JP2017069323A - Laser amplifier system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser amplifier system in which, by changing a position of laser reflection spot, a thermal load acting on a laser gain medium is dispersed.SOLUTION: A laser amplifier system includes: a first optical element (40; 40') which receives a seed light A and an excitation light B and outputs the seed light A and the excitation light B as a coaxial light C; an amplifier (60;60':60") for amplifying the seed light A; an input-side optical system (50;50';50";50''') for supplying the coaxial light C to the amplifier (60;60':60"); a drive mechanism (80;80';80") for changing an incident position 65/incident direction D of the coaxial light C with regard to the amplifier (60;60':60") by driving the input-side optical system (50;50';50";50'''); and a control device 90 for controlling the drive mechanism (80;80';80").SELECTED DRAWING: Figure 3A

Description

  The present invention relates to a laser amplification system, and more particularly to a laser amplification system that disperses a thermal load acting on a laser gain medium by changing the position of a laser reflection spot.

  In recent years, research and development of active mirror type solid-state laser systems (reflection-type solid-state laser systems) has been conducted. In an active mirror type solid-state laser system, a part of the surface of a disk or plate-like laser gain medium is covered with a reflective film. Laser light is introduced into the laser gain medium from a surface different from the surface covered with the reflective film, reflected by the reflective film, and output to the outside of the laser gain medium from a surface different from the surface covered with the reflective film. .

  Incidentally, in the fields of laser processing and defense, the required laser output increases, and the thermal load acting on the laser gain medium tends to increase.

  As a related technique, Patent Document 1 describes a solid-state laser device. The solid-state laser device described in Patent Literature 1 includes a solid-state laser gain medium, a refrigerant that cools the solid-state laser gain medium, and a refrigerant container that stores the refrigerant. The solid laser gain medium is disposed in the opening of the refrigerant container. When the solid laser gain medium is pressed toward the inner surface of the cooling container, the opening of the refrigerant container is closed by the solid laser gain medium. The solid laser gain medium is cooled when the laser reflecting surface comes into contact with the coolant.

  Patent Document 2 describes a laser oscillator and a laser amplifier. The laser oscillator and the laser amplifier described in Patent Document 2 include an optical medium and a laser gain medium joined to the optical medium. Cooling means is provided around the laser gain medium. The cooling means cools the back side of the laser gain medium.

  Patent Document 3 describes a laser wavelength conversion device. A laser wavelength conversion device described in Patent Document 3 includes a laser resonator, a nonlinear optical crystal disposed in the laser resonator, and a parallel plate transmission for laser beam optical path shift disposed upstream of the nonlinear optical crystal. A plate and a vibration mechanism for vibrating the transmission plate. The nonlinear optical crystal is a crystal that generates a harmonic beam from an incident laser beam. The optical path of the laser beam is shifted by vibrating the parallel plate transmission plate for shifting the laser beam optical path. Due to the optical path shift of the laser beam, the passage path of the laser beam in the nonlinear optical crystal changes. Due to the change of the passage path, the temperature increase of the nonlinear optical crystal is suppressed.

  Patent Document 4 describes a harmonic laser device. The harmonic laser device described in Patent Document 4 includes an excitation semiconductor laser, a condenser lens, a reflection mirror, a solid-state laser medium, a nonlinear optical crystal, and an output mirror. In addition, the harmonic laser device is a moving mechanism that moves the position of the nonlinear optical crystal in a direction perpendicular to the optical axis of the laser light, or a movement that changes the passing position of the laser light on the nonlinear optical crystal in conjunction with laser irradiation. Including optical element with mechanism. By using the moving mechanism or the optical element with the moving mechanism, the passage path of the laser beam in the nonlinear optical crystal changes. Due to the change of the passage path, the temperature increase of the nonlinear optical crystal is suppressed.

  Patent Document 5 describes a solid-state laser device. The solid-state laser device described in Patent Document 5 includes a semiconductor laser light source, a rod lens, a VBG, a ball lens, a mirror, a solid-state laser crystal, a wavelength conversion element, and a concave mirror. The concave mirror is arranged to be inclined from the optical axis of the laser. By disposing the concave mirror at an angle from the optical axis, the laser light transmission region in the solid laser crystal or the wavelength conversion element is expanded. By increasing the transmission region of the laser light, the temperature rise of the solid laser crystal and the wavelength conversion element is suppressed.

Japanese Patent No. 5424320 Japanese Patent No. 5330801 JP-A-7-22686 JP 2004-22946 A JP 2009-259854 A

  An object of the present invention is to provide a laser amplification system that disperses a thermal load acting on a laser gain medium by changing the position of a reflected spot of the laser. Due to the dispersion of the thermal load, the temperature increase of the laser gain medium is suppressed.

  These objects and other objects and benefits of the present invention can be easily confirmed by the following description and the accompanying drawings.

  Hereinafter, means for solving the problem will be described using the numbers and symbols used in the embodiments for carrying out the invention. These numbers and symbols are added with parentheses for reference in order to show an example of the correspondence between the description of the claims and the mode for carrying out the invention. Accordingly, the claims should not be construed as limiting due to the bracketed description.

  The laser amplification system according to some embodiments receives the seed light (A) and the excitation light (B), and outputs the seed light (A) and the excitation light (B) as coaxial light (C). Amplification obtained by receiving the optical element (40; 40 ′) and the coaxial light (C), amplifying the seed light (A) using the excitation light (B), and amplifying the seed light (A) An amplifier (60; 60 ′: 60 ″) that outputs light (M) is disposed between the first optical element (40; 40 ′) and the amplifier (60; 60 ′: 60 ″). , Receiving the coaxial light (C) from the first optical element (40; 40 ′) and supplying the coaxial light (C) to the amplifier (60; 60 ′: 60 ″). 50 ′; 50 ″; 50 ′ ″) and the input side optical system (50; 50 ′; 50 ″; 50; ″) To drive the drive mechanism (80; 80 ′) to change the incident position (65) or the incident direction (D) of the coaxial light (C) to the amplifier (60; 60 ′: 60 ″). 80 ″) and a control device (90) for controlling the drive mechanism (80; 80 ′; 80 ″). The amplifier (60; 60 ′: 60 ″) receives the coaxial light (C) and amplifies the seed light (A), a first laser gain medium (62), and the coaxial light (C). And a first reflective layer (67) for reflection. The control device (90) controls the drive mechanism (80; 80 ′; 80 ″) to change the incident position (65) or the incident direction (D), thereby the first reflective layer. The position of the reflection spot (68) of the coaxial light (C) in (67) is moved.

  In the laser amplification system, the input-side optical system (50; 50 ″; 50 ′ ″) includes a first mirror (50; 50 ″; 50-1) that reflects the coaxial light (C). You may go out. The drive mechanism (80; 80 ″) includes a first drive mechanism (80; 80 ″; 80-1) that swings or rotates the first mirror (50; 50 ″; 50-1). You may go out.

A laser amplification system according to claim 2,
In the laser amplification system, the control device (90) causes the first mirror (50; 50 ″; 50-1) to swing or rotate about the first axis (X; X1; AX1). The first drive mechanism (80; 80 ''; 80-1) may be controlled. When the first mirror (50; 50 ''; 50-1) swings or rotates around the first axis (X; X1; AX1), the reflection spot (68) is changed to the first reflection. You may move on the layer (67).

  In the laser amplification system, the control device (90) causes the first mirror (50 ″) to swing or rotate around a second axis (AX2) different from the first axis (AX1). The first driving mechanism (80 ″) may be controlled. The first mirror (50 ″) swings or rotates about the first axis (AX1) and swings or rotates about the second axis (AX2), whereby the reflection spot (68). May move two-dimensionally on the first reflective layer (67).

  In the laser amplification system, the input-side optical system is disposed between the first mirror (50-1) and the amplifier (60; 60 ′: 60 ″), and the first mirror (50-1). ) To receive the coaxial light (C) and reflect the coaxial light (C). The drive mechanism (80) may include a second drive mechanism (80-2) that swings or rotates the second mirror (50-2). Moreover, the said control apparatus (90) may perform the parallel incident mode which changes the said incident position (65) in the state which fixed the said incident direction (D).

  In the laser amplification system, an output side optical system (55; 55 ′) that receives the amplified light (M), collects the amplified light (M), and outputs the amplified light (M) in a fixed direction. May further be included. The output side optical system (55; 55 ') may output the amplified light (M) in the fixed direction (F) regardless of the movement of the position of the reflection spot (68).

  In the laser amplification system, the output-side optical system (55 ') may be a fixed condensing optical system.

  In the laser amplification system, the input side optical element constituting the input side optical system (50 ′ ″) and the output side optical element constituting the output side optical system (55) are arranged symmetrically to each other. May be.

  In the laser amplification system, a third mirror (55-3) that receives the amplified light (M) from the amplifier (60; 60 ′: 60 ″) and reflects the amplified light (M); The amplified light (M) from the third mirror (55-3) is incident, and the fourth mirror (55-4) that reflects the amplified light (M) and the third mirror (55-3) are swung. A third drive mechanism (85-3) that moves or rotates and a fourth drive mechanism (85-4) that swings or rotates the fourth mirror (55-4) may be further included. The third mirror (55-3) and the fourth mirror (55-4) may constitute the output-side optical system (55).

  In the laser amplification system, the amplifier (60 ′; 60 ″) receives the coaxial light (C) from the first laser gain medium (62) and amplifies the seed light (A). You may comprise a laser gain medium (62-2) and the 2nd reflection layer (67-2) which reflects the said coaxial light (C).

  The laser amplification system may further include a cooling mechanism (70) for cooling the first laser gain medium (62).

  In the laser amplification system, the cooling mechanism (70) may include a heat sink (70) disposed in contact with the first reflective layer (67).

  In the laser amplification system, the cooling mechanism (70) may include a refrigerant channel (72) and a refrigerant supply mechanism (74) that supplies the refrigerant to the refrigerant channel (72).

