which shows a sharp increase near 350°C for pure TiO², did not increase measurably for the films with SiO² admixture of 5% or greater.