Self-double-pass angle-multiplexed slab laser gain medium and laser gain module

Abstract

The present invention discloses a self-double-pass angle multiplexing slab laser gain medium and a laser gain module. The self-double-pass angle multiplexing slab laser gain medium comprises: a main body, the main body comprises a first side surface, a first end surface, a second side surface, and a second end surface which are sequentially connected in the first position, the first side surface is parallel to the second side surface, the angle α1 between the first end surface and the second side surface is 45°, and the angle α2 between the second end surface and the first side surface is according to the formula: wherein L represents the distance between the center point of the first end surface and the center point of the second end surface, d represents the distance between the first side surface and the second side surface, N1 represents the number of times the light beam is reflected in the direction from the first end surface to the second end surface after entering the main body from the first end surface, and N2 represents the number of times the light beam is reflected in the direction from the second end surface to the first end surface after entering the main body from the first end surface. The present invention can greatly simplify the optical path structure and improve reliability.

Description

Technical Field

[0001] The invention relates to the technical field of lasers, and in particular to a self-double-pass angle multiplexing slab laser gain medium and a laser gain module. Background Art

[0002] Commonly used solid laser gain media have three structures: rod structure, sheet structure, and slab structure. Among them, the light beam is transmitted in a zigzag shape in the slab structure gain medium, which can compensate for the wavefront distortion and polarization characteristic changes caused by the temperature gradient, which is beneficial to improve the output power and obtain good beam quality. At present, solid lasers using slab structure gain media have been widely used in continuous operation or pulse operation.

[0003] In the related art, the slat structure can achieve multi-pass amplification by angle multiplexing. Generally, a slat laser module has several discrete angles that can be used as the incident angle. The usual practice is that after the laser passes through the slat at an incident angle of 1 in a single pass, it folds the light path through several lenses and then enters the slat at an incident angle of 2 to achieve double-pass amplification, and then uses the polarization characteristics of the laser to achieve four-pass amplification. However, this structure is relatively complex, especially in order to achieve angle multiplexing, it uses three reflectors and two lenses to achieve it, and cannot meet the urgent requirements of the new generation of various solid-state lasers for slat amplifiers for higher beam quality, higher efficiency, smaller size, and higher reliability. Summary of the invention

[0004] The embodiment of the present invention provides a self-double-pass angle multiplexing slab laser gain medium and a laser gain module, which are used to solve the problems of large volume and complex structure of the slab amplifier in the prior art.

[0005] A self-double-pass angle-multiplexed slab laser gain medium according to an embodiment of the present invention comprises:

[0006] The main body includes a first side surface, a first end surface, a second side surface, and a second end surface which are sequentially connected, the first side surface is parallel to the second side surface, an angle α1 between the first end surface and the second side surface is 45°, and an angle α2 between the second end surface and the first side surface is calculated according to Formula 1-Formula 3:

[0007]

[0008]

[0009]

[0010] Wherein, L represents the distance between the center point of the first end face and the center point of the second end face, d represents the distance between the first side face and the second side face, N1 represents the number of times the light beam is reflected in the direction from the first end face to the second end face after entering the main body from the first end face, and N2 represents the number of times the light beam is reflected in the direction from the second end face to the first end face after entering the main body from the first end face.

[0011] According to some embodiments of the present invention, the self-double-pass angle-multiplexed slab laser gain medium further comprises:

[0012] A first evanescent wave film, disposed on the first side surface;

[0013] A second evanescent wave film, disposed on the second side surface;

[0014] A laser anti-reflection film, provided on the first end surface;

[0015] The laser reflection film is arranged on the second end surface.

[0016] According to some embodiments of the present invention, the thickness of the first evanescent wave film and the second evanescent wave film are both 3 μm.

[0017] According to some embodiments of the present invention, both the first evanescent wave film and the second evanescent wave film are made of silicon dioxide material.

[0018] According to some embodiments of the present invention, β1 ≥ 53.3°, β2 ≥ 53.3°.

[0019] According to some embodiments of the present invention, the main body is a laser crystal, a laser glass component, or a laser ceramic component.

[0020] According to some embodiments of the present invention, the body portion comprises:

[0021] a first white YAG region, wherein the first end surface is located in the first white YAG region;

[0022] a second white YAG region, wherein the second end surface is located in the first white YAG region;

[0023] The doped YAG region is located between the first white YAG region and the second white YAG region.

[0024] According to some embodiments of the present invention, the activation ions of the doped YAG region are Nd, Yb, Er, or Tm.

