Light beam quality analyzer

Abstract

The invention provides a light beam quality analyzer, and relates to the technical field of laser, the light beam quality analyzer comprises a light source, a spectrum filter, a light filtering unit, an achromatic lens group, a reflector group and an image sensor, the spectrum filter, the light filtering unit, the achromatic lens group and the reflector group are sequentially arranged along the light emitting direction of the light source; laser emitted by the light source sequentially penetrates through the spectrum filter, the light filtering unit and the achromatic lens group, the achromatic lens group outputs an adjusting light beam, and the adjusting light beam is reflected by the reflector group so as to be transmitted to the image sensor; the achromatic lens group comprises a first lens, a second lens and a third lens which are sequentially arranged in the light emitting direction of the light source; the focal length of the first lens and the focal length of the second lens meet the following condition: f / 5 < f1 < f2 < f / 4. According to the invention, the measurement precision and stability of the light beam quality analyzer can be improved.

Description

Technical Field

[0001] The invention relates to the field of laser technology, and in particular to a beam quality analyzer. Background Art

[0002] With the rapid development of laser technology, laser beams are increasingly used in scientific research, industry, medical treatment and other fields. As an important indicator of laser performance, beam quality directly affects the efficiency and stability of the laser system.

[0003] The Chinese patent with announcement number CN108287059B discloses a high-precision near-infrared laser beam quality measurement and analysis device, which sequentially places a laser power adjustable attenuation device, an aberration-free focusing lens, a high-reflection mirror group, a spectroscope and two charge-coupled device cameras along the optical path. The laser power adjustable attenuation device is composed of neutral density filters with different attenuation levels placed on a rotating wheel; the second high-reflection mirror is placed on the reflection light path of the first high-reflection mirror, and the two are placed together on a movable guide rail; the first CCD camera is placed on the reflection light path of the spectroscope, and the second CCD camera is placed on the transmission light path of the spectroscope. The above scheme does not perform spectral filtering on the measurement laser, and cannot eliminate the influence of stray spectra in the laser on the measurement under general measurement, and does not perform achromatic processing, resulting in insufficient measurement accuracy of wide-spectrum light. Therefore, it is very necessary to provide a beam quality analyzer to improve the measurement accuracy and stability of the beam quality analyzer. Summary of the invention

[0004] In view of this, the present invention proposes a beam quality analyzer. By adopting the achromatic design of a three-piece achromatic mirror group, the chromatic aberration of light of different wavelengths can be effectively compensated, the dispersion phenomenon in the optical system is reduced, and the measurement accuracy and stability of the beam quality analyzer are improved.

[0005] The present invention provides a beam quality analyzer, comprising a light source, a spectral filter, a filter unit, an achromatic mirror group, a reflector group and an image sensor, wherein:

[0006] The spectral filter, the filter unit, the achromatic mirror group and the reflector group are sequentially arranged along the light emitting direction of the light source;

[0007] The laser light emitted by the light source sequentially passes through the spectral filter, the filter unit and the achromatic mirror group, the achromatic mirror group outputs an adjusted light beam, and the adjusted light beam is reflected by the reflector group so that the adjusted light beam is transmitted to the image sensor;

[0008] The achromatic lens group comprises a first lens, a second lens and a third lens arranged in sequence along the light emitting direction of the light source;

[0009] The focal length of the first lens and the focal length of the second lens satisfy:

[0010] f / 5<|f1|<|f2|<f / 4

[0011] Wherein, f1 represents the focal length of the first lens, f2 represents the focal length of the second lens, and f represents the focal length of the achromatic lens group.

[0012] On the basis of the above technical solution, preferably, the object side surface of the first lens is convex at the near optical axis, the image side surface of the first lens is convex at the near optical axis, the radius of curvature of the object side surface of the first lens is smaller than the radius of curvature of the image side surface of the first lens, the object side surface of the second lens is concave at the near optical axis, the image side surface of the second lens is flat at the near optical axis, the object side surface of the third lens is convex at the near optical axis, the image side surface of the third lens is concave at the near optical axis, and the radius of curvature of the object side surface of the third lens is smaller than the radius of curvature of the image side surface of the third lens.

[0013] On the basis of the above technical solution, preferably, the achromatic mirror set meets the following conditions:

[0014] 6<|R1 / R2|<6.2

[0015] 1.3<|R5 / R4|<1.4

[0016] Among them, R1 represents the curvature radius of the object side surface of the first lens, R2 represents the curvature radius of the image side surface of the first lens, R4 represents the curvature radius of the object side surface of the third lens, and R5 represents the curvature radius of the image side surface of the third lens.

