JPH06122531A - Fluoride laser glass containing eu or tb as deactivating agent for emission of ho 2.9mum light - Google Patents

Abstract

PURPOSE:To provide a laser glass containing Ho<3+> to emit light of 2.9mum wavelength, utilizable for bloodless operation, enabling repeated radiation of beam and having high light intensity. CONSTITUTION:The fluoride laser glass contains Ho<3+> as an emission center and emits light of 2.9mum wavelength. It contains <=0.5cat% of Eu<3+> or Tb<3+> as a deactivating agent for the <5>I7 level of Ho<3+>. An example of the laser glass is a fluoride laser glass containing 8-19cat% of Yb<3+> and 1-10cat% of Ho<3+>. The laser glass emits laser light of 2.9mum wavelength by the irradiation of a semiconductor laser beam of 0.97mum wavelength.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to Eu ³⁺ or T as a quenching agent for the ⁵ I ₇ level of Ho ³⁺ in a 2.9 μm emitting fluoride laser glass containing Ho ³⁺ as an emission center.
It relates to a laser glass containing b ³⁺ . Furthermore, the present invention provides Eu ³⁺ or T as a quencher of the ⁵ I ₇ level of Ho ^3+.
The present invention relates to a Ho fluoride laser glass which contains b ³⁺ and emits a 2.9 μm laser containing Yb ions as a sensitizer.

[0002]

2. Description of the Related Art Conventionally, a wavelength of 2.7 μm using a glass having an Er ion (Er ³⁺ ) as an emission center by excitation by a laser diode (LD) having a wavelength of about 0.98 μm. Lasers are known. This Er ³⁺ laser is used as a laser knife for bleeding-free surgery.

On the other hand, Ho ³⁺ is theoretically ⁵ I ₆ to ⁵
When transitioning to I ₇ , it emits a 2.9 μm (2.84 μm) laser beam (see FIG. 1). The wavelength of 2.9 μm of this Ho ³⁺ laser is the absorption wavelength (2.89 μm) of the OH group of water.
Since it is almost the same as μm), the Ho ³⁺ laser may also be used for hemorrhage-free surgery (laser scalpel). Therefore, if Ho ³⁺ 2.9 μm light emission of practical intensity can be obtained, application of a laser knife can be expected.

However, the fluorescence lifetime of ⁵ I ₇ of Ho ³⁺ is ⁵ I
_Since it is longer than that of ₆ , it has not been possible to obtain a 2.9 μm Ho ³⁺ laser beam having a sufficient emission intensity up to now. On the other hand, the present inventors previously found that Ho fluoride laser glass that emits a 2.9 μm laser containing Yb ions as a sensitizer has a high emission intensity and filed a patent application (Patent application 4-148
522).

However, the Ho fluoride laser glass described above cannot be highly repeated because the Ho ^{3+ 5} I ₇ fluorescence lifetime is as long as about 30 ms. Further, in the Ho fluoride laser glass, as a result of light emission, the density of the lower level of ⁵ I ₇ of Ho ³⁺ may be gradually increased and oscillation may be stopped.

Therefore, an object of the present invention is to provide a laser glass having a large emission intensity at a wavelength of 2.9 μm due to Ho ³⁺ , which can prevent automatic stop and can repeatedly oscillate.

[0007]

SUMMARY OF THE INVENTION The present invention is a 2.9 μm emitting fluoride laser glass containing Ho ³⁺ as an emission center, which is used as an activator of Ho ^{3+ at} the ⁵ I ₇ level of 0.1.
The present invention relates to a fluoride laser glass containing 5 cat% or less of Eu ³⁺ or Tb ³⁺ .

The present invention further provides Yb ³⁺ at 8 to 19 cat.
%, Ho ^{3+ of 1} to 10 cat%, and Eu ³⁺ or Tb ³⁺
Is contained in an amount of 0.5 cat% or less. In the present specification, ca
t% means cation% (cationic%).

