JP2805046B2 - Laser beam integrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a laser beam integrator for converting a large number of laser beams into one high-power Stokes light using stimulated scattering amplification.

[0002]

2. Description of the Related Art As a conventional laser beam integrator, Th
e Journal of the Optical Society of America B, Vo
The thing shown in FIG. 1 published in l.3 No.10 / October p. 1383, 1986 is known. In this laser beam integrator, a large number of excitation light beams P1 to P4 are incident on a light guide (Raman medium container) 1 and their energy is increased by one Stokes light S propagating in the axial direction of the light guide 1. Forward guided Raman conversion was performed for efficiency, and beam integration was performed.

FIG. 2 shows an IEEE Journal of the IEEE
Quantum Electronics Vol QE-18, No.3 March P.405 19
In the laser beam integrator described on page 82, since the backward guided Raman amplification is used, the Stokes light S travels in the light guide 1 in the direction opposite to the pumping light P1, P2, and the two pumping light P1, P2 The light was integrated into one Stokes light S.

[0004] Excitation lights P1 to P4 of these beam combiners
Since the light propagates while being reflected up and down in the light guide 1, the intensity distribution of the integrated Stokes light S in the beam section can be made uniform.

In the conventional beam integrator shown in FIG. 1, since the angles of incidence of many excitation lights (P1 to P4) on the ride guide 1 are different, the axial direction of the light guide 1 for each of the excitation lights P1 to P4 is different. When the pulse width of the excitation light is reduced due to the difference in the propagation speed of each beam to the light guide, the beams are shifted from each other as they propagate through the light guide 1. Further, the Stokes light S and the excitation lights P1 to P4
Since the light guides 1 have different speeds in the axial direction, there is a problem that the light guides 1 deviate as they propagate.

Since the beam integrator shown in FIG. 2 is a backward guided Raman amplifier, the length of the light guide 1, which is a medium container, is determined by the distance between the excitation light pulse and the Stokes light pulse. In addition, the Raman gain proportional to the length of the container becomes small, and there is a problem that a sufficient conversion from pump light to Stokes light cannot be obtained.

Prior to the present application, one of the inventors of the present invention stated, "First, two opposing reflecting mirrors for repeatedly reflecting input excitation light for exciting a Raman medium.
Reflection means, and second reflection means constituting two opposing reflection mirrors for repeatedly reflecting input Stokes light traveling in the Raman medium are arranged in the Raman medium,
The first reflection means and the second reflection means are combined so as to form a hollow quadrangular prism, and the two reflection mirrors constituting the first reflection means are coupled to the input excitation light. Stimulated Raman pulse amplifier having a structure that does not reflect the spontaneous primary Stokes light generated by the input light, and the two reflecting mirrors that constitute the second reflecting means have a structure that does not reflect the spontaneous secondary Stokes light generated by the input Stokes light. (Japanese Patent No. 1976374 (Japanese Patent Publication No. 7-28075)). Applying such a configuration using a wavelength selection mirror that reflects only the excitation light and attenuates the spontaneous Stokes light as the light guide 1 of the multiple beam combiner of FIG. In the beam integration, the excitation light P is applied to the light guide 1 at different angles.
1 to P4 are incident, so it is difficult. Therefore, it is difficult for the laser beam integrator of FIG. 1 to suppress the spontaneous Stokes light caused by the excitation light itself.

The Stokes light S shown in FIGS.
Since the light was not reflected by the light guide 1, the higher-order spontaneous Stokes light was not attenuated. In order to attenuate the higher-order Stokes light, a method of arranging a wavelength selective mirror in the optical path is conceivable, but there is a problem that the pump light and the Stokes light are lost.

[0009]

Accordingly, it is an object of the present invention to provide a laser beam integrator which solves the above-mentioned conventional problems. That is, the problem of the present invention is that the excitation light and the Stokes light in the light guide do not shift with propagation, and even when the excitation light is a short pulse, the conversion from the excitation light to the Stokes light is sufficiently performed. Another object of the present invention is to provide a laser beam integrator capable of suppressing spontaneous Stokes light by the excitation light itself and attenuating higher-order spontaneous Stokes light.

