Optical switch common-cavity laser
By designing an optical switch common cavity laser, using the optical switch to select the beam path output by the frequency multiplication crystal, the switching between circular and point annular light spots is solved, and the problems of low absorption rate and difficult shape switching when processing non-ferrous metals in the prior art are solved, and the processing effect and flexibility are improved.
Patent Information
- Application Number
- CN202411592964.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-08
- Publication Date
- 2025-03-07
AI Technical Summary
When existing fiber lasers process nonferrous metals, the near-infrared light absorption rate is low, resulting in poor processing effect and it is difficult to quickly switch spots of different shapes to adapt to different processing environments.
An optical switch common cavity laser is designed, and the subsequent optical paths of the first and second light beams output by the frequency doubling crystal are selected through the optical switch to realize the switching of the circular spot and the point annular spot. The laser includes a laser light source, a beam splitter, a beam-combining mirror and a coupled optical fiber. The beam splitter drive element controls the rotation of the beam splitter to achieve different combinations of the beam.
It improves energy utilization, achieves diversified light field absorption, can quickly switch light spots of different shapes, adapt to more processing environments, and improves processing effect and flexibility.
Smart Images
Figure CN119581982A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of lasers, and in particular to an optical switch common cavity laser. Background Art
[0002] In the field of fiber lasers, the processing of non-ferrous metals (aluminum, copper, etc.) is a research hotspot. Most mature fiber lasers on the market use near-infrared lasers of about 1000nm for processing operations. However, the absorption rate of non-ferrous metals to near-infrared light is only about 5%, which affects the processing effect. Studies have found that the absorption rate of non-ferrous metals to green light is more than 40%, which is significantly higher than that of near-infrared light. In the prior art, near-infrared light is usually doubled to green light by a frequency-doubling crystal to greatly improve the absorption rate of metals to lasers. However, in the prior art, there is a situation where the second fundamental frequency beam that has not been doubled is absorbed by the optical trash can or the shell, and energy is wasted; during the processing process, sometimes, the laser needs to form a circular spot on the processing surface; in another case, the laser needs to form a dot ring spot on the processing surface to preheat the processing surface. Therefore, this scheme proposes an optical switch common cavity laser, which uses an optical switch to select the subsequent optical paths of the first and second beams output by the frequency-doubling crystal to obtain a composite light spot of different shapes that can be switched at any time. Summary of the invention
[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to propose an optical switch common cavity laser, which can use the optical switch to select the subsequent optical path of the light beam output by the frequency doubling crystal to obtain a circular light spot and a dot ring light spot that can be switched.
[0004] In order to achieve the above-mentioned purpose and other related purposes, the purpose of the present application is to provide an optical switch common cavity laser, including a laser light source, a beam splitter, a beam combiner and a coupling optical fiber arranged in sequence, the laser light source is used to emit a first light beam and a second light beam in the same direction, the beam splitter is used to introduce the first light beam and the second light beam into the beam combiner to further form a composite light beam, and the coupling optical fiber homogenizes and transmits the composite light beam; the optical switch common cavity laser also includes a beam splitter driving element connected to the beam splitter, and the beam splitter driving element drives the beam splitter to rotate.
[0005] Optionally, the beam splitter driving element drives the beam splitter to rotate to form a first angle with the optical axis, and the first light beam and the second light beam output from the laser light source are both transmitted to the beam combining mirror along the first channel.
[0006] Optionally, the beam splitter driving element drives the beam splitter to rotate to form a second angle with the optical axis, and the first light beam and the second light beam output from the laser light source are separated. The separated first light beam is transmitted along the first channel, and the second light beam is transmitted along the second channel. The optical paths of the first channel and the second channel are different.
[0007] Optionally, the optical switch common cavity laser further comprises a beam displacement element, which is located in the first channel and / or the second channel and is used for translating the optical axis.
