JPH0558596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dye laser using a dye as a laser material, and particularly to a laser device that performs multi-wavelength laser oscillation.

[Prior art] Figure 6 is shown, for example, in Optics Communication, 1973, Volume 7, page 233 (Optics
1 is a diagram illustrating a conventional multi-wavelength oscillation laser device disclosed in Communications Vol. 7 233 (1973). In the figure, 101 is a dye container containing a dye solution consisting of a dye as a laser substance and its solvent;
102 is an output mirror that emits laser beams of wavelengths λ' ₁ and λ' ₂ and is used for the optical resonance system; 103 is located at a position opposite to the side on which the output mirror 102 is arranged with respect to the dye container 101; The disposed beam splitter 104 includes a diffraction grating 105 disposed so that a light wave of a specific wavelength among the light waves reflected by the beam splitter 103 is reflected with a high reflectance.
is a diffraction grating placed at a position that reflects a light wave of a specific wavelength among the light waves transmitted through the beam splitter 103 with a high reflectance. In addition, if necessary, the space between the beam splitter 103 and the diffraction grating 104 and between the beam splitter 103 and the diffraction grating 1 may be
Place either a polarizer, ND filter, or beam expander between the 05 and 05. In addition,
A dye solution container 101 containing a dye solution and an output mirror 10
2. Beam splitter 103 and diffraction grating 10
4 constitutes an optical resonator for light waves of wavelength λ' ₁ ,
A dye container 101 containing a dye solution, an output mirror 102,
Beam splitter 103 and diffraction grating 105 constitute an optical resonator for light waves with wavelength λ' ₂ .

Next, the operation will be explained. Pumping light 106 output from a pumping light source (not shown) and focused by an optical system (not shown) is transmitted to the dye container 101.
Irradiate the dye in the dye solution. As a result, the dye enters a population inversion state, and a light wave in a specific long region unique to the dye is generated from the dye. Here, the diffraction grating 1
The diffraction grating 104 is rotated and adjusted so that the reflectance of the light wave with the wavelength λ' ₁ is maximized with respect to the light wave incident on the light wave 04. Further, the diffraction grating 105 is rotated and adjusted so that the reflectance of the light wave having the wavelength λ' ₂ becomes maximum with respect to the light wave incident on the diffraction grating 105. A light wave with a wavelength λ' ₁ is lased by the above-mentioned optical resonator consisting of the components from the output mirror 102 to the diffraction grating 104,
The light wave with wavelength λ' ₂ is transmitted from the output mirror 102 to the diffraction grating 10.
Laser oscillation is performed by the above-mentioned optical resonator consisting of up to five components. A part of the light waves with wavelengths λ' ₁ and λ' ₂ are output to the output mirror 10 as laser beams with wavelengths λ' ₁ and λ' ₂ , respectively.
It emits from 2.

[Problem that the invention seeks to solve]

Conventional laser devices that emit multi-wavelength light waves are configured as described above, so the wavelength range of light waves that can be oscillated is determined by a single dye in a single dye container, and that range is Maximum about 80 nanometers (80 nm) (difference between wavelength λ' ₁ and wavelength λ' ₂ is within about 8 nm)
In addition, because multiple wavelengths are oscillated using the same dye, there is strong interaction between the oscillated light waves due to attraction phenomena, etc., and the output power, output waveform, oscillation timing, etc. cannot be stabilized. .

This invention was made in order to solve the above-mentioned problems, and the present invention has wavelengths that exceed the wavelength range of light waves obtained by bombing a single dye of a single concentration using a single solvent. has
The object of the present invention is to obtain a laser device that can stably oscillate a laser by weakening the interaction between each oscillating light wave.

