JP2017005069A - Laser equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide laser equipment by which higher output and higher beam quality of output light are possible while suppressing increase in size and cost.SOLUTION: Laser equipment 1A is provided with: an excitation light source 11 for outputting excitation light L11; an excitation light source 12 electrically connected in series with the excitation light source 11 to output excitation light L12; a power supply unit 13 for supplying driving current to the excitation light source 11 and the excitation light source 12; a laser oscillation part 14 for making the excitation light L11 incident to output seed light L14; a lens 45 for condensing the excitation light L11 toward the laser oscillation part 14; an amplifier medium 15a for making the excitation light L12 and the seed light L14 incident to amplify the seed light L14; and a light shielding member 20 arranged between the excitation light source 11 and the lens 45 on an optical axis of the excitation light L11 to shield a part Lp of the excitation light L11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser apparatus.

  Patent Document 1 describes a laser device. This laser device includes an excitation light source, a laser that receives excitation light from the excitation light source and oscillates pulse laser light, and an optical amplifier that amplifies the pulse laser light from the laser. The optical amplifier includes a gain medium and a pumping light source different from the pumping light source. The pulsed laser light oscillated from the laser is combined with the excitation light from the excitation light source of the optical amplifier in the gain medium of the optical amplifier. As a result, amplified pulsed laser light is generated.

US Pat. No. 7,203,209

  Currently, there is a demand for higher output of laser light and higher beam quality. For this purpose, for example, it is conceivable to generate high-quality seed light with low output, and to increase the output by amplifying the seed light. Taking the above laser device as an example, the drive current of the laser excitation light source is reduced to suppress the light intensity of the excitation light, and the drive current of the excitation light source of the optical amplifier is increased to increase the light intensity of the excitation light. It is possible. However, in this case, two power supply devices for generating different drive currents are required. When two power supply apparatuses are used, a significant increase in cost and an increase in the size of the entire apparatus cannot be avoided.

  An object of the present invention is to provide a laser device capable of increasing the output power and the beam quality while suppressing an increase in size and cost.

  The present invention includes a first excitation light source that outputs first excitation light, a second excitation light source that is electrically connected in series to the first excitation light source and outputs second excitation light, Power supply unit for supplying a driving current to the first excitation light source and the second excitation light source, a laser medium for generating emission light upon receiving the first excitation light, and a saturable absorber whose light absorption rate is reduced by saturation of light absorption A first reflector that transmits the first excitation light, and a laser resonator that has a laser medium and a saturable absorber on the resonance optical path to resonate the emitted light together with the first reflector. A laser oscillating unit that outputs a part of the emitted light as seed light, a condensing unit that condenses the first excitation light toward the laser oscillating unit, and a second A first amplifier medium that amplifies the seed light by entering the excitation light and the seed light; and a first amplifier medium on the optical axis of the first excitation light. It is disposed between the excitation light source and the condenser portion of provided with a light blocking member for blocking a part of the first excitation light.

  In this laser apparatus, a part of the first excitation light output from the first excitation light source and incident on the laser oscillation unit is blocked (cut) by the light shielding member. For this reason, even when substantially the same drive current is supplied to the first and second excitation light sources, the second excitation light having a relatively high light intensity is incident on the first amplifier medium. In addition, the light intensity of the first excitation light incident on the laser oscillation unit can be reduced. For this reason, according to this laser device, the output light can be increased by sufficiently amplifying the high-beam quality seed light. In particular, in this laser apparatus, substantially the same drive current can be supplied to the first and second excitation light sources when increasing the output of high-beam quality seed light as described above. For this reason, it is not necessary to prepare a plurality of power supply devices, and an increase in size and cost can be suppressed.

  In the laser apparatus according to the present invention, the light shielding member may include a light shielding part that shields a part of the first excitation light and a passage part that is provided in the light shielding part and allows the remaining part of the first excitation light to pass therethrough. . In this case, the beam shape of the first excitation light can be controlled by appropriately setting the shape of the passing portion. Therefore, the beam quality of the seed light can be further improved.

  In the laser apparatus according to the present invention, the passage portion may be an opening provided in the light shielding portion so as to form a circular shape when viewed from the optical axis direction of the first excitation light. In this case, the beam shape of the first excitation light can be shaped into a circular shape.

  In the laser apparatus according to the present invention, the light blocking member blocks a part of the first excitation light on one side in a predetermined direction intersecting the optical axis of the first excitation light, and on the other side in the predetermined direction. You may let the remainder of 1st excitation light pass. In this case, for example, when the first excitation light source is a laser diode array, if a predetermined direction is associated with the array direction, the laser light from the thermally stable portion outside the array direction in the laser diode array is The remaining portion of the excitation light of 1 can be incident on the laser oscillation unit. For this reason, the beam quality of seed light can be improved.

  In the laser apparatus according to the present invention, the light shielding member includes a reflection part that reflects a part of the first excitation light, and the part of the first excitation light reflected by the reflection part is the second excitation light. At the same time, it may be incident on the amplifier medium. In this case, the light intensity of the excitation light incident on the amplifier medium can be improved.

  A laser apparatus according to the present invention is electrically connected in series to a first excitation light source and a second excitation light source, and is amplified by a third excitation light source that outputs third excitation light, and a first amplifier medium. And a second amplifier medium that further amplifies the seed light. The power supply unit includes a first excitation light source, a second excitation light source, and a second excitation light source. A driving current may be supplied to the three excitation light sources. In this case, the output light can be further increased without preparing a plurality of power supply devices.