[0008] Optionally, the beam displacement element can be moved parallel to the optical axis to change the position of the optical axis of the optical channel where the beam displacement element is located.
[0009] Optionally, the beam displacement element includes a first reflector and a second reflector which are sequentially arranged along the beam emission direction.
[0010] Optionally, the optical switch common cavity laser further includes a first focusing mirror, which is arranged in front of the coupling optical fiber to converge the first light beam and the second light beam and couple them into the coupling optical fiber.
[0011] Optionally, the coupling optical fiber includes but is not limited to multimode optical fiber, multi-core optical fiber, multi-clad optical fiber and ring optical fiber.
[0012] Optionally, the laser light source includes a fundamental frequency light source, a half-wave plate and a frequency doubling crystal arranged in sequence, wherein the fundamental frequency light source is used to emit a fundamental frequency light beam; the half-wave plate is used to change the polarization direction of the fundamental frequency light beam; the frequency doubling crystal is used to double the frequency of part of the fundamental frequency light beam, and output a composite light beam formed by the doubled frequency light beam and a second fundamental frequency light beam that has not been doubled, wherein the composite light beam includes the first light beam and the second light beam.
[0013] Optionally, the fundamental frequency light beam is formed by combining a continuous laser beam and a pulsed laser beam.
[0014] Compared with the prior art, this solution has at least the following advantages: 1. The composite application of the first light beam and the second light beam can be realized, which improves the energy utilization rate. The two light beams have different wavelengths, and the processing materials have different absorption rates of the two light beams. By cooperating with each other, a variety of light field absorption rates can be obtained; 2. Give the first light beam and the second light beam different combination forms, and the different combination forms can be switched through an optical switch, which can quickly switch the light form and adapt to more processing environments; 3. After coupling into the optical fiber for homogenized output, a circular spot with the same spot size as the first beam and the second beam can be formed, or a dot-ring spot with the first beam in the center and the second beam in the outer ring can be formed, which can achieve the effect of preheating the molten pool and suppress welding spatter. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.
[0016] Figure 1 Schematic diagram of the structure of the optical switch common cavity laser described in the embodiment. DETAILED DESCRIPTION
[0017] In order to facilitate the understanding of this application, Figure 1 The present application is described in more detail with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements can exist between them. When an element is described as being "electrically connected to" another element, it can be directly connected to the other element, or one or more intermediate elements can exist between them. The terms "upper", "lower", "inner", "outer", "bottom" and the like used in this specification indicate orientation or positional relationships based on the Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0018] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.
[0019] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0020] The present application provides an optical switch common cavity laser, such as Figure 1 As shown, it includes a laser light source 110 arranged in sequence, which is used to emit a first light beam and a second light beam in the same direction; a beam splitter 17, which is used to introduce the first light beam and the second light beam into a beam combiner 20 to further form a composite light beam; the beam combiner 20 and a coupling optical fiber 16, which are used to homogenize and transmit the composite light beam; and also includes a beam splitter driving element connected to the beam splitter 17, which drives the beam splitter 17 to rotate. The beam splitter 17 has two rotation directions. When the beam splitter 17 is located in two rotation directions, the optical axes of the first light beam and the second light beam do not completely overlap, and the formed composite light spot has different components and different shapes.
[0021] Compared with the prior art, this solution has at least the following advantages: 1. The first light beam and the second light beam can be combined to improve the energy utilization rate. The two light beams have different wavelengths, and the processing materials have different absorption rates of the two light beams. By cooperating with each other, a variety of light field absorption rates can be obtained; 2. The output spot type can be controlled by the beam splitter driving element to obtain a variety of composite spot output forms, which are suitable for different processing scenarios.
[0022] Optionally, the beam splitter driving element drives the beam splitter to rotate to form a first angle with the optical axis, and the first light beam and the second light beam output from the laser light source are transmitted to the beam combiner 20 along the first channel. Figure 1 At the rotation angle of the position indicated by the dotted line, the first light beam and the second light beam emitted by the laser light source 110 directly enter the first channel and the beam combining mirror 20 without passing through the beam splitter 17, and are output as a composite light beam after passing through the beam combining mirror 20.