[0017] More preferably, the achromatic mirror set meets the following conditions:

[0018] L1 / L2>3

[0019] L2<L3<L4

[0020] Wherein, L1 represents the center thickness of the first lens, L2 represents the center thickness of the second lens, L3 represents the distance between the second lens and the third lens, and L4 represents the center thickness of the third lens.

[0021] More preferably, the first lens and the second lens form a cemented lens, and the focal length of the cemented lens satisfies:

[0022] 2.5f<f12<3f

[0023] Among them, f12 is the focal length of the cemented lens, and f is the focal length of the achromatic lens group.

[0024] More preferably, the ratio of the focal length of the cemented lens to the focal length of the third lens satisfies:

[0025] 1.8<f12 / f3<2

[0026] Wherein, f12 represents the focal length of the cemented lens, and f3 represents the focal length of the third lens.

[0027] More preferably, the refractive index of the first lens is 1.55-1.59, the dispersion coefficient of the first lens is 68-75, the refractive index of the second lens is 1.6-1.63, the dispersion coefficient of the second lens is 53-58, the refractive index of the third lens is 1.52-1.56, and the dispersion coefficient of the third lens is 58-62.

[0028] More preferably, it further comprises a movable guide rail, the reflector group is fixed on a slider of the movable guide rail, and the movable guide rail is used to adjust the distance between the reflector group and the achromatic mirror group.

[0029] More preferably, the reflector group includes a first reflector and a second reflector with an inclination angle of 45°, the first reflector and the second reflector are arranged perpendicular to each other, and the center of the first reflector and the center of the light source are located on the same optical axis.

[0030] Further preferably, the filter unit, the achromatic mirror group, the reflector group and the movable guide rail are all arranged in a packaging shell, the spectral filter and the image sensor are arranged outside the packaging shell, the spectral filter is arranged between the light source and the filter unit, and the image sensor and the second reflector are located on the same optical axis.

[0031] The beam quality analyzer provided by the present invention has the following beneficial effects compared with the prior art:

[0032] (1) By adopting the achromatic design of the three-piece achromatic lens group, the chromatic aberration of light of different wavelengths can be effectively compensated, and the dispersion phenomenon in the optical system can be reduced. At the same time, the first lens is set to have positive refractive power, while the second lens has negative refractive power. The combination of the two lenses, one positive and one negative, makes the incident light transition smoothly, which is conducive to correcting the on-axis spherical aberration of the achromatic lens group. The combination of the first lens and the second lens and the third lens with positive refractive power can balance their respective spherical aberrations and on-axis chromatic aberrations, and configure the focal length to be f / 5<|f1|<|f2|<f / 4. With the characteristics of high and low dispersion coefficients of the two lens materials, the dispersion is reduced and the spherical aberration of the cemented lens is controlled. Through the achromatic lens group, the beam analyzer can achieve accurate measurement of wide-spectrum light.

[0033] (2) The focal length relationship f / 5<|f1|<|f2|<f / 4 ensures the appropriate convergence and divergence of the light beam. The curvature ratios of the first and third lenses (6<|R1 / R2|<6.2 and 1.3<|R5 / R4|<1.4) optimize the spherical aberration and aberration correction effects. The specific configurations of lens thickness and spacing (L1 / L2>3 and L2<L3<L4) reasonably control the optical path difference, giving the optical system a good compensation capability. This not only ensures the feasibility of the optical system's processing and manufacturing, but also achieves precise control of the beam quality and stable and reliable optical performance.

[0034] (3) The spectral filter can eliminate the stray spectral components contained in the measurement laser, thereby measuring the beam quality of the main laser, which is beneficial to improving the accuracy of beam measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of a process flow of a beam quality analyzer provided by the present invention;

[0037] Figure 2 A schematic diagram of the structure of the achromatic mirror assembly provided by the present invention;

[0038] Figure 3 Axial aberration curve diagram of the achromatic lens assembly provided by the present invention;

[0039] Figure 4 A light fan diagram of the light rays of the achromatic lens assembly provided by the present invention;

[0040] Figure 5 This is a point diagram of the achromatic mirror assembly provided by the present invention.

