JPH0648770A - Er-tm-ho-doped laser glass emitting light at 2mum wavelength - Google Patents

Abstract

PURPOSE:To provide laser glass, capable of providing a homogeneous material having larger dimensions than those of a laser crystal and high luminous intensity at 2mum wavelength. CONSTITUTION:This fluoride laser glass comprises 2-10mol% Er<3+>, 2-11mol% Tm<3+> and 0.5-5mol% Ho<3+>. The laser glass contains, e.g. Zr, Hf, Al, Mg, Ca, Sr or Ba as cations other than the Yb, Tm and Ho and at least fluorine as an anion. A laser beam at 2mum can be emitted by irradiating this laser glass with a semiconductor laser beam at 0.68mum wavelength.

Description

Detailed Description of the Invention

[0001]

The present invention relates to Er ³⁺ , Tm ³⁺ and H
It relates to a fluoride laser glass doped with o ³⁺ .

[0002]

2. Description of the Related Art Recently, crystals of YSGG, YAG, etc. doped with Tm ³⁺ or Ho ³⁺ as activating ions have an oscillation wavelength of around 2 μ, and have an energy driver for medical applications, laser detection, and laser fusion. And has been used as a light source for aqueous solution spectra. Furthermore, 2.0 μm
The Er-Tm-Ho laser crystal uses the long life of Ho ³⁺ as an eye-safe laser light source.
− Applications as switch lasers and high-power lasers that utilize large accumulated energy are also being promoted (TY Fan (Fan) et al., IEEE Journal of Quantum Electronics (IEEE JOURNA
L OF QUANTUM ELECTRONICS), Vol.24 (1988) P924-933,
TY Fan (Fan), Optics Letters (OPTIC
S LETTERS), Vol.12 (1987) P678-679].

[0003]

However, the above-mentioned Y
It is quite difficult to grow a crystal such as SGG, and it is very difficult to make a large crystal (for example, 40 cmφ × 30 cm). Therefore, 2μ used in these applied devices
Instead of crystals, to reduce the cost of the laser,
A Tm ³⁺ -doped silica glass using a glass that is easy to manufacture as a medium of a Tm ³⁺ laser is known.

However, the quantum efficiency of Tm ³⁺ -doped silica glass is as low as 6%, which is a drawback. It is considered that this is because the phonon energy of silica glass is large. (DC Hanna, RM Percival (Per
cival). RG Smart AC Tropper (Tropp
er), Optics Communications
ications), 75 3/4 (1990) 283].

Therefore, an object of the present invention is to provide a laser glass having an oscillation wavelength in the vicinity of 2 μm, which has a size larger than that of a laser crystal and which makes it possible to obtain a more homogeneous material. Further, an object of the present invention is to provide a laser glass having higher performance such as emission intensity than a laser crystal.

[0006]

The present invention provides Er ³⁺ of 2 to
It relates to a fluoride laser glass containing 10 mol%, Tm ³⁺ of 2 to 11 mol% and Ho ³⁺ of 0.5 to 5 mol%.

The light emitting mechanism of the fluoride glass containing Er ³⁺ , Tm ³⁺ and Ho ³⁺ of the present invention will be described. Figure 1
^Shows the energy level diagram of Er ³⁺ , Tm ³⁺ and Ho ³⁺ .
The emission of 2 μm is caused by the ground transition of Ho ³⁺ from ⁵ I ₇ to ⁵ I ₈ . Irradiation with a LD of 0.67 μm causes Er
³⁺ is excited from the ground state to ⁴ F _9/2, and the excited Er
Energy ³⁺ transitions to ³ F _2,3 of Tm ^3+, further ³
Relax from F _2,3 to stable ³ F ₄ . ³ F ₄ → ³ H ₄ ,
³ H ₆ → ³ H ₄ and the cross Rirakuze over John occurs, ³
The quantum efficiency at H ₄ is 2. Then ³ H of Tm ³⁺
₄ transits to ⁵ I ₇ of Ho ³⁺ from the ground state from the ⁵ I ₇ ⁽⁵
It is considered to emit light of 2 μm when radiatively transiting to I ₈ ).

