JPH02302086A - Dye laser device - Google Patents

Abstract

PURPOSE:To perform excitation uniformly as compared with the excitation from one direction by dividing exciting laser beams and entering them from two directions that dye cells are opposed. CONSTITUTION:Exciting beam components 8 reflected by a beam splitter 28 are condensed by a codensing lens 29, and are entered in one side of a dye cell 30. On the other hand, the exciting beam components 9 divided by a beam splitter 28 are reflected by high reflecting mirrors 31, 32, and 33 and enter the other side of the dye cell. The beams passing through a first division 28a among the exciting beam components P9 are about 80% of the incident beams, and the beams passing through a second division 28b are about 50% of the incident beams, and the beams passing through a third division 28c are about 20% of the incident beams. This way, the exciting beam components P9 whose permittivities are different by stages show light intensity distribution in contrast to the other exciting beam components P8. The light intensity distributions of these exciting components P8 and P9 are applied in the conditions that the light intensity increases gradually as they go to the advancing direction of a dye layer beam L.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a dye laser device that excites a dye cell from two directions by, for example, splitting excitation light into two beams.

(Prior Art) There is an amplification device for amplifying dye laser light as shown in FIG. This laser device 1 is provided with an excitation laser beam generator 2 (not shown) that generates an excitation laser beam p. A beam splitter 3 is arranged at an angle of 45'' in the optical path of the excitation laser beam p.The reflecting surface of the beam splitter 3 has a dielectric material on which the excitation laser beam p is reflected with a reflectance of about 50%. A body multilayer is formed.And,
A dye cell 4 is provided on the optical path of the excitation light component p1 reflected by the beam splitter 3.

This dye cell 4 is constructed so that the dye circulates in the depth direction of the drawing, and the dye laser light travels from the bottom to the top in the drawing. Note that the excitation light component p1
is condensed by a condensing lens 5 and made incident on the dye cell 4.

On the other hand, the excitation light component p that has passed through the beam splitter 3
2, three high-reflection mirrors 6, 7, and 8 are sequentially arranged on the optical path at an angle of 45 degrees. Thereby, the excitation laser beam p2 goes around to the opposite side of the dye cell 4 while being reflected. The last high-reflection mirror 8 is arranged to reflect the excitation light component p2 toward the dye cell 4. A condenser lens 5 is also inserted between the high reflection mirror 8 and the dye cell 4, so that the excitation light p2 is condensed and made to enter the dye cell 4.

According to the above configuration, the dye laser beam passing through the dye cell 4 in the direction indicated by the arrow is excited and amplified substantially uniformly throughout by the excitation light components p1 and p2.

However, in the laser device 1, if the output of the excitation laser light p is too large, ASE (spontaneous emission amplified light: Al1plified 5pontaneousE), which is a noise component,
This will result in the occurrence of a problem. This ASE causes damage to the monochromaticity of dye laser light.

Therefore, when generating ASE, a second dye cell 9 is provided as shown in FIG. 6, and the same excitation light p
There is a laser device 10 that excites two dye cells 4 and 9 by dividing the dye cell. With such a configuration, it is possible to prevent the occurrence of ASE and to amplify the dye laser beam with high efficiency. Note that the laser device 10 includes a first beam splitter 11 and a first beam splitter 1.
The second beam splitter 12 further splits approximately 50% of the excitation light p1 reflected by the second beam splitter 12. Excitation light component p3 passed through this second beam splitter 12
is condensed by a condensing lens 13 and incident on the dye cell 4. Further, the excitation light component p4 reflected by the second beam splitter 12 is transmitted to three high reflection mirrors 14, 1.
The light is sequentially reflected at an angle of 5° 16, condensed by a condenser lens 17, and incident on the dye cell 4.

On the other hand, the excitation light component p2 that has passed through the first beam splitter 11 is reflected by the high reflection mirror 18 and enters the third beam splitter 19.

The luminescent component p that passed through this third beam splitter 19
5 is condensed by a condensing lens 20 and enters the dye cell 9. Further, the excitation light component p6 reflected by the third beam splitter 19 is transmitted to the three high reflection mirrors 21, 22.2.
3, the light is condensed by a condenser lens 24, and is incident on the dye cell 9.

With this configuration, the light intensity of the excitation light p is reduced to excite the two dye cells 4 and 9, thereby achieving
The dye laser beam can be amplified with high efficiency while preventing the occurrence of the dye laser beam. However, when the number of dye cells is increased to a plurality, the size of the device itself increases.

