JP2017007920A - Glass material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material showing a higher Faraday effect in a low wavelength range compared to the conventional art.SOLUTION: A glass material comprises Tb, where a Verdet constant absolute value Vat wavelength 400 nm, a Verdet constant absolute value Vat wavelength 800 nm, and a Verdet constant absolute value Vat wavelength 1100 nm satisfy the following relational expression: V/(V-V)≤0.21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a glass material suitable for a magneto-optical element constituting a magnetic device such as an optical isolator, an optical circulator, and a magnetic sensor.

  It is known that a material having magnetism exhibits a Faraday effect which is one of magneto-optical effects. The Faraday effect is an effect of rotating the polarization plane of linearly polarized light passing through a material placed in a magnetic field. Such effects are used in optical isolators, magnetic field sensors, and the like.

  The optical rotation (rotation angle of the polarization plane) θ by the Faraday effect is expressed by the following equation, where H is the strength of the magnetic field and L is the length of the substance through which the polarized light passes. In the formula, V is a constant depending on the type of substance, and is called Verde's constant. The Verde constant is a positive value for a diamagnetic material and a negative value for a paramagnetic material. The greater the absolute value of the Verde constant, the greater the absolute value of the optical rotation, resulting in a large Faraday effect.

    θ = VHL

SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —Tb ₂ O ₃ glass material (see Patent Document 1), P ₂ O ₅ —B ₂ O ₃ as a glass material exhibiting a Faraday effect in a wavelength region of 1100 nm or less. -tb ₂ O ₃ based glass material (see Patent Document 2), or _P (the R alkaline earth metal) _{2 O} 5 -TbF ₃ -RF 2 are known, such as glass material (see Patent Document 3).

Japanese Patent Publication No.51-46524 Japanese Patent Publication No. 52-32881 Japanese Patent Publication No.55-42942

  In recent years, the wavelength range in which optical isolators and magnetic field sensors are used is diversified, and use in a low wavelength range (especially at a wavelength of 800 nm or less) is being studied. Although the glass materials described above exhibit a certain Faraday effect even in the low wavelength region, in recent years, since the miniaturization of magnetic devices has been progressing further, the Faraday effect can be further improved so that even a small member can exhibit sufficient optical rotation. It is requested.

  In view of the above, an object of the present invention is to provide a material that exhibits a Faraday effect greater than that of the conventional one in a low wavelength region.

  As a result of intensive studies by the inventor, the inventors have paid attention to Verde constants at a plurality of wavelengths and found that the above problems can be solved when they have a specific relationship, and have proposed the present invention.

That is, the glass material of the present invention is a glass material containing Tb, absolute value _{V 400} of the Verdet constant in the wavelength 400 nm, the absolute value _{V 800} of Verdet constant at wavelengths 800nm and, the absolute of the Verdet constant in the wavelength 1100nm The value V ₁₁₀₀ satisfies the following relational expression.
_{V 800 / (V 400 -V 1100} ) ≦ 0.21

In general, the magnetic material containing Tb tends to increase the absolute value of the Verde constant from the high wavelength side to the low wavelength side. Here, V ₈₀₀ / (V ₄₀₀ −V ₁₁₀₀ ) is an index for comparing the increase rate of the absolute value of the Verde constant at a wavelength of ₁₁₀₀ nm to 800 nm and the increase rate of the Verde constant at a wavelength of 800 nm to 400 nm. As the value is smaller, the increase rate of the absolute value of the Verde constant at a wavelength of 800 nm to 400 nm is large, and as a result, the absolute value of the Verde constant in a low wavelength region (800 nm or less, particularly 600 nm or less) tends to increase. That is, in the glass material of the present invention, when the absolute value of the Verde constant at each wavelength satisfies the above relational expression, the wavelength dependency of the Verde constant increases, and a large Faraday effect is easily exhibited in a low wavelength region.

Glass material of the present invention _preferably satisfies the V _{400 -V 1100} ≧ 1.3. According to this configuration, since the value of V ₈₀₀ / (V ₄₀₀ −V ₁₁₀₀ ) can be reduced, the wavelength dependency of the Verde constant is increased, and a large Faraday effect is easily exhibited in a low wavelength region.

The glass material of the present invention preferably has V ₄₀₀ ≧ 1.45.

The glass material of the present invention preferably contains 30% or more of Tb ₂ O ₃ in mol%.

