JPH06196825A - Dye laser device - Google Patents

Abstract

PURPOSE:To obtain a dye laser device, in which super-radiation is reduced, which has a high output and high quality and from which a stable dye laser output is acquired. CONSTITUTION:A single-mode optical fiber 31 is mounted on an optical path between a dye laser oscillator 22 and the dye cell 3 of a first optical amplifier while the optical path length L of the dye laser oscillator 22 and the dye cell 3 is disposed so as to satisfy L>=0.5X tPXC when the full-width at a half maximum of optical pulses from the copper vapor laser 33 as the light source for optical pumping of the first optical amplifier is represented by tP and light velocity by C, and an optical isolator 29, an optical fiber coupler 30, the optical fiber 31 and an incident optical system 32 are arranged between the oscillator 22 and the dye cell 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dye laser device having a plurality of dye cells for amplifying dye laser light emitted from an oscillating means upon irradiation with excitation light.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional dye laser device disclosed in, for example, Japanese Patent Laid-Open No. 64-81388. In the figure, 1 is an excimer laser as an excitation light source, 2 is an oscillation stage dye cell that emits laser light by irradiation of excitation light, 3, ..., 3 are serially connected in the laser light output direction of the oscillation stage dye cell 2. Is a dye cell for light amplification for amplifying the dye laser light emitted from the oscillation stage dye cell 2 arranged in the above.

An optical fiber 4 guides the dye laser light,
Reference numeral 4a is a reflection filter, 5 is a dye pump for circulating a solution in which the dye in the dye cell is circulated, and 6 is a linear pumping light on the bottom surface of each of the oscillation stage dye cell 2 and the light amplification dye cell 3. A cylindrical lens 7 for condensing light is a quartz plate arranged in front of the oscillation stage dye cell 2, and a lens 8, a diffraction grating 9 and a plane mirror 10 arranged behind it.
Together with this, it constitutes a resonator. Reference numeral 11 is a half mirror provided in the excitation light guiding system, and 12 and 13 are also mirrors.

Next, the operation will be described. A solution obtained by dissolving a dye in an organic solvent or the like is circulated at a high speed inside the oscillation stage dye cell 2 and the plurality of light amplification dye cells 3 ... 3 by a dye pump 5. And each cell 2, 3
The pulsed excitation light from the excimer laser 1, which is the excitation light source placed on the oscillation stage dye cell 2 side, is included in half mirrors 11 ... 11, mirrors 12 ...
It is guided by the excitation light guide system constituted by 3 and is irradiated so as to be linearly focused on the bottom surface of each cell via the cylindrical lenses 6 ...

A crystal plate 7 is provided in front of the oscillation stage dye cell 2.
And a lens 8, a diffraction grating 9 and a plane mirror 10 are disposed in the rear of the resonator, and these constitute a resonator, and a part of the light emitted from the oscillation stage dye cell 2 due to the excitation light irradiation. Is reflected by the crystal plate 7 and passes through the cell 2 again,
The light is collimated by the lens 8 and is incident on the diffraction grating 9, and the diffracted light whose wavelength is selected is totally reflected by the plane mirror 10. This reflected light again passes through the active dye that is emitting light in the oscillation stage dye cell 2 and is emitted to the amplification stage via the quartz plate 7.

The crystal plate 7 and the first-stage optical amplification dye cell 3
, And between each of the optical amplification dye cells 3 ... 3 and further in the subsequent stage of the final stage optical amplification dye cell 3, an optical fiber 4 is disposed, and each optical fiber 4 ...
.. and 4 and the dye cells 2, 3 ... 3 are respectively provided with reflection filters 4a.
The dye laser beams emitted from 3 ... 3 are configured to be guided to the dye cell 3 in the next stage or the irradiation target W through the inside of the optical fiber 4. Here, the material of the optical fibers 4 ... 4 used is selected so that the wavelength of the light emitting region of the dye used can be sufficiently transmitted.

