CN115313135B - Elliptical light spot laser - Google Patents

Abstract

The invention provides an elliptical light spot laser, which belongs to the technical field of laser, and comprises a gain medium, a seed laser generation module and at least one pumping module; the pumping module comprises a pumping source and a pumping shaping lens group positioned between the pumping source and the gain medium; the seed laser generation module comprises a seed source and a seed source shaping mirror group positioned between the seed source and the gain medium; the pump shaping mirror group is used for shaping circular pump light output by the pump source, outputting elliptical pump light and irradiating the elliptical pump light to the gain medium; the seed source shaping mirror group is used for shaping the circular seed laser output by the seed source, outputting the elliptical seed laser and inputting the elliptical seed laser to the gain medium. According to the invention, both the pump light and the seed laser are incident to the gain medium in an elliptical shape, and the area of the elliptical shape is increased compared with that of a circular shape, so that the pump power and the pulse energy output by the elliptical light spot laser are increased, and the increase of the laser power density and the thermal lens effect is not involved, so that the gain medium is not damaged.

Description

Elliptical light spot laser

Technical Field

The invention relates to the technical field of laser, in particular to an elliptical light spot laser.

Background

The solid laser is a device for obtaining high-power and high-beam-quality laser output, and a laser gain medium adopted in the current solid laser is in a shape of a lath or a rod, wherein the rod-shaped gain medium has the advantages of low price, simple structure and capability of realizing high-power laser output, and is widely used in the fields of industry, scientific research and the like.

In the existing solid laser, a circular seed light spot and a circular pumping light spot are adopted to be incident to a gain medium for coupling amplification, a part of pumping light absorbed by the gain medium is converted into heat energy to be deposited inside the gain medium, and meanwhile, the gain medium is cooled by the outside, so that non-uniform temperature field distribution is formed inside the gain medium, and further, non-uniform expansion in the gain medium is caused, and thermal stress is caused; under the action of temperature distribution unevenness (non-uniform temperature field distribution) and thermal stress, the refractive index of the gain medium changes non-uniformly, and then the seed laser passes through the gain medium similarly to a lens, so that a thermal lens effect is generated. In order to improve the pulse energy output by the solid-state laser, the thermal lens effect is increased by increasing the pumping power, so that the gain medium is damaged, and the solid-state laser is damaged.

Disclosure of Invention

The invention provides an elliptical light spot laser, which is used for solving the defect that the increase of pumping power in the prior art can increase the thermal lens effect and cause the damage of a gain medium.

The invention provides an elliptical light spot laser, comprising: the device comprises a gain medium, a seed laser generation module and at least one pumping module; the pumping module comprises a pumping source and a pumping shaping mirror group, and the pumping shaping mirror group is positioned between the pumping source and the gain medium; the seed laser generation module comprises a seed source and a seed source shaping mirror group, and the seed source shaping mirror group is positioned between the seed source and the gain medium;

the pump shaping mirror group is used for shaping circular pump light output by the pump source, outputting elliptical pump light and enabling the elliptical pump light to be incident to the gain medium;

the seed source shaping mirror group is used for shaping the circular seed laser output by the seed source, outputting elliptical seed laser and enabling the elliptical seed laser to be incident to the gain medium.

According to the elliptical light spot laser provided by the invention, the light spot size of the elliptical seed laser incident to the gain medium is smaller than or equal to the light spot size of the elliptical pump light incident to the gain medium.

According to the elliptical spot laser provided by the invention, the gain medium comprises a slab gain medium or a rod gain medium.

According to the elliptical light spot laser, the rod-shaped gain medium comprises an elliptical rod-shaped gain medium or a rectangular rod-shaped gain medium.

According to the elliptical light spot laser provided by the invention, the slab gain medium comprises a light-passing end face and a non-light-passing face;

the elliptical pumping light and the elliptical seed laser are both incident to the light-transmitting end face of the gain medium.

According to the elliptical light spot laser provided by the invention, the elliptical light spot laser further comprises a heat dissipation structure arranged on at least one non-light-passing surface of the slab gain medium.

According to the elliptical light spot laser provided by the invention, the non-light-passing surfaces comprise a first non-light-passing surface and a second non-light-passing surface;

the heat dissipation structure comprises a first heat dissipation component arranged on the first non-light-passing surface and a second heat dissipation component arranged on the second non-light-passing surface; the first non-light-transmitting surface and the second non-light-transmitting surface are both parallel to the long axis of the elliptical pump light incident to the slab gain medium.

The invention provides an elliptical light spot laser, which further comprises an output shaping lens group arranged on an output light path of a gain medium;

and the output shaping lens group is used for shaping the elliptical laser output by the gain medium and outputting circular laser.