  In the laser amplification system, the coolant channel (72) may include coolant discharge ports (101A, 101B) that supply the coolant toward the optical element. The refrigerant may wash the optical element.

  In the laser amplification system, a housing (100) surrounding the amplifier (60; 60 ′: 60 ″), and the amplified light (M) from the inside of the housing (100) to the housing (100). An output window (110) for outputting to the outside may be further provided. The optical component to be cleaned may be the output window (110).

  According to the present invention, it is possible to provide a laser amplification system that disperses the thermal load acting on the laser gain medium by changing the position of the reflection spot of the laser.

FIG. 1 is a diagram schematically showing a laser amplifier in a comparative example. The upper view of FIG. 1 is a side view, and the lower view of FIG. 1 is a bottom view. FIG. 2 is a diagram schematically showing a laser resonator in another comparative example. FIG. 3A is a plan view schematically showing the laser amplification system of the first embodiment. FIG. 3B is a side view schematically showing the laser amplification system of the first embodiment. FIG. 3C is a plan view schematically showing a laser amplification system according to a first modification of the first embodiment. FIG. 3D is a plan view schematically showing a laser amplification system according to a second modification of the first embodiment. FIG. 3E is a plan view schematically showing a laser amplification system of a third modified example of the first embodiment. FIG. 3F is a side view schematically showing a laser amplification system of a third modified example of the first embodiment. FIG. 3G is a plan view schematically showing a laser amplification system of a fourth modified example of the first embodiment. FIG. 3H is a side view schematically showing a laser amplification system of a fourth modification example of the first embodiment. FIG. 3I is a plan view schematically showing a laser amplification system of a fourth modified example of the first embodiment. FIG. 3J is a side view schematically showing a laser amplification system of a fourth modified example of the first embodiment. FIG. 3K is a plan view schematically showing a laser amplification system of a fifth modification example of the first embodiment. FIG. 3L is a plan view schematically showing a laser amplification system of a fifth modification example of the first embodiment. FIG. 3M is a plan view schematically showing a laser amplification system of a fifth modification example of the first embodiment. FIG. 4A is a plan view schematically showing the laser amplification system of the second embodiment. FIG. 4B is a side view schematically showing the laser amplification system of the second embodiment. FIG. 4C is a diagram schematically illustrating an example of a parallel incidence mode. FIG. 4D is a plan view schematically showing a laser amplification system of a first modification example of the second embodiment. FIG. 4E is a side view schematically showing a laser amplification system of a first modified example of the second embodiment. FIG. 4F is a plan view schematically showing a laser amplification system of a second modification example of the second embodiment. FIG. 5A is a plan view schematically showing the laser amplification system of the third embodiment. FIG. 5B is a side view schematically showing the laser amplification system of the third embodiment. FIG. 5C is a plan view schematically showing a laser amplification system according to a first modification of the third embodiment. FIG. 5D is a side view schematically showing a laser amplification system of a first modification example of the third embodiment. FIG. 5E is a plan view schematically showing a laser amplification system of a second modification example of the third embodiment. FIG. 5F is a side view schematically showing a laser amplification system of a second modification example of the third embodiment. FIG. 5G is a plan view schematically showing a laser amplification system of a third modified example of the third embodiment. FIG. 6A is a plan view schematically showing the laser amplification system of the fourth embodiment. FIG. 6B is a cross-sectional view schematically showing the laser amplification system of the fourth embodiment.

  Hereinafter, a laser amplification system according to an embodiment will be described with reference to the accompanying drawings.

(Matters recognized by the inventor)
The matters recognized by the inventor will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a diagram schematically showing a laser amplifier 1 in a comparative example. The upper view of FIG. 1 is a side view, and the lower view of FIG. 1 is a bottom view.

  In FIG. 1, the laser amplifier 1 includes a laser gain medium 2 and a reflective film 3. The seed light 4 is introduced into the laser gain medium 2 and reflected by the reflection film 3 at the position of the reflection spot 6. The excitation light 5 is introduced into the laser gain medium 2 and is reflected by the reflection film 3 at the position of the reflection spot 6. Part of the seed light 4 and part of the pumping light 5 are absorbed by the laser gain medium 2 and converted into heat.

  By the way, as in the example described in FIG. 1, in the laser amplifier 1, it is necessary to irradiate the seed light 4 and the excitation light 5 at the same place in the laser gain medium 2. For this reason, generally, the optical path of the seed light 4 and the optical path of the excitation light 5 are fixed and do not change with time.

  Therefore, in the optical path of the seed light 4 and the optical path of the pumping light 5, the thermal load (temperature rise) of the laser gain medium 2 is large. In particular, in the peripheral region of the reflection spot 6, the heat load (temperature increase) increases.

  FIG. 2 is a diagram schematically showing a laser resonator 10 in another comparative example.

  The laser resonator 10 includes a resonator mirror 11, a laser gain medium 13, a parallel plate transmission plate 14, a nonlinear optical crystal 15, a resonator mirror 12, and a lamp 18 for laser excitation. The resonator mirrors 11 and 12 exhibit a high reflectance with respect to the laser beam having the frequency f and a high transmittance with respect to the laser beam having the frequency 2f. The laser gain medium 13 generates laser light having a frequency f. The parallel plate transmission plate 14 changes the optical path of the laser light by using a light refraction phenomenon. The nonlinear optical crystal 15 converts the laser beam having the frequency f into a laser beam having the frequency 2f. The laser excitation lamp 18 excites the laser gain medium 13.

  The laser light having the frequency f generated in the laser gain medium 13 using the laser excitation lamp 18 is introduced into the parallel plate transmission plate 14 and passes through the parallel plate transmission plate 14. When the parallel plate transmission plate 14 is in the first position shown by the broken line in FIG. 2, the laser light passes through the nonlinear optical crystal 15 through the optical path 16. On the other hand, when the parallel plate transmission plate 14 is in the second position shown by the solid line in FIG. 2, the laser light passes through the nonlinear optical crystal 15 through the optical path 17. Laser light passing through the nonlinear optical crystal 15 through the optical path 16 or the optical path 17 is converted into laser light having a frequency of 2f. Then, the laser beam having the frequency 2f passes through the resonator mirror 12 and is extracted toward the outside of the laser resonator 10.

  In the example illustrated in FIG. 2, the optical path of the laser light passing through the nonlinear optical crystal 15 is changed (between the optical path 16 and the optical path 17), so that the temperature increase of the nonlinear optical crystal 15 is suppressed. However, the example shown in FIG. 2 shows a temperature rise suppression technique applied to a laser resonator, and does not show a temperature rise suppression technique applicable to a laser amplifier. For example, in the case of a laser amplifier, it is necessary to be introduced into the laser gain medium so that laser light (seed light and excitation light) having different frequencies is irradiated to the same place. However, the example shown in FIG. 2 is not suitable for such a case. For example, in the optical path change using the swing of the parallel plate transmission plate, two lights having different frequencies may be separated from each other, in other words, the coaxial light may not be maintained.

  Further, the above-mentioned Patent Document 4 does not show a temperature rise suppression technique applicable to a laser amplifier. For example, Patent Document 4 describes an optical axis shift caused by the movement of the optical element 22 with the moving mechanism. When the technique described in Patent Document 4 is applied to an amplifier, the coaxial light may not be maintained due to the deviation of the optical axis.

  FIG. 1 and FIG. 2 are diagrams for explaining matters recognized by the inventor and do not indicate a known problem or the like.

(First embodiment)
The laser amplification system 30 according to the first embodiment will be described with reference to FIGS. 3A and 3B. 3A is a plan view schematically showing the laser amplification system 30, and FIG. 3B is a side view schematically showing the laser amplification system 30 (a side view when FIG. 3A is viewed along the direction of the arrow T). . In FIG. 3B, in order to avoid complication of the drawing, components other than the input side optical system 50 and the amplifier 60 are not shown.

  The laser amplification system 30 includes a first optical element 40, an input side optical system 50, an amplifier 60, a drive mechanism 80, and a control device 90. The laser amplification system 30 may include at least one of a seed light source 98 and an excitation light source 99.

(light source)
The seed light source 98 is a light source of the seed light A to be amplified. The seed light A has a wavelength λ1. The seed light A is incident on the first optical element 40. One or more optical elements may be arranged between the seed light source 98 and the first optical element 40.

  The excitation light source 99 is a light source of excitation light B that excites a first laser gain medium 62 described later. The excitation light B has a wavelength λ2 different from the wavelength λ1 of the seed light A. The wavelength λ2 of the excitation light may be larger than the wavelength λ1 of the seed light, or may be smaller than the wavelength λ1 of the seed light. The excitation light B is incident on the first optical element 40. One or more optical elements may be arranged between the excitation light source 99 and the first optical element 40.

(First optical element)
The first optical element 40 receives the seed light A and the excitation light B, and outputs the seed light A and the excitation light B as the coaxial light C. In this specification, “coaxial” means that the traveling direction of the seed light A is the same as the traveling direction of the excitation light B (the traveling direction of the seed light A is substantially the same as the traveling direction of the excitation light B). And a state in which at least a part of the seed light A and at least a part of the excitation light B overlap each other. That is, the coaxial light C includes the seed light A and the excitation light B, and the traveling direction of the seed light A constituting the coaxial light C is the same as the traveling direction of the excitation light B constituting the coaxial light C (substantially). And at least a part of the seed light A constituting the coaxial light C and at least a part of the excitation light B constituting the coaxial light C overlap each other. In the coaxial light C, the optical path of the excitation light B may completely include the optical path of the seed light A. For example, the diameter of the excitation light B in a cross section perpendicular to the traveling direction of the excitation light B may be larger than the diameter of the seed light A in a cross section perpendicular to the traveling direction of the seed light A. In the coaxial light C, the central axis of the excitation light B and the central axis of the seed light A may coincide with each other or may be slightly offset from each other.