[Means for solving problems]

In the laser device according to the present invention, a plurality of dye containers are arranged in series at intervals, and a semi-transparent mirror-like output mirror is provided on one side of the dye container group to emit laser beams of a plurality of wavelengths and to emit laser light. A first wavelength selection means for selectively reflecting a light wave of a specific wavelength is disposed on the other side of the dye container group, and a beam splitter for splitting the light wave reflected from the output mirror is disposed between the dye containers. A second wavelength selection means for selectively reflecting a light wave of a specific wavelength is disposed at a position where the light wave reflected by the beam splitter is incident, the dye is housed in the dye device together with its solvent, and the output mirror The dye solution is arranged so that short wavelength light waves are generated by pumping in the order of proximity to the dye solution, and the pumping means is arranged so that the dye solution is irradiated with pumping light from the pumping means.

[Effect]

In this invention, each of the dyes in the plurality of dye containers is arranged at a position close to the output mirror in the order of short wavelength side of the laser oscillation wavelength within the wavelength range of the excitation light generated by pumping. The wavelength of the oscillated light wave exists on the longer wavelength side than the wavelength range where the light absorption of the dye in the previous stage is high, and as a result, the oscillation wave can be transmitted without being absorbed, which greatly increases the width of the range in which multiple wavelengths of light waves that can be oscillated exist. This enables stable multi-wavelength laser oscillation by weakening the interaction between oscillated light waves.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. As a first example, consider the case of laser oscillation of light waves with two wavelengths λ' ₁ and λ' ₂ . In Figure 1,
A first dye container 1a contains a well-known dye as a laser material for generating a first light wave of wavelength λ ₁ together with its solvent as a first dye solution.A first dye container 1b contains a laser material for generating a second light wave of wavelength λ ₂ . a second dye container containing a well-known dye as a second dye solvent together with its solvent, these first and second dye containers 1;
a and 1b are arranged in series at intervals.
Note that the first dye has a combination such that the first laser oscillation wavelength λ ₁ is shorter than the second laser oscillation wavelength λ ₂ .
and stored in second dye containers 1a and 1b, respectively,
The wavelength difference between wavelength λ ₁ and wavelength λ ₂ is larger than the maximum wave difference between laser beams emitted by a multi-wavelength laser using a single dye. Reference numeral 2 denotes an output mirror disposed opposite to the first dye container 1a, and a first output mirror having wavelengths λ ₁ and λ ₂ respectively.
It emits a laser beam corresponding to the second light wave and is used for laser oscillation, and its reflective surface, which forms a semi-transparent mirror and faces the first dye container 1a, is perpendicular to the axis 3a of the resonator, which will be described later. I am doing it. Reference numeral 3 denotes a beam splitter disposed between the first and second dye containers 1a and 1b so that its reflective surface faces and is inclined to the reflective surface of the output mirror 2, and the axis 3a of the optical resonator It is divided into an optical resonator axis 3b for a light wave with a laser oscillation wavelength λ ₁ , which will be described later, and an optical resonator axis 3c for a light wave with a laser oscillation wavelength λ ₂ , which will be described later. Reference numeral 4 denotes a first wavelength selection means arranged to selectively enter and reflect the light wave of wavelength λ ₁ reflected by the beam splitter 3 with a high reflectance, and in this embodiment, it is of the Littrow type. A first diffraction grating is used. Reference numeral 5 denotes a second wavelength selection means arranged to selectively enter and reflect the light wave of wavelength λ ₂ reflected by the output mirror 2 and transmitted through the beam splitter 3 with a high reflectance; In the example, a second diffraction grating is used in the Littrow type. Pumping lights 6a and 6b pump the dyes in the first and second dye containers 1a and 1b, respectively;
is incident on the first dye container 1a from a direction substantially perpendicular to the axis 3a, and the pumping light 6b is incident on the second dye container 1a.
The light enters the dye container 1b from a direction substantially perpendicular to the axis 3c.