  According to the present invention, it is possible to provide a laser device capable of increasing the output light and improving the beam quality while suppressing an increase in size and cost.

It is a figure which shows the laser apparatus which concerns on 1st Embodiment. It is typical sectional drawing which shows a light shielding member. It is a figure which shows the laser apparatus which concerns on 2nd Embodiment. It is a figure which shows the laser apparatus which concerns on 3rd Embodiment. It is a figure which shows the laser apparatus which concerns on 4th Embodiment. It is a figure which shows the laser apparatus which concerns on 5th Embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or equivalent part, and the overlapping description may be abbreviate | omitted.
[First Embodiment]

  FIG. 1 is a diagram illustrating a laser apparatus according to the first embodiment. A laser apparatus 1A shown in FIG. 1 is a microchip laser apparatus using a microchip laser, for example. The laser device 1A includes an excitation light source (first excitation light source) 11, an excitation light source (second excitation light source) 12, a power supply unit 13, a laser oscillation unit 14, an amplifier 15, optical systems 16 and 17, mirrors 18 and 19, And the light shielding member 20 is provided.

  The excitation light source 11, the excitation light source 12, and the power supply unit 13 are electrically connected to each other in series. The excitation light source 11 is driven by a drive current from the power supply unit 13 and outputs excitation light (first excitation light) L11 for the laser oscillation unit 14. The excitation light source 12 is driven by a drive current from the power supply unit 13 and outputs excitation light (second excitation light) L12 for the amplifier 15. The excitation light source 11 and the excitation light source 12 are, for example, a laser diode array including a plurality of active layers arranged along the slow axis direction.

  The laser diode array here is a semiconductor laser formed using, for example, a semiconductor. For example, the excitation light source 11 and the excitation light source 12 are substantially the same semiconductor laser. The excitation light L11 and the excitation light L12 are, for example, pulse laser beams. For example, the wavelength of the excitation light L11 and the wavelength of the excitation light L12 are about 808 nm or about 940 nm.

  The power supply unit 13 supplies drive current to the excitation light source 11 and the excitation light source 12 at once. More specifically, the power supply unit 13 is electrically connected to, for example, the negative electrode of the excitation light source 11 and the positive electrode of the excitation light source 12. The power supply unit 13 is a single power supply device, and generates drive currents for the excitation light source 11 and the excitation light source 12 by a single drive circuit. Therefore, the power supply unit 13 supplies substantially the same drive current to the excitation light source 11 and the excitation light source 12. For example, the power supply unit 13 supplies a pulsed drive current to the excitation light source 11 and the excitation light source 12. Since the power supply unit 13 and the excitation light sources 11 and 12 are connected in series, the excitation light sources 11 and 12 can be stably operated.

  The laser oscillation unit 14 is, for example, a microchip laser. The laser oscillation unit 14 receives the excitation light L11 from the excitation light source 11, and outputs seed light (for example, pulsed laser light) L14. More specifically, the laser oscillation unit 14 includes a reflection unit (first reflection unit) 31, a laser medium 32, a saturable absorber 33, and a reflection unit (second reflection unit) 34. The reflection unit 31, the laser medium 32, the saturable absorber 33, and the reflection unit 34 are sequentially arranged along the optical axis of the excitation light L11 and are integrated with each other. For integration, for example, direct bonding (surface activated bonding technology) can be used.

  The laser medium 32 receives the excitation light L11 and generates emission light. Specifically, the laser medium 32 contains a photoactive substance. The laser medium 32 generates emitted light when the photoactive substance is excited by the excitation light L11. The laser medium 32 is, for example, a crystal such as Nd: YAG and Yb: YAG. The thickness of the laser medium 32 along the optical axis of the excitation light L11 is, for example, about 0.01 mm to 1.5 mm. The wavelength of the emitted light from the laser medium 32 is, for example, about 1064 nm or about 1030 nm.

  The saturable absorber 33 has a characteristic that the light absorptance becomes small due to saturation of light absorption. For this reason, the saturable absorber 33 functions as a passive Q switch in the laser resonator of the laser oscillation unit 14. That is, the saturable absorber 33 has a high light absorption rate when the light intensity is low, and when the light intensity exceeds a certain value, the light absorption is saturated and the light absorption rate decreases rapidly. The saturable absorber 33 is, for example, a crystal such as Cr: YAG, V: YAG, or GaAs.

  The reflector 31 transmits the excitation light L11 and reflects the light emitted from the laser medium 32. The reflector 34 transmits part of the light emitted from the laser medium 32 and reflects the remaining part. Part of the emitted light that has passed through the reflecting section 34 is output from the laser oscillation section 14 as seed light L14. The reflector 34 reflects the excitation light L11 as an example.

  The reflectivity of the reflector 34 with respect to the wavelength of the emitted light from the laser medium 32 is, for example, about 90%. The reflection part 31 and the reflection part 34 are dielectric multilayer films, for example. The reflector 31 and the reflector 34 constitute a laser resonator that resonates the light emitted from the laser medium 32. The laser medium 32 and the saturable absorber 33 are disposed on the resonant optical path. That is, the reflection unit 34 includes a laser resonator that has the laser medium 32 and the saturable absorber 33 on the resonance optical path and resonates the emitted light together with the reflection unit 31.

