Magneto-Optical Material for Downsized Optical Isolators
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Solution Overview
Problem
Current magneto-optical materials for optical isolators, such as terbium gallium garnet and terbium aluminium garnet, are unsuitable for fiber lasers due to their large size and high light absorption at wavelengths of 0.9 to 1.1 μm, necessitating a material with a high Verdet constant and high transmittance for downsizing these devices.
Innovation Solution
A magneto-optical material comprising terbium oxide with a high Verdet constant and high transmittance, specifically (TbxR1−x)2O3, where x is between 0.4 and 1.0, and R includes elements like scandium, yttrium, and lanthanum, offering a large Verdet constant of at least 0.18 min/(Oe·cm) and transmittance of at least 70% at 1.06 μm, suitable for use in a Faraday rotator and optical isolator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If terbium gallium garnet or terbium aluminium garnet single crystal is used as Faraday rotator material, then the material has high transmittance at laser wavelength, but the Verdet constant is insufficient requiring a long Faraday rotator length of 20 to 25 mm
Solution Approach 1:
The invention changes the material composition parameters by incorporating iron-containing yttrium iron garnet with specific terbium oxide content (40-100 wt%) to achieve a Verdet constant of 0.14 to 0.28 min/(Oe·cm) at 1.06 μm wavelength, thereby reducing the required Faraday rotator length while maintaining high transmittance
Solution Approach 2:
The invention uses a composite material system combining iron-containing yttrium iron garnet and terbium oxide, leveraging the high Verdet constant of YIG and the high transmittance of Tb2O3 to achieve both magnetic optical activity and light transmission in the same material
2Length of moving object
If iron-containing yttrium iron garnet single crystal is used to achieve large Faraday rotation angle per unit length, then the Verdet constant is high, but the material has large light absorption at wavelength of 0.9 μm affecting the wavelength range of 0.9 to 1.1 μm
Solution Approach 1:
The invention optimizes the terbium oxide content parameter within 40-100 wt% range to balance the Verdet constant and transmittance, achieving a Verdet constant of 0.14 to 0.28 min/(Oe·cm) while maintaining transmittance of 70% or more at 1.06 μm, thereby reducing absorption losses
Solution Approach 2:
The invention enhances the local magnetic optical properties by incorporating iron-containing yttrium iron garnet phases with specific crystal structures that provide high Faraday rotation, while the terbium oxide matrix maintains high transmittance in the target wavelength range
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed material enables a downsized optical isolator with improved performance, providing a high Verdet constant and transmittance, suitable for fiber lasers, addressing the limitations of existing materials by enhancing the Faraday rotation angle and reducing the size of optical isolators.
Implementation Method 1
The optical isolator functions based on its property that when light comes in the Faraday rotator thereof under the condition where a magnetic field is applied to the Faraday rotator in the direction parallel to the light running direction, then the plane of polarization rotates in the Faraday rotator, or that is, the Faraday effect.
Data Source
AI summary
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), TbxR1−x)2O3, 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 %.