Mirrors 12 ... 12 provided on the excitation light optical path between the excitation light induction system oscillation stage dye cell 2 and the first stage light amplification dye cell 3 form an excitation light delay section. There is. That is, the optical path length of the excitation light is increased by the mirrors 12 ... 12, and the amount of increase is set to an amount corresponding to the delay of dye laser emission from the resonator of the oscillation stage. As a result, each of the light amplification dye cells 3 ...
The arrival of the excitation light with respect to the oscillation stage dye cell 2 is delayed by the sum of the above-mentioned dye laser emission delay time and the time corresponding to the distance from the oscillation stage dye cell 2 to each cell 3 ... Become.

According to the above structure, the dye laser light emitted from the resonator of the oscillation stage and each of the dye cells for optical amplification 3 ... 3 is guided into the optical fiber 4 through the reflection filter 4a. The light is guided again into the next-stage optical amplification dye cell 3 via the reflection filter 4a, and the excitation light is irradiated in each of the optical amplification cells 3 ... 3 almost in synchronization with the passage of the dye laser light. The laser light does not leak to the outside between the dye cells of each stage and is not stimulated to be emitted, and becomes a dye laser beam with high efficiency and good monochromaticity. Similarly, the reflection filter 4a
And is guided to the irradiation target W through the inside of the optical fiber 4.

[0009]

Since the conventional dye laser device is constructed as described above, in the amplification system,
The spontaneous emission light that is generated is also taken into the optical fiber 4 at the same time, which deteriorates the laser quality and complicates the configuration of connecting the cells with the optical fiber. Further, in the high-output dye laser device, there is a problem that the laser output becomes large and the optical fiber 4 is easily damaged.

The present invention has been made to solve the above-mentioned problems of the conventional example, and an object thereof is to obtain a high-quality laser beam and a dye laser device having a long life and a high output. .

[0011]

According to a first aspect of the present invention, there is provided a dye laser device comprising: a dye laser oscillating means for oscillating a dye laser beam; and an optical amplifying means for amplifying the dye laser light. It is provided with a single mode optical fiber.

A dye laser device according to a second aspect of the present invention is
The optical path length between the dye laser oscillating means for oscillating the dye laser light and the optical amplifying means for amplifying the dye laser light is L, the full width at half maximum of the optical pulse of the excitation light source of the optical amplifying means is Δt _P , When the speed of light in air is C, the optical path length L is set to satisfy L ≧ 0.5 × Δt _P × C.

A dye laser device according to a third aspect of the present invention is
At the exit of the dye laser oscillating means for oscillating the dye laser light, the light amplifying means for amplifying the dye laser light returns to the dye laser oscillating means and is reflected in the dye laser oscillating means and again the optical amplifying means An optical isolator that removes the return light that is incident on is provided.

Further, in the dye laser device according to the fourth aspect, a polarization-maintaining optical fiber is provided between the dye laser oscillation means for oscillating the dye laser light and the optical amplification means for amplifying the dye laser light. It is a thing.

[0015]

According to the first aspect of the present invention, the single mode optical fiber is provided between the dye laser oscillating means for oscillating the dye laser light and the optical amplifying means for amplifying the dye laser light. By utilizing the fact that the output optical axis of the optical fiber is held constant regardless of the incident optical axis, the path and the length of the optical fiber, the incident optical axis to the optical amplifying means with the largest optical axis change is kept constant. Maintain and maximize laser light at all times. In addition, since no difference in optical phase is generated during optical transmission, a bright and dark stripe pattern does not occur in the emitted beam, and the proportion of superradiation ASE of spontaneously emitted return light amplified during laser amplification is reduced.

