JPH04292436A - Fluorescent glass and laser device using the same glass - Google Patents

Abstract

PURPOSE:To enlarge an oscillation wavelength range of variable wavelength laser by covering at least one of an excitation light source and a laser medium with a fluorescent glass tube of SiO2 glass doped with Tb and Al. CONSTITUTION:A sol obtained by hydrolyzing ethyl silicate with an aqueous solution of hydrochloric acid is mixed with TbCl3 and AlCl3 in a given molar ratio to prepare colloidal SiO2. Then the colloidal SiO2 is adjusted to proper pH by adding an aqueous solution of NH3, gelatinized, heated and dried to give a dry gel, which is heated to a given temperature to give a fluorescent quartz glass doped with Tb and Al. A Ti/Al2O3 rod 41 is covered with a quartz glass tube 44 by a laser device, cooling water 46 is made to flow in the tube. On the other hand, xenon flash lamps 42 are covered with doped quartz glass tubes 45, the cooling water 46 is made to flow in the tubes, light rays from the xenon lamps 42 are reflected from a condensed light reflecting mirror 43, passed through a fluorescent glass tube, light rays at <=300nm short wavelength are cut to double luminance of light rays in 400-550nm wavelength. An oscillation wavelength range of variable wavelength laser can be widened.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a doped quartz glass capable of wavelength conversion of light and a laser device with high energy efficiency.

0002

[Prior art] In the case of a Ti:Al2O3 laser, a xenon flash lamp is used as an excitation light source, a condensing reflector is used to irradiate light onto an Al2O3 rod, which is a laser medium, and a resonator consisting of a mirror system is used to oscillate the laser. . Because the xenon lamp generates high heat, the lamp and Al2O3 rod are surrounded by a quartz tube and cooling water is circulated. However, Ti:Al2O3 performs laser transition only for excitation light of 400 to 600 nm, whereas the emission spectrum of a xenon lamp is almost flat over the entire wavelength range. 400
Light with a wavelength shorter than 600 nm causes rod deterioration.
Light with longer wavelengths becomes a source of heat generation, resulting in a large loss of energy.

[0003] Therefore, it has been proposed that the energy efficiency can be increased and the deterioration of the laser medium can be prevented by changing the emission spectrum of the excitation light source using doped quartz glass (Japanese Patent Laid-Open No. 60-76933) that can convert the wavelength of light. (Patent application No. 2-128771). This effect was confirmed in Nd:YAG and alexandrite (Cr:BeAl2O4).

0004

[Problems to be Solved by the Invention] However, even if the above-mentioned conventional technology is applied to a laser medium that uses titanium as an active ion, there is no fluorescent glass that matches the required excitation wavelength, and an efficient laser device is not available. Therefore, there was a problem in that it was not possible to widen the oscillation wavelength range of the wavelength tunable laser.

The present invention is intended to solve the above-mentioned problems, and aims to provide a fluorescent glass that matches the excitation wavelength of a laser medium containing titanium as an active ion. Another object of the present invention is to provide a laser device that has good energy efficiency and can widen the oscillation wavelength range of a wavelength tunable laser.

[0006]

[Means for Solving the Problems] The present invention provides a fluorescent glass characterized in that silica glass is doped with terbium and aluminum.

In a laser device consisting of an excitation light source, a laser medium containing titanium as an active ion, and a resonator, at least one of the excitation light source and the laser medium is a fluorescent glass tube made of silica glass doped with terbium and aluminum. Characterized by surrounding.

