| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that the improvement of the device performance is limited because an available conventional lithium tantalate single crystal has a congruent composition including several percentage of disproportionation defect although the lithium tantalate single crystal is expected as a material for an optical element because the single crystal having excellent optical characteristics, a large caliber and high composition homogeneity can be supplied at a comparatively inexpensive price. SOLUTION: This lithium tantalate single crystal grown from a molten liquid having a composition containing excess Li compared to the fixed ratio composition, and having >=0.490 and <0.500 molar fraction of Li2O/(Ta2O5+Li2O) is characterized by 0.1-3 mol% one or more kinds of elements selected from Mg, Zn, Sc and In included therein based on the lithium tantalate single crystal. The optical element and the method of production are also provided.</p> |