[0023] Since the optical surface of the beam splitter 17 in the optical path has to transmit one of the light beams and reflect one of the light beams, the beam splitter controlled by the beam splitter driving element can only rotate within an angle range. Continue to observe Figure 1 It should be noted that when the optical surface of the beam splitter 17 and the laser light source 110 form a laser external cavity based on the light beam reflected by the optical surface of the beam splitter 17, the laser light source 110 will be burned. Therefore, the beam splitter driving element controls the beam splitter 17 to rotate arbitrarily, and it has the following features: Figure 1 Two typical rotation angles are shown by the solid and dashed lines.
[0024] Optionally, in one embodiment, the beam splitter driving element drives the beam splitter 17 to rotate to form a second angle with the optical axis, so that the first light beam output from the laser light source 110 is separated from the second light beam, and the separated first light beam is transmitted along the first channel, and the second light beam is transmitted along the second channel, and the optical path of the first channel and the second channel are different. The beam splitter 17 is located as shown in FIG. Figure 1 At the position indicated by the solid line, the second light beam emitted by the laser light source 110 and the first light beam are split after passing through the beam splitter, the first light beam after the splitting enters the first channel, and the second light beam after the splitting enters the second channel.
[0025] Optionally, the optical switch common cavity laser further includes a beam displacement element 180, which is located in the first channel and / or the second channel for translating the optical axis. The function of the beam displacement element 180 is to increase the optical path length of the optical path in which it is located, and to form a larger light spot on the action surface according to the divergence effect of the light beam; at the same time, the beam displacement element 180 can offset the optical axis of one of the split light beams, change the degree of overlap of the two light beams after beam combination, and form an eccentric light spot. Optionally, the beam displacement element 180 includes a first reflector 18 and a second reflector 19 sequentially arranged along the optical path, and is used to change the optical path length and optical axis position of the light beam entering the first channel and / or the second channel. In one embodiment, when the beam splitter 17 is located at the first rotation angle, the second light beam and the first light beam emitted by the laser light source 110 do not pass through the beam splitter 17, and directly enter the first channel. At this time, the beam displacement element 180 is located in the second channel and does not work. The first light beam and the second light beam pass through the beam combiner 20 and then emit to form a circular light spot in which the light spot positions of the first light beam and the second light beam coincide with each other. In one embodiment, when the beam splitter 17 is located at the second rotation angle, the second light beam and the first light beam emitted by the laser light source 110 are split by the beam splitter 17, the first light beam enters the first channel, and the second light beam enters the second channel. At this time, the beam displacement element 180 is located in the second channel, and simultaneously moving the first reflector 18 and the second reflector 19 in parallel at equal distances can increase the optical path of the second light beam. Simultaneously moving the first reflector 18 and the second reflector 19 in parallel, or fixing the first reflector 18 and moving the second reflector 19 in parallel, or fixing the second reflector 19 and moving the first reflector 8 in parallel can parallel move the optical axis of the second light beam, thereby forming a straw hat light spot with a variable light spot size or a teardrop-shaped light spot with a variable light spot size and a variable degree of eccentricity after the beam combiner 20. In one embodiment, when the beam splitter driving element controls the beam splitter 17 to be periodically at different angles at a control frequency of the same order of magnitude as the repetition frequency of the pulsed laser, the purpose of rapidly changing the output light spot shape can be achieved. It can be understood that when the beam displacement element 180 is set in the first channel, the solution of the beam splitter 17 being at the first rotation angle and the second rotation angle is also included in the present case, which is not a limitation of the present case.