  The first optical element 40 is, for example, a dichroic mirror. In the example shown in FIG. 3A, the dichroic mirror (first optical element 40) is a mirror that transmits the seed light A having the wavelength λ1 and reflects the excitation light B having the wavelength λ2. Alternatively, the dichroic mirror (first optical element 40) may be a mirror that reflects the seed light A having the wavelength λ1 and transmits the excitation light B having the wavelength λ2. In the latter case, in FIG. 3A, the position of the seed light source 98 may be changed to the position of the excitation light source 99 in FIG. 3A, and the position of the excitation light source 99 may be changed to the position of the seed light source 98 in FIG.

(Input side optical system)
The input side optical system 50 is an optical system disposed between the first optical element 40 and the amplifier 60. The input side optical system 50 receives the coaxial light C from the first optical element 40. Further, the input side optical system 50 supplies the coaxial light C to the amplifier 60.

  In the example described in FIGS. 3A and 3B, the input-side optical system 50 includes a polygon mirror (first polygon mirror). In the polygon mirror, for example, the mirror is arranged on each side of the regular polygonal column. As the polygon mirror rotates around the X axis, the traveling direction of the coaxial light C reflected by the polygon mirror changes. For example, in FIG. 3B, the optical path C1 indicates the optical path of the coaxial light C when the polygon mirror is at the first position, and the optical path C2 indicates the optical path of the coaxial light C when the polygon mirror is at the second position. Show.

  In the example shown in FIG. 3A, the polygon mirror is rotated by the drive mechanism 80 (first drive mechanism). In the example shown in FIG. 3A, the drive mechanism 80 includes a motor 81 and an output shaft 82, and the output shaft 82 and the polygon mirror are mechanically coupled. An appropriate power transmission mechanism may be disposed between the motor 81 and the polygon mirror.

  The drive mechanism 80 is driven based on a command signal (for example, an electrical signal) from the control device 90. In the example illustrated in FIG. 3A, the control device 90 and the drive mechanism 80 are electrically connected, and the drive mechanism 80 is based on a command signal from the control device 90 and the polygon mirror (input-side optical system 50). Drive. The drive mechanism 80 rotates the polygon mirror, for example, around the X axis at a constant angular velocity.

  The input side optical system 50 may include other optical elements in addition to the polygon mirror.

(amplifier)
The amplifier 60 receives the coaxial light C from the input side optical system 50. The amplifier 60 includes a first laser gain medium 62 and a first reflective layer 67.

  The first laser gain medium 62 is excited to a high energy state by the excitation light B. Further, the seed light A passes through the excited first laser gain medium 62, whereby energy is stimulated and emitted. As a result, the seed light A is amplified. The amplified seed light A is output from the amplifier 60 as amplified light M. In this specification, laser light output from an amplifier is referred to as “amplified light”.

A solid laser gain medium may be used as the first laser gain medium 62. When a solid laser gain medium is used as the first laser gain medium 62, for example, yttrium aluminum garnet (YAG) containing ytterbium trivalent ions (Yb ³⁺ ) may be selected as the solid laser gain medium. Alternatively, a liquid laser gain medium may be used as the first laser gain medium 62. When a liquid laser gain medium is used as the first laser gain medium 62, for example, a liquid in which a fluorescent organic dye (for example, oxazine-based dye) is dissolved in a solvent (for example, alcohol) is selected as the liquid laser gain medium. May be.

  The first laser gain medium 62 includes a surface 63 on the side on which the coaxial light C is incident and a surface 64 disposed in contact with the first reflective layer 67.

  The first reflective layer 67 is disposed in contact with the surface 64 of the first laser gain medium 62. The first reflective layer 67 reflects the coaxial light C. The first reflective layer 67 may be a reflective film, a reflective film, or a reflective coating. The first reflective layer 67 is, for example, a dielectric multilayer film.

  As can be understood from FIGS. 3A and 3B, when the polygon mirror (input-side optical system 50) is driven, the incident position 65 or the incident direction of the coaxial light C to the amplifier 60 (first laser gain medium 62). D is changed. In the example described in FIGS. 3A and 3B, both the incident position 65 and the incident direction D are changed. The incident direction D is inclined with respect to the surface 63 (and the first reflective layer 67). In other words, the incident angle with respect to the surface 63 in the incident direction D is, for example, larger than 0 degree and smaller than 90 degrees.

  By changing the incident position 65 or the incident direction D, the position of the reflective spot 68 in the first reflective layer 67 moves. In the example shown in FIG. 3B, the reflection spot 68 corresponding to the optical path C1 is the reflection spot 68D1, and the reflection spot 68 corresponding to the optical path C2 is the reflection spot 68D2. When the polygon mirror is continuously rotated around the X axis in the R direction (see FIG. 3A), the position of the reflection spot 68 is directed from the position indicated by reference numeral 68D1 to the position indicated by reference numeral 68D2. It moves continuously (see arrow indicated by E in FIG. 3B). When the coaxial light C passes through the corner 51 (see FIG. 3B) of the polygon mirror due to the rotation of the polygon mirror, the position of the reflection spot 68 is indicated by reference numeral 68D1 from the position indicated by reference numeral 68D2. Move discontinuously to the position.

  The rotation of the polygon mirror around the X axis may be continuous rotation or intermittent rotation. When the polygon mirror is intermittently rotated, the position of the reflection spot 68 moves intermittently from the position indicated by the reference numeral 68D1 toward the position indicated by the reference numeral 68D2. However, in order to obtain a more uniform amplified light M, it is preferable to continuously rotate the polygon mirror rather than intermittently rotate the polygon mirror.

  In the first embodiment, the input-side optical system 50 is driven during the operation of the laser amplification system 30 (in other words, during the output of the amplified light M). More specifically, in the first embodiment, the position or angle of an optical element (for example, a polygon mirror) constituting the input-side optical system 50 changes during operation of the laser amplification system 30 (for example, position Or the angle changes periodically). When the input side optical system 50 is driven, the position of the reflection spot 68 of the coaxial light C in the first reflection layer 67 moves. As a result, the thermal load acting on the first laser gain medium 62 is dispersed.

  In the first embodiment, the input side optical system 50 is constituted by a polygon mirror. For this reason, for example, the axial deviation between the seed light A and the excitation light B is suppressed as compared with the case where the swing of the parallel plate transmission plate is used. As a result, the incident position (or incident direction) of the seed light A constituting the coaxial light C into the first laser gain medium and the incident position (or the incident light) of the pumping light B constituting the coaxial light C into the first laser gain medium (or Deviation from the incident direction) is suppressed.

  Further, when a polygon mirror is employed as the input side optical system 50, the position of the reflection spot 68 periodically changes as shown in FIG. 3B. More specifically, the position of the reflection spot moves from the position indicated by reference numeral 68D1 toward the position indicated by reference numeral 68D2, and the movement is periodically repeated. On the other hand, when a swinging mirror is employed as the input-side optical system 50, the position of the reflection spot 68 is periodically between the position indicated by the reference numeral 68D1 and the position indicated by the reference numeral 68D2. Move back and forth. In the latter example (an example of a swinging mirror), the intermediate portion between the position indicated by reference numeral 68D1 and the position indicated by reference numeral 68D2 is a portion (end portion) or reference numeral corresponding to the position indicated by reference numeral 68D1. It is easier to be heated by the coaxial light than the portion (end portion) corresponding to the position indicated by 68D2. On the other hand, in the former example (polygon mirror example), the heating of the intermediate portion by the coaxial light and the heating of the end portion by the coaxial light tend to be approximately the same. For this reason, the former example (polygon mirror example) is more advantageous than the latter example (oscillating mirror example) from the viewpoint of obtaining uniform amplified light.

(First modification of the first embodiment)
FIG. 3C is a plan view schematically showing a laser amplification system 30A of a first modification example of the first embodiment. Note that in the laser amplification system 30A of the first modified example, the same reference numerals are assigned to the components having the same functions as the components of the laser amplification system 30 of the first embodiment, and repeated description is omitted.

  In the example shown in FIG. 3C, the first optical element 40 of FIG. 3A is replaced with a first optical element 40 '. The other configuration in FIG. 3C is the same as the configuration in FIG. 3A.

  The first optical element 40 'is, for example, a diffraction grating. The first optical element 40 ′ receives the seed light A and the excitation light B, and outputs the seed light A and the excitation light B as the coaxial light C. The seed light A having the wavelength λ1 and the excitation light B having the wavelength λ2 are incident on the first optical element 40 '(diffraction grating) at different incident angles. Further, the coaxial light C is output from the first optical element 40 '(diffraction grating). In the example shown in FIG. 3C, the first optical element 40 'is a reflection type diffraction grating, but a transmission type diffraction grating may be adopted instead.

(Second modification of the first embodiment)
FIG. 3D is a plan view schematically showing a laser amplification system 30B of a second modification example of the first embodiment. Note that, in the laser amplification system 30B of the second modification, the same reference numerals are assigned to the components having the same functions as the components of the laser amplification system 30 of the first embodiment, and repeated description is omitted.

  In the example shown in FIG. 3D, the input side optical system 50 of FIG. 3A is replaced with an input side optical system 50 ', and the drive mechanism 80 is replaced with a drive mechanism 80' (first drive mechanism). Other configurations in FIG. 3D are the same as those in FIG. 3A.

  The input side optical system 50 ′ is an optical system disposed between the first optical element 40 and the amplifier 60. The input side optical system 50 ′ receives the coaxial light C from the first optical element 40. The input side optical system 50 ′ supplies the coaxial light C to the amplifier 60. In the example described in FIG. 3D, the input-side optical system 50 'includes an optical fiber. The end of the optical fiber on the emission side is connected to a drive mechanism 80 '(for example, a manipulator). By driving the drive mechanism 80 ′, the end portion on the emission side of the optical fiber moves continuously or intermittently. When the optical fiber is at the position indicated by the solid line in FIG. 3D, the coaxial light C travels along the optical path C1. The coaxial light C is reflected at the reflection spot 68D1. On the other hand, when the optical fiber is at the position indicated by the broken line in FIG. 3D, the coaxial light C travels along the optical path C2. The coaxial light C is reflected at the reflection spot 68D2.