[0010]

According to a first aspect of the present invention, there is provided a laser beam integrator according to the present invention, wherein a plurality of laser excitation lights and Stokes lights are incident on a light guide and stimulated scattering is performed. In a laser beam integrator that integrates the plurality of laser excitation lights into one Stokes output light by amplification, excitation light incidence means for causing the multiple laser excitation lights to enter the light guide at a constant incident angle, Stokes light incidence means for causing the incident Stokes light to enter the light guide at an angle equal to a constant incident angle of the excitation light, and output Stokes light integration for integrating a plurality of Stokes lights output from the light guide into one beam. Means.

According to a second aspect of the present invention, there is provided the laser beam integrator according to the first aspect, wherein the excitation light incident means includes a semi-transparent mirror that divides the excitation light in two directions, At least one set of reflecting mirrors for reflecting the divided excitation light toward the light guide at a certain angle is provided.

According to a third aspect of the present invention, in the laser beam integrator according to the second aspect, the propagation angles of a plurality of excitation lights having different propagation angles are fixed in front of the incident side of the semi-transparent mirror. And a segment mirror for adjusting the distance is further provided.

The laser beam integrator according to a fourth aspect of the present invention is the laser beam integrator according to the first aspect, wherein the Stokes light incidence means includes: a semi-transparent mirror that divides the excitation light in two directions; At least one set of reflecting mirrors for reflecting the divided excitation light toward the light guide at a predetermined angle is provided.

According to a fifth aspect of the present invention, there is provided the laser beam integrator according to the first aspect, wherein the excitation light incident means is further provided with the light guide.
An optical path length adjusting means is provided for aligning the positions of the end faces of the respective pulse waveforms of the plurality of excitation lights in the axial direction of the light guide to reduce the deviation between the respective excitation lights.

Further, in the laser beam integrator according to claim 6 of the present invention, in the laser beam integrator according to claim 5, the optical path length adjusting means makes the plurality of reflecting mirrors have the same inclination angle and sets the installation horizontal position. It is characterized by comprising optical systems arranged differently.

According to a seventh aspect of the present invention, in the laser beam integrator according to the first aspect, the Stokes light incident means further includes a plurality of Stokes lights in the light guide 1. An optical path length adjusting means is provided for reducing the deviation between the Stokes lights by aligning the positions of the pulse waveform end faces in the axial direction of the light guide.

In the laser beam integrator according to an eighth aspect of the present invention, in the laser beam integrator according to the seventh aspect, the optical path length adjusting means shifts the inclination angle of each of the two sets of reflecting mirrors. It is characterized by comprising an installed optical system.

According to a ninth aspect of the present invention, in the laser beam integrator according to the seventh aspect, the optical path length adjusting means includes a plurality of high refractive indexes made of a material having a high refractive index and having different thicknesses. It is characterized by being combined with a light transmitting layer.

According to a tenth aspect of the present invention, in the laser beam integrator according to the fifth aspect, the optical path length adjusting means according to the eighth or ninth aspect is further provided as an optical path length fine adjusting means. It is characterized by having.

The laser beam integrator according to claim 11 of the present invention is the laser beam integrator according to claim 1, wherein the output Stokes light integrating means includes a reflector for intersecting a plurality of output Stokes lights with each other; Λ which rotates one polarization direction of the plurality of output Stokes lights by 90 degrees
And a polarizing plate provided at a crossing position of the plurality of output Stokes lights.

According to a twelfth aspect of the present invention, in the laser beam integrator according to the eleventh aspect, the output Stokes light integrating means is the optical path length adjusting means according to the eighth or ninth aspect. Is further provided as an optical axis direction position adjusting means for the plurality of output Stokes lights in which the input and output directions are reversed.

The laser beam integrator according to a thirteenth aspect of the present invention is the laser beam integrator according to the first aspect, wherein two opposing reflecting mirrors for repeatedly reflecting input excitation light for exciting the Raman medium. A first reflecting means and a second reflecting means forming two opposing reflecting mirrors for repeatedly reflecting input Stokes light traveling in the Raman medium are arranged in the Raman medium; The first reflecting means and the second reflecting means are combined so as to form a hollow quadrangular prism, and two reflecting mirrors constituting the first reflecting means are moved by the input excitation light. The two reflecting mirrors constituting the second reflecting means are configured to reflect the spontaneous secondary Stokes light generated by the input Stokes light. It stimulated Raman pulse amplifier and have structures characterized by using as the light guide.