[0026] Optionally, the composite light beam formed after the beam combining by the beam combining mirror 20 can enter the first focusing mirror 15 for convergence. The composite light beam formed after the beam combining by the beam combining mirror 20 consists of the first light beam and the second light beam. The first light beam and the second light beam are both Gaussian beams, and extending the optical path will increase the divergence effect of the light beam. In order to increase the power density of the light beam and facilitate the subsequent coupling of the composite light beam into the optical fiber for beam homogenization, a first focusing mirror 15 can be set between the beam combining mirror 20 and the coupling optical fiber 16 to converge the first light beam and the second light beam and then output them.
[0027] Optionally, the coupling optical fiber 16 includes but is not limited to a ring optical fiber, a multi-core optical fiber, a multi-clad optical fiber and a multimode optical fiber. In one embodiment, when the beam splitter 17 is located at a first rotation angle, the second light beam and the first light beam emitted by the laser light source 110 directly enter the first channel without passing through the beam splitter 17. The second light beam and the first light beam can be combined by the beam combiner 20 to form a circular light spot with overlapping light spot positions. The circular light spot can be coupled into a multimode optical fiber with a core diameter of 100 μm in the form of spatial light and then homogenized and output. The frequency-doubled light spot formed by the output first light beam and the fundamental frequency light spot formed by the second light beam are approximately the same size. In one embodiment, when the beam splitter 17 is located at a second rotation angle, the second light beam and the first light beam emitted by the laser light source 110 are split by the beam splitter 17, the first light beam enters the first channel, and the second light beam enters the second channel. Continue to observe Figure 1, the second light beam is shaped by the beam displacement element 180 or the beam shaping element and then enters the beam combiner for beam combining; the beam displacement element 180 is moved in parallel, and cooperates with the first focusing lens 15. The composite light beam output by the beam combiner 20 can be coupled into the 100 / 300 / XX annular optical fiber in the form of spatial light after being converged by the first focusing lens 15; in one embodiment, the beam displacement element 180 is moved in parallel to make the second light beam coincide with the composite light spot formed after the first light beam is combined, at this time, the central first light beam and the part of the second light beam that coincides with the optical axis of the first light beam are converged by the first focusing lens 15 and then coupled into the inner core of the 100 / 300 / XX annular optical fiber, the second light beam with a larger spot diameter cannot be completely coupled into the inner core of the 100 / 300 / XX annular optical fiber, and the part of the second light beam that fails to enter the inner core of the 100 / 300 / XX annular optical fiber is converged by the first focusing lens 15 and then coupled into the outer core of the 100 / 300 / XX annular optical fiber, and a point ring light spot is formed based on the homogenization effect of the optical fiber on the light beam. Among them, the central point light spot is formed by the first light beam and part of the second light beam, and the peripheral annular light spot is formed by the second light beam. In one embodiment, the moving beam displacement element 180 makes the composite light spot formed by the second light beam and the first light beam eccentric. At this time, the central first light beam is converged by the first focusing mirror 15 and coupled into the inner core of the 100 / 300 / XX annular optical fiber, and the peripheral second light beam is converged by the first focusing mirror 15 and coupled into the outer core of the 100 / 300 / XX annular optical fiber. Based on the homogenization effect of the optical fiber on the light beam, a point ring light spot is formed in which the central point light spot is formed by the first light beam and the annular light spot is formed by the second light beam. In one embodiment, the beam splitter driving element controls the beam splitter 17 to switch between two rotation angles. At this time, the composite light beam output by the beam combiner 20 can be converged by the first focusing mirror 15 and coupled into the 100 / 300 / XX annular optical fiber. The beam splitter 17 switches between the two rotation angles to form a spot morphology switching effect of alternating between a circular light spot and a point ring light spot. In one embodiment, when the beam splitter driving element controls the beam splitter 17 to be periodically at different angles at a control frequency of the same order of magnitude as the repetition rate of the pulsed laser, the purpose of rapidly outputting alternating light spot shapes can be achieved.
