Magneto-optical material, Faraday rotator, and optical isolator

Patent metadata

Field	Value
Publication number	US-9482888-B2
Application number	US-201113877603-A
Country	US
Kind code	B2
Filing date	Oct 5, 2011
Priority date	Oct 6, 2010
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

It is an object of the present invention to provide a magneto-optical material containing as a main component an oxide that includes a terbium oxide and having a large Verdet constant at a wavelength in the 1.06 μm region (0.9 to 1.1 μm) and high transparency, and to provide a small-sized optical isolator suitably used in a fiber laser for a processing machine. The magneto-optical material of the present invention contains an oxide represented by Formula (I), Tb x R 1−x ) 2 O 3 , where x satisfies 0.4≦×≦1.0 and R includes at least one element selected from the group consisting of scandium, yttrium, and lanthanoid elements other than terbium, at a content of at least 99 wt %.

First claim

What is claimed is:

1. A magneto-optical material comprising an oxide represented by Formula (I) below at a content of at least 99 wt %,
(Tb x R 1−x ) 2 O 3   (I)

wherein in Formula (I), x satisfies 0.4<×<0.8 and R comprises at least one element selected from the group consisting of scandium, yttrium, and lanthanoid elements other than terbium, and
wherein the magneto-optical material further comprises an additional oxide or compound including an oxide of an alkaline earth metal, a Group 11 element, a Group 12 element, an oxide of a Group 13 element, an oxide of a Group 14 element, a Group 15 element, a Group 16 element, oxides of a Group 4 element, a Group 5 element, a Group 6 element, or a compound of a Group 17 element, wherein a content of the additional oxide or compound is at least 0.00001 wt % but no greater than 1.0 wt %.

2. The magneto-optical material according to claim 1 , wherein in Formula (I), R is selected from the group consisting of scandium, yttrium, lanthanum, europium, gadolinium, ytterbium, holmium, and lutetium.

3. The magneto-optical material according to claim 1 , wherein it comprises an oxide of an alkaline earth metal at a content of at least 0.00001 wt % but no greater than 1.0 wt %.

4. The magneto-optical material according to claim 3 , wherein the magneto-optical material comprises an oxide of an alkaline earth metal at a content of at least 0.0001 wt % but no greater than 0.01 wt %.

5. The magneto-optical material according to claim 1 , wherein it is a single crystal.

6. The magneto-optical material according to claim 5 , wherein the single crystal is produced by a production method selected from the group consisting of a floating zone melting method, a micro-pulling-down method, a pulling up method, a skull melting method, the Bridgman method, the Bernoulli method, and the EFG method.

7. The magneto-optical material according to claim 1 , wherein it is a ceramic.

8. A Faraday rotator for a wavelength of at least 0.40 μm but no greater than 1.2 82 m employing the magneto-optical material according to claim 1 .

9. An optical isolator comprising the Faraday rotator according to claim 8 and a polarizing material placed in front of and to the rear of the Faraday rotator.

10. The magneto-optical material according to claim 1 , wherein the magneto-optical material has a Verdet constant at a wavelength of 1.06 μm of at least 0.18 min/(Oe·cm), a transmittance for an optical path length of 3 mm at a wavelength of 1.06 μm of at least 70%, and an extinction ratio at an optical path length of 3 mm of at least 25 dB.

11. The magneto-optical material according to claim 1 , wherein in Formula (I), R is selected from the group consisting of yttrium, gadolinium and lutetium.

12. The magneto-optical material according to claim 1 , wherein in Formula (I), R is yttrium.

13. The magneto-optical material according to claim 1 , wherein in Formula (I), x satisfies 0.45 <×<0.75.

14. The magneto-optical material according to claim 1 , wherein the magneto-optical material comprises an oxide of Group 13 element, Group 14 element, Group 4 element, Group 6 element, or a compound of a Group 17 element at a content of at least 0.00001 wt % but no greater than 1.0 wt %.

Assignees

• Makikawa Shinji
• Watanabe Toshiaki
• Yamanaka Akio
• Naruse Hirotaka
• Shinetsu Chemical Co

Inventors

• Makikawa Shinji
• Watanabe Toshiaki
• Yamanaka Akio
• Naruse Hirotaka

Classifications

• C01F17/32

  oxide or hydroxide being the only anion, e.g. NaCeO2 or MgxCayEuO · CPC title

• G02F1/0036

  Magneto-optical materials · CPC title

• C30B13/24

  using electromagnetic waves · CPC title

• G02F1/0955 Primary

  used as non-reciprocal devices, e.g. optical isolators, circulators · CPC title

• H01S3/0064

  Anti-reflection devices, e.g. optical isolaters (absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955) · CPC title