JPS6011245A - Glass for laser - Google Patents

Abstract

PURPOSE:To obtain glass for laser preventing the association of rare earth metallic ions and having a significant effect of improving a long-lived spectrum by doping SiO2 glass with a rare earth metallic oxide and P2O5 and/or Al2O3. CONSTITUTION:A gaseous mixture of a rare earth metallic compound such as NdCl3 with an Si compound such as SiCl4 is mixed with a gaseous P compound such as POCl3 and/or a gaseous Al compound by an amount (mole) >=10 times the amount of the rare earth metallic compound, and they are reacted in an oxidizing plasma flame to cause vitrification. SiO2 glass doped with a rare earth metallic oxide and P2O5 and/or Al2O3 is obtd. as glass for laser.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser glass activated by doping 5ick glass with rare earth ions.

Nd”, Yb”, Ho Todoro+, Qd! Glass doped with rare earth ions such as + is known to exhibit laser action. Especially those containing Nd"+ are 1.06μ
It has been put into practical use as a glass laser that oscillates light of m and is widely used. In this case, a multi-component silicate or phosphate glass containing alkali, alkaline earth oxides, etc. is used as the matrix glass, and phosphate glasses in particular have excellent properties. .

However, there are still many problems that need to be improved. The first is heat load characteristics (thermal conductivity/thermal expansion coefficient/
Young's modulus) is significantly inferior to that of crystalline materials. This is a serious drawback considering that glass lasers are often used as energy storage lasers under harsh conditions.

Furthermore, from the standpoint of laser application technology, the development of glass lasers with short wavelength oscillation is expected, but in this case, multi-component glasses with poor transparency in the ultraviolet region cannot be used as a matrix, and conventional Glass lasers also had many drawbacks in terms of luminous efficiency.

On the other hand, Sin and glass have small coefficients of thermal expansion;
It is known as a substance with excellent ultraviolet transparency. Furthermore, when compared with multicomponent glass, it has particularly excellent mechanical strength, heat resistance, and chemical durability, and also has high thermal conductivity and low refractive index. All of these properties are desirable for the base material of a glass laser. Therefore, if this 5in2 glass can be activated with rare earth ions, it is expected that a new glass laser will be developed that has an order of magnitude better heat load resistance and features that have never existed before.

However, there are several problems that need to be solved in order to develop a new laser glass by doping SjO with rare earth ions.

The first is that because the melting point of sio is extremely high at 1720° C., it is impossible to obtain high-quality glass uniformly doped with rare earth ions using the conventional melt quenching method.

However, this problem has been solved by the inventors of the present application developing a new glass synthesis method applying the plasma torch CVD method (patent pending).

However, Sin doped with other rare earth ions.

In order to use glass as a laser glass, problems remain from the viewpoint of light emission characteristics.

That is, although there are generally various conditions for determining whether or not a good laser material can be obtained by doping with rare earth ions, the most basic condition is (α) that the rare earth ions are uniformly dispersed. If they are associated, the lifetime of the fluorescence will be shortened due to concentration quenching, and therefore they will not be able to contribute to the laser action. (b
) The intensity of the emission spectrum in the wavelength range used for laser action is high, and the width of the wavelength range is as narrow as possible.

However, there is a large immiscible region between the rare earth oxide and the 5in2 binary system, and due to this influence, some of the doped rare earth ions cause microscopic association. Therefore, these rare earth ions do not have an extremely short fluorescence lifetime due to concentration quenching and do not contribute to the laser action.

Furthermore, even though the rare earth ions that remain unassociated have long fluorescence lifetimes and can therefore contribute to laser action, they generally have weak emission intensity and a wide spectrum width, so they do not exhibit emission characteristics that are effective for laser action. do not have.

This is the ionic radius of the rare earth ion (about 1.1X) and S
It is presumed that this is because the difference with the ionic radius (o, 59X) of the i4+ ion is too large, causing a structural mismatch.
alone cannot make a good glass laser (Jap,
J, Appl, Letters are being submitted).

In view of the above circumstances, this invention was developed as a result of intensive research aimed at developing a laser glass in which rare earth ions are uniformly dispersed in 5i02 glass.
By doping Sin with one or a combination of tOn glazes, the associativity and structural mismatch of the rare earths mentioned above can be solved at once without significantly changing the properties of Sin and glass as laser base materials. It was discovered that glass for lasers could be obtained in the early 1990s.

The laser glass according to the present invention contains Pz as a rare earth oxide.
It is made by doping 5iO1 with a combination of Oll and Alton, and this production is carried out by, for example, adding one or both of P compound gas and Al compound gas to a mixed gas of a rare earth compound and a Si compound using a known method. This involves mixing seeds and reacting the mixed gas with oxidizing plasma flame to vitrify it.