The multi-wavelength oscillation laser configured as above is
The output mirror 2, the first dye container 1a containing the dye solution, the beam splitter 3 and the diffraction grating ₄
The oscillation wavelength is determined by an output mirror 2, a first dye container 1a containing a dye solution, a beam splitter 3, a second dye container 1b containing a dye solution, and a diffraction grating 5. It constitutes a second optical resonator 8 for emitting light waves of λ ₂ . Note that the axis of the first optical resonator 7 for light wave oscillation consists of 3a and 3b, and the axis of the second optical resonator 8 for light wave oscillation consists of 3a and 3c.

FIG. 2 shows pumping means for generating the pumping lights 6a, 6b of FIG. In FIG. 2A, reference numeral 9 denotes a flash lamp, a Q-switch chilby laser, a second harmonic generation source thereof, a molecular ultraviolet laser, and the like that generate the pumping light 6.
Any one of the second optical harmonic generation source of YAG laser, etc.
10 is a beam splitter that splits pumping light 6 emitted from pumping light source 9 into pumping light 6a and pumping light 6b; 11 beam splitter 10 splits pumping light 6b reflected by pumping light 6a;
Total reflection mirrors 12 and 13 facing in the same direction are cylindrical lenses that condense the pumping light 6a transmitted through the beam splitter 10 and the pumping light 6b reflected by the total reflection mirror into a linear shape, respectively. In addition, the pumping light 6 by the cylindrical lens 12 and 13
The first light beam shown in FIG.
and the dyes in the second dye containers 1a, 1b are arranged. In FIG. 2B, 9 is a first pumping light source, 14 is a second pumping light source, and 15 is a synchronized pumping light source 9 and 6c.
A synchronization connection line used to emit each
12 and 13 are cylindrical lenses for pumping light 6a and 6
Focus c. In this embodiment, the pumping means shown in FIG. 2A is used, but when the pumping means shown in FIG. 2B is applied to FIG. 1, the pumping light 6b of FIG. It may be replaced with the pumping light 6c. In addition, in FIG. 2B, when helical flash lamps are used as the first and second pumping light sources 9 and 14, the cylindrical lenses 6a and 6c are unnecessary.

Next, the operation of this invention will be explained. Pumping light 6 emitted from pumping light source 9 is split into two by beam splitter 10 into pumping light 6a and 6b. The pumping light 6a is condensed by the cylindrical lens 12, and at the same time, the pumping light 6b is totally reflected by the total reflection mirror 11 and condensed by the cylindrical lens 13. These concentrated pumping lights 6a, 6b are transmitted to the first and second dye containers 1a, 1b.
irradiate each dye within at the same time. This results in
Each dye in the first and second dye containers 1a and 1b is in a state of population inversion, and excitation light is output from each dye. The wavelength λ ₁ from the dye in the first dye container 1a
A light wave including a first light wave of is generated, and the second dye container 1
A light wave including a second light wave of wavelength λ ₂ is generated from the dye b. The first light wave with the wavelength λ ₁ is selectively reflected by the diffraction grating 4 and oscillated in the first light wave oscillation optical resonator 7, and a part of the light is emitted from the output mirror 2 as a laser beam with the wavelength λ ₁ . do. The second light wave with wavelength λ ₂ is selectively reflected by the diffraction grating 5 and lased within the second light wave oscillation optical resonator 8, and a part of the light is emitted from the output mirror 2 as a laser beam with wavelength λ ₂ . do.

Here, the singlet absorption spectrum and fluorescence spectrum of the dye as a laser substance generally have characteristics as shown in Figure 3, and the wavelength region near the peak of the fluorescence spectrum is the area where laser oscillation is possible. An absorption spectrum exists on the shorter wavelength side of the wavelength region.
Therefore, the optical characteristics shown in FIG.
Assuming the characteristics of the dye in b, the absorption and fluorescence characteristics of the dye in the first dye container 1a are similar to the characteristic curve obtained by shifting the curve in FIG. 3 to the shorter wavelength side. Therefore, the laser oscillation wavelength λ ₂ of the second light wave obtained by lasing the excitation light of the dye in the second dye container 1b falls within the wavelength region of the portion of the dye in the first dye container 1a where the light absorption rate is high. Never. Therefore, the second light wave with the laser oscillation wavelength λ ₂ reaches the output mirror 2 without being absorbed by the dye in the first dye container 1a, is partially reflected, and oscillates as a second light wave between it and the diffraction grating 5. An optical resonant system is created, and the oscillation operation is performed as if the first dye container 1a were not present.