The amplifier 15 includes an amplifier medium (first amplifier medium) 15a. The amplifier medium 15a receives the excitation light L12 and the seed light L14 and amplifies the seed light L14. The amplifier medium 15a includes an end surface 15s serving as an incident surface for the excitation light L12 and an end surface 15r opposite to the end surface 15s. A reflecting portion (not shown) is provided on the end face 15s. The reflection part of the end face 15s transmits the excitation light L12 and reflects the seed light L14. On the other hand, a non-reflective coating (AR coating) for at least the wavelength of the seed light L14 is applied to the end face 15r. The amplifier medium 15a is, for example, Nd: YAG, Yb: YAG, Nd: YVO ₄ or the like. The seed light L14 amplified by the amplifier 15 is emitted from the amplifier 15 as output light L15.

  The optical system 16 is disposed between the excitation light source 11 and the laser oscillation unit 14. The optical system 16 includes a collimator 41, a collimator 42, a lens 43, a collimator 44, and a lens (light collecting unit) 45. The collimator 41, the collimator 42, the lens 43, the collimator 44, and the lens 45 are arranged in this order on the optical axis of the excitation light L11. The optical system 16 is a shaping optical system that performs beam shape adjustment and parallelization.

  The collimator 41 collimates the excitation light L11 output from the excitation light source 11 in the fast axis direction. A rotator (not shown) is provided on the rear side of the optical path of the excitation light L11 in the collimator 41. The rotator rotates the excitation light L11 from the collimator 41 by 90 ° in a plane orthogonal to the optical axis. The collimator 42 collimates the excitation light L11 emitted from the rotator in the fast axis direction (original slow axis direction). Thereby, the excitation light L11 is collimated in both the fast axis direction and the slow axis direction. Instead of using a rotator, a collimator that collimates the excitation light L11 emitted from the collimator 41 in the slow axis direction may be used.

  The lens 43 condenses the excitation light L11 emitted from the collimator 42 in the slow axis direction. The collimator 44 collimates the excitation light L11 emitted from the lens 43 in the slow axis direction. The lens 45 collects the excitation light L <b> 11 emitted from the collimator 44 toward the laser oscillation unit 14. Here, the lens 45 condenses the excitation light L11 in the fast axis direction and the slow axis direction. The condensing position of the excitation light L11 is in the vicinity of the end surface 32s (boundary surface of the resonator) of the laser medium 32 on the lens 45 side.

  More specifically, the lens 45 can focus the excitation light L11 on the end surface 32s of the laser medium 32, for example. In this case, the size of the beam spot of the excitation light L11 is minimized at the end face 32s of the laser medium 32. For this reason, the beam quality of the seed light L14 is the best. Further, the lens 45 can collect the excitation light L11 inside the laser medium 32 from the end face 32s of the laser medium 32. In this case, the overlapping part of the excitation light L11 and the oscillation mode of the laser oscillation unit 14 is increased, and the utilization factor of the excitation light L11 is improved.

  Further, the lens 45 may focus the excitation light L11 on the lens 45 side (outside the laser medium 32) from the end face 32s of the laser medium 32. In this case, a portion where the excitation light L11 overlaps the oscillation mode of the laser oscillation unit 14 is reduced, and the excitation loss can be arbitrarily adjusted. In this case, the size of the beam spot of the excitation light L11 in the laser medium 32 increases and the light density decreases, and only the central portion of the excitation mode contributes to the oscillation of the seed light L14. For this reason, the balance between the beam quality and output of the seed light L14 is good.

  From the viewpoint of the beam quality of the seed light L14, when the excitation light L11 is condensed on the end surface 32s of the laser medium 32, when the excitation light L11 is condensed outside the laser medium 32, the excitation light L11 is emitted from the laser medium 32. This is a preferred mode in the order in which the light is condensed inside. On the other hand, from the viewpoint of increasing the output of the seed light L14, when the excitation light L11 is condensed inside the laser medium 32, when the excitation light L11 is condensed outside the laser medium 32, the excitation light L11 is converted into the laser medium. It is a preferable aspect in order in the case of condensing on 32 end surfaces 32s. Therefore, the condensing position of the excitation light L11 by the lens 45 may be appropriately set according to demand.

  The optical system 17 is disposed between the excitation light source 12 and the amplifier 15. The optical system 17 includes a collimator 51, a collimator 52, a lens 53, a collimator 54, and a lens 55. The collimator 51, the collimator 52, the lens 53, the collimator 54, and the lens 55 are arranged in this order on the optical axis of the excitation light L12. The optical system 17 is a shaping optical system that performs beam shape adjustment and parallelization.

  The collimator 51 collimates the excitation light L12 output from the excitation light source 12 in the fast axis direction. A rotator (not shown) is provided on the rear side of the optical path of the excitation light L12 in the collimator 51. The rotator rotates the excitation light L12 from the collimator 51 by 90 ° in a plane orthogonal to the optical axis. The collimator 52 collimates the excitation light L12 emitted from the rotator in the fast axis direction (original slow axis direction). Thereby, the excitation light L12 is collimated in both the fast axis direction and the slow axis direction. Instead of using a rotator, a collimator that collimates the excitation light L12 emitted from the collimator 51 in the slow axis direction may be used.

  The lens 53 condenses the excitation light L12 emitted from the collimator 52 in the slow axis direction. The collimator 54 collimates the excitation light L12 emitted from the lens 53 in the slow axis direction. The lens 55 condenses the excitation light L12 emitted from the collimator 54 toward the amplifier 15 (amplifier medium 15a). Here, the lens 55 condenses the excitation light L12 in the fast axis direction and the slow axis direction. The condensing position of the excitation light L12 is, for example, the end surface 15s of the amplifier medium 15a.