[0025] A double-pass laser gain module according to an embodiment of the present invention comprises:

[0026] A gain medium, which is a self-double-pass angle-multiplexed slab laser gain medium as described above;

[0027] A microchannel heat sink is arranged on the peripheral wall of the gain medium;

[0028] A first pump structure is disposed near one end of the gain medium;

[0029] The second pumping structure is disposed close to the other end of the gain medium, and the second pumping structure and the first pumping structure are respectively located on two sides of the gain medium.

[0030] A four-pass laser gain module according to an embodiment of the present invention comprises:

[0031] A double-pass laser gain module, which is the double-pass laser gain module as described above;

[0032] A polarizer, coaxial with the gain medium and spaced apart;

[0033] A first reflector, located between the polarizer and the gain medium;

[0034] A lens is spaced apart from the first reflector, and a line connecting the lens and the first reflector is perpendicular to a central axis of the gain medium;

[0035] A λ / 4 wave plate, coaxial with the lens and spaced apart;

[0036] The second reflecting mirror is coaxial with the λ / 4 wave plate and spaced apart from the λ / 4 wave plate.

[0037] By adopting the embodiment of the present invention, the geometric configuration of the slab laser gain medium is reasonably designed, so that the laser light that passes through the slab laser gain medium once is reflected at the other end face, and passes through the gain medium again after changing the angle, while satisfying the two conditions of total reflection and integer optical path length. Therefore, the optical path structure can be greatly simplified, and the folded optical path of three reflectors and the image transmission system composed of two lenses are reduced. In this way, the difficulty of debugging the laser amplification link is reduced, and the volume is greatly compressed. In addition, because the use of optical components is reduced, the static optical distortion of the entire system is reduced and the reliability is improved.

[0038] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of the embodiments below. The accompanying drawings are only used to illustrate the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings:

[0040] Figure 1 Schematic diagram of the structure of a self-double-pass angle-multiplexed slab laser gain medium in an embodiment of the present invention;

[0041] Figure 2 Schematic diagram of the structure of a self-double-pass angle-multiplexed slab laser gain medium in an embodiment of the present invention;

[0042] Figure 3 Schematic diagram of the structure of a double-pass laser gain module in an embodiment of the present invention;

[0043] Figure 4 Schematic diagram of the structure of a four-pass laser gain module in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0045] like Figure 1-Figure 2 As shown, the self-double-pass angle-multiplexed slab laser gain medium 1 according to an embodiment of the present invention comprises:

[0046] The main body includes a first side surface S3, a first end surface S1, a second side surface S4, and a second end surface S2 which are connected in sequence. The first side surface S3 is parallel to the second side surface S4. The angle α1 between the first end surface S1 and the second side surface S4 is 45°. The angle α2 between the second end surface S2 and the first side surface S3 is calculated according to Formula 1-Formula 3:

[0047]

[0048]

[0049]

[0050] Among them, L represents the distance between the center point of the first end surface S1 and the center point of the second end surface S2, d represents the distance between the first side surface S3 and the second side surface S4, N1 represents the number of times the light beam is reflected in the direction from the first end surface S1 to the second end surface S2 after entering the main body from the first end surface S1, and N2 represents the number of times the light beam is reflected in the direction from the second end surface S2 to the first end surface S1 after entering the main body from the first end surface S1.

[0051] By adopting the embodiment of the present invention, the geometric configuration of the self-double-pass angle multiplexing slab laser gain medium 1 is reasonably designed, so that the laser light that passes through the self-double-pass angle multiplexing slab laser gain medium 1 once is reflected at the other end face, and passes through the gain medium again after changing the angle, while satisfying the two conditions of total reflection and integer optical path. Therefore, the optical path structure can be greatly simplified, and the folded optical path of three reflectors and the image transmission system composed of two lenses can be reduced. In this way, the difficulty of debugging the laser amplification link is reduced, and the volume is greatly compressed. In addition, because the use of optical components is reduced, the static optical distortion of the entire system is reduced and the reliability is improved.

[0052] On the basis of the above-mentioned embodiments, various variant embodiments are further proposed. It should be noted that, in order to make the description concise, only the differences from the above-mentioned embodiments are described in each variant embodiment.

[0053] According to some embodiments of the present invention, the self-double-pass angle-multiplexed slab laser gain medium 1 further comprises:

[0054] A first evanescent wave film, provided on the first side surface S3;

[0055] A second evanescent wave film, disposed on the second side surface S4;

[0056] A laser anti-reflection film, provided on the first end surface S1;

[0057] The laser reflective film is provided on the second end surface S2.