[0008]

[Example] (Example 1) Terbium (III) chloride and aluminum chloride were added and dissolved in a sol obtained by hydrolyzing ethyl silicate with an aqueous hydrochloric acid solution, and the average particle size was 0.1.
5 microns of colloidal silica was mixed. Appropriate values can be selected for the amounts of terbium and aluminum added, but here the composition is expressed as a molar ratio (SiO2:Tb:Al=1:
0.001:0.015). Gradually add a diluted aqueous solution of ammonia to the sol, adjust the pH of the sol between 3 and 6, gel it in a hydrophobic container such as polyfluoroethylene, and cover with a lid with an appropriate opening ratio. 40℃ to 90℃
A dry gel was obtained by drying at a temperature of ℃. When heated to a temperature of 1100° C. to 1300° C. using an appropriate heating program, a colorless and transparent doped quartz glass was obtained.

When the fluorescence characteristics of quartz glass doped with trivalent terbium and aluminum were measured, it was found that 220~
It absorbed ultraviolet light of 300 nm and emitted light in a wide wavelength range of 400 to 550 nm. Figure 1 shows the emission spectrum of quartz glass doped with trivalent terbium and aluminum. For comparison, FIG. 2 shows the emission spectrum of quartz glass doped only with trivalent terbium. Further, FIG. 3 shows the absorption spectrum of Ti:Al2O3, which is a laser medium. It was confirmed that quartz glass doped with trivalent terbium and aluminum is a fluorescent glass that matches the excitation wavelength of a laser medium with titanium as the active ion.

FIG. 4 shows a conceptual diagram of the cross-sectional structure of a Ti:Al2O3 laser device. Al2O3 rod 41
was surrounded by a quartz glass tube 44, and cooling water 46 was passed through it. On the other hand, the xenon flash lamp 42 was surrounded by the aforementioned quartz glass tube 45 doped with trivalent terbium and aluminum, and cooling water was allowed to flow therethrough. The light emitted from the xenon flash lamp passes through a fluorescent glass tube, making it 300n
Light with wavelengths shorter than m was cut, and the brightness in the wavelength range of 400 to 550 nm was doubled. When the wavelength-converted light was irradiated onto a laser medium by the condensing reflector 43 and the laser beam was extracted by the resonator, the laser output intensity was approximately 1.5 times that of the conventional one.

[0011] Therefore, the oscillation wavelength range of the wavelength tunable laser has been changed from the conventional 700 to 950 nm to 650 to 1050 nm.
I was able to expand it to m. Also, even if used for a long time, the Al
The 2O3 rod and the terbium- and aluminum-doped quartz glass tube did not undergo any deterioration due to solarization, and no change in laser characteristics was observed. (Example 2) Terbium(III) nitrate and aluminum chloride were added and dissolved in a sol obtained by hydrolyzing methyl silicate with an aqueous nitric acid solution, and colloidal silica having an average particle size of 0.2 microns was further mixed therein. Appropriate values can be selected for the amounts of terbium and aluminum added, but here the composition is expressed as a molar ratio (SiO2:Tb:Al=1:0.005).
:0.05). A diluted aqueous solution of ammonia was gradually added to the sol, the pH of the sol was adjusted between 3 and 6, and the sol was gelled in a hydrophobic container such as polypropylene, covered with a lid with an appropriate opening ratio, and heated at 40°C. A dry gel was obtained by drying at a temperature of 90°C. 1100℃ with an appropriate heating program
When heated to a temperature of 1,300° C., a colorless and transparent doped quartz glass was obtained.

When the fluorescence characteristics of quartz glass doped with trivalent terbium and aluminum were measured, it was found that 220~
It was confirmed that the fluorescent glass absorbs ultraviolet light of 300 nm, emits light in a wide wavelength range of 400 to 550 nm, and matches the excitation wavelength of a laser medium containing titanium as an active ion.