According to a second aspect of the present invention, the optical path length between the dye laser oscillating means for oscillating the dye laser light and the light amplifying means for amplifying the dye laser light is L, and the optical amplifying means is L. When the full width at half maximum of the light pulse of the pumping light source is Δt _P and the speed of light in air is C, by setting the optical path length L satisfying L ≧ 0.5 × Δt _P × C A delay optical path is provided so that the superradiation ASE of the output of the optical amplifying means is not amplified, and the return time of the returning light from the dye laser oscillating means side is set to the generation of the excitation light in the optical amplifying means. The delay outside the period prevents a decrease in laser output and a decrease in quality due to stimulated emission.

According to a third aspect of the present invention, the emission port of the dye laser oscillating means for oscillating the dye laser beam,
By providing an optical isolator for returning the return light from the optical amplification means for amplifying the dye laser light to the dye laser oscillation means and reflected in the dye laser oscillation means and again entering the optical amplification means, The optical transmission from the optical amplifying means to the dye laser oscillating means is blocked, and the light is generated from the optical amplifying means and transmitted to the dye laser oscillating means via the incident optical system, and is reflected in the dye laser oscillating means. The generation of return light that returns and enters the optical amplifying means again is removed as much as possible to reduce the superradiation ASE.

Further, in the dye laser device according to a fourth aspect of the present invention, polarization plane preserving light is provided between the dye laser oscillating means for oscillating the dye laser light and the optical amplifying means for amplifying the dye laser light. By providing the fiber, the light of the polarization direction most suitable for the amplification can be incident, and the amplification efficiency is improved.

[0019]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a dye laser device according to the first embodiment. In FIG. 1, 21 is an argon ion laser as an excitation light source, 22 is a dye laser oscillator that emits dye laser light by irradiation of excitation light from the argon ion laser 21, and this dye laser oscillator 2 is from the argon ion laser 21. Condensing mirror 23 for condensing the excitation light of the above into the dye stream 24, total reflection mirrors 25, 26 and partial reflection mirror 27, and a wavelength selection element provided between said total reflection mirror 26 and partial reflection mirror 27. An optical resonator is constructed with 28.

Reference numeral 29 is an optical isolator for transmitting the dye laser light emitted from the dye laser oscillator 22 in the direction of the optical fiber coupling device 30 and for blocking the reverse transmission.
0 is an optical fiber coupling device (for example, Newport Inc., single mode fiber automatic alignment system FX-1000G5 type) for introducing the dye laser light through the optical isolator 29 into the single mode optical fiber 31;
Reference numeral 32 is an incident optical system which is composed of a lens and a pinhole and is shaped into a beam.

Reference numeral 33 denotes a copper vapor laser which emits pumping light having a pulse width of 50 ns, for example. The pumping light output is split by the half mirror 11 and beam-formed by the cylindrical lens 6 to form the dye cell 3 of the first optical amplifier. And the beam is shaped by the cylindrical lens 6 by being guided by the mirror 13 to excite the dye in the dye cell 3 of the second optical amplifier. Reference numeral 34 denotes a first lens which is composed of a lens and a pinhole and is arranged in series in the lens light output direction.
And between the dye cells 3 and 3 of the second optical amplifier, the beam shape and the beam quality of the laser light amplified by the dye that is emitted from the incident optical system 31 and enters the dye cell 3 and is excited. It is an interstage optical system to be arranged.

In the above structure, the dye laser oscillator 22
The dye laser light emitted from the laser beam enters the optical fiber coupling device 30 through the optical isolator 29, and is introduced into the single mode optical fiber 31 by the optical fiber coupling device 30. Then, the laser light emitted from the optical fiber 31 is shaped into a beam by an incident optical system 32 composed of a lens and a pinhole.

On the other hand, the excitation light is emitted from the copper vapor laser 32, the excitation light output is divided by the half mirror 11, the beam is shaped by the cylindrical lens 6, and the pigment (not shown) in the pigment cell 3 is excited. Along with this, the laser light emitted from the incident optical system 32 and incident on the dye cell 3 is amplified by the excited dye, and the beam shape and the beam quality are adjusted by the interstage optical system 34 composed of a lens and a pinhole. And enters the dye cell 3 of the second optical amplifier. The first
The distance between the dye cell 3 of the optical amplifier and the partial reflection mirror 27 of the dye laser oscillator 22 was 6 m. Further, slits may be used instead of pinholes.