[0058] According to some embodiments of the present invention, the thickness of the first evanescent wave film and the second evanescent wave film are both 3 μm.

[0059] According to some embodiments of the present invention, both the first evanescent wave film and the second evanescent wave film are made of silicon dioxide.

[0060] According to some embodiments of the present invention, β1 ≥ 53.3°, β2 ≥ 53.3°.

[0061] According to some embodiments of the present invention, the main body is a laser crystal, a laser glass component, or a laser ceramic component.

[0062] like Figure 2 As shown, according to some embodiments of the present invention, the main body includes:

[0063] A first white YAG region 10, wherein the first end surface S1 is located in the first white YAG region 10;

[0064] The second white YAG region 11, the second end surface S2 is located at the first white YAG region 10;

[0065] The doped YAG region 12 is located between the first white YAG region 10 and the second white YAG region 10 .

[0066] According to some embodiments of the present invention, the activation ions of the doped YAG region 12 are Nd, Yb, Er, or Tm.

[0067] like Figure 3 As shown, the double-pass laser gain module 2 according to an embodiment of the present invention includes:

[0068] Gain medium 1, which is the self-double-pass angle-multiplexed slab laser gain medium as described above;

[0069] A microchannel heat sink 22 is provided on the peripheral wall of the gain medium 1;

[0070] A first pump structure 20 is disposed close to one end of the gain medium 1;

[0071] The second pumping structure 21 is disposed close to the other end of the gain medium 1 , and the second pumping structure 21 and the first pumping structure 20 are respectively located on two sides of the gain medium 1 .

[0072] By adopting the embodiment of the present invention, the geometric configuration of the slab laser gain medium 1 is reasonably designed, so that the laser light that passes through the slab laser gain medium 1 once is reflected at the other end face, and passes through the gain medium again after changing the angle, while satisfying the two conditions of total reflection and integer optical path length, thereby greatly simplifying the optical path structure, reducing the folded optical path of three reflectors and the image transmission system composed of two lenses, thus reducing the difficulty of debugging the laser amplification link and greatly compressing the volume. In addition, because the use of optical components is reduced, the static optical distortion of the entire system is reduced and the reliability is improved.

[0073] like Figure 2 As shown, the first pump structure 20 includes a laser diode array 201, a first lens 202, and a second lens 203, and the first lens 202 and the second lens 203 constitute a pump coupling lens group. The laser diode array 201, the first lens 202, and the second lens 203 are coaxially spaced, and the first lens 202 is located between the laser diode array 201 and the second lens 203.

[0074] like Figure 2 As shown, in some embodiments of the present invention, the central axis of the first pump structure 20 and the central axis of the gain medium 1 are at an acute angle. The central axis of the second pump structure 21 is perpendicular to the central axis of the gain medium 1 .

[0075] like Figure 3 As shown, the four-pass laser gain module 3 according to an embodiment of the present invention includes:

[0076] Double-pass laser gain module 2, which is the double-pass laser gain module as described above;

[0077] A polarizer 31, coaxial with the gain medium 1 and spaced apart;

[0078] A first reflector 32, located between the polarizer 31 and the gain medium 1;

[0079] The lens 33 is spaced apart from the first reflector 32, and the line connecting the lens 33 and the first reflector 32 is perpendicular to the central axis of the gain medium 1;

[0080] A λ / 4 wave plate 34 is coaxial with the lens 33 and spaced apart from the lens 33;

[0081] The second reflecting mirror 35 is coaxial with the λ / 4 wave plate 34 and spaced apart from it.

[0082] By adopting the embodiment of the present invention, the geometric configuration of the slab laser gain medium 1 is reasonably designed, so that the laser light that passes through the slab laser gain medium 1 once is reflected at the other end face, and passes through the gain medium again after changing the angle, while satisfying the two conditions of total reflection and integer optical path length, thereby greatly simplifying the optical path structure, reducing the folded optical path of three reflectors and the image transmission system composed of two lenses, thus reducing the difficulty of debugging the laser amplification link and greatly compressing the volume. In addition, because the use of optical components is reduced, the static optical distortion of the entire system is reduced and the reliability is improved.

[0083] It should be noted that, in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention.

[0084] In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. The specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. For example, in the claims, any one of the embodiments claimed for protection can be used in any combination.