  The mirror 18 and the mirror 19 cause the seed light L14 output from the laser oscillation unit 14 to enter the amplifier 15. More specifically, the mirror 18 and the mirror 19 deflect the optical path of the seed light L14 by reflection so that the seed light L14 enters the end face 15r of the amplifier medium 15a.

  The light shielding member 20 is provided between the excitation light source 11 and the lens 45 on the optical path of the excitation light L11. Here, the light shielding member 20 is disposed between the collimator 44 and the lens 45. The light blocking member 20 blocks (cuts) a part Lp of the excitation light L11 so that only the remaining portion Lr of the excitation light L11 enters the lens 45 and the laser oscillation unit 14. That is, the light shielding member 20 reduces the light intensity of the excitation light L11 and makes it incident on the laser oscillation unit 14 (laser medium 32 and saturable absorber 33).

  FIG. 2 is a schematic cross-sectional view showing the light shielding member. As shown in FIGS. 1 and 2, the light shielding member 20 includes a light shielding part 21 that shields a part Lp of the excitation light L11 and a passage part 22 that is provided in the light shielding part 21 and passes the remaining part Lr of the excitation light L11. Including. Here, as an example, the passage part 22 is an opening (hole) provided in the light shielding part 21. The passage portion 22 has a circular shape when viewed from the optical axis direction of the excitation light L11. Therefore, the light shielding member 20 has an annular shape as a whole. However, the overall shape of the light shielding member 20 can be arbitrarily set.

  And the light shielding member 20 is arrange | positioned so that the center of the passage part 22 and the center of the beam spot of the excitation light L11 may substantially correspond, for example. Accordingly, here, the outer edge portion (of the beam spot) of the excitation light L11 is a part Lp shielded by the light shielding portion 21, and the central portion is the remaining portion Lr that passes through the passage portion 22. The light shielding member 20 is an aperture, for example.

  In the laser apparatus 1 </ b> A configured as described above, first, a drive current is supplied from the power supply unit 13 to the excitation light source 11 and the excitation light source 12. Thereby, the excitation light L11 is output from the excitation light source 11, and the excitation light L12 is output from the excitation light source 12. The excitation light L11 output from the excitation light source 11 is partially blocked by the light blocking member 20 and the remaining portion Lr is directed to the lens 45.

  The remaining portion Lr of the excitation light L11 is collected by the lens 45 and enters the laser oscillation unit 14. Then, the excitation light L11 excites the laser medium 32, whereby the seed light L14 is output from the laser oscillation unit 14. The seed light L14 output from the laser oscillation unit 14 is deflected by the mirror 18 and the mirror 19 and enters the amplifier 15.

  On the other hand, the excitation light L12 output from the excitation light source 12 passes through the optical system 17 and enters the amplifier 15 (amplifier medium 15a). That is, the excitation light L12 and the seed light L14 are incident on the amplifier 15. The seed light L14 incident on the amplifier 15 is amplified according to the excitation of the amplifier medium 15a by the excitation light L12. Thereby, the amplified seed light L14 is output to the outside from the amplifier 15 and the laser device 1A as output light L15.

  As described above, in the laser apparatus 1 </ b> A, a part Lp of the excitation light L <b> 11 output from the excitation light source 11 and incident on the laser oscillation unit 14 is blocked by the light shielding member 20. Therefore, even when substantially the same drive current is supplied to the excitation light sources 11 and 12, laser oscillation is performed while the excitation light L12 having relatively high light intensity is incident on the amplifier 15 (amplifier medium 15a). The light intensity of the excitation light L11 incident on the portion 14 can be reduced. For this reason, according to the laser apparatus 1A, the output light L15 can be increased in output power by sufficiently amplifying the high-beam quality seed light L14.

  In particular, in the laser apparatus 1A, when the high-beam-quality seed light L14 is increased in output as described above, substantially the same drive current is applied to the excitation light source 11 and the excitation light source 12 by the single power source unit 13. Can be supplied. For this reason, it is not necessary to prepare a plurality of power supply devices, and an increase in size and cost can be suppressed. That is, according to the laser apparatus 1A, it is possible to increase the output power and the beam quality of the output light L15 while suppressing an increase in size and cost.

  In the laser apparatus 1A, the light shielding member 20 includes a light shielding part 21 that shields a part Lp of the excitation light L11 and a passage part 22 that is provided in the light shielding part 21 and allows the remaining part Lr of the excitation light L11 to pass therethrough. Yes. For this reason, it is possible to control the beam shape of the excitation light L11 by appropriately setting the shape of the passage portion 22. Therefore, the beam quality of the seed light L14 can be further improved.

  Furthermore, in the laser apparatus 1A, the passage portion 22 is an opening provided in the light shielding portion 21 so as to form a circular shape when viewed from the optical axis direction of the excitation light L11. For this reason, the beam shape of the excitation light L11 can be shaped into a circular shape.

Here, in the laser apparatus 1A, as an example, the beam diameter of the excitation light L11 when passing through the collimator 44 is on the order of several mm (for example, 1 mm). Further, as an example, the beam diameter of the excitation light L11 when passing through the lens 45 and entering the laser oscillation unit 14 is on the order of several hundred μm (for example, 100 μm). That is, the excitation light L11 is reduced to about 10 times by the lens 45. In the laser apparatus 1 </ b> A, the light amount is adjusted by the light shielding member 20 with respect to the parallel excitation light L <b> 11 having a large beam diameter before being narrowed by the lens 45. For this reason, the amount of light can be easily and accurately adjusted.
[Second Embodiment]

  FIG. 3 is a diagram illustrating a laser apparatus according to the second embodiment. As shown in FIG. 3, the laser device 1 </ b> B is different from the laser device 1 </ b> A in that it includes a light shielding member 20 </ b> B instead of the light shielding member 20 and further includes a mirror 60. Other configurations of the laser device 1B are the same as those of the laser device 1A.