(Problems to be Solved by the Invention) When the excitation light intensity is increased in a dye laser device, ASE (Amplified Spontane Light) occurs.
ousEm! 5sion), which impairs the monochromaticity of the laser beam. For this reason, a method has been proposed in which a plurality of dye cells are arranged in the optical path of the same laser beam and each is irradiated with divided excitation light to perform highly efficient laser beam amplification. However, such a device that increases efficiency by providing a plurality of dye cells has the drawback of increasing the number of optical systems and increasing the size.

The present invention has been made focusing on the above-mentioned problems, and has been developed to provide a highly efficient method without increasing the size of the device and without impairing monochromaticity.
An object of the present invention is to provide a dye laser device capable of oscillation without guiding light.

[Structure of the invention]

(Means for Solving the Problems) (1) The present invention circulates a dye laser medium through a dye cell,
An excitation laser beam generation means for exciting the dye laser medium through the dye cell is provided, and an optical co-prefecture means is provided with the dye cell in between to resonate the dye laser beam, and the laser beam is directed in two directions. A dividing means is provided for dividing and irradiating both sides of the dye cell, and this dividing means has an incident surface formed with a partial reflection surface with a transmittance that changes stepwise or steplessly along one direction, and the reflected light is or a partial reflecting mirror is provided so that the irradiation intensity of the dye laser beam is increased from the incident side of the dye cell to the passing side and irradiates one of the dye cells;
Light guiding means is provided for irradiating the passing light that has passed through the partially reflecting mirror onto one of the dye cells and the other opposing dye cell, increasing the irradiation intensity from the incident side of the dye laser beam to the passing side of the dye cell. It is located in a dye laser device.

(2) In the present invention, two dye cells are provided so that the same dye laser light passes through them sequentially, a dye laser medium is circulated through these dye cells, and an excitation 1/- light guide generation means is provided, so that the excitation laser A splitting means for splitting the light into two directions is provided, and the splitting means is used to increase the irradiation intensity of the light reflected from the partially reflecting surface from the incident side of the dye laser beam to the transmission side of the dye cell so that one of the dye cells is A dye laser device formed of a partial reflecting mirror provided to irradiate, and a projected image reversing means for inverting a projected image of a light component that has passed through the partially reflecting mirror and irradiating the other dye cell. be.

(Function) (1) Each of the excitation light components divided into two directions is incident on different parts of the same dye laser medium in a state where the light intensity increases sequentially in the direction in which the dye laser light travels.

(2) For each of the two dye cells through which the same dye laser beam passes sequentially, the light intensity of one of the two divided excitation light components increases sequentially in the direction of movement of the dye laser beam. The excitation light component of the other is incident on one dye cell in a state where the excitation light component is in a state where the projected image is inverted by a projected image reversing means, and the light intensity is sequentially increased in the traveling direction of the dye laser beam. is incident on the dye cell.

(Example) A first embodiment of the present invention will be described with reference to the drawings.

A dye laser device 26 shown in FIG. 1 is a device for amplifying the output of dye laser light, and has excitation laser generating means. This excitation laser generating means is, for example, SHG.
(Second)larmoniefienera
ter: second harmonic): YAG laser oscillation device 27. A beam splitter 28 is provided at an angle of approximately 45'' in the optical path of the excitation laser beam p7 output from this YAG laser oscillation device 27. The excitation light component p8 reflected by the beam splitter 28 is condensed by the condenser lens 29, and the excitation light component p8 is condensed by the condenser lens 29,
is incident on one side of the This dye cell 30 has a circulation means (not shown) that circulates the dye laser medium in the depth direction in the figure, so that the dye laser light passes from the bottom to the top in the figure. The reflective surface of the beam splitter 28 is coated with a dielectric multilayer film having, for example, three sections, as shown in FIG. 4 when viewed from the front. First, the first division range 28a closest to the YAG laser oscillation device 27, which has a reflective surface tilted at approximately 45 degrees, is the SHG of the YAG laser beam.
It has a reflectance of about 20%. Further, the second division range 28b in the center has a reflectance of about 50%. Further, the third partition range 28c located closest to the dye cell 30 has a reflectance of about 80%.

That is, as shown in the graph G1 on the left side of FIG. 2, the intensity of the excitation light increases sequentially in the direction of travel of the dye laser beam.