Glass material of the present invention, in _{mol%, Tb 2 O 3 30~80%} , SiO 2 0~70%, B 2 O 3 0~70%, preferably contains _Al 2 O 3 _0~70% .

  The glass material of the present invention is preferably used as a magneto-optical element.

  The glass material of the present invention is preferably used as a Faraday rotation element.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the material which shows the Faraday effect larger than before in a low wavelength region.

It is typical sectional drawing which shows one Embodiment of the apparatus for manufacturing the glass material of this invention. It is a graph which shows the relationship between the absolute value of the Verde constant of the glass material of Example 1 and a comparative example, and a wavelength.

Glass material of the present invention is a glass material containing Tb, absolute value _{V 400} of the Verdet constant in the wavelength 400 nm, the absolute value _{V 800} of Verdet constant at wavelengths 800nm and, the absolute value V of the Verdet constant in the wavelength 1100nm ₁₁₀₀ satisfies the following relational expression.
_{V 800 / (V 400 -V 1100} ) ≦ 0.21

When the absolute value of the Verde constant at each wavelength satisfies the above relational expression, the wavelength dependence of the Verde constant increases, and a large Faraday effect is easily exhibited in a low wavelength region. _{Incidentally, V 800 / (V 400 -V} 1100) is preferably 0.2 or less.

Here, V ₄₀₀ -V ₁₁₀₀ is preferably 1.3 or more, 1.35 or more, 1.4 or more, particularly 1.5 or more. When V ₄₀₀ -V ₁₁₀₀ satisfies this range, the value of V ₈₀₀ / (V ₄₀₀ -V ₁₁₀₀ ) can be reduced, so that the wavelength dependency of the Verde constant increases, and the Faraday effect is large in a low wavelength region. It becomes easy to show.

The glass material of the present invention exhibits a large Faraday effect in a low wavelength region when the absolute value of the Verde constant at each wavelength satisfies the above relationship. Specifically, the glass material of the present invention _{V 400} 1.45 or more, 1.5 or more, and particularly preferably 1.6 or more. Further, the glass material of the present invention has an absolute value V ₆₀₀ of Verde constant at a wavelength of 600 nm of 0.55 or more, 0.57 or more, particularly 0.6 or more, and an absolute value V ₈₀₀ of a Verde constant at a wavelength of 800 nm of 0.29 or more. , More preferably 0.3 or more.

The glass material of the present invention contains Tb. Tb is a component that increases the Faraday effect by increasing the absolute value of the Verde constant. Specifically, the glass material of the present invention preferably contains 30% or more, particularly 35% or more of Tb ₂ O ₃ in mol%. However, if the content is too large, vitrification tends to be difficult. Accordingly, the content of Tb ₂ O ₃ is preferably 80% or less, 75% or less, 70% or less, particularly 65% or less in terms of mol%.

  In addition, although the content of trivalent oxide is prescribed | regulated about Tb, about the oxide other than trivalent, it is preferable that content when converted into a trivalent oxide is in the said range. .

The magnetic moment that causes the Verde constant for Tb is greater for Tb ³⁺ than for Tb ⁴⁺ . Therefore, the larger the ratio of Tb ^{3+ in} the glass material, the greater the Faraday effect, which is preferable. Specifically, the ratio of Tb ^{3+ in} the total Tb is preferably 50% or more, 60% or more, 70% or more, 80% or more, and particularly 90% or more in mol%.

Next, the preferable composition of the glass material of this invention is demonstrated. Glass material of the present invention, in _{mol%, Tb 2 O 3 30~80%} , SiO 2 0~70%, B 2 O 3 0~70%, preferably contains _Al 2 O 3 _0~70% . The reason for limiting the composition range in this way will be described below. In the following description of the content of each component, “%” means “mol%” unless otherwise specified.

Since the content of Tb ₂ O ₃ are as described above, and their explanation is omitted here.

SiO ₂ becomes a glass skeleton and is a component that widens the vitrification range. However, since it does not contribute to the improvement of the Verde constant, if the content is too large, it becomes difficult to obtain a sufficient Faraday effect. Therefore, the content of SiO ₂ is preferably 0 to 70%, particularly preferably 0 to 65%.

B ₂ O ₃ becomes a glass skeleton and is a component that widens the vitrification range. However, since B ₂ O ₃ does not contribute to the improvement of the Verde constant, if the content is too large, it becomes difficult to obtain a sufficient Faraday effect. Therefore, the content of B ₂ O ₃ is preferably 0 to 70%, particularly preferably 0 to 65%.