  The light blocking member 20B is provided between the excitation light source 11 and the lens 45 on the optical path of the excitation light L11. Here, the light shielding member 20 </ b> B is disposed between the collimator 44 and the lens 45. The light blocking member 20B blocks only a part Lp of the excitation light L11 so that only the remaining portion Lr of the excitation light L11 enters the lens 45 and the laser oscillation unit 14. That is, the light shielding member 20B decreases the light intensity of the excitation light L11 and causes the light to enter the laser oscillation unit 14 (laser medium 32 and saturable absorber 33).

  The light shielding member 20B is disposed so as to overlap a part of the optical path of the excitation light L11. In particular, the light blocking member 20B blocks a part Lp of the excitation light L11 on one side in a predetermined direction intersecting the optical axis of the excitation light L11 and allows the remaining portion Lr of the excitation light L11 on the other side in the predetermined direction to pass. . When the excitation light source 11 is a laser diode array, the predetermined direction is associated with the array direction. Specifically, here, since the rotator is provided in front of the light shielding member 20B, the predetermined direction can be a direction obtained by rotating the array direction of the laser diode array by 90 °.

  On the other hand, when the rotator is not used, the predetermined direction can be the array direction of the laser diode array. Thereby, the light blocking member 20B blocks a part Lp of the excitation light L11 from the one side portion in the array direction in the laser diode array and allows the remaining portion Lr of the excitation light L11 from the other side portion in the array direction to pass. It will be. That is, here, the laser light from the outer portion in the array direction of the laser diode array is incident on the laser oscillation unit 14 as the remaining portion Lr of the excitation light L11.

  Further, at least the overlapping portion of the light shielding member 20B with the excitation light L11 is a reflection part that reflects light having the wavelength of the excitation light L11. Therefore, a part Lp of the excitation light L11 is reflected by the reflection part. That is, the light shielding member 20B includes a reflection part that reflects a part Lp of the excitation light L11. This reflection part is also a light-shielding part that blocks a part Lp of the excitation light L11.

  The mirror 60 is provided between the excitation light source 12 and the lens 55 on the optical path of the excitation light L12. Here, the mirror 60 is disposed between the collimator 54 and the lens 55. Further, the mirror 60 is disposed so as not to overlap with the excitation light L12 (for example, disposed above the beam of the excitation light L12). The light shielding member 20 </ b> B reflects a part Lp of the excitation light L <b> 11 toward the mirror 60.

  The mirror 60 further reflects a part Lp of the excitation light L11 from the light shielding member 20B toward the lens 55. Accordingly, here, a part Lp of the excitation light L11 reflected by the light shielding member 20B is collected by the lens 55 together with the excitation light L12 and enters the amplifier 15 (amplifier medium 15a).

  As described above, according to the laser device 1B, the same effect as that of the laser device 1A can be obtained except that the beam shape of the excitation light L11 can be shaped into a circular shape. Further, according to the laser device 1B, the light blocking member 20B includes a reflecting portion that reflects a part Lp of the excitation light L11. Then, a part Lp of the excitation light L11 reflected by the reflection part of the light shielding member 20B is further reflected by the mirror 60 and enters the amplifier medium 15a together with the excitation light L12. For this reason, the seed light L14 can be reliably amplified by improving the light intensity of the excitation light incident on the amplifier medium 15a.

Further, in the laser apparatus 1B, the light blocking member 20B blocks a part Lp of the excitation light L11 on one side in a predetermined direction intersecting the optical axis of the excitation light L11, and the excitation light L11 on the other side in the predetermined direction. The remaining portion Lr is allowed to pass through. Therefore, for example, when the excitation light source 11 is a laser diode array, if a predetermined direction is associated with the array direction, the laser light from the thermally stable outer portion of the laser diode array is converted to the remaining portion Lr of the excitation light L11. As shown in FIG. For this reason, the beam quality of the seed light L14 can be improved.
[Third Embodiment]

  FIG. 4 is a diagram illustrating a laser apparatus according to the third embodiment. As shown in FIG. 4, the laser device 1 </ b> C is different from the laser device 1 </ b> A in that it includes a light shielding member 20 </ b> B instead of the light shielding member 20 and further includes a half-wave plate 71 and a polarization beam splitter 72. ing. The other configuration of the laser device 1C is the same as that of the laser device 1A.

  The polarization beam splitter 72 is disposed between the excitation light source 12 and the lens 55 on the optical path of the excitation light L12. Here, the polarization beam splitter 72 is disposed between the collimator 54 and the lens 55. Further, the polarization beam splitter 72 is disposed so as to overlap the excitation light L12. That is, the polarization beam splitter 72 is disposed in the beam of the excitation light L12. Further, the polarization beam splitter 72 transmits light in the polarization direction of the excitation light L12. Accordingly, the excitation light L12 passes through the polarization beam splitter 72 and travels toward the lens 55.

  The light blocking member 20 </ b> B reflects a part Lp of the excitation light L <b> 11 toward the polarization beam splitter 72. The half-wave plate 71 is disposed on the optical path of a part Lp of the excitation light L11 that goes toward the polarization beam splitter 72. Accordingly, the polarization direction of the part Lp of the excitation light L11 is changed by the half-wave plate 71. Thereby, the polarization direction of a part Lp of the excitation light L11 becomes a polarization direction different from the polarization direction of the excitation light L12. Thereafter, a part Lp of the excitation light L <b> 11 is reflected toward the lens 55 by the polarization beam splitter 72. Therefore, a part Lp of the excitation light L11 is coupled to the excitation light L12 and enters the amplifier medium 15a together with the excitation light source 12.