According to the elliptical light spot laser provided by the invention, the at least one pumping module comprises a first pumping module and a second pumping module; the light-transmitting end face comprises a first light-transmitting end face and a second light-transmitting end face;

the elliptical pump light output by the first pump module is incident to the first light-transmitting end face; and the elliptical pump light output by the second pump module is incident to the second light-transmitting end face.

According to the elliptical light spot laser provided by the invention, the pumping module further comprises a filter device arranged between the pumping shaping mirror group and the gain medium;

and the filter device is used for filtering stray light in the elliptical pump light output by the pump shaping mirror group.

The elliptical light spot laser provided by the invention has the advantages that the circular pump light output by the pump source is shaped by the pump shaping mirror group, the elliptical pump light is output after shaping, the circular seed laser output by the seed source is shaped by the seed source shaping mirror group, the elliptical seed laser is output, the pump light and the seed laser are incident to the gain medium in an elliptical shape, and the elliptical shape is increased compared with the circular shape, so that the pump power and the pulse energy output by the elliptical light spot laser are increased, the increase of the laser power density and the thermal lens effect is not involved, and the gain medium is not damaged.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of an elliptical spot laser according to the present invention;

FIG. 2 is a schematic diagram of a gain medium according to the present invention;

FIG. 3 is a schematic diagram of a prior art structure of a circular pump light incident gain medium;

FIG. 4 is a second schematic structural diagram of a gain medium provided by the present invention;

fig. 5 is a third schematic structural diagram of a gain medium provided by the present invention;

FIG. 6 is a schematic structural diagram of a pump shaping lens set according to the present invention;

FIG. 7 is a second schematic view of an elliptical spot laser according to the present invention;

fig. 8 is a third schematic structural diagram of an elliptical spot laser provided by the present invention;

FIG. 9 is a fourth schematic view of an elliptical spot laser according to the present invention;

FIG. 10 is a fifth schematic view of an elliptical spot laser according to the present invention;

reference numerals:

101. a pumping module; 102. a pump source; 103. a pump shaping lens group; 104. a gain medium; 105. a seed laser generation module; 106. a seed source; 107. a seed source shaping lens group;

201. a light-transmitting end face;

301. a circular pumping spot; 302. a heat dissipation structure;

401. elliptical pumping light spots;

501. a first heat dissipating member; 502. a second heat sink member;

601. a spherical mirror; 602. a first cylindrical mirror; 603. a second cylindrical mirror;

701. a first reflector; 702. a second reflector; 703. a light splitter; 704. a third reflector; 705. a fourth mirror; 706. a fifth reflecting mirror; 707. and a sixth mirror.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

The elliptical spot laser of the present invention is described below in conjunction with fig. 1-10.

Fig. 1 is a schematic structural diagram of an elliptical spot laser provided by the present invention, and as shown in fig. 1, the elliptical spot laser includes a gain medium 104, a seed laser generation module 105, and at least one pump module 101, and in fig. 1, there is shown one pump module 101, where the pump module 101 includes a pump source 102 and a pump shaping mirror group 103, and the pump shaping mirror group 103 is located between the pump source 102 and the gain medium 104; the seed laser generation module 105 comprises a seed source 106 and a seed source shaping mirror group 107, wherein the seed source shaping mirror group 107 is positioned between the seed source 106 and the gain medium 104.

The pump shaping mirror group 103 is configured to shape the circular pump light output by the pump source 102, output elliptical pump light, and inject the elliptical pump light into the gain medium 104.

The seed source shaping mirror group 107 is configured to shape the circular seed laser output by the seed source 106, output an elliptical seed laser, and inject the elliptical seed laser into the gain medium 104.

The pumping light output by the pumping module 101 of the elliptical light spot laser excites an atomic system of the gain medium 104 to increase the number of particles at an upper energy level, so that the number of particles in the gain medium 104 is reversed, the seed laser output by the seed source 106 is incident to the gain medium 104, the seed laser performs pumping coupling amplification on the gain medium 104 under the action of the pumping light, the gain medium 104 outputs the amplified laser, and accordingly the power of the seed laser output by the seed source 106 is improved.