On the other hand, three high-reflection mirrors 31, 3 are placed on the optical path of the excitation light component p9 split by the beam splitter 28.
2.33 are sequentially arranged at an angle of approximately 45'' with respect to the optical axis.These three high reflection mirrors 31, 32.33 are reflecting means, and the high reflection mirror 33 performs the final reflection. The reflected excitation light p9 is condensed by a condensing lens 34 and is made to enter the other side of the dye cell 30.Here, the excitation light component p9 passes through the first division range 28a. The light emitted is about 80% of the incident light, and the second
The light passing through the partition range 28b is approximately 50% of the incident light. The amount of light passing through the third division range 28c is about 20% of the incident light. The excitation light component p9, whose transmittance varies stepwise, is represented by the graph G shown on the right side of FIG.
2 shows a light intensity distribution symmetrical to one excitation light component p8. The light intensity distribution of the excitation light components p8 to p9 is such that the light intensity increases sequentially as the dye laser beam advances.

Here, the excitation light component p8. The rate of change of the p9 light intensity distribution with respect to the traveling direction of the dye laser beam is selected within a range in which ASE does not occur.

By having the above-mentioned configuration, it is possible to prevent the occurrence of ASE even when a high excitation light intensity is applied, compared to a conventional dye laser device having a substantially similar configuration. It can be amplified into a monochromatic dye laser beam with high output. In other words, high efficiency can be achieved without increasing the size of the device.

A second embodiment of the present invention will be described with reference to FIGS. 3 and 4. A dye laser oscillation device 36 shown in FIG. 3 is a device for amplifying the output of dye laser light, and has excitation laser generating means. This excitation laser generating means is, for example, SHG (Second 1 Larioni).
c Generator: second harmonic): YAG laser oscillation device 37. This YAG l nose oscillation device 3
A beam splitter 38 as a splitting means and a high reflection mirror 39 as an optical path changing means are sequentially disposed on the optical path of the excitation laser beam plO outputted from the pump laser beam plO, and each of them serves as a first and a second dye cell 40, which will be described later. It is provided at a position corresponding to .41 at an angle of approximately 459 with respect to the optical axis of the excitation light plO. The reflective surface of the beam splitter 38 is coated with a dielectric multilayer film consisting of three vertically divided areas as shown in FIG. 4 when viewed from the front. The first YAG laser oscillation device 37 among these three division ranges
The first division range 38a near the S
The reflectance of HG is about 20%, and the second division range 38b in the center has a reflectance of about 50%. Furthermore, the first
The third partition range 38c near the dye cell 40 is approximately 80%
It has a reflectance of

Here, the first and second dye cells 40 and 41 are arranged so that the same dye laser beam passes through them sequentially, and the beam splitter 38 reflectance is increased. Also, the beam splitter 38 and the first dye cell 4
A condensing lens 40a is inserted between the dye cell 40 and the excitation light component 40a. With this configuration, the excitation light component pH of the excitation laser beam plo reflected by the beam splitter 38 has an excitation light intensity distribution as shown in graph G3.

On the other hand, the excitation light component p1 that has passed through the beam splitter 38
In the optical path of No. 2, a pair of 17 lenses 42 and 43 are inserted between the beam splitter 38 and the high reflection mirror 39. The projected image of this 42° lens pair is rotated approximately 180° and is incident on the three high-reflection mirrors. Here, the lens pair 42 and 43 are projected image reversing means.

Further, a condensing lens 41a is inserted between the second dye cell 41 and the three high-reflection mirrors, and the excitation light component p12 after the projected image is inverted is condensed into the second dye cell 41. It is designed to be incident.

Here, the excitation light component p entering the second dye cell 41
The light intensity distribution of No. 12 is as shown in graph G4 shown in the figure. In other words, the excitation light intensity increases in the direction in which the dye laser light travels.

In the dye laser device 36 configured as described above, the same dye laser light that sequentially passes through the first and second dye cells 40 and 41 is divided into two excitation light components ple,
p12, each is strongly excited in the direction of travel. Note that the rate of increase in the excitation light intensity along the traveling direction of the dye laser beam is selected within a range that does not cause ASE in the dye laser beam. In other words, the intensity of the dye laser light increases sequentially in its traveling direction due to the traveling wave amplification effect, and the intensity increase rate of this dye laser light in the laser medium and the intensity increase rate of the excitation light in the traveling direction The occurrence of ASE is suppressed by ensuring consistency between the two.

As a result, ASE does not occur during dye laser light, and
Highly efficient dye laser light amplification can be performed. It is equipped with two dye cells 40 and 41, each of which has 91 excitation light components divided along the dye laser beam, p
For example, the eight structures excited by 12 can have the same structure symmetrically on the right side. This makes it possible to provide a dye laser device with high efficiency and high output.

Note that the present invention is not limited to the first and second embodiments described above. For example, in the above embodiment, the excitation laser beam generating means is the SHG:YAG laser oscillation device 2.
7.37, but is not limited to this.

