GROWTH OF FLUORIDE LASER CRYSTALS WITH ELECTROCHEMICAL MONITORING AND CONTROL OF COMPOSITION AND PURITY

VARIETY OF SOLID STATE LASERS BASED ON LUMINESCENT TRANSITION METAL OR RARE EARTH IONS IN FLUORIDE HOSTS SHOW GREAT PROMISE FOR HIGH EFFICIENCY BROAD TUNABILITY. THE PURITY OF THE CRYSTALS, WITH RESPECT TO OXIDE/HYDROXIDE,FOREIGN METAL IONS AND VALENCE STATE ON THE LUMINESCING IONS, IS CRITICAL TO PERFORMANCE AND REPRODUCIBILITY. THE COMPOSITION OF THE MELT PRIOR TO AND DURING CRYSTAL GROWTH CAN BE MONITORED AND CONTROLLED USING IN SITU ELECTROCHEMICAL PROBES. IT IS PROPOSED FOR PHASE I TO DEMONSTRATE THE APPLICATION OF HIGH TEMPERATURE MOLTEN SALT ELECTROCHEMICAL METHODS TO PURITY CONTROL IN ONE LASER MATERIAL, SRA1F5:CR+3. VOLTAMMETRY WILL BE EMPLOYED AS AN ELECTRO-ANALYTICAL METHOD FOR QUANTITATING WATER (AND HYDROLYSIS PRODUCTS) IN THE MELT, AS WELL AS THE PRESENCE OR EVOLUTION OF UNDESIRABLE CR+2. STEADY STATE ELECTROLYSIS METHODS WILL BE EMPLOYED FOR REMOVING OXIDES AND HYDROXIDES, OXIDIZING CR+2 TO CR+3, AND INTRODUCING CR+3 DIRECTLY FROM A HIGH PURITY CR METAL SOURCE.