In this way, since the first light wave and the second light wave are generated from different dyes in separate dye containers 1a and 1b, the wavelength λ ₁ of the first light wave and the second light wave are different from each other.
The wavelength of the light wave λ ₂ can be made larger, and the interaction between the oscillating light waves can be weaker.

Therefore, by using the output mirror 2 in common, it is possible to realize an optical resonant system in which light waves of different wavelengths can be generated independently from each other on the same axis 3a, thereby stably performing multi-wavelength laser oscillation.

As described above, the first and second dye containers 1
Since laser oscillation is performed with different dyes in a and 1b in a population inversion state, laser beams having a large difference between both wavelengths λ ₁ and λ ₂ can be simultaneously emitted from the output mirror 2 on the same central axis.

In the above embodiment, different dyes are placed in the first and second dye containers 1a and 1b, but it is also possible to place the same dye in the first and second dye containers 1a and 1b, and to make the dye solutions containing the dyes have different concentrations and/or different solvents. 1. By adjusting the rotation of the second diffraction gratings 4 and 5, it is also possible to stably launch light waves of different wavelengths with a large wavelength difference.

Further, in the above embodiment, the axis of the first laser oscillation resonator 7 is separated from the axis of the second laser oscillation resonator 8 by the beam splitter 3, but the dye in the first dye container 1a is The first light plate and the second light plate are separated using a dielectric multilayer mirror so that the reflectance of the opposite slope of the beam splitter 3 is maximized for light waves of a specific wavelength within the laser oscillation wavelength range. You can also do better. In addition, polarizers are inserted between the beam splitter 3 and the diffraction grating 4 and between the diffraction grating 5 and the second dye container 1b as shown by the dashed lines in the figure. Only one light wave and only the second light wave may be made to enter efficiently. Furthermore, instead of inserting a polarizer between the second dye container 1b and the diffraction grating 5, a polarizing beam splitter of the beam splitter 3 may be used. Furthermore, ND can be used instead of a polarizer if necessary.
A filter or beam expander may be interposed.

FIG. 4 shows another embodiment of a laser device that performs laser oscillation of light waves of three wavelengths λ ₁ , λ ₂ , and λ ₃ . In the figure, 1c is a third dye container containing a dye as a laser material for a third light wave of wavelength λ ₃ together with its solvent as a third dye solvent, 16 is a beam splitter, and 17 is a laser material for wavelength λ ₃ This is a diffraction grating that selectively enters and reflects light waves with high reflectance. The configurations of the first dye container 1a, the second dye container 1b, the output mirror 2, the beam splitter 3, and the diffraction grating 4 are the same as those in FIG. Three dye containers 1c and a diffraction grating 17 are arranged in order, and receive the second light wave of wavelength λ ₂ reflected by the beam splinter 16.
A diffraction grating 5 is placed at a position where light is reflected. Note that the wavelength λ ₃ is shorter than the wavelength λ ₂ . The optical resonator for emitting a light wave at wavelength λ ₁ has the same configuration as in FIG. 1, but the optical resonator for laser oscillation at wavelength λ ₂ includes an output mirror 2, a first dye container 1a containing a first dye solution, and a beam splitter. 3. second dye table container 1b containing second dye solution;
The optical resonator for oscillating a light wave of wavelength λ ₃ , which is composed of a beam splitter 16 and a diffraction grating 5, is composed of the remaining components of the configuration shown in FIG. 3 except for the diffraction gratings 4 and 5. When performing laser oscillation, the pumping lights 6a, 6b, 6d are
When each of the dyes in the third dye containers 1a to 1c is irradiated simultaneously, light waves with wavelengths λ ₁ , λ ₂ , and λ ₃ are oscillated, and laser beams with these three wavelengths are emitted from the output mirror 2 .