[0009] The fluorescence lifetime of the ⁵ I ₇ of Ho ³⁺ is, of Ho ^{3+ 5}
It was considered that the length can be shortened by coexisting a quenching agent having an energy level substantially the same as that of I ₇ .
However, a quenching agent for shortening the fluorescence lifetime of Ho ^{3+ 5} I ₇ has not been known so far. Therefore, based on the energy level table of each atom, Nd, Eu, Tb, etc. are defined as atoms having an energy level substantially the same as ⁵ I _{7 of} Ho ³⁺ .
Select 5 atoms of Sm and Pr, and set the ion of each atom to H
The emission intensity from ⁵ I ₆ to ⁵ I ₇ of fluorescence lifetime and Ho ³⁺ of ⁵ I ₇ of Ho ³⁺ when allowed to coexist in o ³⁺ were measured. As a result, as shown in FIG. 2 and FIG. 3, inactivation which can reduce the density of ⁵ I ₇ while maintaining the emission intensity of Ho ³⁺ from ⁵ I ₆ to ⁵ I ₇ of 2.9 μm to some extent. It has been found that Eu ³⁺ and Tb ³⁺ are the most suitable agents.

Further, as shown in FIG. 2 and FIG. 3, Eu ³⁺ and Tb ³⁺ as the quenching agent increase the content of Ho ^{3+ 5} I ₇ as much as the content in the fluoride laser glass increases. Although the fluorescence lifetime is shortened, the emission intensity of 2.9 μm is also reduced at the same time. Therefore, from the viewpoint of having a practical level of emission intensity and shortening the fluorescence lifetime of ⁵ I ₇ of Ho ³⁺ , the upper limit of the content of Eu ³⁺ and Tb ^{3+ in} the fluoride laser glass is set. , 0.5 cat% respectively is suitable. On the other hand, the lower limit of the content of the fluoride laser glass of Eu ³⁺ and Tb ^3+, the fluorescence lifetime of ⁵ I ₇ of Ho ³⁺ is, it shorter than the fluorescence lifetime of ⁵ I ₆ of Ho ³⁺ values And it is sufficient. From such a viewpoint, the lower limit of the content of Eu ³⁺ and Tb ^{3+ in} the fluoride laser glass can be set to 0.05 cat%, for example. Both Eu ³⁺ and Tb ³⁺ can coexist in the fluoride laser glass of the present invention. In that case, the content of Eu ³⁺ and Tb ³⁺ is such that the sum of both is within the above range of 0.05 ca.
It is suitable to be t% to 0.5 cat%.

In the present invention, in particular, a fluoride laser glass containing 8 to 19 cat% of Yb ³⁺ and 1 to 10 cat% of Ho ³⁺ as a sensitizer, which has a high emission intensity of 2.9 μm. , A quenching agent and Eu ³⁺ or Tb ³⁺ .
An example is a fluoride laser glass containing 5 cat% or less.

The emission mechanism of the fluoride glass containing Yb ³⁺ and Ho ³⁺ will be described below. In Figure 1, Yb ³⁺
And the energy level diagram of Ho ³⁺ are shown. The emission of 2.9 μm is caused by the transition of Ho ³⁺ from ⁵ I ₆ to ⁵ I ₇ . L
When irradiated with 0.97 μm of D, Yb ³⁺ becomes ground state ² F
The energy of Yb ³⁺ excited from _7/2 to ² F _5/2 (about 10 ⁴ cm ⁻¹ ) is ⁵ I ₆ (8600c of Ho ³⁺ ).
m ^-1 ). Ho ³⁺ ions of ⁵ I ₆ which received the energy of 0.98 μm of Yb ³⁺ are ⁵
It is considered to emit light of 2.9 μm when moving to I ₇ .

The Ho ion acts as a luminescence center, but if the amount is less than 1 cat%, sufficient luminescence intensity cannot be obtained, and if it exceeds 10 cat%, the luminescence intensity tends to decrease. Therefore, it is suitable to set Ho ³⁺ to 1 to 10 cat%. On the other hand, Yb ions have a function of sensitizing 2.9 μm emission due to Ho ions. The amount is 8
If it is less than cat%, a sufficient sensitizing effect tends not to be obtained, while if it exceeds 19 cat%, the sensitizing effect tends to decrease. Therefore, it is suitable to set Yb ³⁺ in the range of 8 to 19 cat%.