  In the second modification example illustrated in FIG. 3D, the position of the reflection spot 68 of the coaxial light C in the first reflection layer 67 moves. As a result, the thermal load acting on the first laser gain medium 62 is dispersed. In the second modification, the input side optical system 50 ′ is configured by an optical fiber. For this reason, for example, the axial deviation between the seed light A and the excitation light B is suppressed as compared with the case where the swing of the parallel plate transmission plate is used.

  A prism can also be used as the input side optical system. However, when the input side optical system includes an optical element (such as a prism) that uses refraction, the seed light A and the excitation light B may be separated by refraction. For this reason, unless the difference between the wavelength λ1 of the seed light A and the wavelength λ2 of the excitation light B is not large, the input side optical system should not include an optical element utilizing refraction.

(Third Modification of First Embodiment)
FIG. 3E is a plan view schematically showing a laser amplification system 30C of a third modified example of the first embodiment. FIG. 3F is a side view schematically showing a laser amplification system 30C of a third modified example of the first embodiment. Note that, in the laser amplification system 30C of the third modification, the same reference numerals are assigned to the components having the same functions as the components of the laser amplification system 30 of the first embodiment, and repeated description is omitted.

  In the example described in FIGS. 3E and 3F, the amplifier 60 of FIGS. 3A and 3B is replaced with an amplifier 60 '. Other configurations in FIGS. 3E and 3F are the same as those in FIGS. 3A and 3B.

  The amplifier 60 'includes a first stage amplification unit 60-1 and a second stage amplification unit 60-2. The first stage amplification unit 60-1 includes a first laser gain medium 62 and a first reflection layer 67. The first laser gain medium 62 and the first reflective layer 67 are the same as the first laser gain medium 62 and the first reflective layer 67 described in FIGS. 3A and 3B, respectively. Therefore, repeated descriptions of the first laser gain medium 62 and the first reflective layer 67 are omitted.

  The second stage amplification unit 60-2 includes a second laser gain medium 62-2 and a second reflection layer 67-2. The second laser gain medium 62-2 is excited to a high energy state by the excitation light B. Further, the seed light A passes through the second laser gain medium 62-2 in the excited state, whereby energy is stimulated and emitted. As a result, the seed light A is amplified. The material of the second laser gain medium 62-2 may be the same as or different from the material of the first laser gain medium 62. In the example illustrated in FIGS. 3E and 3F, the second laser gain medium 62-2 is disposed away from the first laser gain medium 62.

  The second laser gain medium 62-2 includes a surface 63-2 on the side on which the coaxial light C is incident and a surface 64-2 disposed in contact with the second reflective layer 67-2.

  The second reflective layer 67-2 is disposed in contact with the surface 64-2 of the second laser gain medium 62-2. The second reflective layer 67-2 reflects the coaxial light C. The material of the second reflective layer 67-2 may be the same as or different from the material of the first reflective layer 67.

  As can be understood from FIGS. 3E and 3F, when the input-side optical system 50 is driven, the incident position 65-2 or the incident direction D ′ of the coaxial light C to the second laser gain medium 62-2 is changed. Is done. In the example described in FIGS. 3E and 3F, both the incident position 65-2 and the incident direction D 'are changed.

  Further, the position of the reflection spot 68-2 in the second reflection layer 67-2 is moved by changing the incident position 65-2 or the incident direction D '. In the example illustrated in FIG. 3F, the reflection spot 68-2 corresponding to the optical path C1 is the reflection spot 68D1-2, and the reflection spot 68-2 corresponding to the optical path C2 is the reflection spot 68D2-2. When the input-side optical system 50 is continuously rotated around the X axis in the R direction, the position of the reflection spot 68-2 is changed from the position indicated by reference numeral 68D1-2 to the position indicated by reference numeral 68D2-2. Continuously moving (refer to the arrow indicated by E ′ in FIG. 3F). When the coaxial light C passes through the corner 51 of the polygon mirror due to the rotation of the input side optical system 50, the position of the reflection spot 68-2 is changed from the position indicated by reference numeral 68D2-2 to reference numeral 68D1-2. Move discontinuously to the position indicated by.

  In the third modification of the first embodiment, the position of the reflection spot 68-2 of the coaxial light C in the second reflection layer 67-2 moves. As a result, the thermal load acting on the second laser gain medium 62-2 is dispersed. In the third modification, the amplifier includes a first-stage amplification unit 60-1 and a second-stage amplification unit 60-2. For this reason, in the third modification, it is possible to realize a laser amplification system having a higher seed light amplification factor as compared with the examples described in FIGS. 3A and 3B.

  3E and 3F, the number of amplification units is two, but the number of amplification units may be three or more. In the example described in FIGS. 3E and 3F, the input-side optical system 50 is configured by a polygon mirror. Alternatively, the input-side optical system 50 may be configured by an optical fiber illustrated in FIG. 3D or a mirror other than a polygon mirror (for example, a galvano mirror, a piezo mirror, or a MEMS mirror).

(Fourth modification of the first embodiment)
FIG. 3G is a plan view schematically showing a laser amplification system 30D of a fourth modification example of the first embodiment. FIG. 3H is a side view schematically showing a laser amplification system 30D of the fourth modification example of the first embodiment. Note that in the laser amplification system 30D of the fourth modified example, the same reference numerals are given to the components having the same functions as the components of the laser amplification system 30 of the first embodiment, and repeated description is omitted.

  In the example described in FIGS. 3G and 3H, the input-side optical system 50 in FIGS. 3A and 3B is replaced with the input-side optical system 50 ″, and the drive mechanism 80 in FIGS. 3A and 3B is replaced with a drive mechanism 80 ′. It is replaced with '(first drive mechanism). Other configurations in FIGS. 3G and 3H are the same as those in FIGS. 3A and 3B.

  The input-side optical system 50 ″ is an optical system that is disposed between the first optical element 40 and the amplifier 60. The input side optical system 50 ″ receives the coaxial light C from the first optical element 40. The input side optical system 50 ″ supplies the coaxial light C to the amplifier 60. In the example described in FIGS. 3G and 3H, the input-side optical system 50 '' includes a mirror (first mirror). The mirror is, for example, a galvanometer mirror (a mirror of a type that oscillates the mirror around an axis), a piezo mirror (a mirror that is driven to swing by a piezo element), or a MEMS mirror (a mirror that is driven by a MicroElectro Mechanical System). is there.

  The mirror (input-side optical system 50 ″) illustrated in FIGS. 3G and 3H is connected to the drive mechanism 80 ″ and driven by the drive mechanism 80 ″. When the mirror is a piezo mirror, the drive mechanism 80 ″ includes a piezo element. When the mirror is a MEMS mirror, the drive mechanism 80 ″ includes a MEMS element. By driving the drive mechanism 80 ″, the mirror rotates or swings continuously or intermittently.

  In the example illustrated in FIG. 3G, the drive mechanism 80 ″ swings the mirror (input-side optical system 50 ″) about the first axis AX1. The first axis AX1 may be parallel to the reflection surface of the first reflection layer 67 or may be non-parallel. As the mirror (input-side optical system 50 ″) swings around the first axis AX 1, the reflection spot 68 moves in a direction parallel to the direction indicated by the arrow E 1 in FIG. 3H.

  In the example illustrated in FIG. 3G, the drive mechanism 80 ″ swings the mirror (input-side optical system 50 ″) also about the second axis AX2. The second axis AX2 is an axis different from the first axis AX1. The second axis AX2 may be an axis perpendicular to the first axis AX1, an axis perpendicular to the first axis AX1, and an axis parallel to the reflective surface of the first reflective layer 67. As the mirror (input-side optical system 50 ″) swings around the second axis AX 2, the reflection spot 68 moves in a direction parallel to the direction indicated by the arrow E 2 in FIG. 3G.

  In the fourth modification example shown in FIGS. 3G and 3H, the position of the reflection spot 68 of the coaxial light C in the first reflection layer 67 moves. As a result, the thermal load acting on the first laser gain medium 62 is dispersed. In the fourth modification, the mirror (input-side optical system 50 ″) swings or rotates about the first axis AX 1 and swings or rotates about the second axis AX 2. For this reason, the reflection spot 68 of the coaxial light C in the first reflection layer 67 moves two-dimensionally on the first reflection layer 67. As a result, the thermal load acting on the first laser gain medium 62 is further dispersed. In the fourth modification, the input side optical system 50 ″ is configured by a mirror. For this reason, the axial deviation between the seed light A and the excitation light B is suppressed as compared with the case where the swing of the parallel plate transmission plate is used.

  In the fourth modification, the example in which the mirror (input-side optical system 50 ″) swings or rotates around the first axis AX 1 and swings or rotates around the second axis AX 2 has been described. However, the swing or rotation of the mirror (input-side optical system 50 ″) may be performed only around one axis. In the example described in FIGS. 3I and 3J, the mirror swings or rotates about the first axis AX1, but does not swing or rotate about an axis different from the first axis AX1. In this case, the mirror (input-side optical system 50 ″) swings or rotates around the first axis AX1, so that the reflection spot 68 is one-dimensionally, that is, linearly, on the first reflection layer 67. Moving. In the example described in FIGS. 3I and 3J, the drive mechanism 80 ″ can be further simplified as compared with the example described in FIGS. 3G and 3H.

(Fifth modification of the first embodiment)
3K to 3M are plan views schematically showing a laser amplification system 30E of a fifth modified example of the first embodiment. Note that in the laser amplification system 30E of the fifth modified example, the same reference numerals are assigned to the components having the same functions as the components of the laser amplification system 30 of the first embodiment, and repeated description is omitted.

  The example shown in FIGS. 3K to 3M is different from the example shown in FIG. 3A in that the cooling mechanism 70 is arranged in the amplifier 60. Other configurations in FIGS. 3K to 3M are the same as those in FIG. 3A. The cooling mechanism 70 is a mechanism for cooling the amplifier 60 (in particular, a laser gain medium such as the first laser gain medium 62).

