Controlled Energetic Deposition of Tertiary Compounds for Graded Index of Refraction Coatings

Our innovation is a sputter-deposition process to create optical coatings with a well-controlled, selectable index of refraction. The fixed index of refraction in available materials severely constrains the design of coatings. Optical filters use two materials of different indices of refraction in multi-layer, multi-interface coatings. In Phase I, we will demonstrate processes for sputter-depositing a tertiary compound (metal-Ox-Fy). We will show that by controlling the stoichiometry of the compound in this deposition process, we can (1) select and fine-tune the index of refraction in coating, and (2) create a continuous, controlled variation in the index of refraction through the coating thickness. A tuned index of refraction is useful for anti-reflection coatings for laser diodes. For sensor applications, the ability to control the index with thickness enables totally flexible design of filters without undesirable side-bands or transmission losses caused by the interfaces in multiple layers. The sputter-deposition process will generate a uniform, high-quality film across the substrate even at large surface area. We will quantify the characteristics of these coatings, such as the reflective and transmissive properties, which will be useful from the UV through the IR range.| Benefits: A selectable index or refraction coating enables the use of laser diodes as amplifiers for advanced lasers. For sensor applications, a graded index gives an optical filter with excellent characteristics, superior durability, and lower scatter. Multi-function coatings may be deposited by this approach due to the absence of side-bands. This process has commercial applications for laser optics, satellite sensors, CRT screens, lenses, energy-saving glazings for windows, and advanced electro-optic devices.