Ho ions act as emission centers, but as shown in Table 1, Ho ³⁺ alone is 2 to 3 mol%.
The emission intensity becomes maximum at. Furthermore, the sensitizer Tm ³⁺
In the coexistence with, the emission intensity of Tm ³⁺ at 1.86 μm decreases and the emission intensity of Ho ³⁺ at 2 μm increases. That is, T
An energy transition occurs from m to Ho. As shown in Table 2, when the amount of Ho ³⁺ is less than 0.5 mol%, 2 μm (Ho ³⁺ )
, The emission intensity of 1.86 μm Tm ³⁺ is still high. When it exceeds 5%, the emission of Tm ³⁺ almost disappears but the emission intensity of Ho ³⁺ also decreases. Further, as shown in Table 3 and FIG. 2, in the three-component system of Er ³⁺ -Tm ³⁺ -Ho ³⁺ , Ho ³⁺ is 0.5% or more and Ho ³⁺ is 2 μm.
m emission increases sharply, and the 1.87 μm emission of Tm ³⁺ decreases significantly. Therefore, Ho ³⁺ is limited to 0.5 to 5 mol%, preferably 1 to 3 mol%. Also, Tm
³⁺ is suitably 2 to 11 mol%, preferably 6 to 11 mol%. If the amount of Tm ³⁺ is less than 2 mol%, the sensitizing effect is insufficient, and if it exceeds 11 mol%, concentration quenching occurs and light emission decreases, which is not preferable. As shown in Table 3, when the amount of Er ³⁺ is 2 to 10 mol%, the sensitizing effect is shown,
In particular, as shown in FIG. 3, 4 to 7 mol% is preferable because the sensitizing effect is high.

The laser glass of the present invention comprises Er ions,
In addition to Tm ions and Ho ions, for example, as cations constituting glass, Zr ions, Hf ions, Al ions, Mg ions, Ca ions, Sr ions, Ba ions are included, 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 Ma ions, Ca ions, Sr ions, and Ba ions is 20 to 70%, and at least F ions are contained as anions constituting the glass. It can be a fluoride glass in which the proportion of F ions therein is 80 to 100% in terms of mol%. Fluoride glass has a small phonon energy, a glass medium of the non-radiative transition, 2.mu. of Ho ³⁺
Since the emission intensity of m can be increased, it is preferable as compared with other glass media.

As cations other than Er ion, Tm ion and Ho ion, Zr ion, Hf ion, Al ion, Mg ion, Ca ion, Sra ion and Ba ion 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. However, the amount of Cl ions is 20
%, Br ions and I ions each exceed 10%, the glass is likely to crystallize and the chemical durability is deteriorated. Therefore, Cl ions are 0 to 20 mol%, and Br ions are 0%.
10 mol% and I ion are 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. Therefore, the total amount of Cl ions, Br ions, and I ions is limited to 20 mol% or less.

The laser glass of the present invention comprises HoF ₃ , TmF ₃ and ErF ₃ mixed and prepared to have a predetermined composition.
It can be obtained by heating and melting a glass raw material containing, for example, etc. by a conventional method and then cooling.

The laser glass of the present invention is approximately 0.68 μm.
Laser light of 2 μm is given by irradiating a semiconductor laser of m.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples. Example 1 ZrF ₄ , AlF ₃ , MgF ₂ , CaF as starting materials
₂ , SrF ₂ , BaF ₂ , NaCl, HoF ₃ , ErF
₃ , TmF ₃ is used, and the cation component constituting the glass finally obtained is expressed in mol% and Zr ion is 12.8.
%, Al ion 25.1%, Mg ion 3.7%, Ca
Ion 13.8%, Sr ion 12.2%, Ba ion 11.3%, Na ion 5.6%, Er ion 6%, H
O ion 1.5%, Tm ion 8%, and anion component in mol% F ion 94.4%, Cl ion 5.6%
Were weighed and mixed to obtain a batch.