As described above, according to the laser device 1C, the same effect as that of the laser device 1A can be obtained except that the beam shape of the excitation light L11 can be shaped into a circular shape. Further, according to the laser device 1C, the light blocking member 20B includes a reflecting portion that reflects a part Lp of the excitation light L11. Then, a part Lp of the excitation light L11 reflected by the reflection part of the light shielding member 20B is made incident on the amplifier medium 15a together with the excitation light L12 by the half-wave plate 71 and the polarization beam splitter 72. For this reason, the seed light L14 can be reliably amplified by improving the light intensity of the excitation light incident on the amplifier medium 15a. Furthermore, according to the laser device 1C, for the same reason as the laser device 1B, for example, when the excitation light source 11 is a laser diode array, the beam quality of the seed light L14 can be improved.
[Fourth Embodiment]

  FIG. 5 is a diagram showing a laser apparatus according to the fourth embodiment. As shown in FIG. 5, the laser apparatus 1D is different from the laser apparatus 1A in that it includes a light shielding member 20D instead of the light shielding member 20 and further includes a mirror 60D. Other configurations of the laser device 1D are the same as those of the laser device 1A.

  The light shielding member 20D is provided between the excitation light source 11 and the lens 45 on the optical path of the excitation light L11. Here, the light shielding member 20 </ b> D is disposed between the collimator 44 and the lens 45. The light blocking member 20D blocks only a part Lp of the excitation light L11 so that only the remaining portion Lr of the excitation light L11 enters the lens 45 and the laser oscillation unit 14. That is, the light shielding member 20D decreases the light intensity of the excitation light L11 and makes it incident on the laser oscillation unit 14 (laser medium 32 and saturable absorber 33).

  The light shielding member 20D includes a light shielding part 21D that shields a part Lp of the excitation light L11 and a passage part 22 that is provided in the light shielding part 21D and allows the remaining part Lr of the excitation light L11 to pass therethrough. When viewed from the optical axis direction of the excitation light L11, the light shielding portion 21D has a disk shape, and the passage portion 22 has a circular shape. Therefore, the light shielding member 20D has an annular shape when viewed from the optical axis direction of the excitation light L11. However, the outer shape of the light shielding part 21D (that is, the overall shape of the light shielding member 20D) can be arbitrarily set. For example, the light shielding member 20D is disposed so that the center of the passage portion 22 and the center of the beam of the excitation light L11 substantially coincide with each other. Therefore, here, the outer edge portion of the beam of the excitation light L11 is a part Lp that is blocked by the light shielding portion 21D, and the central portion is the remaining portion Lr that passes through the passage portion 22.

  Here, the incident surface of the excitation light L11 in the light shielding part 21D is a reflection part that reflects light having the wavelength of the excitation light L11. Therefore, the light shielding part 21D reflects a part Lp of the excitation light L11. The mirror 60D is provided between the excitation light source 12 and the lens 55 on the optical path of the excitation light L12. Here, the mirror 60 is disposed between the collimator 54 and the lens 55. The light shielding unit 21D reflects a part Lp of the excitation light L11 toward the mirror 60.

  The mirror 60D includes a reflection part 61D that reflects a part Lp of the excitation light L11 from the light shielding member 20D, and a passage part 62 that is provided in the reflection part 61D and allows the excitation light L12 to pass therethrough. When viewed from the optical axis direction of the excitation light L12, the reflection portion 61D has a disk shape, and the passage portion 62 has a circular shape. Therefore, the mirror 60D has an annular shape when viewed from the optical axis direction of the excitation light L12. As an example, the mirror 60D and the light shielding member 20D have substantially the same shape. However, the outer shape of the reflecting portion 61D (that is, the overall shape of the mirror 60D) can be arbitrarily set. For example, the mirror 60D is arranged so that the center of the passing portion 62 and the center of the beam of the excitation light L12 substantially coincide. Accordingly, a part Lp of the excitation light L11 is disposed on the outer edge of the beam of the excitation light L12, is coupled to the excitation light L12, and enters the amplifier medium 15a together with the excitation light L12.

As described above, according to the laser device 1D, the same effect as that of the laser device 1A can be obtained. Further, according to the laser device 1D, the light shielding member 20D includes a reflecting portion that reflects a part Lp of the excitation light L11. Then, a part Lp of the excitation light L11 reflected by the reflection part of the light shielding member 20D is further reflected by the mirror 60D and is incident on the amplifier medium 15a together with the excitation light L12. For this reason, the seed light L14 can be reliably amplified by improving the light intensity of the excitation light incident on the amplifier medium 15a.
[Fifth Embodiment]

  FIG. 6 is a diagram showing a laser apparatus according to the fifth embodiment. As shown in FIG. 6, the laser apparatus 1E is different from the laser apparatus 1B in that it further includes an excitation light source (third excitation light source) 23, an amplifier 24, an optical system 17E, a mirror 25, and a mirror 26. ing. Other configurations of the laser device 1E are the same as those of the laser device 1B.

  The excitation light source 23 has the same configuration as the excitation light L11 and the excitation light L12. The excitation light source 23 is electrically connected in series with the excitation light source 11, the excitation light source 12, and the power supply unit 13. The excitation light source 23 is driven by a drive current from the power supply unit 13 and outputs excitation light (third excitation light) L23 for the amplifier 24. The power supply unit 13 supplies drive current to the excitation light source 11, the excitation light source 12, and the excitation light source 23 in a lump.