In the prior art, a solid laser generally adopts circular pump light and circular seed laser to enter a gain medium 104 for coupling amplification, and when the circular pump light enters the gain medium 104, non-uniform temperature field distribution is formed inside the gain medium 104, so that non-uniform expansion in the laser gain medium 104 is caused to cause thermal stress; under the action of uneven temperature distribution and thermal stress, the refractive index of the gain medium 104 changes unevenly, so that the seed laser passes through the gain medium 104 similarly to a lens, a thermal lens effect is generated, and the seed laser beam is distorted and depolarized, and then due to the influence of the thermal lens and coupling, an energy cavity appears in a light spot, namely the light spot center has weak energy distribution, so that the light beam quality is poor, the coupling amplification efficiency is low, and the seed laser beam quality and the coupling efficiency are seriously influenced. Therefore, the invention designs the spot shape of the pump light output by the pump source 102 and the spot shape of the seed laser output by the seed source 106 to reduce the thermal lens effect and improve the coupling efficiency of the pump light and the seed laser.

The spot shape of the pump light output by the pump source 102 may be designed by disposing a pump shaping mirror set 103 on an emergent light path of the pump source 102.

Illustratively, circular pump light output by the pump source 102 is incident to the pump shaping mirror 103, the pump shaping mirror 103 shapes the circular pump light output by the pump source 102, outputs elliptical pump light after shaping, and emits the elliptical pump light to the gain medium 104.

Illustratively, when the pumping module 101 outputs elliptical pumping light, the spot shape of the seed laser output by the seed source 106 is also designed to be an elliptical spot, so that the pumping light incident to the gain medium 104 and the seed laser are matched.

Illustratively, the circular seed laser output by the seed source 106 is incident to the seed source shaping mirror 107, and the seed source shaping mirror 107 shapes the circular seed laser output by the seed source 106 into an elliptical seed laser and emits the elliptical seed laser to the gain medium 104.

It should be noted that the cross section of the seed laser injected into the gain medium 104 is elliptical and has a larger area than that of a circular seed laser, thereby allowing a larger laser pulse energy to be output without damaging the laser thin film.

According to the elliptical light spot laser, the circular pump light output by the pump source is shaped through the pump shaping mirror group, the elliptical pump light is output after shaping, the circular seed laser output by the seed source is shaped through the seed source shaping mirror group, the elliptical seed laser is output, the elliptical laser and the seed laser are incident to the gain medium in an elliptical mode, the area of the ellipse is increased compared with that of the circle, and therefore the pulse energy output by the elliptical light spot laser is increased, the increase of the pump power is not involved, and therefore the pulse energy of the elliptical light spot laser can be increased on the premise that the gain medium is not damaged.

According to the elliptical light spot laser provided by the embodiment of the invention, the circular seed laser output by the seed source 106 is shaped into the elliptical seed laser through the seed source shaping mirror group 107, so that the seed laser injected into the gain medium 104 is matched with the pump light, and the amplification factor can be improved at the same time.

Optionally, the spot size of the elliptical seed laser incident on the gain medium 104 is smaller than or equal to the spot size of the elliptical pump light incident on the gain medium 104.

In order to improve the coupling efficiency of the elliptical seed laser and the elliptical pump light, the spot size of the elliptical seed laser incident on the gain medium 104 is designed to be smaller than or equal to the spot size of the elliptical pump light incident on the gain medium 104, so that the elliptical seed laser and the elliptical pump light are matched.

Optionally, the gain medium 104 comprises a slab gain medium or a rod gain medium.

Wherein, the gain medium 104 may adopt a rod-like structure, and then the gain medium 104 is a rod-like gain medium; further, the rod-shaped gain medium may have an elliptical or rectangular cross section, and the rod-shaped gain medium is an elliptical rod-shaped gain medium or a rectangular rod-shaped gain medium.

Fig. 2 is a schematic structural diagram of a gain medium provided by the present invention, and as shown in fig. 2, the gain medium 104 may adopt a slab structure with a large width-to-height ratio, and the gain medium 104 is a slab gain medium; the elliptic pump light is injected into the slab gain medium with a large width-height ratio, so that the higher pump energy storage than that of the rod-shaped gain medium is realized on the premise that the thermal stress does not damage the slab gain medium, and the amplification factor can be effectively improved.

Optionally, the gain medium 104 includes a light-passing end face 201 and a non-light-passing face; the elliptical pump light and the elliptical seed laser are both incident to the light-transmitting end face 201 of the gain medium.

If the gain medium 104 is a slab gain medium, as shown in fig. 2, two end faces of the slab gain medium with the smallest size are light-transmitting end faces 201, and surfaces except the two light-transmitting end faces 201 are non-light-transmitting faces; if the gain medium 104 is a rod-shaped gain medium, the two end surfaces of the gain medium 104 are light-transmitting end surfaces, and the outer circular surface between the two end surfaces is a non-light-transmitting surface.

It should be noted that the pumping mode of the elliptical spot laser of the present invention adopts an end-pumping mode.

Optionally, the elliptical spot laser further comprises a heat dissipation structure 302 disposed on at least one non-light-passing side of the slab gain medium.