[0013] The Ti:BeAl2O4 rod was surrounded by a quartz glass tube doped with trivalent terbium and aluminum, and cooling water was allowed to flow through it. On the other hand, the xenon flash lamp was surrounded by a quartz glass tube and cooling water was passed through it. The light emitted from the xenon flash lamp was reflected by a condensing reflector and passed through a fluorescent glass tube, thereby cutting out light with wavelengths shorter than 300 nm and doubling the brightness in the wavelength range of 400 to 550 nm. When the laser beam was extracted using a resonator, the intensity of the laser beam was almost twice that of the conventional one. Therefore, the oscillation wavelength range of the wavelength tunable laser has been changed from 700 to 95
It was possible to widen the range from 0 nm to 650 to 1100 nm. Further, even after long-term use, the Al2O3 rod and the terbium- and aluminum-doped quartz glass tube did not deteriorate due to solarization, and no change in laser characteristics was observed.

(Example 3) A Ti:Al2O3 rod and a xenon flash lamp were surrounded by a quartz glass tube doped with trivalent terbium and aluminum prepared in the same manner as in Example 1, and cooling water was flowed through the tube. When the light emitted from a xenon flash lamp passes through a fluorescent glass tube, it emits 300
Light with wavelengths shorter than nm is cut, 400-550 nm
The brightness in the wavelength range has doubled. When the Ti:Al2O3 rod was irradiated with the light whose wavelength had been converted in this way and the laser was extracted from the resonator, the output intensity of the laser increased to nearly twice that of the conventional method. Therefore, the oscillation wavelength range of the wavelength tunable laser has been changed from the conventional 700 to 950 nm to 650 to 110 nm.
It was possible to spread it to 0 nm. Even if you use it for a long time,
No deterioration due to solarization occurred in the Al2O3 rod and the terbium and aluminum doped quartz glass tube, and no change in laser characteristics was observed. In addition, in order to maintain the laser output intensity at the same level as before,
By cutting the operating energy of a xenon lamp by about half, it was possible to extend the lamp life by nearly 10 times.

Although the embodiments of several types of laser devices have been described above, the excitation light source and the type of laser medium are not limited in any way. Furthermore, various concentrations of doping substances in quartz glass and manufacturing methods can be considered.

[0016]

As described above, according to the present invention, by doping silica glass with terbium and aluminum, it has been possible to provide fluorescent glass that matches the excitation wavelength of a laser medium containing titanium as an active ion. Since it has the properties of quartz glass, it is chemically and thermally stable, and is expected to be widely used as optical components.

[0017] It is also an object of the present invention to provide a laser device which has good energy efficiency and can widen the oscillation wavelength range of a wavelength tunable laser by surrounding at least one of the excitation light source and the laser medium containing titanium as an active ion with the fluorescent glass tube. I was able to achieve it. Since it is a solid-state laser, it is easy to handle, can cover most of the wavelength range of semiconductor lasers, and can emit high-power laser with good waveform characteristics. It can be widely used for research and development purposes and other purposes.

[Brief explanation of drawings]

FIG. 1 is an emission spectrum diagram of quartz glass doped with trivalent terbium and aluminum according to the present invention.

FIG. 2 is an emission spectrum diagram of quartz glass doped only with trivalent terbium.

FIG. 3 is an absorption spectrum diagram of Ti:Al2O3, which is a laser medium.

FIG. 4: Ti:Al2O3 in Example 1 of the present invention
FIG. 2 is a diagram illustrating the concept of a cross-sectional structure of a laser device.

[Explanation of symbols]

1 Emission spectrum of quartz glass doped with trivalent terbium and aluminum 2 Emission spectrum of quartz glass doped with trivalent terbium 3 Absorption spectrum of Ti:Al2O3 41
Ti:Al2O3 rod 42 Xenon flash lamp 43 Concentrating reflector 44 Quartz glass tube 45 Quartz glass tube doped with trivalent terbium and aluminum 46 Cooling water

Claims (2)

[Claims] 1. A fluorescent glass characterized in that silica glass is doped with terbium and aluminum. 2. A laser device comprising an excitation light source, a laser medium containing titanium as an active ion, and a resonator, in which at least one of the excitation light source and the laser medium is made of fluorescent glass in which silica glass is doped with terbium and aluminum. A laser device that uses fluorescent glass and is surrounded by a tube.