Al ₂ O ₃ is a component that enhances glass forming ability. However, since Al ₂ O ₃ does not contribute to the improvement of the Verde constant, if the content is too large, it becomes difficult to obtain a sufficient Faraday effect. Therefore, the content of Al ₂ O ₃ is preferably 0 to 70%, particularly preferably 0 to 65%.

  In addition to the above components, the glass material of the present invention may contain the following components.

La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ have the effect of stabilizing vitrification. However, when there is too much the content, it will become difficult to vitrify on the contrary. Therefore, the contents of La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and Yb ₂ O ₃ are each preferably 10% or less, particularly preferably 5% or less.

Dy ₂ O ₃ , Eu ₂ O ₃ and Ce ₂ O ₃ stabilize vitrification and contribute to the improvement of the Verde constant. However, when there is too much the content, it will become difficult to vitrify on the contrary. Therefore, the contents of Dy ₂ O ₃ , Eu ₂ O ₃ and Ce ₂ O ₃ are each preferably 15% or less, particularly preferably 10% or less. In addition, about Dy, Eu, and Ce, the content of the trivalent oxide is specified, but for oxides other than trivalent (for example, CeO ₂ etc.), the content when converted to the trivalent oxide The amount is preferably within the above range.

  MgO, CaO, SrO, and BaO have effects of stabilizing vitrification and improving chemical durability. However, since it does not contribute to the improvement of the Verde constant, if the content is too large, it becomes difficult to obtain a sufficient Faraday effect. Therefore, the content of these components is preferably 0 to 10%, particularly 0 to 5%.

GeO ₂ is a component that enhances glass forming ability. However, since GeO ₂ does not contribute to the improvement of the Verde constant, it is difficult to obtain a sufficient Faraday effect if its content is too large. Therefore, the content of GeO ₂ is preferably 0 to 15%, 0 to 10%, particularly preferably 0 to 9%.

P ₂ O ₅ is a component that enhances glass forming ability. However, if the content is too large, devitrification tends to occur, and chemical durability tends to decrease. Further, since no contribution to the improvement of the P ₂ O ₅ is the Verdet constant, when the content is too large, a sufficient Faraday effect difficult to obtain. Therefore, the content of P ₂ O ₅ is preferably 0 to 7%, particularly preferably 0 to 5%.

Ga ₂ O ₃ has the effect of increasing the glass forming ability and expanding the vitrification range. However, when there is too much the content, it will become easy to devitrify. Further, since the Ga ₂ O ₃ it does not contribute to the improvement of the Verdet constant, when the content is too large, a sufficient Faraday effect difficult to obtain. Therefore, the Ga ₂ O ₃ content is preferably 0 to 6%, particularly preferably 0 to 5%.

Fluorine has the effect of increasing the glass forming ability and expanding the vitrification range. However, if its content is too large, it may volatilize during melting and cause composition fluctuations, or it may adversely affect vitrification. Therefore, the content of fluorine _{(F 2} equivalent) 0-10%, 0-7%, particularly preferably 0 to 5%.

Sb ₂ O ₃ can be added as a reducing agent. However, the content is preferably 0.1% or less in order to avoid coloring or in consideration of environmental load.

  The glass material of the present invention preferably has a light transmission loss as small as possible particularly when used as a magneto-optical element such as an isolator. For example, the light transmittance of the glass material of the present invention is preferably 50% or more, 60%, particularly 70% or more at a wavelength of 633 nm.

  The glass material of the present invention can be produced, for example, by a containerless floating method. FIG. 1 is a schematic cross-sectional view showing an example of a manufacturing apparatus for producing a glass material by a containerless floating method. Hereinafter, the manufacturing method of the glass material of this invention is demonstrated, referring FIG.

  The glass material manufacturing apparatus 1 has a mold 10. The mold 10 also serves as a melting container. The molding die 10 has a molding surface 10a and a plurality of gas ejection holes 10b opened in the molding surface 10a. The gas ejection hole 10b is connected to a gas supply mechanism 11 such as a gas cylinder. Gas is supplied from the gas supply mechanism 11 to the molding surface 10a via the gas ejection hole 10b. The type of gas is not particularly limited, and may be, for example, air or oxygen, or a reducing gas containing nitrogen gas, argon gas, helium gas, carbon monoxide gas, carbon dioxide gas, or hydrogen. Good.