For example, the heat dissipation structure 302 may be provided on the non-light-transmitting surface of the gain medium 104, the heat dissipation structure 302 may be provided on the entire non-light-transmitting surface of the gain medium 104, or the heat dissipation structure 302 may be provided on one or more non-light-transmitting surfaces of the gain medium 104.

The heat dissipation structure 302 may be water-cooled, air-cooled, or conduction-cooled.

When the gain medium 104 is a slab gain medium, the heat dissipation structure 302 is disposed on two non-light-transmitting surfaces of the gain medium 104, which may be two adjacent non-light-transmitting surfaces, or two opposite non-light-transmitting surfaces.

It should be noted that, if the heat dissipation structure 302 is disposed on the whole non-light-passing surface of the gain medium 104, the cooling form of the gain medium 104 is peripheral cooling; the heat dissipation structures 302 are disposed on two opposite non-light-passing surfaces of the gain medium 104, so that the gain medium 104 is cooled in a two-side manner.

Exemplarily, fig. 3 is a schematic structural diagram of a gain medium with a circular pump light incident thereon in the prior art, and fig. 4 is a second schematic structural diagram of a gain medium provided by the present invention, wherein a heat dissipation structure 302 is disposed on all non-light-transmitting surfaces of the gain medium 104 in fig. 3 and 4, that is, the outer side surface of the gain medium 104 adopts a peripheral cooling manner, and the gain medium 104 is a slab gain medium.

For example, in fig. 3, the pump light output by the pump source 102 is a circular pump light, and then the spot of the circular pump light incident on the light-transmitting end surface 201 of the gain medium 104 is a circular pump light spot 301, the length of the arrow in fig. 3 represents the strength of the thermal diffusion, and as can be seen from fig. 3, the strength of the thermal diffusion from the circular pump light spot 301 to the periphery is the same, that is, the size of the thermal lens in each direction is the same, and the thermal lens is obvious.

In fig. 4, the circular pump light output by the pump source 102 is shaped into the elliptical pump light by the pump shaping mirror group 103, then the light spot of the elliptical pump light incident on the light-transmitting end surface 201 of the gain medium 104 is an elliptical pump light spot 401, and the length of the arrow in fig. 4 represents the strength of thermal diffusion, and through comparison between fig. 3 and fig. 4, it can be seen that the length of the arrow in the short axis direction of the elliptical pump light spot 401 is shorter than the length of the arrow of the circular pump light spot 301, and the length of the arrow in the long axis direction of the elliptical pump light spot 401 is much shorter than the length of the arrow of the circular pump light spot 301, that is, when the elliptical pump light is incident on the gain medium 104, the thermal lens in the short axis direction is significantly improved, and the thermal lens in the long axis direction becomes very small.

Note that an arrow in the major axis direction of the elliptical pump spot 401 is an arrow parallel to the major axis direction of the elliptical pump spot 401; the arrow in the minor axis direction of the elliptical pump spot 401 is an arrow arranged along the major axis direction of the elliptical pump spot 401; that is, the arrows horizontally to the left and horizontally to the right in fig. 4 are the arrows in the major axis direction of the elliptical pump spot 401, and the remaining arrows are the arrows in the minor axis direction of the elliptical pump spot 401.

It should be noted that, when the gain medium 104 has a slab structure, the cross section of the gain medium 104 has a rectangular shape, the length dimension of the cross section of the gain medium 104 is greater than the dimension of the long axis of the elliptical pump spot 401, and the width dimension of the cross section of the gain medium 104 is greater than the dimension of the short axis of the elliptical pump spot 401.

It should be noted that when the minor axis of the elliptical pump spot 401 is equal to the radius of the circular pump spot 301, and the area of the ellipse is larger than the area of the circle, the pump light and the seed laser are changed into the ellipse in the present invention, so that the thermal lens effect is not increased while the pump power is increased, and thus the pulse energy of the ultrafast laser is increased on the premise of not damaging the surface film of the gain medium 104.

According to the elliptical light spot laser provided by the embodiment of the invention, circular pump light output by the pump source 102 is shaped into elliptical pump light by the pump shaping mirror group 103, and the heat dissipation structure 302 is matched, so that seed laser is incident on the gain medium 104, a thermal lens in the major axis direction of the elliptical pump light is obviously reduced, a thermal lens in the minor axis direction is also improved, and the pulse energy of ultrafast laser can be increased on the premise of not damaging a surface film of the gain medium 104.