[0023]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, first, a specific correlation is provided in the angle of incidence of the excitation light and the Stokes light into the light guide. Secondly, there is provided an incident means for adjusting an incident angle of each light beam before being incident on the light guide for realizing a specific incident angle of the excitation light and the Stokes light on the light guide.

With this configuration, according to the present invention, the pump light and the Stokes light in the light guide do not shift with the propagation, and the conversion from the pump light to the Stokes light is sufficient even when the pump light is a short pulse. The present invention is to provide a laser beam integrator capable of suppressing spontaneous Stokes light by the excitation light itself and attenuating higher-order spontaneous Stokes light.

Such an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 3, the axis of the light guide 1 is the Z axis, and the excitation lights P1 to P6 propagate on the XZ plane, and the Stokes light S propagates on the YZ plane. Hereinafter, the X-axis direction is referred to as up and down, and the Y-axis direction is referred to as left and right direction.

In order to make the velocities of the many excitation lights P1 to P6 in the axial direction of the light guide 1 the same, the excitation light P
1 to P6 are incident on a pair of reflecting mirrors 6a and 6b arranged in the light guide 1 so as to face each other in the vertical direction at a fixed angle.
FIG. 4 shows the optical axis of the excitation light on the XZ plane in this case. On the other hand, in the Stokes light, a set of left and right reflecting mirrors 7a and 7b, which are not used for the excitation light, are applied to the Stokes light S so as to have the same velocity as the excitation light in the axial direction.
At an angle equal to a constant incident angle of the excitation light. Therefore, the optical arrangement of the Stokes light in this case is the same as that of the excitation light, and the number of beams from two directions is one.
This corresponds to the case of a book. FIG. 5 shows the optical axis of the Stokes light on the YZ plane in this case.

Further, in the present invention, the adjustment for making the incident angles of the plurality of light beams having different propagation angles to the light guide 1 constant is performed by using the incident means as shown in FIGS. Do. First, as shown in FIG. 6, a large number of pump lights P1 to P3 having different propagation angles are propagated in the same direction using a segment mirror 2 in which a large number of mirrors whose inclination angles can be independently set are assembled. The excitation light thus propagated in the same direction is then split by the semi-transparent mirror 3 as shown in FIG.
The light is uniformly incident on the light guide 1 by using the light guide 4.

Further, in another configuration of the present invention, the Stokes light S is made incident using an incidence means as shown in FIG. That is, after the two beams are formed by the semi-transparent mirror 5, the beams are uniformly incident on the light guide 1 from the left and right directions by using the reflecting mirrors 8 and 8 arranged on the left and right.

In the light guide 1, as shown in FIG. 9, the axis (Z axis) of the light guide 1 and the excitation lights P1, P2,
The position of the pulse waveform end face of each beam in the Z-axis direction is shifted due to the relationship between the angle of P3 and the optical axis. Therefore, it is necessary to reduce the deviation of each beam by aligning the positions of the pulse waveform end faces of the respective beams in the Z-axis direction as shown in FIG. In order to align the end faces of the respective excitation lights in the light guide 1 in the axial direction of the light guide 1 as shown in FIG.
An optical path length adjusting means as shown in FIG. That is, on the incident side of the light guide 1, the plurality of reflecting mirrors M1, M
2 and M3 have the same inclination angle, and constitute an optical system arranged at different installation horizontal positions.
2 and M3 by reflecting the respective excitation lights P1, P2 and P3. If the optical path length adjusting means for the Stokes light described below is used together as the optical path length fine adjusting means in each beam, more precise position control can be performed.

The two separated Stokes beams S11, S1
As shown in FIG. 12, two sets of reflecting mirrors M1 and M
An optical system is used in which 3 and M2 and M4 are installed with the inclination angle of each pair shifted. These reflecting mirrors M1, M3 and M2,
M4 reflects the Stokes lights S11 and S12, respectively. As described above, after the Stokes light is spatially divided and the optical path length of each portion is adjusted by the reflecting mirrors M1 to M4,
Combine.