Therefore, in the dye laser device as described above, the incident optical axis is aligned by the optical fiber coupling device 30 so that the amount of light reflected from the optical fiber 31 is minimized, and the incident power is kept constant. By making the laser optical axis incident on the dye cell 3 of the first optical amplifier via 32 constant, the superradiation ASE (Amplified Spontanious Emis) of the output of the dye cell 3 is set.
sion) amount and output can be kept to a minimum.

Further, the fact that the output optical axis of the optical fiber is kept constant regardless of the incident optical axis, the path and the length of the optical fiber makes use of the dye laser oscillator 22 having the largest optical axis change. By arranging the optical fiber 31 on the optical axis between the dye cell 3 of the first optical amplifier and the dye cell 3 of the first optical amplifier, the incident optical axis of the dye cell 3 of the first optical amplifier can be kept constant. The light is always maximum. Further, by providing the incident optical system 3 between the optical fiber 31 and the dye cell 3, it is possible to shape the beam into an optimum beam shape for amplification, the amplification efficiency is increased, and a high output is obtained.

Further, since the optical fiber 31 is a single mode fiber, no difference in optical phase is caused during optical transmission, so that a bright and dark fringe pattern does not occur in the emitted beam, and the natural phase amplified during laser amplification is not generated. The ratio of the superradiation ASE of the emitted return light decreases.

That is, when a multimode fiber is used, many different phases are generated during long transmission and the beam converging property is deteriorated. Even if the focusing lens is used, the light signal of the dye laser oscillator 22 can be secured and the beam intensity is improved, so that the gain is increased and the output is increased. Therefore, the superradiation ASE is reduced. Become. For example, when the graded index optical fiber was changed to a single mode fiber, the divergence angle was reduced to 1/2, the output was improved by 20%, and the superradiation ASE was reduced to 1/2.

In the above embodiment, the optical path length between the dye laser oscillator 22 and the dye cell 3 of the first optical amplifier is L.
Then, when the full width at half maximum of the optical pulse of the copper vapor laser 33 as the excitation light source of the first optical amplifier is Δt _P , the optical path length L is arranged so as to satisfy the following expression (1),
Furthermore, a stable laser output of high quality and high output can be obtained. L ≧ 0.5 × (Δt _P × C) (1) C: speed of light in air

That is, now, the excitation light pulse from the copper vapor laser 33 is incident on the dye cell 3 of the first optical amplifier via the half mirror 11 and the cylindrical lens 6 to excite the dye, and this excitation causes the excitation. Fluorescence is generated during the light generation period, and when there is no signal light from the dye laser oscillator 22 side at the time of fluorescence generation, stimulated emission is not performed and amplification is not performed, but the signal light of the dye laser oscillator 22 is a continuous wave. It is amplified because it exists.

However, the signal light of the dye laser oscillator 22 does not completely coincide with the fluorescence generation region, and
Fluorescence that does not accompany the stimulated emission that is not on the optical axis is emitted in all directions, and assuming that part of the fluorescence emitted in all directions is incident on the dye laser oscillator 22 side, the fluorescence constitutes a resonator. The light is reflected by the total reflection mirrors 25 and 28 and the partial reflection mirror 27 in the dye laser oscillator 22 and returns to the dye cell 33 of the first optical amplifier again.

For this reason, if fluorescence generated by the excitation light and return light from the dye laser oscillator 22 side due to the generation of the fluorescence exist at the same time during the generation period of the excitation light, stimulated emission is performed, and the dye laser oscillator is generated. It is output together with the signal light of No. 22, which lowers the required laser output and the quality.

