Control of the radial gradient-index profile by leaching of a gel

A new method for controlling the shape and increasing the maximum index change in the radial gradient-index profile of sol-gel bodies is demonstrated. This is accomplished by modifying the relative rates of the intricate reactions responsible for forming the gradient. In practice the changes reported here are effected solely by varying the leaching conditions. Through the proper choice of a solution to arrest the leaching action, the index change can be maximized for a given shape to double that of the previous technique. A detailed composition analysis of the data reveals that dopant diffusion and precipitation are the dominant factors influencing the observed results.