The position adjustment of the Stokes light may be performed by the optical path length adjusting means as shown in FIG. 13 instead of the optical path length adjusting means using the reflecting mirrors M1 to M4 as described above. That is, each beam is used as an optical path length adjusting means by combining high refractive index light transmitting layers V1 and V2 of different thicknesses made of a material V with a high refractive index, and these layers V1 and V
2, the position of the Stokes light in the light guide 1 can be adjusted by adjusting the optical path length.

On the other hand, the same optical system as that shown in FIG. 12 or 13 can be used as the optical axis direction position adjusting means for adjusting the position in the optical axis direction in the output Stokes light. That is, as described above, the leading ends of the pulses of the output Stokes light that are shifted because the wavelength ends are aligned in the Z-axis direction in the light guide 1 are aligned again in the optical axis direction. Therefore, in the optical arrangement shown in FIGS.
The optical path of S12 is reversed and made incident.

Since the Stokes light output from the light guide 1 is composed of two beams, as shown in FIG. 14, they are crossed by a pair of reflecting mirrors 9 and 9 to be integrated into one beam. And the polarization direction of one beam is λ / 2
The light is rotated 90 degrees by the wave plate 10 and integrated into one beam by the polarizing plate 11.

As shown in FIG. 3, the excitation lights P1 to P6 and the Stokes lights S1 and S2 are formed by a pair of reflecting mirrors 6a and 6b facing the light guide 1 in the vertical and horizontal directions, respectively.
And 7a and 7b are propagated by multiple reflection at a fixed incident angle. Respective reflecting mirrors 6a, 6b and 7
For a and 7b, a dielectric multilayer mirror that reflects only the excitation light and the Stokes light is used.

(Function) The speed Vz in the axial direction of the light guide 1 is given by Vz = θ, where θ is the angle between the propagation direction of the excitation light and Stokes light and the axial direction of the light guide 1 and v is the speed.
vcos θ. That is, the velocities of the excitation light and the Stokes light in the axial direction of the light guide 1 are determined by the angle of incidence on the light guide 1. In the case of excitation light, each beam P
By making the incident angles 1 to P6 the same, the speed in the axial direction is made equal. By setting the incident angle of the Stokes light equal to the incident angle of the excitation light, the axial velocities of the Stokes light and the excitation light become equal.

The Stokes light incident from the left-right direction with respect to the excitation light incident from the vertical direction is split by the semi-transparent mirror 5 as shown in FIG. At the entrance of the light guide 1, the split beams of the excitation light and the Stokes light are inverted and overlapped in the vertical and horizontal directions, so that the intensity within the cross section of the light guide 1 is symmetrical and uniform.

As shown in FIG. 14, two beams of output Stokes light S1 _o and S2 _o are incident on the polarizing plate 11 by a pair of reflecting mirrors 9 and 9 which are opposed to each other in the left-right direction. One Stokes light S1 _o is reflected by the polarizing plate 11, while the other Stokes light S2 _o is reflected by the λ / 2 wave plate 10 and has a polarization direction of 90 _°.
Since the light rotates, the light passes through the polarizing plate 11 and is integrated into one beam. In this case, after the Stokes light S2 _o is the left and right intensity distribution at the exit of the light guide 1 has been inverted, the overlap with the other of the Stokes light S1 _o, the intensity in the cross section of the integrated Stokes light S _o uniform becomes symmetrical Become

As described above, in the present invention, as shown in FIG. 3, the excitation lights P1 to P6 and the Stokes lights S1 and S2 are separated from each other by different reflecting mirrors 6a and 6b and 7a and 7b.
The light propagates through the light guide 1 while maintaining a constant incident angle with respect to the light. Therefore, as described in Japanese Patent No. 1976374, by configuring each of the reflecting mirrors 6a, 6b and 7a, 7b of the light guide 1 so as to reflect only light of a specific wavelength, each of the reflecting mirrors 6a, 6b and 7a, 7b can be formed by excitation light and Stokes light. Spontaneous Stokes light can be suppressed.