The laser glass of the present invention comprises Yb ions,
In addition to Ho ions and Eu or Tb ions, for example, as cations constituting glass, Zr ions, Hf ions, Al ions, Mg ions, Ca ions, Sr ions, Ba ions are included, and each of the cations is included. The proportion of ions is expressed in mol%, the total amount of Zr ions and Hf ions is 1 to 25%, the amount of Al ions is 20 to 45%, the total amount of Ma ions, Ca ions, Sr ions and Ba ions is 20%.
The fluoride glass may be ˜70% and contain at least F ions as anions constituting the glass, and the ratio of F ions in the anions is 80 to 100% in terms of mol%.

Yb ion, Ho ion, and Eu or T
As cations other than b ions, Zr ions, Hf ions, Al ions, Mg ions, Ca ions, Sra ions, and Ba ions can be used. Among these, Zr ions, Hf ions, and Al ions are components that form the glass skeleton, and the amounts thereof are preferable because the stability against crystallization of glass is increased within the above limits.
Further, Mg ion, Ca ion, Sr ion, and Ba ion are glass modifying components, and their amounts are preferable because the stability against crystallization of glass is improved and the chemical durability is improved within the above-mentioned limits.

Further, alkali metal ions such as Li ion, Na ion, K ion and Cs ion, Y ion, S
c ion, Gd ion, Zn ion, Pb ion, Cd
Ions, In ions, Ga ions and the like also increase the stability of the glass against crystallization and can be used as the cation component of the glass. Alkali metal ions reduce the chemical durability of the glass if the amount is large, so 20 mol% or less is preferable, and the amount of Y ions, Sc ions, Gd ions, Zn ions, Pb ions, and Cd ions is large. On the contrary, since the stability against crystallization of glass is deteriorated, 20 mol% or less is preferable, and Sc ion, In ion, and Ga ion are also preferably 5 mol% or less.

Next, the anion will be described. F ions are the basic component of glass. Further, Cl ions, Br ions, and I ions can be contained by substituting with F ions. The amount is 20% for Cl ions, Br
If the content of each of the ions and I ions exceeds 10%, the glass is likely to crystallize and the chemical durability is deteriorated.
Cl ion is limited to 0 to 20 mol%, Br ion is limited to 0 to 10 mol%, and I ion is limited to 0 to 10 mol%. If the amount of F ions is less than 80%, it becomes difficult to obtain a glass having high stability against crystallization.
The total amount of r ions and I ions is limited to 20 mol% or less.

The laser glass of the present invention comprises HoF ₃ , YbF ₃ and EuF ₃ mixed and prepared to have a predetermined composition.
Alternatively, it can be obtained by heating and melting a glass raw material containing TbF ₃ or the like by a conventional method, and then cooling.

The laser glass of the present invention is 0.97 μm
It is possible to generate a laser beam of 2.9 μm by irradiating the semiconductor laser.

[0020]

EXAMPLES The present invention will be described in more detail below with reference to examples. Example 1 ZrF ₄ 11.8 mol% and AlF ₃ 2 as starting materials
3.1 mol%, MgF ₂ 3.4 mol%, CaF ₂ 14.
2 mol%, SrF ₂ 12.6 mol%, BaF ₂ 11.7
Mol%, NaCl 2.8 mol%, NaF 2.4 mol%,
HoF ₃ 2 mol% and YbF ₃ 16 mol% were used, and further EuF ₃ was used in a composition of 0.1 mol%, 0.2 mol%, 0.5 mol%, 1.0 mol% and 2.0 mol%. The raw materials were weighed and mixed so as to obtain a batch.

Then, the obtained batch is put in a crucible made of carbon and placed in a heating furnace, and while the argon gas is being supplied into the furnace, the above batch is heated and melted at 950 ° C. for 45 minutes under this atmosphere. Then, a glass melt was obtained. After this, the obtained glass melt was cooled to 20 Tg at 398 ° C.
It was held for minutes, cooled to 50 ° C. below Tg at a cooling rate of 10 ° C./min, and naturally cooled to obtain a fluoroalumino zirconate glass (AZF) of the present invention.

The Ho ^{3+ 5} I ₇ fluorescence lifetime and emission intensity of each of the obtained AZFs were measured and shown in FIGS. 2 and 3, respectively (◯ in the figure). 2 and 3, the fluorescence lifetime of Ho ^{3+ 5} I ₇ becomes shorter as the amount of Eu ions increases.
At the same time, the emission intensity also decreases. Therefore, from the viewpoint of having a practical level of emission intensity and shortening the fluorescence lifetime of ⁵ I ₇ of Ho ³⁺ , the upper limit of the content of Eu ^{3+ in} the fluoride laser glass is 0.5 cat. It is appropriate to set it as%.