  In the example described in FIG. 3K, the cooling mechanism 70 includes a heat sink. The heat sink is made of a material having high thermal conductivity, for example, a metal material. In the example illustrated in FIG. 3K, the heat sink (cooling mechanism 70) is disposed on the back side of the first laser gain medium 62 (the side on which the first reflective layer 67 is provided). The heat sink is disposed in contact with the first reflective layer 67.

  In the example illustrated in FIG. 3K, the cooling mechanism 70 further suppresses the temperature increase of the first laser gain medium 62. The cooling mechanism 70 may be applied to the amplifier 60 (more specifically, the back surface side of the first laser gain medium 62) in the examples described in FIGS. 3C, 3D, 3G, and 3I. The cooling mechanism 70 may be applied to the amplifier 60 'in the example shown in FIG. 3E. For example, the first heat sink (cooling mechanism 70) may be disposed in contact with the first reflective layer 67, and the second heat sink (cooling mechanism 70) may be disposed in contact with the second reflective layer 67-2. .

  In the example illustrated in FIG. 3L, the cooling mechanism 70 supplies the refrigerant channel 72 and a refrigerant (for example, a liquid such as water, liquefied nitrogen, and liquefied helium, or a gas such as air) to the refrigerant channel 72. Supply mechanism 74 (for example, a refrigerant tank, a refrigerant supply pump, etc.). At least a part of the coolant channel 72 may be disposed along the first reflective layer 67. At least a part of the coolant channel 72 may be disposed in parallel to the first reflective layer 67. In the example shown in FIG. 3L, the refrigerant flow path 72 is disposed on the back side of the first laser gain medium 62 (the side on which the first reflective layer 67 is provided).

  In the example illustrated in FIG. 3L, the temperature rise of the first laser gain medium 62 is further suppressed by the refrigerant flowing through the refrigerant flow path 72. The refrigerant flow path 72 may be applied to the amplifier 60 (more specifically, the back surface side of the first laser gain medium 62) in the examples described in FIGS. 3C, 3D, 3G, and 3I. Further, the refrigerant flow path 72 may be applied to the amplifier 60 'in the example shown in FIG. 3E. For example, at least a part of the coolant channel 72 may be disposed along the first reflective layer 67, and at least a part of the coolant channel 72 may be disposed along the second reflective layer 67-2. .

  The example described in FIG. 3M is a combination of the example described in FIG. 3K and the example described in FIG. 3L. The cooling mechanism 70 includes a heat sink, a refrigerant flow path 72, and a refrigerant supply mechanism 74 (for example, a liquid such as water, liquefied nitrogen, liquefied helium, or a gas such as air) supplied to the refrigerant flow path 72. , Refrigerant tank, refrigerant supply pump, etc.). In the example described in FIG. 3M, the refrigerant flow path 72 is provided inside the heat sink. Alternatively, the coolant channel 72 may supply coolant to the surface of the heat sink.

  In the example illustrated in FIG. 3M, the temperature rise of the first laser gain medium 62 is further suppressed by the heat sink and the coolant channel 72. Note that the heat sink and the coolant channel 72 may be applied to the amplifier 60 (more specifically, the back surface side of the first laser gain medium 62) in the examples described in FIGS. 3C, 3D, 3G, and 3I. Good. Further, the heat sink and the refrigerant flow path 72 may be applied to the amplifier 60 'in the example shown in FIG. 3E. For example, the first heat sink and the refrigerant flow path 72 are arranged on the back side of the first laser gain medium 62, and the second heat sink and the second refrigerant flow path are arranged on the back side of the second laser gain medium 62-2. May be.

(Second Embodiment)
A laser amplification system 30A-1 according to the second embodiment will be described with reference to FIGS. 4A and 4B. FIG. 4A is a plan view schematically showing the laser amplification system 30A-1, and FIG. 4B is a side view schematically showing the laser amplification system 30A-1. In FIG. 4B, the components other than the input-side optical system 50 ′ ″ and the amplifier 60 are not shown in order to avoid complication of the drawing. In addition, in the laser amplification system 30A-1 in the second embodiment, components having the same functions as the components of the laser amplification system 30 in the first embodiment are given the same reference numerals, and repeated descriptions are given. Omitted.

  The laser amplification system 30A-1 in the second embodiment is different from the input side optical system 50 in the laser amplification system 30 in the first embodiment in the configuration of the input side optical system 50 '' '.

  The input side optical system 50 ″ ″ is an optical system disposed between the first optical element 40 and the amplifier 60. The input-side optical system 50 ″ ″ receives the coaxial light C from the first optical element 40. The input side optical system 50 ″ ″ supplies the coaxial light C to the amplifier 60. The input side optical system 50 ″ ″ includes a first mirror 50-1 and a second mirror 50-2.

  The first mirror 50-1 receives the coaxial light C from the first optical element 40. The first mirror 50-1 reflects the coaxial light C and supplies the coaxial light C to the second mirror 50-2. The second mirror 50-2 is disposed between the first mirror 50-1 and the amplifier 60. The coaxial light C from the first mirror 50-1 is incident on the second mirror 50-2, and the second mirror 50-2 reflects the coaxial light C. The coaxial light C reflected by the second mirror 50-2 is supplied to the amplifier 60.

  The first mirror 50-1 is a polygon mirror in the example shown in FIG. 4A, but may be other mirrors (galvano mirror, piezo mirror, MEMS mirror). The second mirror 50-2 is a polygon mirror in the example shown in FIG. 4A, but may be other mirrors (galvano mirror, piezo mirror, MEMS mirror).

  In the example shown in FIG. 4A, the first drive mechanism 80-1 rotates or swings the first mirror 50-1. The first drive mechanism 80-1 includes, for example, a motor and a power transmission mechanism. In the example illustrated in FIG. 4A, the first drive mechanism 80-1 is mechanically coupled to the first mirror 50-1.

  The first drive mechanism 80-1 is driven based on a command signal (for example, an electric signal) from the control device 90. In the example illustrated in FIG. 4A, the control device 90 and the first drive mechanism 80-1 are electrically connected, and the first drive mechanism 80-1 is based on a command signal from the control device 90. One mirror 50-1 is driven. The first drive mechanism 80-1 rotates or swings the first mirror 50-1 around the axis X1 continuously or intermittently.

  In the example illustrated in FIG. 4A, the second mirror 50-2 is rotated or swung by the second drive mechanism 80-2. The second drive mechanism 80-2 includes, for example, a motor and a power transmission mechanism. In the example illustrated in FIG. 4A, the second drive mechanism 80-2 is mechanically coupled to the second mirror 50-2.

  The second drive mechanism 80-2 is driven based on a command signal (for example, an electric signal) from the control device 90. In the example shown in FIG. 4A, the control device 90 and the second drive mechanism 80-2 are electrically connected, and the second drive mechanism 80-2 is based on a command signal from the control device 90. 2 The mirror 50-2 is driven. The second drive mechanism 80-2 rotates or swings the second mirror 50-2 around the axis X2 continuously or intermittently. The first drive mechanism 80-1 and the second drive mechanism 80-2 constitute a drive mechanism that drives the input-side optical system 50 '' '.

(Parallel incidence mode)
The control device 90 transmits a control signal to the drive mechanisms (the first drive mechanism 80-1 and the second drive mechanism 80-2). In the example described in FIGS. 4A and 4B, the controller 90 can execute the parallel incident mode in which the incident position 65 to the amplifier 60 is changed while the incident direction D to the amplifier 60 is fixed. In the parallel incidence mode, amplified light M (see the optical path M1 and the optical path M2 in FIG. 4B) is output from the amplifier 60. The incident angle with respect to the surface 63 in the incident direction D is, for example, larger than 0 degree and smaller than 90 degrees.

  An example of the parallel incidence mode will be described with reference to FIG. 4C. FIG. 4C shows the first mirror 50-1 and the second mirror 50-2. The first mirror 50-1 includes a first reflecting surface 52-1, and the second mirror 50-2 includes a second reflecting surface 52-2. The coaxial light C incident on the first mirror 50-1 is reflected by the first reflecting surface 52-1 of the first mirror 50-1 and the second reflecting surface 52-2 of the second mirror 50-2. The light is emitted along the optical path C1 or the optical path C2. In the example described in the upper diagram of FIG. 4C, the first reflecting surface 52-1 and the second reflecting surface 52-2 are parallel. For this reason, the coaxial light C incident on the first mirror 50-1 and the coaxial light emitted along the optical path C1 are parallel to each other.

  4C, the first mirror 50-1 is rotated by a first angle θ in the R1 direction and the second mirror 50-2 is in the R2 direction (R1 direction) from the state shown in the upper diagram of FIG. 4C. In the same direction) after the second angle θ (first angle = second angle). In the example described in the lower diagram of FIG. 4C, the first reflecting surface 52-1 and the second reflecting surface 52-2 are parallel. For this reason, the coaxial light C incident on the first mirror 50-1 and the coaxial light emitted along the optical path C2 are parallel to each other. From the above, in FIG. 4C, it is understood that the optical path C1 and the optical path C2 are parallel to each other. That is, in the example illustrated in FIG. 4C, the control device 90 includes a drive mechanism (first drive mechanism 80-1) such that the first reflective surface 52-1 and the second reflective surface 52-2 are parallel to each other. And a control signal is transmitted to the second drive mechanism 80-2). As a result, a parallel incidence mode is realized.

  In the example shown in FIGS. 4A to 4C, the control device 90 determines that the swing speed or rotation speed of the first mirror 50-1 is equal to the swing speed of the second mirror 50-2. The first drive mechanism 80-1 and the second drive mechanism 80-2 may be controlled so as to be equal to the size or the rotation speed. Further, the control device 90 is configured such that the swing direction or the rotation direction of the first mirror 50-1 (the swing direction R1 or the rotation direction R1 around the axis X1) is the swing of the second mirror 50-2. The first drive mechanism 80-1 and the second drive mechanism 80-2 may be controlled so as to be in the same direction as the direction or rotation direction (swing direction R2 or rotation direction R2 around the axis X2).

