Sm²⁺ドープホウ酸塩ガラスの常温ホールバーニング(II)アルカリの影響

抄録

It is expected that persistent spectral hole burning (PHB) materials will be used as a high density memory disk in future. For the application of PHB materials to memory disk, both high operation temperature and high optical multiplicity (inhomogeneous linewidth/homogeneous linewidth) at high temperature are required. Recently, our research group has discovered persistent spectral hole burning in Sm²⁺-doped alkali borate glasses at room temperature. These materials have high optical multiplicity and chemical stability, and can be made easier than fluoride PHB glasses or single crystals. In this paper, the effect of alkali ions on the hole burning behavior is studied. The glasses were made by melting boron oxide, alkali carbonate, and samarium oxide at 1400°C for 30minutes in Ar(98)/H₂(2) atmosphere. Holes were burnt by 600mW/mm² DCM dye laser at the vicinity of 683nm, which is tuned to ⁵D₀-⁷F₀ transition, and detected by ⁵D₀←⁷F₀ excitation spectrum excited by 6mW/mm² DCM dye laser scanning and monitored at ⁵D₀→⁷F₂ emission. The width and depth of holes were measured as functions of alkali content and alkali ion size in alkali borate glasses. It was found that the hole width and depth increased with increasing the size and quantity of alkali ions. This alkali effect was discussed from the view point of glass structure.