Examination of Possibility of Formation of Aggregated Color Centers in Inorganic Glasses and Their Application to Photochemical Hole Burning

聚集的F中心，如M中心和R中心，在碱卤化物晶体中表现为光化学烧孔(PHB)。如果在无机玻璃中产生聚集的缺氧型点缺陷，我们可以预期在无机玻璃中实现PHB的可能性不伴随着作为PHB中心的染料分子的掺杂。在本研究中，我们用可调谐的激光研究了无机玻璃中聚集色心的形成及其光学吸收带上的空洞的形成。结果总结如下：(1)在强还原气氛中熔融的铝酸钙玻璃表现出光致变色。光致变色中心是被Ca~(2+)~(2+)和Gt~(2+)离子包围的氧空位上的电子，即CaO中的f~(++)中心。在4.2K下，当激光照射中心位于560 nm附近的吸收带时，没有观察到光谱空穴的形成。(2)在SiO_2玻璃中，通过注入Si~(++)或O~(2+)、Si-Si键和中性氧空位产生了两种类型的氧缺陷。它们的浓度与注入离子的浓度是相容的，这表明注入离子与衬底结构中的氧发生化学反应，留下氧缺陷。没有观察到这两种缺陷的零声子线。

Aggregated F-centers such as M and R-centers show photochemical hole burning (PHB) in alkali halide crystals. If aggregated oxygen-deficient type point defects are produced in inorganic glasses, we may expect a possibility that PHB is realized in inorganic glasses without accompanying doping of a dye molecule as a PHB center. In this study, we examined the formation of aggregated color centers in inorganic glasses and of a pertinent hole in their optical absorption bands with a tunable laser light.The results obtained are summarized as follows :(1) Calcium aluminate glasses melted in strongly reduced atmosphere were found to show photochromism. Light-induced EPR led the conclusion that the photochromic center is an electron trapped at the site of oxygen vacancy surrouned by Ca^<2+> ions, i. e., likeF^+ center in CaO. No spectral hole formation was observed when the laser light illuminated the absorption band centered around 560 nm at 4.2K.(2) Two types of oxygen-deficient defects were produced in SiO_2 glass by implantation of Si^+orP^+, Si-Si bonds and neutral oxygen vacancies. Their concentrations are compatible to those of implanted ions, suggesting that implanted ions react chemically with oxygen in the substrate structure leaving oxygen deficiency defects. No zoro-phonon line was observed for either of these defects.