Optionally, fig. 5 is a third schematic structural diagram of the gain medium provided by the present invention, and as shown in fig. 5, the non-light-passing surfaces include a first non-light-passing surface and a second non-light-passing surface; the heat dissipation structure 302 comprises a first heat dissipation part 501 arranged on the first non-light-passing surface and a second heat dissipation part 502 arranged on the second non-light-passing surface; the first non-light-transmitting surface and the second non-light-transmitting surface are both parallel to the long axis of the elliptical pump light incident to the slab gain medium.

Illustratively, the gain medium 104 is cooled by two sides, and the non-light-passing surfaces of the gain medium 104 include a first non-light-passing surface and a second non-light-passing surface which are oppositely arranged; the heat dissipation structure 302 comprises a first heat dissipation part 501 arranged on the first non-light-passing surface and a second heat dissipation part 502 arranged on the second non-light-passing surface; when the elliptical pump light is incident on the first non-light-transmitting surface or the second non-light-transmitting surface of the gain medium 104, the first heat sink member 501 and the second heat sink member 502 are located at two sides of the major axis of the elliptical pump light, and then both the first non-light-transmitting surface and the second non-light-transmitting surface of the gain medium 104 are parallel to the major axis of the elliptical pump light incident on the gain medium 104.

The gain medium of fig. 5 has the same structure as the gain medium 104 of fig. 4, but differs from the gain medium of fig. 4 in that a heat dissipation structure 302 is provided, fig. 4 shows that the heat dissipation structure 302 is provided on the entire non-light-transmitting surface of the gain medium 104 (four-side cooling), and fig. 5 shows that the heat dissipation structure 302 is provided on a part of the outer surface of the gain medium 104 (two-side cooling). As can be seen from comparison between fig. 5 and fig. 4, when the elliptical pump light is injected into the light-transmitting end surface 201 of the gain medium 104, the elliptical pump spots 401 are formed on the gain medium 104, the arrows in the short axis direction of the elliptical pump spots 401 cooled at both sides become shorter than those in the cooling at the four sides, and the arrows do not exist in the long axis direction, that is, the thermal lens in the short axis direction becomes smaller, and the thermal lens does not exist in the long axis direction.

It should be noted that, when the slab gain medium in fig. 5 is cooled on both sides, the thermal lens is generated only in the minor axis direction of the ellipse, so that the pumping power is increased by increasing the size of the major axis of the ellipse without increasing the thermal lens effect, thereby increasing the pulse energy of the ultrafast laser.

In the elliptical light spot laser provided by the embodiment of the invention, the heat dissipation structure 302 on the outer side of the gain medium 104 is designed into a structure with a two-side cooling mode, so that when elliptical pump light is injected into the gain medium 104, a thermal lens in the major axis direction is eliminated, and a thermal lens in the minor axis direction is further reduced, thereby further improving the quality of a laser beam output by the gain medium 104 and improving the coupling efficiency.

In the elliptical spot laser provided by the embodiment of the invention, the heat dissipation structures 302 are arranged on the two opposite non-light-passing surfaces of the gain medium 104 for cooling the two sides, so that elliptical pump light forms a thermal lens in the slab gain medium in a quasi-one-dimensional manner, and the focal length of the thermal lens is not shortened along with the increase of the pump power, so that the pump power is effectively increased under the condition of reducing the thermal lens.

Optionally, an output shaping lens group disposed on an output optical path of the gain medium 104 is further included.

The output shaping lens group is configured to shape the elliptical laser output by the gain medium 104 and output a circular laser.

Illustratively, an output shaping lens group is disposed on the output light path of the gain medium 104, and the light-transmitting output shaping lens group shapes the elliptical laser light output by the gain medium 104 into a circular shape.

Further, the output shaping lens group may employ a pair of cylindrical lenses or a wedge mirror.

According to the elliptical light spot laser provided by the embodiment of the invention, the output shaping lens group is arranged on the output light path of the gain medium 104 and used for reshaping the elliptical laser beam output by the gain medium 104 into a circle, so that the universality of the elliptical light spot laser is improved.

Optionally, the pump shaping mirror group 103 includes a cylindrical lens group or a wedge-shaped mirror disposed on the exit optical path of the circular pump light output by the pump source 102.

Illustratively, the pump shaping mirror set 103 may output elliptical pump light by stretching a circular spot in one direction using a pair of cylindrical lenses or wedge mirrors, as opposed to a circular pump light used by a rod amplifier.

Specifically, fig. 6 is a schematic structural diagram of the pump shaping mirror group provided by the present invention, and as shown in fig. 6, the pump shaping mirror group 103 may include a spherical mirror 601, a first cylindrical mirror 602, and a second cylindrical mirror 603, which are sequentially disposed on an exit optical path of the circular pump light output by the pump source 102.

