Development of F-doped Core-free YAG Single Crystal as UV Optical Device

2008.07.28

National Institute for Materials Science

Dr. Kiyoshi Shimamurac, Group Leader, and Dr. Garcia Villora, Senior Researcher, of the Frequency Conversion Group, Optronic Materials Center, National Institute for Materials Science, in joint work with Dr. Yasuhiko Kuwano, Group Leader, of the New Materials Research Department, Dai-Ichi Dentsu Ltd., developed a fluorine-doped core-free Y3Al5O12 single crystal as an optical device with a high refractive index in the vacuum ultraviolet region.

Abstract

  1. Dr. Kiyoshi Shimamurac, Group Leader, and Dr. Garcia Villora, Senior Researcher, of the Frequency Conversion Group, Optronic Materials Center, National Institute for Materials Science (President: Prof. Teruo Kishi), in joint work with Dr. Yasuhiko Kuwano, Group Leader, of the New Materials Research Department, Dai-Ichi Dentsu Ltd. (President and Representative Director: Masazumi Shiroi), developed a fluorine-doped core-free Y3Al5O12 single crystal as an optical device with a high refractive index in the vacuum ultraviolet region.
  2. The single crystal developed in this work is a yttrium aluminum garnet (Y3Al5O12: YAG) in which the core was eliminated by optimization of the crystal growth conditions. The crystal was also doped with fluorine (F). Elimination of the core will make it possible to produce optical devices such as lenses with an uniform distribution of the refractive index, while doping with F enables improved transmittance. This crystal displays a large refractive index of 2.1 at 193nm.
  3. In the ultraviolet/vacuum ultraviolet (UV/VUV) region, few choices are available as materials for optical devices, centering on lenses. In particular, the number is limited when restricted to cubic crystal systems. Therefore, new materials which can be used in the UV/VUV region have been considered necessary in semiconductor-related equipment such as next-generation lithography for industrial applications, and in optical-related equipment such as microscopes and cameras. As distinctive features of the newly-developed F-doped core-free YAG, this is a novel cubic crystal optical material for the UV/VUV region, and thus is expected to expand the range of alternatives available in material selection for UV/VUV.
  4. The results of this research are scheduled to be announced at various international conferences, beginning with the Spring Meeting of the Japan Society of Applied Physics to be held in March 2009, and at the Annual Meeting of the Ceramic Society of Japan, also in March.
"FigureFig. 1 F-doped core-free YAG single crystal." Image

FigureFig. 1 F-doped core-free YAG single crystal.