LITHIUM TRIOBORATE SINGLE CRYSTAL

• Main Authors: NUMATA TOSHIO, SATO MASAZUMI, SUTEIIBUN EI MAAKUGURAFU
• Format: Patent
• Language: English
• Published: 16.05.1995
• Edition: 6
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMISTRY; CRYSTAL GROWTH; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DEVICES USING STIMULATED EMISSION; ELECTRICITY; FREQUENCY-CHANGING; METALLURGY; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

PURPOSE:To provide the single crystal of specified fluorine content, thus prevented from moisture resistance decline under high temperature and high humidity circumstances, and contributing to improving the characteristics of SHG devices such as stability and increased output and to expanding its wide applications to laser devices other than the SHG devices. CONSTITUTION:Lithium triborate (LBO) and B are melted in a platinum crucible and then super-quenched and heat treated to effect crystallization of LBO phase, and the resultant LBO glass-ceramic is hung with a platinum wire and dipped into another batch of the melt to form LBO crystals which are then sorted to obtain crack- free seed crystal. A platinum crucible is then heated to 900 deg.C in an oven and drawn from the oven and then charged with Li2CO3 and B2O3 of a composition close to the peritectic composition (20mol% of Li3O/80mol% of B2O3) followed by addition of lithium fluoride as flux, and the resultant mixture is heated to produce a melt. The seed crystal is homogenized by accelerated crystal rotation method in a nitrogen gas atmosphere and a melt is produced, and it is cooled at a rate of ca.0.3 deg.C /day during crystal growth, and the resultant crystal is pulled from the melt and then cooled to room temperature in 3 to 4 days, thus obtaining the objective single crystal <=500ppm in fluorine content.