Further, the focal length of the spherical mirror 601 is

，

Satisfies the inequality:

。

the focal length of the first cylindrical mirror 602 in the first direction is

，

Satisfies the inequality:

。

the focal length of the second cylindrical lens 603 in the second direction is

，

Satisfies the inequality:

(ii) a The second direction is perpendicular to the first direction.

Preferably, the focal length of the spherical mirror 601

30mm, the focal length of the first cylindrical mirror 602 in the first direction

25mm, focal length of the second cylindrical mirror 603 in the second direction

Is 60mm.

It should be noted that, the cylindrical mirror has a focal length in only one direction, the first cylindrical mirror 602 has a focal length in the first direction, and the second cylindrical mirror 603 has a focal length in the second direction, and since the first direction is perpendicular to the second direction, the first cylindrical mirror 602 and the second cylindrical mirror 603 are disposed perpendicularly, and the first cylindrical mirror 602 and the second cylindrical mirror 603 disposed perpendicularly may form a pair of cylindrical lenses.

Further, as shown in fig. 6, the distance between the light emitting surface of the pump source 102 and the light incident surface of the spherical mirror 601 is

，

Satisfies the inequality:

。

the distance between the light incident surface of the spherical mirror 601 and the light incident surface of the first cylindrical mirror 602 is

，

Satisfies the inequality:

。

the distance between the light incident surface of the first cylindrical mirror 602 and the light incident surface of the second cylindrical mirror 603 is

，

Satisfies the inequality:

。

preferably, the distance between the light-emitting surface of the pump source 102 and the light-in surface of the spherical mirror 601

Is 10mm; the distance between the light incident surface of the spherical mirror 601 and the light incident surface of the first cylindrical mirror 602

Is 34mm; the distance between the light incident surface of the first cylindrical mirror 602 and the light incident surface of the second cylindrical mirror 603

Is 106mm.

It should be noted that the seed shaping mirror 107 may also have the same structure as the pump shaping mirror 103.

Optionally, the at least one pump module 101 comprises a first pump module and a second pump module; the light-transmitting end face 201 comprises a first light-transmitting end face and a second light-transmitting end face.

The elliptical pump light output by the first pump module is incident to the first light-transmitting end face; the elliptical pump light output by the second pump module is incident to the second light-transmitting end face.

The number of the pumping modules 101 is two, and the two pumping modules are respectively a first pumping module and a second pumping module; the light-transmitting end surface 201 of the gain medium 104 includes a first light-transmitting end surface and a second light-transmitting end surface which are oppositely arranged.

Illustratively, the elliptical pump light output by the first pump module is incident on the first light-passing end face of the gain medium 104; the elliptical pump light output by the second pump module is incident on the second light-transmitting end face of the gain medium 104.

The elliptical light spot laser provided by the embodiment of the invention adopts the two pumping modules to enter the gain medium 104, and elliptical pumping light of the two pumping modules 101 is overlapped in the gain medium 104, so that the amplification factor can be effectively improved.

Optionally, the pump module 101 further comprises a filter device disposed between the pump shaping mirror set 103 and the gain medium 104.

The filter device is configured to filter stray light in the elliptical pump light output by the pump shaping mirror group 103.

For example, in the elliptical light spot laser, both the pump light output by the pump module 101 and the seed laser output by the seed source 106 are incident into the gain medium 104, and the seed laser may be mixed into the pump light during transmission, so that the filter device is arranged on the emergent light path of the second cylindrical mirror 603 to filter the seed laser mixed into the pump light; in addition, due to processing errors of the spherical mirror 601, the first cylindrical mirror 602, and the second cylindrical mirror 603, stray light may also be generated when the pump light is transmitted in the spherical mirror 601, the first cylindrical mirror 602, and the second cylindrical mirror 603; therefore, the stray light may include stray light generated by the seed laser and the pump light during the transmission process.

Further, the filter device may be a plane mirror disposed at 45 °, and the plane mirror transmits the elliptical pump light output by the second cylindrical mirror 603 and reflects stray light.

It should be noted that the plane mirror is set at 45 ° so that the incident plane of the plane mirror and the optical axis of the elliptical pump light output by the second cylindrical mirror 603 form an angle of 45 °.

According to the elliptical light spot laser provided by the embodiment of the invention, the filter device arranged between the second cylindrical mirror 603 and the gain medium 104 can filter stray light in elliptical pump light output by the second cylindrical mirror 603, so that the beam quality of the elliptical pump light is improved, and the pumping efficiency of seed laser is improved.

Fig. 7 is a second schematic structural diagram of an elliptical spot laser according to an embodiment of the present invention, and as shown in fig. 7, the elliptical spot laser includes a seed laser generation module 105, a pumping module 101, a gain medium 104, and a first mirror 701.

