Magnetooptical material, manufacturing method therefor, and magnetooptical device

Patent metadata

Field	Value
Publication number	US-2016201222-A1
Application number	US-201414917149-A
Country	US
Kind code	A1
Filing date	Sep 11, 2014
Priority date	Sep 12, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

This invention provides a transparent magnetooptical material that is suitable for use in a magnetooptical device such as an optical isolator. Said magnetooptical material comprises either a transparent ceramic consisting primarily of a complex oxide that can be represented by formula (1) or a single crystal of such a complex oxide. Said magnetooptical material does not absorb fiber-laser light in the 0.9-1.1 μm wavelength range, does not cause heat lensing, and has a higher Verdet constant than TGG crystals, with a Verdet constant of at least 0.14 min/(Oe·cm) at a wavelength of 1,064 nm.
Tb 2 R 2 O 7   (1)

(In formula (1), R represents one or more elements selected from among the group consisting of silicon, germanium, titanium, tantalum, tin, hafnium, and zirconium (but not silicon only, germanium only, or tantalum only).)

First claim

1 . A magneto-optical material characterized by comprising a transparent ceramic containing as a main component a complex oxide of formula (1) below, or comprising a single crystal of a complex oxide of formula (1) below
Tb 2 R 2 O 7   (1)
(wherein R is at least one element selected from the group consisting of silicon, germanium, titanium, tantalum, tin, hafnium and zirconium (but not silicon alone, germanium alone or tantalum alone)), and having a Verdet constant at a wavelength of 1064 nm that is at least 0.14 min/(Oe·cm).

2 . The magneto-optical material of claim 1 which is characterized in that when laser light having a wavelength of 1064 nm is input thereto at a beam diameter of 1.6 mm, for an optical path length of 10 mm, the maximum input power of laser light which does not generate a thermal lens is 30 W or more.

3 . The magneto-optical material of claim 1 which, for an optical path length of 10 mm, has an in-line transmittance of light at a wavelength of 1064 nm that is at least 90%.

4 . The magneto-optical material of claim 1 which has a main phase comprising a cubic structure having a pyrochlore lattice.

5 . The magneto-optical material of claim 1 , wherein the transparent ceramic has an average sintered particle diameter of not more than 2.5 μm.

6 . A method of manufacturing a magneto-optical material, comprising the steps of: firing terbium oxide powder and at least one oxide powder selected from the group consisting of silicon oxide, germanium oxide, titanium oxide, tantalum oxide, tin oxide, hafnium oxide and zirconium oxide (but not silicon oxide alone, germanium oxide alone or tantalum oxide alone) in a crucible to produce a fired starting material containing, as a main component, a cubic pyrochlore-type oxide; grinding the fired starting material to form a starting powder; pressing the starting powder to a predetermined shape and then sintering the pressed powder; and subsequently hot isostatic pressing so as to obtain a transparent ceramic sintered body containing as a main component a complex oxide of formula (1) below
Tb 2 R 2 O 7   (1)
(wherein R is at least one element selected from the group consisting of silicon, germanium, titanium, tantalum, tin, hafnium and zirconium (but not silicon alone, germanium alone or tantalum alone)).

7 . The magneto-optical material manufacturing method of claim 6 which is characterized in that the firing temperature is at least 1200° C. and lower than the temperature in subsequent sintering.

8 . A magneto-optical device which is constructed using the magneto-optical material of claim 1 .

9 . The magneto-optical device of claim 8 which is an optical isolator that comprises the magneto-optical material as a Faraday rotator and a polarizing material at front and back sides of the Faraday rotator on an optical axis thereof, and that can be used in a wavelength range of at least 0.9 μm and 1.1 μm or less.

10 . The magneto-optical device of claim 9 , wherein the Faraday rotator has an antireflective coating on an optical face thereof.

11 . The magneto-optical material of claim 2 which, for an optical path length of 10 mm, has an in-line transmittance of light at a wavelength of 1064 nm that is at least 90%.

12 . The magneto-optical material of claim 2 which has a main phase comprising a cubic structure having a pyrochlore lattice.

13 . The magneto-optical material of claim 3 which has a main phase comprising a cubic structure having a pyrochlore lattice.

14 . The magneto-optical material of claim 2 , wherein the transparent ceramic has an average sintered particle diameter of not more than 2.5 μm.

15 . The magneto-optical material of claim 3 , wherein the transparent ceramic has an average sintered particle diameter of not more than 2.5 μm.

16 . The magneto-optical material of claim 4 , wherein the transparent ceramic has an average sintered particle diameter of not more than 2.5 μm.

17 . A magneto-optical device which is constructed using the magneto-optical material of claim 2 .

18 . A magneto-optical device which is constructed using the magneto-optical material of claim 3 .

19 . A magneto-optical device which is constructed using the magneto-optical material of claim 4 .

20 . A magneto-optical device which is constructed using the magneto-optical material of claim 5 .

Assignees

• Shinetsu Chemical Co

Inventors

• Ikari Masanori

Classifications

• C04B35/462

  based on titanates · CPC title

• C04B35/01

  based on oxide ceramics · CPC title

• G02F1/093

  used as non-reciprocal devices, e.g. optical isolators, circulators (G02F1/0955 takes precedence) · CPC title

• G02F1/0036

  Magneto-optical materials · CPC title

• C04B35/457

  based on tin oxides or stannates · CPC title