[0028] Optionally, the laser light source 110 includes a fundamental frequency light source 11, a half-wave plate 12 and a frequency doubling crystal 14 which are arranged in sequence, wherein the fundamental frequency light source 11 includes a fiber laser and a semiconductor laser, and is used to output a fundamental frequency light beam in the near-infrared band; the half-wave plate 12 is used to change the light polarization direction of the fundamental frequency light beam; it is understandable that a second focusing mirror 13 is usually required to be arranged between the half-wave plate 12 and the frequency doubling crystal 14, which is used to converge the fundamental frequency light beam whose polarization direction is changed by the half-wave plate 12 and then input it into the frequency doubling crystal 14; the frequency doubling crystal 14 is used to frequency double part of the fundamental frequency light beam, wherein the degree of overlap between the polarization direction of the fundamental frequency light beam and the phase matching direction of the frequency doubling crystal affects the frequency doubling efficiency, and the polarization direction of the fundamental frequency light beam can be adjusted by the half-wave plate 12; after the frequency doubling crystal 14 frequency doubles the fundamental frequency light beam, it outputs a composite light beam formed by the second fundamental frequency light beam that has not been frequency doubled and the frequency doubling light beam, and the composite light beam contains the first light beam and the second light beam. The frequency-doubled beam can be used as the first beam output by the laser light source 110, and the second fundamental frequency beam without frequency-doubled beam can be used as the second beam output by the laser light source 110; the second fundamental frequency beam without frequency-doubled beam can also be used as the first beam output by the laser light source 110, and the frequency-doubled beam can be used as the frequency-doubled beam output by the laser light source 110. By controlling the rotation of the half-wave plate 12 by a servo motor or other means, the degree of adaptation between the polarization direction of the fundamental frequency beam and the phase matching direction of the frequency-doubled crystal 14 can be changed, thereby changing the frequency-doubled efficiency of the frequency-doubled crystal 14, thereby changing the power ratio of the first beam and the second beam emitted by the laser light source 110, giving the present application more means for adjusting the light field absorption rate, and changing the absorption rate of the processing material to the light field.
[0029] Optionally, the fundamental frequency beam is formed by combining a continuous laser beam and a pulsed laser beam. For example, when the fundamental frequency laser source 11 only outputs a continuous laser beam, the efficiency of converting the fundamental frequency beam into a frequency-doubled beam is constant, and the power proportion K1 of the frequency-doubled beam in the composite beam is constant; under the condition that the fundamental frequency laser source 11 only outputs a pulsed laser beam with the same power as the above-mentioned continuous laser beam, the efficiency of converting the second fundamental frequency beam that has not been frequency-doubled into a frequency-doubled beam is constant, and the power proportion K2 of the frequency-doubled beam in the composite beam is constant. When a continuous laser beam or a pulsed laser beam is used alone, the effect of changing the power on the frequency-doubled efficiency is small, while by combining a continuous laser beam and a pulsed laser beam, when the total light output power of the continuous laser beam and the pulsed laser beam remains unchanged, the power proportion of the two laser beams is adjusted, and the frequency-doubled efficiency of the fundamental frequency beam by the frequency-doubled crystal 14 can also be changed, thereby changing the power proportion of the first beam and the second beam emitted by the laser light source 110. Therefore, by combining a continuous laser beam and a pulsed laser beam to form a fundamental frequency beam and changing the energy ratio of the continuous laser beam and the pulsed laser beam, the power ratio of the first beam and the second beam emitted by the laser light source 110 can be changed, giving the present application more means of adjusting the light field absorption rate and changing the absorption rate of the processed material to the light field.