The gain medium 104 is a slab gain medium, and the pumping mode of the elliptical spot laser is end-pumped.

Illustratively, the elliptical seed laser output by the seed laser generating module 105 is incident on a first light-transmitting end face of the gain medium 104, the elliptical pump light output by the pumping module 101 is incident on a second light-transmitting end face of the gain medium 104, a part of the elliptical pump light is absorbed by the gain medium 104 and is used for amplifying the elliptical seed laser, so that the gain medium 104 outputs the amplified laser, the first reflector 701 is arranged on an output light path of the gain medium 104 and is used for reflecting and outputting the amplified laser, and the other part of the elliptical pump light generates heat in the gain medium 104 to form a thermal lens; and the pulse energy of the elliptical spot laser can be increased without causing damage to the gain medium 104.

Exemplarily, fig. 8 is a third schematic structural diagram of an elliptical spot laser provided by the present invention, and as shown in fig. 8, the elliptical spot laser includes a seed laser generating module 105, a pumping module 101, a gain medium 104, a second mirror 702, and a beam splitter 703.

The gain medium 104 is a slab gain medium, and the pumping mode of the elliptical spot laser is end-pumped.

Illustratively, the elliptical seed laser output by the seed laser generating module 105 is incident on the first light-transmitting end surface of the gain medium 104, the elliptical pump light output by the pumping module 101 is incident on the second light-transmitting end surface of the gain medium 104, a part of the elliptical pump light is absorbed by the gain medium 104 and used for amplifying the elliptical seed laser, the amplified laser output by the gain medium 104 is reflected by the second reflecting mirror 702 and then enters the gain medium 104 again for amplifying again, the laser after amplifying again is incident on the beam splitter 703, the beam splitter 703 outputs the laser after amplifying again, another part of the elliptical pump light generates heat in the gain medium 104 to form a thermal lens, and since the pump light injected into the gain medium 104 is designed into an elliptical light spot, the thermal lens can be effectively reduced, and therefore, the elliptical seed laser can be effectively reduced in distortion and depolarization when passing through the gain medium 104, and thus the beam quality of the amplified laser output by the gain medium 104 is improved; and the pulse energy of the elliptical spot laser can be increased without causing damage to the gain medium 104.

It should be noted that the second reflecting mirror 702 is used to fold back the optical path of the laser beam emitted from the gain medium 104, so that the laser beam enters the gain medium 104 again for re-amplification, and therefore, a plurality of second reflecting mirrors 702 may be disposed on the emission optical path of the gain medium 104 to achieve multiple times of amplification.

In addition, in the multiple amplification processes, stray light such as raman light is generated to affect the beam quality of the laser light, and therefore, in the present invention, a beam splitter 703 is provided on the output optical path of the gain medium 104 to separate the amplified laser light from the stray light such as raman light and output the amplified laser light.

It should be noted that the optical splitter 703 may be an inclined optical splitter, which means that the light incident surface of the optical splitter and the optical axis of the incident light beam are inclined; the optical splitter 703 may also be a filter device, which filters stray light such as raman light and outputs laser light with the stray light such as raman light filtered.

Exemplarily, fig. 9 is four of the schematic structural diagrams of the elliptical spot laser provided by the present invention, and as shown in fig. 9, the elliptical spot laser includes a seed laser generating module 105, a gain medium 104, a third mirror 704, a fourth mirror 705, and two pumping modules 101.

Wherein, the gain medium 104 is a slab gain medium, and the pumping mode of the elliptical light spot laser is end pumping; the two pumping modules 101 are a first pumping module and a second pumping module, respectively.

Illustratively, the elliptical seed laser output by the seed laser generation module 105 is reflected by the third reflector 704 and then enters the first light-passing end face of the gain medium 104, the elliptical pump light output by the first pump module enters the first light-passing end face of the gain medium 104, a part of the elliptical pump light is absorbed by the gain medium 104, the elliptical pump light output by the second pump module enters the second light-passing end face of the gain medium 104, a part of the elliptical pump light is absorbed by the gain medium 104, two parts of the elliptical pump light absorbed by the gain medium 104 overlap in the gain medium 104, at this time, the elliptical seed laser absorbs the elliptical pump light energy in the gain medium 104 to achieve laser amplification, the amplified laser output by the gain medium 104 is reflected by the fourth reflector and then output, another part of the elliptical pump light of the first pump module and another part of the elliptical pump light of the second pump module generate heat in the gain medium 104 to form a thermal lens, the pump light spot injected into the gain medium 104 of the present invention is designed as an elliptical light spot, which can effectively reduce the thermal lens, and thus the distortion of the elliptical laser output beam after passing through the gain medium 104 can be effectively reduced, thereby improving the quality of the amplified elliptical laser output; and the pulse energy of the elliptical spot laser can be increased without causing damage to the gain medium 104.