Therefore, by delaying the returning time of the return light from the dye laser oscillator 22 side outside the generation period of the excitation light, it is possible to prevent the deterioration of the laser output and the deterioration of the quality. Even if the return light is delayed outside the generation period of the excitation light, the return light advances very slightly in the same direction as the signal light from the dye laser oscillator 22, but the quality of the return light is diverged due to poor quality. It is almost never included.

That is, it is sufficient to change the timing at which the fluorescence is generated, the fluorescence is reflected from the dye laser oscillator 22 side and excited, that is, the timing of returning to the dye cell 3 of the first optical amplifier is changed. The dye laser oscillator 22
The round trip time Δt between the dye cell 3 and the dye cell 3 of the first optical amplifier and returning is Δt = 2L / C (2), and this round trip time Δt is defined as the excitation light generation period, That is, by making it larger than the full width at half maximum Δt _p of the light pulse of the copper vapor laser 33, it is possible to ignore the influence of the above-mentioned return light, and therefore the optical path length L is L ≧ 0. 5 × Δt _p × C is required.

Here, assuming that the pulse width of the optical pulse of the excitation light emitted from the copper vapor laser 33 is t _p and the repetition frequency is f ₁ , the pause period t between the optical pulses of the excitation light repeatedly emitted is t. _R is represented by t _R = 1 / f−t _P (3), and therefore the round trip time Δt of the return light is the optical path length L so that the relationship of t _P ≦ Δt ≦ t _R (4) holds. Must be limited, and without this limitation, the return light will be amplified during the sending period of the next optical pulse of the pumping light.

In this way, the superradiation ASE is reduced to 1/2 by setting the optical path length L and providing the delay optical path so that the superradiation ASE of the output of the dye cell 3 due to the returning light is not amplified. Below,
The output result has increased by 20%.

Further, in the above embodiment, by providing the optical isolator 29 at the emission port of the dye laser oscillator 22, it is possible to prevent the optical transmission in the direction from the dye cell 3 to the dye laser oscillator 22 side. It is possible to eliminate as much as possible the generation of return light that is generated from the cell 3, reflected by the partial reflection mirror in the dye laser oscillator 22 via the incident optical system 31, and then returns to the dye cell 3 again. Radiation ASE is reduced.

Example 2. Although the single mode fiber is used as the optical fiber 31 in the first embodiment, a polarization-maintaining optical fiber can also be used. The polarization-maintaining optical fiber can enter the light of the polarization direction most suitable for amplification, and the amplification efficiency is improved. In that case, the output was about 20% higher than when using a distributed index optical fiber having no polarization plane preserving property. Further, in the case of a single mode fiber, the transverse mode is preserved and the light is transmitted, and the converging property is secured, but there is no polarization information. But,
Experimental data has been obtained that the output is improved by 20% when polarized light is input as a signal, which is useful.

[0038]

As described above, according to claim 1 of the present invention, between the dye laser oscillating means for oscillating the dye laser light and the optical amplifying means for amplifying the dye laser light,
By providing a single-mode optical fiber, the output optical axis of the optical fiber is kept constant regardless of the incident optical axis, the optical fiber path, and the length. The incident optical axis to the optical amplifying means can be kept constant, and the laser light is always maximized. Further, since the optical phase difference is not generated during the optical transmission, the bright and dark fringe pattern does not occur in the emitted beam, and the ratio of the superradiation ASE of the spontaneously radiated return light amplified at the time of laser amplification is reduced. is there.

According to claim 2, the optical path length between the dye laser oscillation means for oscillating the dye laser light and the optical amplification means for amplifying the dye laser light is L, and the optical amplification means is excited. When the full width at half maximum of the light pulse of the light source is Δt _P and the speed of light in air is C, by setting an optical path length L that satisfies L ≧ 0.5 × Δt _P × C, optical amplification by returning light is performed. It is possible to provide a delay optical path in which the superradiation ASE of the output of the means is not amplified, and the return time of the return light from the dye laser oscillation means side is outside the generation period of the excitation light in the optical amplification means. By delaying the delay time, it is possible to prevent a decrease in laser output and a decrease in quality due to stimulated emission.