  Note that the control in the parallel incidence mode is not limited to the example shown in FIG. 4C. If the control in the parallel incident mode is a control for changing the incident position 65 to the amplifier 60 in a state where the incident direction D to the amplifier 60 is fixed, how the first mirror 50-1 and the second mirror 50-2 are controlled. You may control to.

  In the example shown in FIG. 4B, by executing the parallel incidence mode, the reflected spot 68 moves continuously or intermittently from the position indicated by reference numeral 68D1 to the position indicated by reference numeral 68D2 (in FIG. 4B). (See the arrow labeled E). With the movement of the position of the reflection spot 68, the optical path of the amplified light M moves from the optical path indicated by reference numeral M1 to the optical path indicated by reference numeral M2. The optical path M1 and the optical path M2 are parallel to each other.

  The second embodiment has the same effect as that of the first embodiment. In the second embodiment, a parallel incidence mode in which the incident direction D to the amplifier 60 is constant can be executed. In the parallel incidence mode, amplified lights parallel to each other are output. When amplified lights that are parallel to each other are output, compared to the case where amplified lights that are not parallel to each other are output, handling of the amplified light, for example, to the target of the amplified light (processing object or destruction target) It becomes easy to control the guidance. In the first embodiment, the width between the optical paths (the distance between the optical path C1 and the optical path C2 in FIG. 3B) increases in the amplifier as the coaxial light C travels. On the other hand, in the parallel incidence mode, the width between the optical paths (the distance between the optical path C1 and the optical path C2 in FIG. 4B) does not increase as the coaxial light C travels in the amplifier. Therefore, it is possible to reduce the size of the laser gain medium. In particular, when a plurality of amplification units are arranged along the traveling direction of the coaxial light, the effect of downsizing is remarkable. The effect will be described using the following first modification.

(First Modification of Second Embodiment)
FIG. 4D is a plan view schematically showing a laser amplification system 30B-1 according to a first modification of the second embodiment. FIG. 4E is a side view schematically showing a laser amplification system 30B-1 according to a first modification of the second embodiment. The laser amplification system 30B-1 according to the first modification has the same function as the components of the laser amplification system according to the second embodiment and the first embodiment (and each modification of the first embodiment). Constituent elements are given the same figure number, and repeated description is omitted.

  In the example described in FIGS. 4D and 4E, the amplifier 60 of FIGS. 4A and 4B is replaced with an amplifier 60 '. Other configurations in FIGS. 4D and 4E are the same as those in FIGS. 4A and 4B.

  The amplifier 60 'includes a first stage amplification unit 60-1 and a second stage amplification unit 60-2. The first stage amplification unit 60-1 includes a first laser gain medium 62 and a first reflection layer 67. The second stage amplification unit 60-2 includes a second laser gain medium 62-2 and a second reflection layer 67-2. The functions of the first laser gain medium 62 and the first reflective layer 67 shown in FIGS. 4D and 4E are the same as the functions of the first laser gain medium 62 and the first reflective layer 67 shown in FIGS. 3A and 3B, respectively. It is. The functions of the second laser gain medium 62-2 and the second reflection layer 67-2 shown in FIGS. 4D and 4E are the same as those of the second laser gain medium 62-2 and the second reflection layer shown in FIGS. 3E and 3F. The functions of the layer 67-2 are the same. Therefore, repeated descriptions of the first laser gain medium 62, the first reflection layer 67, the second laser gain medium 62-2, and the second reflection layer 67-2 are omitted. In the example described in FIGS. 4D and 4E, the number of amplification units is two, but the number of amplification units may be three or more.

  As can be understood from FIGS. 4D and 4E, when the input-side optical system 50 is driven, the incident position 65-2 of the coaxial light C to the second laser gain medium 62-2 is changed. On the other hand, the incident direction D ′ of the coaxial light C to the second laser gain medium 62-2 is constant.

  By changing the incident position 65-2, the position of the reflection spot 68-2 in the second reflection layer 67-2 moves. In the example shown in FIG. 4E, the reflection spot 68-2 corresponding to the optical path C1 is the reflection spot 68D1-2, and the reflection spot 68-2 corresponding to the optical path C2 is the reflection spot 68D2-2.

  In the example shown in FIG. 4E, the incident direction D of the coaxial light C into the first laser gain medium 62 is constant, and the incident direction D ′ of the coaxial light C into the second laser gain medium 62-2 is constant. . For this reason, in the amplifier 60 ', the width between the optical paths (the distance between the optical path C1 and the optical path C2 in FIG. 4E) does not increase as the coaxial light C travels. Therefore, in the example illustrated in FIG. 4E, the size of the second laser gain medium 62-2 can be further reduced as compared with the example illustrated in FIG. 3F.

  The first modification of the second embodiment has the same effect as the second embodiment. In the first modification, the amplifier includes a first-stage amplification unit 60-1 and a second-stage amplification unit 60-2. For this reason, in the first modification, it is possible to realize a laser amplification system having a higher seed light amplification factor as compared with the examples described in FIGS. 4A and 4B. In addition, in the first modification of the second embodiment, the second laser gain medium 62-2 can be downsized.

(Second modification of the second embodiment)
FIG. 4F is a plan view schematically showing a laser amplification system 30 </ b> C- 1 of the second modification example of the second embodiment. Note that, in the laser amplification system 30C-1 of the second modification, the same reference numerals are given to the constituent elements having the same functions as the constituent elements of the laser amplification system 30A-1 of the second embodiment, and the description is repeated. Is omitted.

  The example shown in FIG. 4F is different from the example shown in FIG. 4A in that the cooling mechanism 70 is arranged in the amplifier 60. The other configuration in FIG. 4F is the same as the configuration in FIG. 4A.

  The cooling mechanism 70 may be the same as the cooling mechanism 70 described in FIG. 3K, the cooling mechanism 70 described in FIG. 3L, or the same as the cooling mechanism 70 described in FIG. 3M. There may be.

  In the example illustrated in FIG. 4F, the temperature rise of the first laser gain medium 62 is suppressed by the cooling mechanism 70.

  The cooling mechanism 70 may be applied to the first modification of the second embodiment (specifically, the amplifier 60 'in the example shown in FIG. 4D).

(Third embodiment)
A laser amplification system 30A-2 according to a third embodiment will be described with reference to FIGS. 5A and 5B. FIG. 5A is a plan view schematically showing the laser amplification system 30A-2, and FIG. 5B is a side view schematically showing the laser amplification system 30A-2. In FIG. 5B, the components other than the input-side optical system 50 ′ ″, the amplifier 60, and the output-side optical system 55 are not shown in order to avoid complication of the drawing. Further, in the laser amplification system 30A-2 in the third embodiment, the same functions as the components of the laser amplification system 30 of the first embodiment or the components of the laser amplification system 30A-1 of the second embodiment. Constituent elements having the same reference numbers are given, and repeated description is omitted.

  The laser amplification system 30A-2 in the third embodiment is different from the laser amplification system 30A-1 in the second embodiment in that an output-side optical system 55 is provided.

  The output side optical system 55 receives the amplified light M from the amplifier 60. The output side optical system 55 collects the amplified light M. The output side optical system 55 emits the amplified light M in the fixed direction F. As will be described later, the output side optical system 55 emits the amplified light M toward the fixed direction F regardless of the movement of the position of the reflection spot 68. The output side optical system 55 may emit the amplified light M from the fixed position P toward the fixed direction F regardless of the movement of the position of the reflection spot 68.

  In the example described in FIGS. 5A and 5B, the output-side optical system 55 includes a third mirror 55-3 and a fourth mirror 55-4. The output side optical system 55 may optionally include one or a plurality of optical elements 55-5 other than the third mirror and the fourth mirror.

  The third mirror 55-3 receives the amplified light M from the amplifier 60. The third mirror 55-3 is disposed between the amplifier 60 and the fourth mirror 55-4. The third mirror 55-3 reflects the amplified light M and supplies the amplified light M to the fourth mirror 55-4. The amplified light M from the third mirror 55-3 is incident on the fourth mirror 55-4, and the fourth mirror 55-4 reflects the amplified light M. The amplified light M reflected by the fourth mirror 55-4 is output as output laser light to the outside of the laser amplification system 30A-2 through an output window (not shown in FIGS. 5A and 5B). The

  The third mirror 55-3 is a polygon mirror in the example illustrated in FIG. 5A, but may be other mirrors (galvano mirror, piezo mirror, MEMS mirror). The fourth mirror 55-4 is a polygon mirror in the example shown in FIG. 5A, but may be other mirrors (galvano mirror, piezo mirror, MEMS mirror).

  In the example shown in FIG. 5A, the third drive 55-3 is rotated or swung by the third drive mechanism 85-3. The third drive mechanism 85-3 includes, for example, a motor and a power transmission mechanism. In the example illustrated in FIG. 5A, the third drive mechanism 85-3 is mechanically coupled to the third mirror 55-3.

  The third drive mechanism 85-3 is driven based on a command signal (for example, an electric signal) from the control device 90. In the example illustrated in FIG. 5A, the control device 90 and the third drive mechanism 85-3 are electrically connected, and the third drive mechanism 85-3 is based on a command signal from the control device 90. 3 mirror 55-3 is driven. The third drive mechanism 85-3 rotates or swings the third mirror 55-3 continuously or intermittently around the axis X3.

  In the example shown in FIG. 5A, the fourth drive mechanism 85-4 rotates or swings the fourth mirror 55-4. The fourth drive mechanism 85-4 includes, for example, a motor and a power transmission mechanism. In the example illustrated in FIG. 5A, the fourth drive mechanism 85-4 is mechanically coupled to the fourth mirror 55-4.

