Sol‐Gel Synthesis of High‐Quality Heavy‐Metal Fluoride Glasses

Fluoride glasses are excellent laser hosts and are very well suited for a broad spectrum of optical applications. However, current fluoride glass synthesis is expensive. The solgel method is an affordable alternative for producing highperformance, optical‐quality heavy‐metal fluoride glasses. The method involves forming a hydrous oxide gel of the constituent metal alkoxides and salts, polymerizing the solution to form a gel, fluorinating the gel with anhydrous HF, melting the amorphous material in an oxidizing atmosphere of SF₆, and casting the melt into desired shapes. ZBLA (57ZrF₄·36BaF₂·4LaF₃·3AlF₃, in mol%) and Nd‐doped (0.3 mol%) ZBLA glass rods were prepared by this process and their properties were measured. The solgel‐based glasses had thermal and optical properties similar to those found in the literature for conventionally prepared fluorides.