  More specifically, the power supply unit 13 is electrically connected to, for example, the negative electrode of the excitation light source 11 and the positive electrode of the excitation light source 23. The power supply unit 13 is a single power supply device, and generates drive currents for the excitation light source 11, the excitation light source 12, and the excitation light source 23 by a single drive circuit. Therefore, the power supply unit 13 supplies substantially the same drive current to the excitation light source 11, the excitation light source 12, and the excitation light source 23. Since the power supply unit 13 and the excitation light sources 11, 12, and 23 are connected in series, the excitation light sources 11, 12, and 23 can be stably operated.

The amplifier 24 includes an amplifier medium (second amplifier medium) 24a. The amplifier medium 24a receives the excitation light L23 and the output light L15 from the amplifier 15, and further amplifies the output light L15. The amplifier medium 24a includes an end surface 24s that is an incident surface of the excitation light L23, and an end surface 24r opposite to the end surface 24s. The end face 24s is provided with a reflecting portion (not shown). The reflection part of the end face 24s transmits the excitation light L23 and reflects the output light L15. On the other hand, a non-reflective coating (AR coating) for at least the wavelength of the output light L15 is applied to the end face 24r. The amplifier medium 24a is, for example, Nd: YAG, Yb: YAG, Nd: YVO ₄ or the like. The output light L15 amplified by the amplifier 24 is emitted from the amplifier 24 as output light L24.

  The optical system 17E is disposed between the excitation light source 23 and the amplifier 24. The configuration of the optical system 17E is the same as that of the optical system 17. That is, the optical system 17E collimates and condenses the excitation light L23, and makes the excitation light L23 enter the amplifier 24 in the same manner as the optical system 17 for the excitation light L12. The mirror 25 and the mirror 26 cause the output light L15 output from the amplifier 15 to enter the amplifier 24. More specifically, the mirror 25 and the mirror 26 deflect the optical path of the output light L15 by reflection so that the output light L15 enters the end surface 24r of the amplifier medium 24a.

  In the laser apparatus 1E, the output light L15 output from the amplifier 15 is deflected by the mirror 25 and the mirror 26 and enters the amplifier 15. On the other hand, the excitation light L23 output from the excitation light source 23 passes through the optical system 17E and enters the amplifier 24 (amplifier medium 24a). That is, the excitation light L23 and the output light L15 are incident on the amplifier 24. The output light L15 incident on the amplifier 24 is amplified according to the excitation of the amplifier medium 24a by the excitation light L23. As a result, the further amplified output light L15 is output as output light L24 from the amplifier 24 and the laser apparatus 1E.

  As described above, according to the laser device 1E, the same effects as those of the laser device 1B can be obtained. Furthermore, according to the laser device 1E, the output light can be further increased without preparing a plurality of power supply devices.

  The above embodiments describe one embodiment of the laser apparatus according to the present invention. Therefore, the laser apparatus according to the present invention is not limited to the laser apparatuses 1A to 1E described above. The laser apparatus according to the present invention can be arbitrarily modified from the laser apparatuses 1A to 1E described above without changing the gist of each claim.

  For example, in the above embodiment, the example in which the light shielding members 20, 20 </ b> B, and 20 </ b> D are disposed between the collimator 44 and the lens 45 has been described. However, the light shielding members 20, 20 </ b> B, and 20 </ b> D can be disposed between the excitation light source 11 and the lens 45 at any position where the part Lp of the excitation light L <b> 11 can be blocked.

  In the subsequent stage of the collimator 42, the excitation light L11 has been collimated in the fast axis direction and the slow axis direction. Therefore, for example, it is conceivable to arrange the light shielding members 20, 20 </ b> B, 20 </ b> D (hereinafter simply referred to as “light shielding member”) between the collimator 42 and the lens 43. However, the excitation light L11 is slightly diverged between the collimator 42 and the lens 43. Therefore, it is difficult to adjust the amount of light between the collimator 42 and the lens 43 by the light shielding member. Further, if the excitation light L11 is not incident on the lens 43 while the spread is small, the size of the lens 43 needs to be increased.

  As an example, a light shielding member may be disposed between the lens 43 and the collimator 44. However, since the excitation light L11 is being condensed between the lens 43 and the collimator 44, the displacement of the light shielding member with respect to the traveling direction of the excitation light L11 is not allowed. Furthermore, as another example, it is conceivable to arrange a light shielding member at the rear stage of the lens 45. However, since the excitation light L11 is being condensed in the same manner, the displacement of the light shielding member with respect to the traveling direction of the excitation light L11 is not allowed for the same reason. Therefore, also in these cases, it is difficult to adjust the light amount by the light shielding member.

  Further, when the excitation light L11 is not sufficiently collimated as when passing through the collimator 44, light diffraction occurs when the light passes through the light shielding member. As a result, light is incident on an extra portion of the laser oscillation unit 14, and the beam quality of the oscillation light in the laser oscillation unit 14 is degraded. That is, after collimating in the fast axis direction and the slow axis direction, the light amount is easily and reliably adjusted by applying the light shielding member to the excitation light L11 that is further condensed and collimated and has a corresponding parallelism. I think it can be done.

  That is, it is considered effective to adjust the light amount by the light shielding member for the excitation light L11 that has passed through the fast axis collimator, the slow axis collimator (rotator + fast axis collimator), the lens, and the collimator in this order. As described above, the light shielding member can be disposed at an arbitrary position between the excitation light source 11 and the lens 45, and it is particularly desirable that the light shielding member be disposed between the collimator 44 and the lens 45.