[0085] Refer to the following Figure 1-Figure 4 The self-double-pass angle multiplexing slab laser gain medium and laser gain module of the embodiment of the present invention are described in detail with a specific embodiment. It is worth understanding that the following description is only an exemplary description, and is not a specific limitation of the present invention. All similar structures and similar variations of the present invention should be included in the protection scope of the present invention.

[0086] like Figure 1-Figure 2 As shown, the self-double-pass angle multiplexing slab laser gain medium 1 of the embodiment of the present invention comprises:

[0087] The main body includes a first side surface S3, a first end surface S1, a second side surface S4, and a second end surface S2 which are connected in sequence. The first side surface S3 is parallel to the second side surface S4. The angle α1 between the first end surface S1 and the second side surface S4 is 45°. The angle α2 between the second end surface S2 and the first side surface S3 is calculated according to Formula 1-Formula 3:

[0088]

[0089]

[0090]

[0091] Among them, L represents the distance between the center point of the first end surface S1 and the center point of the second end surface S2, d represents the distance between the first side surface S3 and the second side surface S4, N1 represents the number of times the light beam is reflected in the direction from the first end surface S1 to the second end surface S2 after entering the main body from the first end surface S1, and N2 represents the number of times the light beam is reflected in the direction from the second end surface S2 to the first end surface S1 after entering the main body from the first end surface S1.

[0092] It can be understood that one end α1 of the self-double-pass angle multiplexing slab laser gain medium 1 is preferably cut at an angle of 45°, and the cutting angle of the other end satisfies the relationship:

[0093] The main body is a non-parallelogram structure, and the acute angles can be on opposite corners or on the same side. In other words, the angle α1 and the angle α2 can be on the same side or on opposite corners.

[0094] The first side surface S3 and the second side surface S4 are both coated with an evanescent wave film of about 3 μm thick, so that the laser can achieve total internal reflection. The evanescent wave film is usually made of silicon dioxide material, and the refractive index is similar to that of quartz, about 1.46. It can be calculated that the total reflection angle β ≥ 53.3°, so the appropriate number of reflections N should be set to meet this condition. The first end surface S1 is coated with a laser anti-reflection film, and the second end surface S2 is coated with a small-angle laser reflective film.

[0095] The main body is a laser crystal, a laser glass component, or a laser ceramic component.

[0096] The main body is an end-pump structure, with white YAG bonded to the two end faces of the main body, and a doped YAG region 12 in the middle. The activation ions of the doped YAG region 12 are Nd, Yb, Er, or Tm. The concentration of each activation ion can be designed as needed.

[0097] The self-double-pass angle-multiplexed slab laser gain medium 1 of the embodiment of the present invention is suitable for a laser gain module of LD single-end pumping or double-end pumping. When the end face angle α1 is 45°, the single-end pumping is perpendicular to the large face of the slab. During double-end pumping, in order to ensure that the pump light is parallel to the large face in the crystal, the pump light needs to be incident at an oblique angle, and the incident angle is 2*(α2-45°).

[0098] The laser gain module composed of the self-double-pass angle multiplexing slab laser gain medium 1 can directly realize the double-pass amplification of the laser, such as Figure 3 As shown, the seed light is injected into the double-pass gain slab laser gain medium 1 at the left end face and then irradiates the right end face through a "Z"-shaped optical path. The right end face reflects the single-pass amplified laser back at another angle according to the designed angle, and finally outputs it at the left end face.

[0099] Based on the double-pass amplification device, four-pass amplification can also be achieved, such as Figure 4 As shown, the seed light is required to be a linearly polarized laser. After passing through the polarizer, it is first double-pass amplified, and then the polarization state is rotated 90° using a wave plate and re-injected into the self-double-pass gain slab laser gain medium 1. After four-pass amplification, it is output in the reverse direction along the seed light path, and the laser after four-pass amplification is totally reflected at the polarizer to separate the seed light from the laser.

[0100] The self-double-pass angle-multiplexing slab laser gain medium of the embodiment of the present invention can be cooled by using a conduction cooling technique or by using a coolant for direct cooling.

[0101] The self-double-pass angle-multiplexed slab laser gain medium 1 of the embodiment of the present invention can adopt end-face pumping or large-surface pumping in the pump coupling design.

[0102] The self-double-pass angle-multiplexed slab laser gain medium 1 of the embodiment of the present invention has two end face angles of the slab structure that need to strictly satisfy a mathematical relationship to ensure an integer optical path and a total reflection angle while taking into account the overlap efficiency.

