| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a single crystal which is capable of making stable and high optical wavelength conversion up to the UV region and has excellent hygroscopicity by forming a rhombic crystal which is a borate single crystal and belongs to a specific space group. SOLUTION: The chemical composition of the borate single crystal is expressed by formula (A: two kinds of elements selected from a group consisting of Li, Na, K, Rb and Cs, 1.5<x<2.5) and the single crystal which is the rhombic crystal belonging to the space group P212121 is chemically and mechanically stable, has a nonlinear optical effect, electro-optic effect and acousto-optic effect and has a nonlinear optical constant larger than LB4. Intrinsically, the single crystal is ought to assume the composition of x=2 but the deficiency and substitution of alkaline ions are liable to occur. The single crystal has a borate ring structure having such characteristics at a fairly wide range (1.5<x<2.5). When the UV light is generated by the crystal, the single crystal exhibits excellent optical characteristics and since a UV laser is capable of generating the UV light repetitively at a high speed, laser beam processing may be efficiently carried out.</p> |
