| 摘要 |
PURPOSE:To obtain a crystal having a high efficiency so as not to generate a core in a grown crystal by respectively specifying x, y, z of single crystal having a garnet structure represented by a chemical composition formula of Gd3-xErxGa5-y-zAlyCrzO12 so that they are in specific composition ranges. CONSTITUTION:In a chemical formula in such part of Ga of GGG crystal is substituted for aluminum, i.e., represented by Gd3-xErxGa5-y-zCrzO12, its optical absorption loss is small in case of 2.5>=y>=0.05, and a single crystal of high quality in actual size and having the generation of a new coloring center due to an exciting light being extremely small can be obtained. In this case, the lower limit of the y value is determined to be minimum content in which validity of coloring is recognized, and the upper limit is determined to be maximum content in which preferable crystallinity is maintained. The Er of active element is required to have x>=0.03 to actually produce an output, and also to have x<=2 to obtain a preferable cryatal. Accordingly, the effective composition range of the Er is 0.03<=x<=2. The Cr of sensitizer cannot recognize its validity in case of z<=0.001, and the output of laser is reduced in case of z>=0.01. |