  The fourth drive mechanism 85-4 is driven based on a command signal (for example, an electric signal) from the control device 90. In the example shown in FIG. 5A, the control device 90 and the fourth drive mechanism 85-4 are electrically connected, and the fourth drive mechanism 85-4 is based on a command signal from the control device 90. 4 mirror 55-4 is driven. The fourth drive mechanism 85-4 rotates or swings the fourth mirror 55-4 around the axis X4 continuously or intermittently. The third drive mechanism 85-3 and the fourth drive mechanism 85-4 constitute a drive mechanism that drives the output-side optical system 55.

(Condensing mode)
The control device 90 transmits a control signal to the drive mechanisms (the third drive mechanism 85-3 and the fourth drive mechanism 85-4). In the example described in FIGS. 5A and 5B, the control device 90 can execute a condensing mode for condensing the amplified light M from the amplifier 60. In the condensing mode, for example, the control device 90 causes the third reflecting surface 56-3 of the third mirror 55-3 and the fourth reflecting surface 56-4 of the fourth mirror 55-4 to be parallel to each other. The third drive mechanism 85-3 and the fourth drive mechanism 85-4 are controlled.

  More specifically, in the condensing mode, the control device 90 determines that the swing speed or the rotational speed of the third mirror 55-3 is equal to the swing speed of the fourth mirror 55-4. Alternatively, the third drive mechanism 85-3 and the fourth drive mechanism 85-4 are controlled so as to be equal to the magnitude of the rotation speed. In the condensing mode, the control device 90 determines that the third mirror 55-3 swings or rotates (swing direction R3 or rotation direction R3 around the axis X3) swings the fourth mirror 55-4. The third drive mechanism 85-3 and the fourth drive mechanism 85-4 are controlled so as to be in the same direction as the direction or the rotation direction (the swing direction R4 or the rotation direction R4 around the axis X4).

  Further, in the condensing mode, the control device 90 determines that the swing direction or the rotation direction of the third mirror 55-3 (the swing direction R3 or the rotation direction R3 around the axis X3) is the same as that of the second mirror 50-2. The second drive mechanism 80-2 and the third drive mechanism 85-3 are controlled so as to be in the same direction as the swing direction or the rotation direction (the swing direction R2 or the rotation direction R2 around the axis X2). Further, the control device 90 makes the magnitude of the swing speed or rotation speed of the third mirror 55-3 equal to the magnitude of the swing speed or rotation speed of the second mirror 50-2. In addition, the second drive mechanism 80-2 and the third drive mechanism 85-3 may be controlled.

  In the condensing mode, the amplified light M is emitted toward the fixed direction F. When the amplified light M is emitted in the fixed direction F, compared to the case where the emission direction of the amplified light M changes, the amplified light is handled, for example, the target of the amplified light (the object to be processed or destroyed). The guidance control to the (object) becomes easy. Note that the control by the control device 90 in the condensing mode is not limited to the above example.

  In the example described in FIGS. 5A and 5B, a first mirror 50-1 that is an optical element constituting the input side optical system 50 ′ ″ and a fourth mirror 55-4 that constitutes the output side optical system 55 are provided. Are arranged symmetrically with each other along the optical path of the seed light (or with respect to the amplifier 60). The first mirror 50-1 and the fourth mirror 55-4 may be configured by the same component. Costs are reduced by sharing parts. 5A and 5B, the second mirror 50-2 that is an optical element constituting the input side optical system 50 ′ ″ and the third mirror 55-3 that constitutes the output side optical system 55. Are arranged symmetrically with each other along the optical path of the seed light (or with respect to the amplifier 60). The second mirror 50-2 and the third mirror 55-3 may be configured by the same component. Costs are reduced by sharing parts. Note that all of the first mirror 50-1 to the fourth mirror 55-4 may be composed of the same components.

  Note that the laser amplification system may include a direction adjuster 59. The direction adjuster 59 receives the amplified light M from the output-side optical system 55 (receives amplified light from the amplifier 60 when the output-side optical system 55 is not present), and sets the target TA (processing object, destruction object, etc.). The traveling direction of the amplified light is adjusted so that the amplified light M travels toward the target. The direction adjuster 59 may include, for example, a drive mechanism 59B (motor or the like) that adjusts the angle between the mirror 59A and the mirror 59A. The configuration of the direction adjuster 59 may be applied to the first embodiment or the second embodiment described above.

(First Modification of Third Embodiment)
FIG. 5C is a plan view schematically showing a laser amplification system 30B-2 according to a first modification of the third embodiment. FIG. 5D is a side view schematically showing a laser amplification system 30B-2 according to a first modification of the third embodiment. In addition, in the laser amplification system 30B-2 of the first modified example, the same reference numerals are given to the constituent elements having the same functions as the constituent elements of the laser amplification system 30B-1 of the third embodiment, and repeated description is given. Is omitted.

  In the example described in FIGS. 5C and 5D, the output-side optical system 55 in FIGS. 5A and 5B is replaced with an output-side optical system 55 '. Other configurations in FIGS. 5C and 5D are the same as those in FIGS. 5A and 5B.

  The output side optical system 55 'is a fixed type condensing optical system. In the fixed type condensing optical system, optical elements (for example, a convex lens 57 and a concave lens 58 described later) are not driven during the operation of the laser amplification system 30B-2. In other words, during the operation of the laser amplification system 30B-2, optical elements (for example, a convex lens 57 and a concave lens 58 described later) that are included in the output-side optical system 55 'are not changed in position and angle are not changed.

  An example of the output-side optical system 55 'will be described with reference to FIGS. 5C and 5D. The output side optical system 55 ′ includes a convex lens 57 and a concave lens 58. The convex lens 57 condenses the amplified light M. Note that when the parallel incidence mode described above is executed, the amplified light M incident on the convex lens 57 is parallel light (in other words, the optical path C1 and the optical path C2 in FIG. 5D are parallel to each other). The concave lens 58 outputs the condensed amplified light M from the fixed position P toward the fixed direction F.

  The first modification of the third embodiment has the same effect as that of the third embodiment. In the example shown in FIGS. 5C and 5D, the output-side optical system 55 'is a fixed condensing optical system. For this reason, in the example described in FIGS. 5C and 5D, the drive mechanism can be simplified or omitted as compared with the example described in FIGS. 5A and 5B.

(Second modification of the third embodiment)
FIG. 5E is a plan view schematically showing a laser amplification system 30C-2 of a second modification example of the third embodiment. FIG. 5F is a side view schematically showing a laser amplification system 30C-2 of the second modification example of the third embodiment. In addition, in the laser amplification system 30C-2 of the second modified example, components having the same functions as the components of the laser amplification system of the third embodiment (and the first modified example of the second embodiment) The same drawing number is assigned and repeated description is omitted.

  In the example described in FIGS. 5E and 5F, the amplifier 60 of FIGS. 5A and 5B is replaced with an amplifier 60 ''. Other configurations in FIGS. 5E and 5F are the same as those in FIGS. 5A and 5B.

  The amplifier 60 ″ includes a first stage amplification unit 60-1, a second stage amplification unit 60-2, and a third stage amplification unit 60-3. The first stage amplification unit 60-1 includes a first laser gain medium 62 and a first reflective layer 67, and the second stage amplification unit 60-2 includes a second laser gain medium 62-2 and a first reflection layer 67. The third amplification unit 60-3 includes the second reflection layer 67-2, and includes the third laser gain medium 62-3 and the third reflection layer 67-3. The material of the third laser gain medium 62-3 and the third reflection layer 67-3 may be the same as the material of the first laser gain medium 62 and the first reflection layer 67. 5E and 5F, the number of amplification units is three. However, the number of amplification units may be two, or four or more.

  In the example shown in FIG. 5E, the incident direction D of the coaxial light C to the first laser gain medium 62 is constant, and the incident direction D ′ of the coaxial light C to the second laser gain medium 62-2 is constant. The incident direction D ″ of the coaxial light C to the third laser gain medium 62-3 is constant. Therefore, the width between the optical paths (the distance between the optical path C1 and the optical path C2 in FIG. 5F) does not increase as the coaxial light C travels in the amplifier 60 ''. Therefore, in the example illustrated in FIG. 5F, the size of the second laser gain medium 62-2 can be reduced as compared with the example illustrated in FIG. 3F. In the example shown in FIG. 5F, the size of the third laser gain medium 62-3 can be reduced.

  The second modification of the third embodiment has the same effect as the third embodiment. In the second modification, the amplifier includes a plurality of amplification units. For this reason, in the second modification, it is possible to realize a laser amplification system having a higher seed light amplification factor as compared with the examples described in FIGS. 5A and 5B. In addition, in the second modification of the third embodiment, the laser gain medium can be reduced in size.

(Third Modification of Third Embodiment)
FIG. 5G is a plan view schematically showing a laser amplification system 30D-2 according to a third modification of the third embodiment. In addition, in the laser amplification system 30D-2 of the third modified example, the same reference numerals are given to the components having the same functions as the components of the laser amplification system 30A-2 of the third embodiment, and repeated description is given. Is omitted.

  The example shown in FIG. 5G is different from the example shown in FIG. 5A in that the cooling mechanism 70 is arranged in the amplifier 60. Other configurations in FIG. 5G are the same as those in FIG. 5A.

  The cooling mechanism 70 may be the same as the cooling mechanism 70 described in FIG. 3K, the cooling mechanism 70 described in FIG. 3L, or the same as the cooling mechanism 70 described in FIG. 3M. There may be.

  In the example illustrated in FIG. 5G, the cooling mechanism 70 suppresses the temperature rise of the first laser gain medium 62.

  The cooling mechanism 70 may be applied to the first modification example or the second modification example of the third embodiment.

(Fourth embodiment)
A laser amplification system 30A-3 according to a fourth embodiment will be described with reference to FIGS. 6A and 6B. FIG. 6A is a plan view schematically showing a laser amplification system 30A-3 of the fourth embodiment. FIG. 6B is a cross-sectional view schematically showing a laser amplification system 30A-3 of the fourth embodiment.

