| 摘要 |
PURPOSE:To allow the easy control of an optical refractive index characteristic and the erasing of a hologram while the hologram is irradiated with a laser beam by adding at least specific two kinds of elements to a material contg. an alkaline earth metal. CONSTITUTION:At least two kinds of the elements 1, 2 selected from the group consisting of rare earth elements, bismuth elements, tin elements and lead elements, are added to the base body material contg. the alkaline earth metal. The additive element 1 is provided with the role of a donor and the additive element 2 with the role of a trap and, therefore, the donor concn. and the trap concn. can be respectively independently controlled if the additive elements 1, 2 are added by respectively independently controlling the addition concns. thereof. The wavelength sensitivity regions of the additive element 1 and the additive element 2 vary and, therefore, the interference does not arise between writing light and erasing light. The material which allows the easy control of the optical refractive index characteristic and can erase the hologram even when kept irradiated with the laser beam is obtd. in such a manner. |
