Sumitomo Metal Mining Company, Ltd.

Shuuji Oosumi

Nobuo Nakamura

Tomio Kajigaya

Hiroshi Hatanaka

Yasutaka Nomi

A bismuth-substituted rare-earth iron garnet crystal film (RIG) which has an insertion loss of less than 0.60 dB and which can be produced in a high yield, as well as an optical isolator, which is grown by liquid phase epitaxy on a non-magnetic garnet substrate represented by a chemical formula of Gd(ScGa)O, wherein the bismuth-substituted rare-earth iron garnet crystal film is represented by a chemical formula of LaGdBiFeO(provided that 0&#x3c;x&#x3c;3 and 0&#x3c;y&#x3c;3), and a composition ratio between the La, Gd, and Bi falls within a numeric value range corresponding to the inside of a quadrilateral having composition points A, B, C, and D as vertices in a La&#x2014;Gd&#x2014;Bi ternary composition diagram: composition point A (La: 0.15, Gd: 1.66, Bi: 1.19), composition point B (La: 0.32, Gd: 1.88, Bi: 0.80), composition point C (La: 0.52, Gd: 1.68, Bi: 0.80), and composition point D (La: 0.35, Gd: 1.46, Bi: 1.19).

Bismuth-substituted rare-earth iron garnet crystal film and optical isolator

A bismuth-substituted rare-earth iron garnet crystal film (RIG) which has an insertion loss of less than 0.6 dB and which can be produced in a high yield, as well as an optical isolator, which is grown by liquid phase epitaxy on a non-magnetic garnet substrate represented by a chemical formula of Gd(ScGa)O, wherein the RIG is represented by a chemical formula of NdGdBiFeO, and x and y satisfy 0.89&#x2266;x&#x2266;1.43 and 0.85&#x2266;y&#x2266;1.19. In contrast to conventional RIGs, the RIG represented by the chemical formula of NdGdBiFeOof the present invention has an insertion loss of less than 0.6 dB and makes it possible to reduce the amount of heat generated because of absorption of light at wavelengths of about 1 &#x3bc;m. Hence, the RIG has such a remarkable effect that the RIG can be used as a Faraday rotator used for an optical isolator in a high-power laser device for processing.

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Tokyo, Japan

Shuuji Oosumi