Further, the excitation light P1 to P6 is
At a certain angle, the light guide 1
As shown in FIG. 9, the excitation lights P1, P2,
P3 will be described as an example.
Due to the angle at which the optical axis of P2 intersects with the axis of the light guide 1, the head of each of the excitation light pulses P1, P2, P3... Is in the optical axis direction of the light guide 1 (Z-axis direction). Shift. Since this shift causes a loss of the effective superposition of the excitation light and the Stokes light in the light guide 1, it is important to adjust the shift before entering the light guide 1. Such an adjustment is realized by adjusting the optical path length of each of the beams P1, P2, and P3 by an optical path adjusting means including the reflecting mirrors M1, M2, and M3 shown in FIG. As a result, as shown in FIG. 10, the leading positions of the pulses of each excitation light in the axial direction of the light guide 1 can be matched. By adjusting the position of the Stokes light in the axial direction of the light guide 1 in the same manner, the excitation light and the Stokes light can be effectively overlapped.

[0041]

Embodiments of the present invention will be described below.

As shown in FIG. 3, the light guide 1 is filled with a stimulated scattering medium. Stokes light S (S
1, S2) propagate on the YZ plane, and the excitation lights P1 to P6 propagate on the XZ plane by multiple reflection in the light guide 1 at a certain angle with respect to the axial direction. A pair of upper and lower reflecting mirrors 6a and 6b of the light guide 1 reflect only the excitation lights P1 to P6, and a dielectric multilayer mirror is used as the reflecting mirrors 6a and 6b so that the reflection of spontaneous Stokes light does not occur. On the other hand, light guide 1
The left and right reflecting mirrors 7a and 7b reflect the Stokes lights S1 and S2 and do not reflect the spontaneous higher-order Stokes lights. The excitation lights P1 to P6 are obtained by dividing the excitation lights P1, P2 and P3 by the semi-transparent mirror 3 shown in FIG. Therefore, the excitation light beams P1 and P6, and P2 and P6
5, P3 and P4 have the same strength as each other. Similarly, the Stokes light beams S1 and S2 have the same intensity because they are obtained by dividing the Stokes light S by the semi-transparent mirror 5.

The output Stokes light S amplified and output in the light guide 1 by these pumping lights P1 to P6
1 _o and S 2 _o are turned into one beam S _o by a set of reflecting mirrors 9 and 9 and a polarizing plate 11. In this case, after one of the Stokes light S2 _o is the left and right intensity distribution at the exit of the light guide 1 is inverted, because the overlap with the other of the Stokes light S1 _o, the intensity in the cross section of the integrated Stokes light S _o is It becomes symmetrical and uniform.

Hereinafter, specific conditions in this embodiment will be described.

Excitation light wavelength 249 nm Excitation light wavelength width 0.5 cm ^-1 Excitation light pulse width 100 ps (corresponding pulse length 3 cm) Incident excitation light intensity 10 ⁹ W / cm ² Number of excitation light beams 6 Pump light beam size 2 × 3 cm Stokes light wavelength 268 nm Stokes light wavelength width 0.5 cm ⁻¹ Stokes light pulse width 100 ps Incident Stokes light intensity 10 ⁶ W / cm ² Stokes light beam number 1 Stokes light beam Size 6 × 6cm Stimulated scattering medium Methane 2 atm Wavelength width of vibration of medium 0.4cm ^-1 Length of light guide 150cm Diameter of light guide Up / down 6cm Left / right 6cm Reflector for excitation light of light guide Incident angle 45 ° Light guide Stokes light reflector 45 ° The Raman gain under the above conditions was 11.2, and the intensity ratio between the incident pump light and the Stokes light was 10 ^-3 . As a result, the conversion efficiency from a large number of excitation lights to a single Stokes light energy is 80% even if a loss due to multiple reflections in the light guide is included.

The Raman gain of the spontaneous Stokes light is increased by 4.3 times to 48 due to the effect of the wavelength width of the pump light and the effect of the difference in the polarization direction between the pump light and the Stokes light. However, the spontaneous Stokes light gain is reduced by 3 each time the light is reflected by the light guide reflector, and the light is reflected 24 times by the light guide reflector under the above conditions, so that the spontaneous Stokes gain can be sufficiently suppressed.