  Although it is conceivable to place a light shielding member in the laser oscillation unit 14 (for example, between the laser medium 32 and the saturable absorber 33), it is very difficult to adjust the optical path and the like. There may be a problem that an extra process is added in manufacturing.

  Here, in the laser devices 1A and 1D, the light shielding members 20 and 20D include the light shielding portions 21 and 21D and the passage portion 22, and substantially include the center of the passage portion 22 and the center of the beam spot of the excitation light L11. The mode of matching the above has been described. However, for example, the center of the passage 22 may be shifted from the center of the beam spot of the excitation light L11.

  In this case, the light-shielding members 20 and 20D are configured to transmit the part Lp of the excitation light L11 on one side (opposite to the shift direction of the passage part 22) in a predetermined direction intersecting the optical axis direction of the excitation light L11. The remaining portion Lr including another part of the excitation light L11 on the other side in the predetermined direction (shift direction side of the passing portion 22) is passed by the passing portion 22 while being shielded by 21D. In this case, for the same reason as the laser devices 1B and 1C, for example, when the excitation light source 11 is a laser diode array, the beam quality of the seed light L14 can be improved.

  Here, in the laser devices 1A to 1E, the seed light L14 may be incident on the amplifier medium 15a from the end face 15s without using the mirrors 18 and 19. In this case, the excitation light L11 may be incident on the amplifier medium 15a from the end face 15s as in the case of the seed light L14, or incident from another end face of the amplifier medium 15a (for example, a side face connecting the end face 15s and the end face 15r). You may let them. However, it is considered that the beam quality is best when each of the excitation light L11 and the seed light L14 is incident on the amplifier medium 15a from the end surfaces of the amplifier medium 15a facing each other. In the laser apparatus 1E, the mirrors 25 and 26 may not be further used for the same reason.

  Moreover, in the said embodiment, the structure which further adds the excitation light source 23, the amplifier 24, etc. with respect to the laser apparatus 1B as the laser apparatus 1E is disclosed. However, the laser apparatus 1E may be configured by adding an excitation light source 23, an amplifier 24, and the like to the laser apparatuses 1A, 1C, and 1D. Further, two or more sets of excitation light sources 23 and amplifiers 24 may be added.

  Further, in the laser device 1B shown in FIG. 3, the light shielding member 20B may not have a function as a reflection part of the excitation light L11. In this case, the mirror 60 is unnecessary in the laser device 1B.

  Further, the laser oscillation unit 14 may be made of ceramic. For example, the laser medium 32 and the saturable absorber 33 can be configured using ceramic.

  DESCRIPTION OF SYMBOLS 1A-1E ... Laser apparatus, 11 ... Excitation light source (1st excitation light source), 12 ... Excitation light source (2nd excitation light source), 13 ... Power supply part, 14 ... Laser oscillation part, 15a ... Amplifier medium (1st Amplifier medium), 20, 20B, 20D ... light shielding member, 21, 21D ... light shielding part, 22 ... passing part, 23 ... excitation light source (third excitation light source), 24a ... amplification medium (second amplifier medium), 45 ... Lens (condenser), L11 ... excitation light (first excitation light), L12 ... excitation light (second excitation light), L14 ... seed light, L23 ... excitation light (third excitation light).

Claims (6)

A first excitation light source that outputs first excitation light;
A second excitation light source electrically connected in series to the first excitation light source and outputting a second excitation light;
A power supply for supplying a drive current to the first excitation light source and the second excitation light source;
A laser medium that receives the first excitation light to generate emission light, a saturable absorber that reduces the light absorption rate by saturation of light absorption, a first reflector that transmits the first excitation light, and A laser beam resonator having the laser medium and the saturable absorber on a resonant optical path to resonate the emitted light is integrated with a second reflecting unit that is configured with the first reflecting unit, and A laser oscillation unit that outputs part of the emitted light as seed light;
A condensing unit that condenses the first excitation light toward the laser oscillation unit;
A first amplifier medium that amplifies the seed light by entering the second excitation light and the seed light;
A light shielding member disposed on the optical axis of the first excitation light between the first excitation light source and the condensing unit and blocking a part of the first excitation light;
Comprising
Laser device. The light shielding member includes a light shielding part that shields a part of the first excitation light, and a passage part that is provided in the light shielding part and allows the remaining part of the first excitation light to pass through.
The laser device according to claim 1. The passage portion is an opening provided in the light shielding portion so as to form a circular shape when viewed from the optical axis direction of the first excitation light.
The laser device according to claim 2. The light shielding member blocks a part of the first excitation light on one side in a predetermined direction intersecting the optical axis of the first excitation light, and the first excitation on the other side in the predetermined direction. Let the rest of the light pass through,
The laser apparatus as described in any one of Claims 1-3. The light shielding member includes a reflecting portion that reflects a part of the first excitation light,
A part of the first excitation light reflected by the reflection unit is incident on the amplifier medium together with the second excitation light.
The laser apparatus as described in any one of Claims 1-4. A third excitation light source electrically connected in series to the first excitation light source and the second excitation light source and outputting a third excitation light;
A second amplifier medium that receives the seed light and the third excitation light amplified by the first amplifier medium and further amplifies the seed light;
Further comprising
The power supply unit supplies a drive current to the first excitation light source, the second excitation light source, and the third excitation light source.
The laser apparatus as described in any one of Claims 1-5.

Images