  When manufacturing a glass material using the manufacturing apparatus 1, first, the glass raw material lump 12 is arrange | positioned on the molding surface 10a. As the glass raw material block 12, for example, a raw material powder integrated by press molding or the like, a sintered body obtained by integrating raw material powder by press molding or the like, and a composition equivalent to the target glass composition are used. For example, an aggregate of crystals.

  Next, the glass raw material block 12 is floated on the molding surface 10a by ejecting gas from the gas ejection holes 10b. That is, the glass raw material block 12 is held in a state where it is not in contact with the molding surface 10a. In this state, the glass material block 12 is irradiated with laser light from the laser light irradiation device 13. Thereby, the glass raw material lump 12 is heated and melted to be vitrified to obtain molten glass. Thereafter, the glass material can be obtained by cooling the molten glass. In the step of heating and melting the glass raw material lump 12 and the step of cooling until the temperature of the molten glass and further the glass material is at least the softening point or less, at least gas ejection is continued, and the glass raw material lump 12, molten glass, Furthermore, it is preferable to suppress contact between the glass material and the molding surface 10a. In addition to the method of irradiating with laser light, the method of heating and melting may be radiant heating.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

  Table 1 shows examples and comparative examples of the present invention.

  Each sample was produced as follows. First, a raw material prepared so as to have a glass composition shown in the table was press-molded, and sintered at 1100 to 1400 ° C. for 12 hours to produce a glass raw material lump.

Next, the glass raw material lump was coarsely pulverized in a mortar to obtain small pieces of 0.05 to 0.5 g. A glass material (diameter: about 1 to 8 mm) was produced by a containerless floating method using an apparatus according to FIG. 1 using small pieces of the obtained glass raw material lump. A 100 W CO ₂ laser oscillator was used as the heat source. Moreover, nitrogen gas was used as gas for suspending a glass raw material lump, and it supplied with the flow volume of 1-30 L / min.

  About the obtained glass material, the Verde constant was measured using the rotation analyzer method. Specifically, the obtained glass material was polished so as to have a thickness of about 1 mm, the Faraday rotation angle at a wavelength of 400 to 1100 nm was measured in a magnetic field of 15 kOe, and the Verde constant was calculated. The wavelength sweep rate was 6 nm / min. The results are shown in Table 1 and FIG.

As is clear from Table 1, in the glass materials of Examples 1 to 3, V ₈₀₀ / (V ₄₀₀ -V ₁₁₀₀ ) is 0.186 to 0.190, and V ₄₀₀ -V ₁₁₀₀ is 1.764 to 2.401. _{Yes, V 400} is as large as 1.930 to 2.632. On the other hand, the glass material of the comparative _{example, V 800 / (V 400 -V} 1100) 0.223, V 400 -V 1100 is _{1.256, V 400} was as small as 1.401. As is clear from FIG. 2, the glass material of Example 1 has a larger wavelength dependency of the absolute value of the Verde constant than the glass material of the comparative example, and the absolute value of the Verde constant in the low wavelength region is large. You can see that

  The glass material of the present invention is suitable as a magneto-optical element constituting a magnetic device such as an optical isolator, an optical circulator, or a magnetic sensor.

1: Glass material manufacturing apparatus 10: Mold 10a: Molding surface 10b: Gas ejection hole 11: Gas supply mechanism 12: Glass raw material block 13: Laser beam irradiation apparatus

Claims (7)

A glass material containing Tb,
Absolute value _{V 400} of the Verdet constant in the wavelength 400 nm, the absolute value _{V 800} of Verdet constant at wavelengths 800nm and, the absolute value _{V 1100} of the Verdet constant in the wavelength 1100 nm, a glass material characterized by satisfying the relationship:.
_{V 800 / (V 400 -V 1100} ) ≦ 0.21 The glass material according to claim 1, wherein V ₄₀₀ −V ₁₁₀₀ ≧ 1.3 is satisfied. The glass material according to claim 1, wherein V ₄₀₀ ≧ 1.45. The glass material according to claim 1, wherein the glass material contains 30% or more of Tb ₂ O ₃ in mol%. In _{mole%, Tb 2 O 3 30~80%} , SiO 2 0~70%, B 2 O 3 0~70%, claims 1 to 4, characterized in that it contains _Al 2 O 3 _0~70% The glass material as described in any one of these.   The glass material according to claim 1, wherein the glass material is used as a magneto-optical element.   The glass material according to claim 6, wherein the glass material is used as a Faraday rotation element.