GROWTH OF TI:YALO(3) FOR TUNABLE SOLID-STATE LASER APPLICATIONS

THE DISCOVERY OF THE TI:AL(2)O(3) TUNABLE SOLID-STATE LASER IN 1982 HAS SPARKED A LOT OF INTEREST IN SOLID-STATE LASER HOSTS FOR TITANIUM. AMONG THE VARIOUS LASER HOSTS, YALO(3) HOLDS THE MOST PROMISE BECAUSE IT IS A HIGH CRYSTAL FIELD MATERIAL. TI:YALO(3) CRYSTALS HAVE BEEN GROWN BY THE CZOCHRALSKI AND GRADIENT FREEZE TECHNIQUES. SPECTROSCOPIC MEASUREMENTS ON SAMPLES HAVE SHOWN AN EMISSION RANGE FROM 500 TO 800 NM AND A LIFETIME OF APPROXIMATELY 10 MICROSEC. THIS DATA SUGGESTS THAT TIYALO(3) WILL BE AN ATTRACTIVE LASER. THE TI:YALO(3) CRYSTALS HAVE NOT BEEN LASED SO FAR AND THIS PERFORMANCE IS ATTRIBUTED TO THE POOR OPTICAL QUALITY OF THE CRYSTALS. THE PRESENT PROPOSAL IS TO SHOW FEASIBILITY OF TI:YALO(3) CRYSTAL GROWTH USING THE HEAT EXCHANGER METHOD (HEM[TM]). THE MAIN PROBLEMS ANTICIPATED IN THE GROWTH OF TI:YALO(3) BY HEM ARE (A) PROBLEMS WITH PHASE TRANSITION; (B) MINIMIZATION OF SCATTERING CENTERS IN THE CRYSTAL; AND (C) MAINTAINING TITANIUM IN THE TRIVALENT STATE. THE LATTER TWO PROBLEMS WERE ALSO ENCOUNTERED IN THE ADAPTATION OF HEM FOR TI:AL(2)O(3) CRYSTALS. SINGLE CRYSTAL SAMPLES GROWN DURING THE PROPOSED PROGRAM WILL BE CHARACTERIZED FOR SPECTROSCOPIC DATA AND LASER PROPERTIES. AT THE END OF THE PROPOSED PROGRAM, IT IS EXPECTED THAT FEASIBILITY OF GROWTH OF TI:YALO(3) FOR LASER APPLICATIONS WILL BE ESTABLISHED.