[0103] The self-double-pass angle-multiplexed slab laser gain medium 1 of the embodiment of the present invention can be used in a resonant cavity for continuous operation, pulsed operation, and Q-switched operation; it can also be used as an amplifier to amplify laser beams of various operating modes using various working modes such as traveling wave amplification, regenerative amplification, and multi-pass amplification.

[0104] The self-double-pass angle-multiplexed slab laser gain medium 1 of the embodiment of the present invention can achieve a laser output greater than 1KW after being processed and formed according to the above dimensions and combined with appropriate pump coupling technology, cooling technology, and resonant cavity technology.

[0105] The self-double-pass angle-multiplexed slab laser gain medium 1 of the embodiment of the present invention can greatly simplify the optical path structure, reduce the folded optical path of three reflectors and the image transmission system composed of two lenses, thereby reducing the difficulty of debugging the laser amplification link and greatly compressing the volume. In addition, because the use of optical elements is reduced, the static optical distortion of the entire system is reduced and the reliability is improved.

[0106] Description of the application documents: Unless otherwise specified, the terms involved in this application are explained as follows: Nd: neodymium; Yb: ytterbium; Er: erbium; Tm: thulium; YAG: yttrium aluminum garnet; Nd: YAG: neodymium-doped yttrium aluminum garnet.

[0107] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A self-double-pass angle-multiplexed slab laser gain medium, characterized in that: include: The main body includes a first side surface, a first end surface, a second side surface, and a second end surface which are sequentially connected, the first side surface is parallel to the second side surface, an angle α1 between the first end surface and the second side surface is 45°, and an angle α2 between the second end surface and the first side surface is calculated according to Formula 1-Formula 3: Wherein, L represents the distance between the center point of the first end face and the center point of the second end face, d represents the distance between the first side face and the second side face, N1 represents the number of times the light beam is reflected in the direction from the first end face to the second end face after entering the main body from the first end face, and N2 represents the number of times the light beam is reflected in the direction from the second end face to the first end face after entering the main body from the first end face.

2. The self-double-pass angle-multiplexed slab laser gain medium according to claim 1, characterized in that: The self-double-pass angle-multiplexed slab laser gain medium further comprises: A first evanescent wave film, disposed on the first side surface; A second evanescent wave film, disposed on the second side surface; A laser anti-reflection film, provided on the first end surface; The laser reflection film is arranged on the second end surface.

3. The self-double-pass angle-multiplexed slab laser gain medium according to claim 2, wherein: The thickness of the first evanescent wave film and the second evanescent wave film are both 3 μm.

4. The self-double-pass angle-multiplexed slab laser gain medium according to claim 2, wherein: The first evanescent wave film and the second evanescent wave film are both made of silicon dioxide material.

5. The self-double-pass angle-multiplexed slab laser gain medium according to claim 4, characterized in that: β1≥53.3°，β2≥53.3°。 6. The self-double-pass angle-multiplexed slab laser gain medium according to claim 1, wherein: The main body is a laser crystal, a laser glass component, or a laser ceramic component.

7. The self-double-pass angle-multiplexed slab laser gain medium according to claim 1, wherein: The main body comprises: a first white YAG region, wherein the first end surface is located in the first white YAG region; a second white YAG region, wherein the second end surface is located in the first white YAG region; The doped YAG region is located between the first white YAG region and the second white YAG region.

8. The self-double-pass angle-multiplexed slab laser gain medium according to claim 7, wherein: The activation ions of the doped YAG region are Nd, Yb, Er, or Tm.

9. A double-pass laser gain module, characterized in that: include: The gain medium is a self-double-pass angle-multiplexed slab laser gain medium according to any one of claims 1 to 8; A microchannel heat sink is arranged on the peripheral wall of the gain medium; A first pump structure is disposed near one end of the gain medium; The second pumping structure is disposed close to the other end of the gain medium, and the second pumping structure and the first pumping structure are respectively located on two sides of the gain medium.

10. A four-pass laser gain module, characterized in that: include: A double-pass laser gain module, which is the double-pass laser gain module according to claim 9; A polarizer, coaxial with the gain medium and spaced apart; A first reflector, located between the polarizer and the gain medium; A lens is spaced apart from the first reflector, and a line connecting the lens and the first reflector is perpendicular to a central axis of the gain medium; A λ / 4 wave plate, coaxial with the lens and spaced apart; The second reflecting mirror is coaxial with the λ / 4 wave plate and spaced apart from the λ / 4 wave plate.

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