On the other hand, as in the conventional beam integrator shown in FIGS. 1 and 2, the excitation lights P1 and P2 propagate between the mirrors of the light guide 1 facing each other at an incident angle of 45 degrees, and the Stokes light S is transmitted along the axis. When the Stokes light S enters the light guide 1 and travels 8.5 cm, the excitation light P1,
P2 advances only 6 cm in the axial direction. The difference between the two is 2.
5 cm. The pulse width of the pump light P1, P2 and the Stokes light S is 100 ps, and the corresponding distance is 3c.
m, the excitation light P1, P2 in the light guide 1
And the pulses of the Stokes light S hardly overlap. On the other hand, in the present application, since the pulse position of the incident light of the excitation light and the Stokes light is adjusted in the direction of the light guide axis, the displacement is eliminated, and highly efficient beam integration can be performed.

In the case of backward Raman scattering amplification of FIG.
The length of the light guide 1 is 1.5 cm, which is half the pulse width of the pumping light P1 and P2. At the pumping light intensity and gas pressure as described above, the Raman gain becomes 1/100 and almost from the pumping light. Does not convert to Stokes light energy. If the pumping light intensity is increased by 10 times or more, dielectric breakdown in the medium may occur. If the gas pressure is increased by 10 times or more, the Raman oscillation bandwidth becomes wide and the Raman gain does not increase, so that backward Raman scattering is performed. Amplification cannot integrate short pulse laser light.

[0049]

As described above, the excitation light and the Stokes light are made to be incident on the light guide composed of a pair of reflecting mirrors arranged opposite to each other at a fixed angle, whereby the short pulse is generated. It becomes possible to integrate multiple beams of laser light with light. Furthermore, since the generation of spontaneous Stokes light can be suppressed and the pump light can be converted into Stokes light with high efficiency, the output of the output Stokes light can be increased and the waveform can be controlled. Due to these advantages, the application of the beam integrator to the short pulse laser light application field can be expected to expand rapidly in the industry.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a conventional laser beam integrator.

FIG. 2 is a schematic configuration diagram showing another example of a conventional laser beam integrator.

FIG. 3 is an optical circuit diagram showing a schematic configuration of a laser beam integrator according to the present invention.

FIG. 4 is an optical circuit diagram showing an optical path of an excitation light beam according to the present invention.

FIG. 5 is an optical circuit diagram showing an optical path of Stokes light in the present invention.

FIG. 6 is a configuration diagram showing a part of an excitation light incident means in the present invention.

FIG. 7 is a configuration diagram showing a remaining portion of the excitation light incidence means in the present invention.

FIG. 8 is a configuration diagram of a Stokes light incidence unit in the present invention.

FIG. 9 is an explanatory diagram showing a leading position of an excitation light pulse in a light guide when an optical path length adjusting unit according to the present invention is not used.

FIG. 10 is an explanatory diagram showing a leading position of an excitation light pulse in a light guide when an optical path length adjusting unit according to the present invention is used.

FIG. 11 is a schematic configuration diagram of an optical path length adjusting means of excitation light in the present invention.

FIG. 12 is a schematic configuration diagram of an example of an optical path length adjusting unit of Stokes light in the present invention.

FIG. 13 is a schematic configuration diagram of another example of the optical path length adjusting means of the Stokes light in the present invention.

FIG. 14 is a schematic configuration diagram of an output Stokes light integrating means in the present invention.

[Description of Signs] 1 Light guide (Raman medium container) 2 Segment mirror constituting excitation light incidence means 3 Semi-transparent mirror constituting excitation light incidence means 4 Reflector mirror constituting excitation light incidence means 5 Configuring Stokes light incidence means 6a, 6b Reflecting mirror for excitation light constituting a light guide 7a, 7b Reflecting mirror for Stokes light constituting a light guide 8 Reflecting mirror constituting incident means of incident Stokes light 9 Output Stokes light reflecting mirror 10 λ / 2 wavelength plate 11 polarizer P1~P6 incident excitation light S1,2 incident Stokes beam S _o, S1 _o, S2 _o constitutes the reflecting mirror V1, V2 optical path length adjusting means constituting the output Stokes beam M1~4 optical path length adjusting means Refractive index light transmitting layer