FIG. 5 shows another embodiment of the present invention, which differs from the laser device shown in FIG. 1 in that the laser device in FIG. 1 uses a diffraction grating 4 as a light wave selection means for wavelength λ ₁ . In FIG. 5, a prism 18 and a total reflection mirror 19 are used in place of the diffraction grating 4. By increasing the distance between the prism 18 and the total reflection mirror 19, the total reflection mirror 19 can have a certain width. In this embodiment, the wavelength of the light wave can be selected by rotating the prism 18 in the direction of arrow A shown in the figure to change the wavelength of the light wave incident on the total reflection mirror 19, or by fixing the prism 18 and changing the wavelength of the light wave incident on the total reflection mirror 19. What is necessary is just to move it so that it may be located at the incident position where light of a specific wavelength is incident from 18. Of course, by rotating the prism 18 and moving the total reflection mirror 19, it is possible to select the wavelength of the light wave. Furthermore, a wavelength selection means consisting of a prism and a total reflection mirror can be used instead of the diffraction grating 5.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of dye containers containing each dye solution as a laser material are configured to oscillate, so that the wavelength existence region capable of multi-wavelength oscillation can be enlarged, and the wavelength range between oscillation light waves can be increased. This has the effect of weakening the interaction between the two and allowing stable multi-wavelength laser oscillation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIGS. 2A and B are block diagrams showing each embodiment of the pumping means used in FIG. 1, and FIG. 3 is a block diagram showing each embodiment of the pumping means used in FIG. A characteristic diagram showing an absorption spectrum and a fluorescent lamp spectrum for light wave generation. Figure 4 is a block diagram showing another embodiment of the present invention that performs laser oscillation at three wavelengths. FIG. 6 is a block diagram showing another embodiment in which a wavelength selection mechanism having selectivity is implemented using a prism and a total reflection mirror. FIG. 6 is a block diagram showing a conventional multi-wavelength oscillation laser device. In the figure, 1a and 1b are dye containers, 2 is an output mirror, 3 is a beam splitter, 4 is a wavelength selection means (diffraction grating), 5 is a wavelength selection means (diffraction grating), 6
a, 6b are pumping lights, 9 is a pumping light source,
10 is a beam splitter, 11 is a total reflection mirror, 1
2 and 13 are cylindrical lenses. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A plurality of dye containers arranged in series at intervals, and a semi-transparent mirror provided on one side of the group of dye containers and used for emitting laser beams of a plurality of wavelengths and for laser oscillation. a first wavelength selection means provided on the other side of the dye container group for selectively reflecting a light wave of a specific wavelength, and a first wavelength selection means provided between the dye containers to split the light wave reflected from the output mirror. a beam splitter, a second wavelength selection means disposed at a position where the light wave reflected by the beam splitter is incident and selectively reflects light waves of a specific wavelength, and a second wavelength selection means housed in the dye container and close to the output mirror. A laser device comprising a dye solution consisting of a dye and its solvent that generates a light wave with a short laser oscillation wavelength by pumping in order, and a pumping means arranged to irradiate the dye solution with pumping light. 2. A reflectance of the beam splitter is maximized for a light wave of a specific wavelength generated by pumping the dye in the dye container disposed on the output mirror side adjacent to the beam splitter. A laser device according to claim 1. 3. The laser device according to claim 1 or 2, wherein the pumping means simultaneously irradiates the dye solution with pumping light. 4. The laser device according to any one of claims 1 to 3, wherein flash lamp light is used as pumping light for the pumping means. 5. The laser device according to claim 1, wherein at least one of the first wavelength selection means and/or the second wavelength selection means is a diffraction grating. 6. The laser device according to claim 1, wherein at least one of the first wavelength selection means and/or the second wavelength selection means is a combination of pribum and total reflection.