Then, the obtained batch is placed in a crucible made of carbon and placed in a heating furnace, and while the inside of the furnace is being supplied with argon gas, the above batch is heated and melted at 980 ° C. for 1 hour. Then, a glass melt was obtained. Then, the obtained glass melt was cooled to room temperature, then reheated and kept at 365 ° C., and then gradually cooled to obtain a fluoroalumino zirconate glass (AZF) of the present invention.

Example 2 In AZF of Example 1, Er ³⁺ and Tm ³⁺ were not added, and the raw materials were weighed and mixed so that the amount of Ho ^{3+ was changed to} the amount shown in Table 1, A glass was obtained in the same manner as in Example 1. The emission intensity of 2 μm obtained by irradiating the obtained glass with a xenon lamp is shown in Table 1. From Table 1, H
It can be seen that the glass having o ³⁺ of 2 to 3 mol% exhibits the strongest emission intensity of 2 μm.

[0018]

[Table 1]

Example 3 In AZF of Example 1, Er ³⁺ was not added, Tm ³⁺ was fixed at 2 mol%, and the amount of Ho ³⁺ was varied to the amount shown in Table 2. The raw materials were weighed and mixed in, and glass was obtained in the same manner as in Example 1. Table 2 shows the emission intensities of 2 μm and 1.86 μm obtained by irradiating the obtained glass with a xenon lamp. It can be seen that even in the coexistence of Tm ³⁺ which is a sensitizer, the emission intensity at 2 μm becomes maximum when Ho ³⁺ is 1 to 2 mol%.

[0020]

[Table 2]

Example 4 The glass of Example 1 was prepared by changing the amounts of Er ³⁺ , Tm ³⁺ and Ho ³⁺ in the AZF of Example 1 to the amounts shown in Table 3 and FIG.
Was obtained in the same manner as. 0.67 μmLD of the obtained glass
2 μm emission intensity and 1.87 μm emission intensity when pumped in Table 3 are shown in Table 3 and FIG. It can be seen from FIG. 2 that the emission intensity of 2 μm becomes maximum when Er ³⁺ is 5 to 6 mol%.

[0022]

[Table 3]

[0023]

According to the present invention, since glass containing fluorine as an anion contains Er ions, Tm ions and Ho ions as cations, Er-Tm-Ho is used.
It is possible to obtain a laser glass which has a larger emission intensity at a wavelength of 2 μm than a laser crystal. Therefore, the laser glass of the present invention can be preferably used as a high power laser for processing as an eye-safe laser, a Q-switch laser material and the like.

[Brief description of drawings]

FIG. 1 is an energy level diagram of Er ³⁺ , Tm ³⁺ and Ho ³⁺ .

FIG. 2 shows the relationship between the Er ³⁺ content and the emission intensity of 2 μm in the laser glass of the present invention.

Claims (3)

[Claims] 1. Er ²⁺ is 2 to 10 mol%, and Tm ³⁺ is 2 to 2.
A fluoride laser glass containing 11 mol% and 0.5 to 5 mol% Ho ³⁺ . 2. Zr is used as a cation constituting glass.
Ions, Hf ions, Al ions, Mg ions, Ca ions, Sr ions, Ba ions, Yb ions, Tm ions, and Ho ions, and the ratio of each ion in the cations is expressed in mol%, and Zr ions and Hf ions are included. The total amount of the ions is 1 to 25%, the Al ions is 20 to 45%, and the total amount of the Mg ions, Ca ions, Sra ions, and Ba ions is 2%.
0-70%, Er ions 2-10%, Tm ions 2
˜11%, Ho ions are 0.5 to 5%, and at least F ions are contained as anions forming the glass.
Fluoride laser glass characterized by being 100%. 3. A method of irradiating the laser glass according to claim 1 or 2 with a semiconductor laser having a wavelength of 0.68 μm to generate a laser beam of 2 μm.