To explain an example in which Nd, O, and P2O are combined and doped to 5ift, NdC15+ 5sCk
The mixed gas is further mixed with POC and the like by a known method, and this mixed gas is reacted with an oxidizing plasma flame to vitrify it.

In this case, if the rare earth oxide is combined with about 10 times the amount of P2O and doped with Sin, the association of rare earth ions will be prevented and the effect of improving the long-life spectrum will begin to appear, so the molar ratio will be more than 10 times that of the rare earth oxide. It is preferable to add and dope PtOs.

Next, we will show the emission spectrum (Figure 1) when SiO2 glass is doped with only Nd and On, and the emission spectrum of NthOs, P, 0. When doped in combination with Ntb Os and Alto
The present invention will be explained in detail in comparison with the emission spectrum of SiOx glass when doped in combination with s (Figs. 2 and 5). In Fig. 1, the dotted lines /, This is the emission spectrum generated from those that are associated. This emission cannot be used as a laser at all because it has an extremely short fluorescence lifetime of about 0.35 μs due to concentration quenching.

Solid line 3. 'I is an emission spectrum resulting from unassociated Nd''+ ions and has a long lifetime of about 450 μs. Therefore, it is possible to cause a laser action by this emission. However, in general, it is activated by Nd3+. The laser is operated as a 4-unit laser, and in this case, the important thing is 'F4/2→'11i/
This is two-transition light emission.

However, as is clear from FIG. 1, this light emission is extremely weak compared to the light emission in the 4FV24≠ transition of 3. Furthermore, the width of the emission spectrum is generally wide. All of these are undesirable properties for laser action.

As described above, when 5iOt glass is doped with only Nd*08, only a part of the doped Nd''+ ions contributes to the laser action, and moreover, the luminous efficiency is poor.

However, as in this invention, Nd, O, and P2O, or Al, 0. When SiO* glass is doped with a combination of
A long-lived spectrum of 50 μs, 6, or? , ff are the only ones observed. Moreover, in the case of Figure 2, the 4th floor of Party B
The emission is gradually stronger than that of the 3/2 J11/2 transition or the S'I9/2 transition, and the spectrum width is narrower overall. That is, this effect is P2O
, is particularly noticeable when doped in combination. In this way, NtbOs and P, 0. Alternatively, by doping with a combination of Aj and O, the association of Nd''+ ions is prevented,
Moreover, it exhibits an emission spectrum that is advantageous for laser action.

Figure 4 shows the intensity of the short-lived spectrum and the long-lived spectrum of 4FV2' 111/! when doped with a combination of 0.05 mol% NtitO and P2O. / 'Fy
2-4■η The relationship between the intensity ratio lOJ and the amount of Plow is shown. According to this, P, 0.0.5 molti,
In other words, simply by combining Nd, O, and about 10 times the amount of Pros and heating it, it is possible to prevent the association of NdB+ ions and begin to have an effect on improving the long-life spectrum.

Generally, glass lasers have 0.5 to 0.5 molt of Ntb.
It is doped with Os.

Therefore, it is necessary to combine 6 to 5 mol of P2O or more. By introducing this amount of P crystal, for example, SiO
The softening point of x is lowered by 100 to 150°C. However, it is still more than 500°C higher than conventional multi-component glasses.

In summary, according to the present invention, by doping a small amount of hos or A l *Ox in combination,
The problems caused by doping IFT glass with rare earth elements can be solved all at once.

As a result, it becomes possible to develop a rare earth-activated glass laser with new characteristics that takes advantage of the characteristics of 5ift glass as a laser matrix.

[Brief explanation of the drawing]

Figure 1 is an emission spectrum diagram when 5ift glass is irradiated with only NdxOs, Figures 2 and 5 are emission spectrum diagrams of 5iOt glass doped with a combination of Nd2O5 and P2O6 or Alto3 according to the present invention, respectively. Figure 4 shows the doping amount of P2O6 added to the NdxOs doping amount of 0.05 molty, the intensity of the short-life spectrum, and 'F3./!-' I 11/2/ 'F3.
It is a relationship curve diagram of the intensity ratio of 10 of the long-life spectrum of /2-4IV2. 1-”- In the figure, the dotted line at 2.7 indicates the short life spec.
The solid lines for 9, j, A,, 7, and g are long-life sudoctors. Designated agent: Agency of Industrial Science and Technology

Claims (2)

[Claims] (1) Rare earth oxide and POs on 5ift glass,
A laser glass characterized by being doped with one type or a combination of two types of Abox. (2) Rare earth oxide and the molar ratio of the rare earth oxide to 1
The laser glass according to claim 1, which is doped in combination with 0 times or more PIOI.