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiro Owadano 1-1-4 Umezono, Tsukuba, Ibaraki Pref., National Institute of Advanced Industrial Science and Technology (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/35 502 G02F 1/35 501

Claims (13)

(57) [Claims] 1. A laser beam integrator for injecting a plurality of laser excitation lights and Stokes light into a light guide and integrating the plurality of laser excitation lights into one Stokes output light by stimulated scattering amplification. Excitation light incidence means for causing the plurality of laser excitation lights to enter the light guide at a constant incident angle; and Stokes light for causing the incident Stokes light to enter the light guide at an angle equal to the constant incident angle of the excitation light. A laser beam integrator comprising: an incident means; and an output Stokes light integrating means for integrating a plurality of Stokes lights output from the light guide into one beam. 2. The excitation light incident means includes a semi-transparent mirror that divides the excitation light in two directions, and a set of reflecting mirrors that reflects the excitation light divided in two directions toward a light guide at a fixed angle. 2. The laser beam integrator according to claim 1, wherein the laser beam integrator has at least. 3. The laser according to claim 2, further comprising a segment mirror for adjusting the propagation angles of a plurality of excitation lights having different propagation angles to each other in front of the incident side of the semi-transparent mirror. Beam integrator. 4. The Stokes light incidence means includes a semi-transparent mirror that divides the excitation light in two directions, and a set of reflection mirrors that reflects the excitation light divided in two directions toward a light guide at a predetermined angle. 2. The laser beam integrator according to claim 1, wherein the laser beam integrator has at least. 5. The pump light incident means further aligns the end faces of the respective pulse waveforms of the plurality of pump lights in the light guide 1 in the axial direction of the light guide to reduce the deviation between the respective pump lights. The laser beam integrator according to claim 1, further comprising an optical path length adjusting means. 6. The laser beam integration according to claim 5, wherein said optical path length adjusting means comprises an optical system in which a plurality of reflecting mirrors are arranged at the same inclination angle and arranged at different installation horizontal positions. vessel. 7. The Stokes light incidence means further aligns the end faces of the pulse waveforms of the plurality of Stokes lights in the light guide 1 in the axial direction of the light guide to reduce the deviation between the Stokes lights. The laser beam integrator according to claim 1, further comprising an optical path length adjusting means. 8. The laser beam integrator according to claim 7, wherein said optical path length adjusting means comprises an optical system in which two sets of reflecting mirrors are installed at different inclination angles of each set. 9. The laser beam integration according to claim 7, wherein the optical path length adjusting means is a combination of a plurality of high-refractive-index light-transmitting layers having different thicknesses made of a high-refractive-index material. vessel. 10. The laser beam integrator according to claim 5, further comprising the optical path length adjusting means according to claim 8 or 9 as an optical path length fine adjusting means. 11. The output Stokes light integrating means includes: a reflector for intersecting a plurality of output Stokes lights with each other; a λ / 2 wavelength plate for rotating one polarization direction of the plurality of output Stokes lights by 90 degrees; The laser beam integrator according to claim 1, further comprising a polarizing plate provided at a crossing position of the plurality of output Stokes lights. 12. An optical system in which the output Stokes light integrating means is configured by reversing the input / output direction of the optical path length adjusting means according to claim 8 or 9 in the optical axis direction of the plurality of output Stokes lights. The laser beam integrator according to claim 11, further comprising a position adjusting unit. 13. A first reflecting means constituting two opposing reflecting mirrors for repeatedly reflecting input excitation light for exciting a Raman medium, and for repeatedly reflecting input Stokes light traveling in the Raman medium. Are disposed in a Raman medium, and the first and second reflecting means form a hollow quadrangular prism. And the two reflecting mirrors constituting the first reflecting means are structured so as not to reflect the spontaneous primary Stokes light generated by the input excitation light, and the two reflecting mirrors constituting the second reflecting means are formed. 2. The stimulated Raman pulse amplifier having a structure in which a reflecting mirror does not reflect spontaneous secondary Stokes light generated by the input Stokes light is used as the light guide. The described laser beam integrator.