According to a third aspect of the present invention, the dye laser oscillating means for oscillating the dye laser light is returned to the dye laser oscillating means from the optical amplifying means for amplifying the dye laser light at the exit of the dye laser oscillating means. By providing an optical isolator that removes the return light reflected in the oscillating means and entering the optical amplifying means again, it is possible to prevent optical transmission in the direction from the optical amplifying means to the dye laser oscillating means, and to generate from the optical amplifying means. Then, it can be transmitted to the dye laser oscillating means through the incident optical system, and the return light which is reflected in the dye laser oscillating means and returns to enter the optical amplifying means again can be removed as much as possible. This has the effect of reducing radiation ASE.

Further, according to claim 4, by providing a polarization-maintaining optical fiber between the dye laser oscillating means for oscillating the dye laser light and the optical amplifying means for amplifying the dye laser light, There is an effect that light having a polarization direction most suitable for amplification can be made incident and the amplification efficiency is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a dye laser device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional dye laser device.

[Explanation of Codes] 3 Dye Cell 22 Dye Laser Oscillator 29 Optical Isolator 31 Optical Fiber 33 Copper Vapor Laser

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[Procedure amendment]

[Submission date] May 11, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

Next, the operation will be described. A solution obtained by dissolving a dye in an organic solvent or the like is circulated at a high speed inside the oscillation stage dye cell 2 and the plurality of light amplification dye cells 3 ... 3 by a dye pump 5. And each cell 2, 3
The pulsed excitation light from the excimer laser 1, which is the excitation light source placed on the oscillation stage dye cell 2 side, is included in half mirrors 11 ... 11, mirrors 12 ...
3 guided by the configuration excitation light inducible system allows each cell Le through respective cylindrical lens 6 ... 6
It is irradiated to linearly condensed on.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

Since the conventional dye laser device is constructed as described above, in the amplification system,
The spontaneous emission light that is generated is also taken into the optical fiber 4 at the same time, which deteriorates the laser quality and complicates the configuration of connecting the cells with the optical fiber. Further, a dye laser system of iteration count number and a large output, the laser output is increased, Ri optical fiber 4 there is a problem such as easily and lose scratches occurred in the previous pulse
Low beam quality due to superradiation ASE
There was a problem to go down.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

A dye laser device according to a second aspect of the present invention is
The optical path length between the dye laser oscillating means for oscillating the dye laser light and the optical amplifying means for amplifying the dye laser light is L, the full width at half maximum of the optical pulse of the excitation light source of the optical amplifying means is Δt _P , Let the speed of light in air be C, and let the refractive index of the transmission medium be n.
Then, the optical path length L is set so as to satisfy L ≧ 0.5 × Δt _P × C ÷ n .

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

According to a second aspect of the present invention, the optical path length between the dye laser oscillating means for oscillating the dye laser light and the light amplifying means for amplifying the dye laser light is L, and the optical amplifying means is L. Let Δt _{P be} the full width at half maximum of the optical pulse of the pumping light source, and let C be the speed of light in the air, and let the refractive index of the transmission medium be n.
Then, by setting the optical path length L satisfying L ≧ 0.5 × Δt _P × C ÷ n , a delay optical path in which the superradiation ASE of the output of the optical amplifying means by the returning light is not amplified is set. By delaying the returning time of the return light from the dye laser oscillating means outside the generation period of the excitation light in the optical amplifying means, it is possible to reduce the laser output and the quality due to the stimulated emission. prevent.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

Reference numeral 29 is an optical isolator for transmitting the dye laser light emitted from the dye laser oscillator 22 in the direction of the optical fiber coupling device 30 and for blocking the reverse transmission.
Reference numeral 0 is an optical fiber coupling device (for example, manufactured by Newport, for introducing the dye laser light through the optical isolator 29 into a single mode optical fiber (refractive index 1.5) 31.
Single mode fiber automatic alignment system FX-1
000G5 type), 32 is an incident optical system formed of a lens and a pinhole and shaped into a beam.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