[0030] Compared with the prior art, this solution has at least the following advantages: 1. The first light beam and the second light beam can be combined to improve the energy utilization rate. The two light beams have different wavelengths, and the processing materials have different absorption rates of the two light beams. By cooperating with each other, a variety of light field absorption rates can be obtained; 2. Give the first light beam and the second light beam different combination forms, and the different combination forms can be switched through an optical switch, which can quickly switch the light form and adapt to more processing environments; 3. After coupling into the optical fiber for homogenized output, a circular spot with the same spot size for the first and second beams can be formed, or a dot-ring-shaped spot with the first beam in the center and the second beam in the outer ring. The circular spot with the same spot size for the first and second beams can be used in the field of laser cutting. After the first beam heats the processing material to a molten state, the processing material also has a high absorption rate for the second beam. The two beams act at the same position with the same spot size, which not only makes up for the deficiency that the green laser cannot increase the power all the time due to the nature of the frequency doubling crystal, but also reduces the back reflection and processing splash caused by the insufficient absorption rate of the processing material to the second beam; the dot-ring-shaped spot with the first beam in the center and the second beam in the outer ring is used in the field of laser welding, which can achieve the effect of preheating the molten pool and suppress welding splash. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.
[0031] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.
Claims
1. An optically switched common cavity laser, characterized in that: The optical switch common cavity laser comprises a laser light source, a beam splitter, a beam combiner and a coupling optical fiber which are arranged in sequence, wherein the laser light source is used to emit a first light beam and a second light beam in the same direction, the beam splitter is used to introduce the first light beam and the second light beam into the beam combiner to further form a composite light beam, and the coupling optical fiber homogenizes and transmits the composite light beam; the optical switch common cavity laser also comprises a beam splitter driving element connected to the beam splitter, and the beam splitter driving element is used to drive the beam splitter to rotate.
2. The optical switch common cavity laser according to claim 1, characterized in that: The beam splitter driving element drives the beam splitter to rotate to form a first angle with the optical axis, and the first light beam and the second light beam output from the laser light source are both transmitted to the beam combining mirror along the first channel.
3. The optical switch common cavity laser according to claim 1, characterized in that: The beam splitter driving element drives the beam splitter to rotate to form a second angle with the optical axis, and the first light beam and the second light beam output from the laser light source are separated. The separated first light beam is transmitted along a first channel, and the second light beam is transmitted along a second channel. The optical paths of the first channel and the second channel are different.
4. The optical switch common cavity laser according to claim 3, characterized in that: The optical switch common cavity laser further includes a beam displacement element, which is located in the first channel and / or the second channel and is used for translating the optical axis.
5. The optical switch common cavity laser according to claim 4, characterized in that: The beam displacement element can move parallel to the optical axis to change the position of the optical axis of the optical channel where the beam displacement element is located.
6. The optical switch common cavity laser according to claim 4, characterized in that: The beam displacement element comprises a first reflector and a second reflector which are sequentially arranged along the beam emission direction.
7. The optical switch common cavity laser according to claim 1, characterized in that: The optical switch common cavity laser further includes a first focusing mirror, which is arranged between the beam combining mirror and the coupling optical fiber, and is used for converging the first light beam and the second light beam and coupling them into the coupling optical fiber.
8. The optical switch common cavity laser according to claim 1, characterized in that: The coupling optical fiber includes but is not limited to a ring optical fiber, a multi-core optical fiber, a multi-clad optical fiber and a multi-mode optical fiber.
9. The optical switch common cavity laser according to claim 1, characterized in that: The laser light source includes a fundamental frequency light source, a half-wave plate and a frequency doubling crystal which are arranged in sequence, wherein the fundamental frequency light source is used to emit a fundamental frequency light beam; the half-wave plate is used to change the light polarization direction of the fundamental frequency light beam; the frequency doubling crystal is used to frequency double a portion of the fundamental frequency light beam, and output a composite light beam formed by the frequency doubled light beam and a second fundamental frequency light beam which has not been frequency doubled, wherein the composite light beam includes the first light beam and the second light beam.
10. The optical switch common cavity laser according to claim 9, characterized in that: The fundamental frequency light beam is formed by combining a continuous laser light beam and a pulsed laser light beam.