  In the laser amplification system 30A-3 of the fourth embodiment, the same components as those of the laser amplification system 30A-2 of the third embodiment (or each modification of the laser amplification system of the third embodiment) are used. Constituent elements having functions are given the same figure number, and repeated description is omitted.

  The laser amplification system 30A-3 of the fourth embodiment includes a housing 100 that surrounds the amplifier 60, and an output window 110 for outputting the amplified light M from the inside of the housing to the outside of the housing. In the housing 100, in addition to the amplifier 60, at least one of a seed light source 98, an excitation light source 99, a first optical element 40, an input side optical system 50, an output side optical system 55, and a refrigerant supply mechanism 74 is disposed. May be.

  The laser amplification system 30A-3 includes a refrigerant channel 72 and a refrigerant supply mechanism 74 that supplies the refrigerant to the refrigerant channel 72. The refrigerant flowing through the refrigerant flow path 72 cools the amplifier 60 (for example, the first laser gain medium 62). The refrigerant flow path 72 includes discharge ports 101 </ b> A and 101 </ b> B that supply the refrigerant toward the output window 110. 101 A of discharge ports are arrange | positioned inside the housing | casing 100, 101 A of discharge ports supply a refrigerant | coolant toward the inner surface (surface inside a housing | casing) of the output window 110. FIG. As a result, the inner surface of the output window 110 is cleaned. The discharge port 101B is disposed outside the housing 100, and the discharge port 101B supplies the refrigerant toward the outer surface of the output window 110 (the surface on the outside of the housing). As a result, the outer surface of the output window 110 is cleaned. The discharge port 101 </ b> B and the portion of the refrigerant flow path 72 in the housing are connected via the on-off valve 103. The refrigerant can be supplied to the discharge port 101B only when the on-off valve 103 is open. Note that dust, dirt, and the like are easily accumulated outside the housing 100 as compared to the inside of the housing 100. For this reason, it is meaningful to provide a mechanism for cleaning the outer surface of the output window 110.

  The refrigerant flow path 72 includes refrigerant recovery mechanisms 102A and 102B. The recovery mechanism 102 </ b> A recovers the refrigerant supplied from the discharge port 101 </ b> A toward the output window 110, and the recovered refrigerant is returned to the refrigerant supply mechanism 74. The recovery mechanism 102B recovers the refrigerant supplied from the discharge port 101B toward the output window 110, and the recovered refrigerant is returned to the refrigerant supply mechanism 74. The recovery mechanism 102 </ b> B and a portion of the refrigerant flow path 72 in the housing are connected via an on-off valve 104.

  In the fourth embodiment, an optical element such as an output window is cleaned using a refrigerant used for cooling the amplifier. As a result, dust, dirt and the like on the optical path are removed. By removing dust, dirt, and the like on the optical path, burn-in of the optical element (output window or the like) is prevented. Further, a decrease in transmission efficiency of the optical element (output window or the like) is prevented, and a decrease in reflection efficiency of the optical element (mirror or the like) is prevented.

  In the example described in FIGS. 6A and 6B, the cleaning mechanism (for example, the discharge ports 101A and 101B) of the output window 110 has been described. However, the cleaning mechanism is the other mechanism that configures the laser amplification system 30-4. It may be used for cleaning optical elements. In this case, a refrigerant discharge port is provided for each optical element to be cleaned, and a refrigerant recovery mechanism is provided for each optical element to be cleaned.

  Further, the optical element cleaning mechanism or the configuration of the housing in the fourth embodiment is also applicable to the first embodiment, the second embodiment, the third embodiment, or each modification of each embodiment. Is possible.

  The present invention is not limited to the embodiments described above, and it is obvious that the embodiments can be appropriately modified or changed within the scope of the technical idea of the present invention. Various techniques used in each embodiment or modification can be applied to other embodiments or modifications as long as no technical contradiction arises. The present invention does not exclude the techniques described in Patent Documents 1 to 5 described above. If the techniques described in Patent Documents 1 to 5 are combined with the present invention, the techniques described in Patent Documents 1 to 5 can be improved.

1: Laser amplifier 2: Laser gain medium 3: Reflection film 4: Seed light 5: Excitation light 6: Reflection spot 10: Laser resonator 11: Resonator mirror 12: Resonator mirror 13: Laser gain medium 14: Parallel plate transmission Plate 15: Nonlinear optical crystal 16: Optical path 17: Optical path 18: Lamp 30: Laser amplification system 40, 40 ′: First optical element 50, 50 ′, 50 ″, 50 ′ ″: Input side optical system 50-1 : First mirror 50-2: Second mirror 51: Corner portion 52-1: First reflection surface 52-2: Second reflection surface 55, 55 ': Output side optical system 55-3: Third mirror 55-4 : Fourth mirror 55-5: Optical element 56-3: Third reflection surface 56-4: Fourth reflection surface 57: Convex lens 58: Concave lens 59: Direction adjuster 59A: Mirror 59B: Drive mechanism 60, 60 ', 60 '': Amplifiers 60-1, 60-2 , 60-3: amplification unit 62: first laser gain medium 62-2: second laser gain medium 62-3: third laser gain medium 63: surface 64: surface 65, 65-2: incident position 67: first Reflection layer 67-2: Second reflection layer 67-3: Third reflection layer 68, 68-2: Reflection spot 70: Cooling mechanism 72: Refrigerant flow path 74: Refrigerant supply mechanism 80, 80 ′, 80 ″: Drive Mechanism 80-1: First drive mechanism 80-2: Second drive mechanism 81: Motor 82: Output shaft 85-3: Third drive mechanism 85-4: Fourth drive mechanism 90: Controller 98: Seed light source 99: Excitation light source 100: casing 101A, 101B: discharge port 102A, 102B: collection mechanism 103: on-off valve 104: on-off valve 110: output window A: seed light B: excitation light C: coaxial light C1: optical path C2: optical path D D ′, D ″: Incident direction M: Increase Width light M1: Optical path M2: Optical path P: Fixed position

Claims (15)

A first optical element that receives seed light and excitation light, and outputs the seed light and excitation light as coaxial light;
An amplifier that receives the coaxial light, amplifies the seed light using the excitation light, and outputs amplified light obtained by amplification of the seed light;
An input-side optical system that is disposed between the first optical element and the amplifier, receives the coaxial light from the first optical element, and supplies the coaxial light to the amplifier;
A drive mechanism for driving the input-side optical system to change an incident position or an incident direction of the coaxial light to the amplifier;
A control device for controlling the drive mechanism,
The amplifier is
A first laser gain medium in which the coaxial light is introduced and amplifies the seed light;
A first reflective layer that reflects the coaxial light,
The said control apparatus controls the said drive mechanism, and moves the position of the reflective spot of the said coaxial light in a said 1st reflective layer by changing the said incident position or the said incident direction Laser amplification system. The laser amplification system according to claim 1,
The input-side optical system includes a first mirror that reflects the coaxial light,
The drive mechanism includes a first drive mechanism that swings or rotates the first mirror. Laser amplification system. A laser amplification system according to claim 2,
The control device controls the first drive mechanism so that the first mirror swings or rotates around a first axis;
The laser amplifying system in which the reflection spot moves on the first reflection layer by the first mirror swinging or rotating around the first axis. A laser amplification system according to claim 3,
The control device controls the first drive mechanism so that the first mirror swings or rotates around a second axis different from the first axis;
When the first mirror swings or rotates around the first axis and swings or rotates around the second axis, the reflection spot moves two-dimensionally on the first reflection layer. Yes Laser amplification system. A laser amplification system according to any one of claims 2 to 4,
The input side optical system is:
A second mirror disposed between the first mirror and the amplifier for receiving the coaxial light from the first mirror and reflecting the coaxial light;
The drive mechanism is
A second drive mechanism for swinging or rotating the second mirror;
The said control apparatus performs the parallel incident mode which changes the said incident position in the state which fixed the said incident direction Laser amplification system. A laser amplification system according to any one of claims 1 to 5,
An output side optical system that receives the amplified light, collects the amplified light, and outputs the amplified light in a fixed direction;
The output side optical system outputs the amplified light in the fixed direction regardless of movement of the position of the reflection spot. Laser amplification system. A laser amplification system according to claim 6,
The output optical system is a fixed condensing optical system. A laser amplification system according to claim 6,
The input side optical element which comprises the said input side optical system, and the output side optical element which comprises the said output side optical system are arrange | positioned symmetrically mutually. Laser amplification system. A laser amplification system according to claim 6,
A third mirror that receives the amplified light from the amplifier and reflects the amplified light;
A fourth mirror that receives the amplified light from the third mirror and reflects the amplified light;
A third drive mechanism for swinging or rotating the third mirror;
A fourth drive mechanism for swinging or rotating the fourth mirror,
The third mirror and the fourth mirror constitute the output-side optical system. Laser amplification system. A laser amplification system according to any one of claims 1 to 9,
The amplifier is
A second laser gain medium in which the coaxial light from the first laser gain medium is introduced and amplifies the seed light;
A laser amplification system comprising: a second reflection layer that reflects the coaxial light. A laser amplification system according to any one of claims 1 to 10,
A laser amplification system further comprising a cooling mechanism for cooling the first laser gain medium. A laser amplification system according to claim 11, comprising:
The cooling mechanism includes a heat sink disposed in contact with the first reflective layer. A laser amplification system according to claim 11 or 12,
The cooling mechanism is
A refrigerant flow path;
A laser amplification system comprising: a refrigerant supply mechanism that supplies the refrigerant to the refrigerant flow path. A laser amplification system according to claim 13,
The refrigerant flow path includes a refrigerant discharge port that supplies the refrigerant toward an optical component,
The refrigerant is a laser amplification system for cleaning the optical component. The laser amplification system according to claim 14,
A housing surrounding the amplifier;
An output window for outputting the amplified light from the inside of the housing to the outside of the housing,
The optical component to be cleaned is the output window. Laser amplification system.

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