On the other hand, the excitation light is emitted from the copper vapor laser 32, the excitation light output is divided by the half mirror 11, the beam is shaped by the cylindrical lens 6, and the pigment (not shown) in the pigment cell 3 is excited. Along with this, the laser light emitted from the incident optical system 32 and incident on the dye cell 3 is amplified by the excited dye, and the beam shape and the beam quality are adjusted by the interstage optical system 34 composed of a lens and a pinhole. And enters the dye cell 3 of the second optical amplifier. The first
The dye cell 3 of the optical amplifier and the partial reflection mirror 27 of the dye laser oscillator 22 are optically coupled using a 6 m optical fiber .
Further, slits may be used instead of pinholes.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

In the above embodiment, the optical path length between the dye laser oscillator 22 and the dye cell 3 of the first optical amplifier is L.
Then, when the full width at half maximum of the optical pulse of the copper vapor laser 33 as the excitation light source of the first optical amplifier is Δt _P , the optical path length L is arranged so as to satisfy the following expression (1),
Furthermore, a stable laser output of high quality and high output can be obtained. L ≧ 0.5 × Δt _P × C / n (1) C: speed of light in air, n: refractive index of medium

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

That is, it is sufficient to change the timing at which the fluorescence is generated, the fluorescence is reflected from the dye laser oscillator 22 side and excited, that is, the timing of returning to the dye cell 3 of the first optical amplifier is changed. The dye laser oscillator 22
The round trip time Δt between the dye cell 3 and the dye cell 3 of the first optical amplifier and returning is Δt = 2L / C (2), and this round trip time Δt is defined as the excitation light generation period, That is, by making it larger than the full width at half maximum Δt _p of the light pulse of the copper vapor laser 33, it is possible to ignore the influence of the above-mentioned return light, and therefore the optical path length L is L ≧ 0. 5 × Δt _p × C / n is required.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

According to claim 2, the optical path length between the dye laser oscillation means for oscillating the dye laser light and the optical amplification means for amplifying the dye laser light is L, and the optical amplification means is excited. The full width at half maximum of the light pulse of the light source is Δt _P , the speed of light in air is C, the refractive index of the transmission medium is n, and the optical path length L is set to satisfy L ≧ 0.5 × Δt _P × C ÷ n By doing so, it is possible to provide a delay optical path in which the superradiation ASE of the output of the optical amplifying means due to the returning light is not amplified, and the returning time of the returning light from the dye laser oscillating means side is set to the above optical amplification. By delaying the generation time of the excitation light by the means, it is possible to prevent a decrease in laser output and a decrease in quality due to stimulated emission.

Claims (4)

[Claims] 1. A dye laser device comprising a single mode optical fiber provided between a dye laser oscillating means for oscillating the dye laser light and an optical amplifying means for amplifying the dye laser light. 2. The optical path length between the dye laser oscillation means for oscillating the dye laser light and the optical amplification means for amplifying the dye laser light is L, and the full width at half maximum of the optical pulse of the excitation light source of the optical amplification means is L. Is set to Δt _P and the speed of light in air is C, and a dye laser device is set to an optical path length L that satisfies L ≧ 0.5 × Δt _P × C. 3. The dye laser oscillating means for oscillating the dye laser light is returned to the dye laser oscillating means from the optical amplifying means for amplifying the dye laser light, and is reflected in the dye laser oscillating means. A dye laser device characterized by further comprising an optical isolator for removing return light that is incident on the optical amplifying means again. 4. A dye laser device comprising a polarization-maintaining optical fiber provided between a dye laser oscillating means for oscillating the dye laser light and an optical amplifying means for amplifying the dye laser light.