Example 2 In the AZF glass composition of Example 1, AZF glass was prepared in which the amount of TbF ₃ was changed instead of EuF ₃ , and H
The fluorescence lifetime and emission intensity of ⁵ I ₇ of o ³⁺ were measured and shown in FIGS. 2 and 3 (Δ in the figure). 2 and 3, the fluorescence lifetime of Ho ^{3+ 5} I ₇ becomes shorter as the amount of Tb ions increases, but at the same time, the emission intensity also decreases. Therefore, it has a practical level of light emission intensity and has a Ho ³⁺ of ⁵
From the viewpoint that the fluorescence lifetime of I ₇ can be shortened, the upper limit of the content of Tb ^{3+ in} the fluoride laser glass is 0.5 ca.
It is suitable to be t%.

Comparative Examples 1 to 3 In the AZF glass composition of Example 1, NdF ₃ , SmF ₃ and PrF ₃ were used in place of EuF ₃ to prepare AZF glasses in which the amounts thereof were changed to prepare Ho ³⁺ . ⁵ I ₇
Was measured for fluorescence lifetime and emission intensity, and are shown in FIGS. 2 and 3, respectively. From FIGS. 2 and 3, when Sm ³⁺ (● in the figure) and Pr ³⁺ (■ in the figure) are used, ⁵ I of Ho ³⁺ is obtained.
The fluorescence lifetime of ₇ becomes shorter as the amount of each ion increases,
However, the emission intensity is extremely reduced. Also, Nd ³⁺
In the case of using ( ³ ) in the figure, the fluorescence lifetime of Ho ³⁺ of ⁵ I ₇ is less shortened as the amount of Nd ³⁺ increases.

[0025]

According to the present invention, the glass containing fluorine as an anion in laser glasses containing Ho ions as cations, Eu ³⁺ or as deactivator ⁵ I ₇ level position of Ho ³⁺ By containing Tb ³⁺ , it is possible to obtain a laser glass that emits light with a wavelength of 2.9 μm that can be repeatedly irradiated. Further, according to one aspect of the invention, Y
A laser glass containing b ions and Ho ions at the same time, which can be repeatedly irradiated and can oscillate a laser beam having a large emission intensity and a wavelength of 2.9 μm can be obtained. Therefore, since the laser glass of the present invention can be repeatedly irradiated, it can be preferably used as a laser light source for hemorrhagic surgery.

[Brief description of drawings]

FIG. 1 is an energy level diagram of a quenching agent, Yb ³⁺ and Ho ²⁺ .

FIG. 2 Eu (○), Tb (△), Nd (□), Sm
(●) and Pr (■) ion concentrations and Ho ^{3+ 5} I ₇
The relationship with the fluorescence lifetime of is shown.

FIG. 3 Eu (◯), Tb (△), Nd (□), Sm
The relationship between each ion concentration of (●) and Pr (■) and the emission intensity is shown.

Claims (3)

[Claims] 1. A 2.9 containing Ho ³⁺ as an emission center.
μm Fluoride Fluoride Laser Glass with Ho ³⁺ of ⁵
A fluoride laser glass containing 0.5 cat% or less of Eu ³⁺ or Tb ³⁺ as an I ₇ level deactivator. 2. Yb ³⁺ is 8 to 19 cat% and Ho ³⁺ is 1.
-10cat%, and Eu ³⁺ or Tb ³⁺ 0.5cat
% Or less of the fluoride laser glass. 3. Zr is used as a cation constituting glass.
Ions, Hf ions, Al ions, Mg ions, Ca ions, Sr ions, Ba ions, Yb ions and Ho ions, and the ratio of each ion in the cations is mol%.
The total amount of Zr ions and Hf ions is 1 to 25 on the display.
%, Al ions are 20 to 45%, the total amount of Mg ions, Ca ions, Sr ions and Ba ions is 20 to 70%,
Yb ions are 8 to 19%, Ho ions are 1 to 10%, Eu ions or Tb ions are 0.5% or less,
Further, a fluoride laser glass containing at least F ions as anions constituting the glass, wherein the proportion of F ions in the anions is 80 to 100% in terms of mol%.