Also, a beam splitter 28 as a beam splitting means.
38 is divided into three ranges of reflectance, but it is not limited to this, and it can also be divided into two or four or more ranges, or a structure in which the reflectance is changed steplessly. Often, this reflectance is not limited to the above-mentioned values either. Furthermore, although a total of three high-reflection mirrors 31, 32, and 33 are provided in the first embodiment, the projected image of the reflected laser beam is reversed, and the excitation light intensity increases in the direction of movement of the dye laser beam. It suffices if the number of sheets is an odd number so that the number of sheets increases. Such inversion can be achieved by using optical fibers instead of only using high-reflection mirrors. That is, the three individual components of the excitation light component p1 and p2 that have passed through the beam splitter 38 can be inverted by guiding them through separate optical fibers. Further, although the device of the above embodiment is a dye laser amplification device, it is also possible to configure a dye laser oscillation device by providing a resonator at both ends of the dye laser light propagation direction with a dye cell sandwiched therebetween.

〔Effect of the invention〕

(1) By splitting the excitation laser beam and making it incident on the dye cell from two opposing directions, excitation can be performed more uniformly than when excitation is from one direction.

Further, since the light intensity of the divided two-directional light increases as it goes in the direction of travel of the dye laser beam, it is possible to suppress the occurrence of ASE. Therefore, a stable monochromatic dye laser can be oscillated with a small device.

(2) For two dye cells sequentially provided on the optical path of the same dye laser beam, the excitation light emitted from the same excitation laser beam generation means is divided into two, and the excitation light is sent to the two dye cells. Since each of the divided excitation lights is irradiated with the light intensity increasing as it goes in the traveling direction of the dye laser light, the occurrence of ASE can be suppressed. This makes it possible to output a more stable monochromatic dye laser despite its small size.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the dye 1 nozzle amplifying device of the first embodiment of the present invention, and FIG. 2 is a plan view of the dye cell shown in FIG. 1 and the excitation light irradiated to the dye cell. FIG. 3 is a plan view of the dye laser amplification device of the second embodiment of the present invention; FIG.
The figure shows the beam splitters shown in the first and second embodiments of the present invention in the respective IV-Ts of FIGS. 1 and 3.
FIG. 5 is a plan view of a conventional dye laser amplification device, and FIG. 6 is a plan view of a dye laser amplification device showing an example of applying the conventional structure. 26... Dye laser device, 27... YAG laser oscillation device (excitation laser beam generation means), 28... Beam splitter (splitting means), 30... Dye cell, 31°3
2.33... High reflection mirror (light guiding means), 36...
Dye laser oscillation device, 37... YAG laser oscillation device (excitation laser beam generation means), 38... Beam splitter (splitting means), 39... High reflection mirror (light path changing means) 40... No. 1 pigment cell (pigment cell), 41...
- Second dye cell (pigment cell), 42.43...lens pair (projection image reversal means).

Claims (2)

[Claims] (1) A dye laser medium circulated in a predetermined flow path having a dye cell, an excitation laser light generating means for irradiating excitation light to the dye laser medium via the dye cell, and the dye cell interposed therebetween. In the dye laser device, the dye laser device is provided with an optical resonant means provided in the dye cell for resonating the dye laser beam, the dividing means splitting the excitation laser beam into two directions and irradiating both sides of the dye cell, the dividing means In this case, the incident surface becomes a partially reflecting surface formed with a transmittance that changes stepwise or steplessly along one direction, and the light reflected from this partially reflecting surface is reflected on the incident side of the dye cell of the dye laser beam. A partial reflecting mirror is provided to increase the irradiation intensity as the passage side increases and irradiate one of the dye cells, and the light passing through the partial reflecting mirror is directed to the other dye cell facing the one side. A dye laser device comprising: a light guiding means provided to increase the irradiation intensity of the dye laser light from the incident side to the passing side of the dye cell. (2) Two dye cells through which the same dye laser light passes sequentially, a dye laser medium that is circulated in a flow path provided in these dye cells, and the dye laser beam transmitted through the two dye cells. A dye laser device comprising: an excitation laser beam generation means for irradiating excitation light onto a medium; The means is such that the incident surface is a partially reflecting surface formed to have a transmittance that changes stepwise or steplessly along one direction, and the light reflected from this partially reflecting surface is incident on the dye cell of the dye laser beam. A partial reflecting mirror is provided to increase the irradiation intensity from the side to the passing side and irradiate the one dye cell, and the other dye cell is inverted by reversing the projected image of the light component that has passed through the partial reflecting mirror. 1. A dye laser device comprising a projected image reversing means provided to increase the irradiation intensity from the incident side to the passing side.