Exemplarily, fig. 10 is a fifth schematic view of a structure of an elliptical spot laser provided by the present invention, and as shown in fig. 10, the elliptical spot laser includes a seed laser generation module 105, a gain medium 104, a fifth mirror 706, a sixth mirror 707, an optical splitter 703, and two pumping modules 101.

Wherein, the gain medium 104 is a slab gain medium, and the pumping mode of the elliptical light spot laser is end pumping; the two pumping modules 101 are a first pumping module and a second pumping module, respectively.

Illustratively, the elliptical seed laser output by the seed laser generation module 105 is reflected by the fifth reflector 706 and then enters the first light-passing end face of the gain medium 104, the elliptical pump light output by the first pump module enters the first light-passing end face of the gain medium 104, a part of the elliptical pump light is absorbed by the gain medium 104, the elliptical pump light output by the second pump module enters the second light-passing end face of the gain medium 104, a part of the elliptical pump light is absorbed by the gain medium 104, two parts of the elliptical pump light absorbed by the gain medium 104 are overlapped in the gain medium 104, at this time, the elliptical seed laser absorbs the elliptical pump light energy in the gain medium 104 to realize laser amplification, the amplified laser output by the gain medium 104 enters the gain medium 104 again after being reflected by the sixth reflector 707 and then being amplified again, the re-amplified laser is reflected by the fifth reflector 706 and then enters the optical splitter 703, and the optical splitter 703 outputs the re-amplified laser; the other part of the elliptical pump light of the first pump module and the other part of the elliptical pump light of the second pump module generate heat in the gain medium 104 to form a thermal lens, and the pump light injected into the gain medium 104 is designed into an elliptical light spot, so that the thermal lens can be effectively reduced, and therefore, the distortion and the depolarization of the elliptical seed laser can be effectively reduced when the elliptical seed laser passes through the gain medium 104, and the beam quality of the amplified laser output by the gain medium 104 is improved; and the pulse energy of the elliptical spot laser can be increased without causing damage to the gain medium 104.

It should be noted that the sixth mirror 707 has the same function as the second mirror 702, and the description of the invention is omitted here.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (5)

1. An elliptical spot laser, comprising: the device comprises a gain medium, a seed laser generation module and at least one pumping module; the pumping module comprises a pumping source and a pumping shaping mirror group, and the pumping shaping mirror group is positioned between the pumping source and the gain medium; the seed laser generation module comprises a seed source and a seed source shaping mirror group, and the seed source shaping mirror group is positioned between the seed source and the gain medium;

the pump shaping mirror group is used for shaping circular pump light output by the pump source, outputting elliptical pump light and enabling the elliptical pump light to be incident to the gain medium;

the seed source shaping mirror group is used for shaping the circular seed laser output by the seed source, outputting elliptical seed laser and enabling the elliptical seed laser to be incident to the gain medium;

the gain medium comprises a lath gain medium or a rod-shaped gain medium, and the rod-shaped gain medium comprises an elliptic rod-shaped gain medium or a rectangular rod-shaped gain medium;

the gain medium comprises a light-transmitting end face and a light-non-transmitting face; the elliptical pump light and the elliptical seed laser are both incident to the light-transmitting end face of the gain medium;

the elliptical light spot laser further comprises a heat dissipation structure arranged on at least one non-light-passing surface of the slab gain medium.

2. The elliptical spot laser of claim 1, wherein a spot size of the elliptical seed laser incident on the gain medium is less than or equal to a spot size of the elliptical pump light incident on the gain medium.

3. The elliptical spot laser of claim 1, wherein the non-light-passing facets include a first non-light-passing facet and a second non-light-passing facet;

the heat dissipation structure comprises a first heat dissipation component arranged on the first non-light-passing surface and a second heat dissipation component arranged on the second non-light-passing surface; the first non-light-transmitting surface and the second non-light-transmitting surface are both parallel to the long axis of the elliptical pump light incident to the slab gain medium.

4. The elliptical spot laser of claim 1, further comprising an output shaping lens group disposed in an output optical path of the gain medium;

and the output shaping lens group is used for shaping the elliptical laser output by the gain medium and outputting circular laser.

5. The elliptical spot laser of claim 1, wherein the at least one pump module comprises a first pump module and a second pump module; the light-transmitting end face comprises a first light-transmitting end face and a second light-transmitting end face;

the elliptical pump light output by the first pump module is incident to the first light-transmitting end face; the elliptical pump light output by the second pump module is incident to the second light-transmitting end face.

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