[0041] Explanation of the accompanying drawings: 1. light source; 2. spectral filter; 3. filter unit; 31. first filter; 32. second filter; 4. light blocking plate; 5. achromatic mirror group; 51. first lens; 52. second lens; 53. third lens; 6. reflector group; 61. first reflector; 62. second reflector; 7. image sensor; 8. movable guide rail; 9. packaging shell. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] See also Figure 1 The embodiment of the present application discloses a beam quality analyzer including a light source 1, a spectral filter 2, a filter unit 3, an achromatic mirror group 5, a reflector group 6 and an image sensor 7, wherein:

[0044] A spectral filter 2, a filter unit 3, an achromatic mirror group 5 and a reflector group 6 are arranged in sequence along the light emitting direction of the light source 1.

[0045] The laser emitted by the light source 1 passes through the spectral filter 2 , the filter unit 3 and the achromatic mirror group 5 in sequence. The achromatic mirror group 5 outputs an adjusted light beam, which is reflected by the reflector group 6 so as to be transmitted to the image sensor 7 .

[0046] In this embodiment, the achromatic lens group 5 includes a first lens 51, a second lens 52 and a third lens 53 which are arranged in sequence along the light emitting direction of the light source 1. The object side surface of the first lens 51 is convex at the near optical axis, and the image side surface of the first lens 51 is convex at the near optical axis. The radius of curvature of the object side surface of the first lens 51 is smaller than the radius of curvature of the image side surface of the first lens 51. The object side surface of the second lens 52 is concave at the near optical axis, and the image side surface of the second lens 52 is a plane at the near optical axis. The object side surface of the third lens 53 is convex at the near optical axis, and the image side surface of the third lens 53 is concave at the near optical axis. The radius of curvature of the object side surface of the third lens 53 is smaller than the radius of curvature of the image side surface of the third lens 53.

[0047] For further information, see Figure 2 There are three lenses with refractive power in the achromatic lens group 5. From the object side to the image side along the optical axis, the achromatic lens group 5 includes a first lens 51 with positive refractive power, a second lens 52 with negative refractive power, and a third lens 53 with positive refractive power.

[0048] In this embodiment, the refractive powers of the three lenses in the achromatic lens group 5 are reasonably configured, that is, the first lens 51 is set to have a positive refractive power, and the second lens 52 has a negative refractive power. The combination of the two lenses, one positive and one negative, can help correct the on-axis spherical aberration of the achromatic lens group 5. At the same time, since the object side surface and the image side surface of the first lens 51 are both convex at the near optical axis, the light entering the first lens 51 can be converged, and the divergent effect of the second lens can reduce the deflection angle of the incident light, thereby achieving a certain convergence effect. The design that the object side surface of the third lens 53 is convex and the image side surface is concave can help suppress the aberration of the achromatic lens group 5, and the combination of the cemented lens and the third lens 53 with positive refractive power is conducive to balancing the spherical aberration and on-axis chromatic aberration generated by each.

[0049] The refractive index of the first lens 51 is 1.55-1.59, and the dispersion coefficient of the first lens 51 is 68-75. The refractive index of the second lens 52 is 1.6-1.63, and the dispersion coefficient of the second lens 52 is 53-58. The refractive index of the third lens 53 is 1.52-1.56, and the dispersion coefficient of the third lens 53 is 58-62. The second lens 52 uses a higher refractive index with a lower dispersion coefficient, the first lens 51 uses a medium refractive index with a higher dispersion coefficient, and the third lens 53 uses a lower refractive index with a medium dispersion coefficient. This gradient configuration enables the three lenses to work together, and while ensuring good light beam transmission efficiency, the chromatic aberration is effectively compensated through the complementary effect of different dispersion coefficients, thereby improving the accuracy of wide-spectrum light measurement.

[0050] In this embodiment, the beam quality analyzer further includes a movable guide rail 8 and a light shield 4. The reflector group 6 is fixed on a slider of the movable guide rail 8. The movable guide rail 8 is used to adjust the distance between the reflector group 6 and the achromatic mirror group 5. The light shield 4 is arranged between the filter unit 3 and the achromatic mirror group 5. The reflector group 6 includes a first reflector 61 and a second reflector 62 with an inclination angle of 45°. The first reflector 61 and the second reflector 62 are arranged perpendicular to each other. The center of the first reflector 61 and the center of the light source 1 are located on the same optical axis. The filter unit 3, the achromatic mirror group 5, the reflector group 6 and the movable guide rail 8 are all arranged in a packaging shell 9. The spectral filter 2 and the image sensor 7 are arranged outside the packaging shell 9. The spectral filter 2 is arranged between the light source 1 and the filter unit 3. The image sensor 7 and the second reflector 62 are located on the same optical axis.

[0051] Furthermore, the light to be measured emitted by the light source 1 passes through the spectral filter 2 and the filter unit 3 in sequence, and the focused light beam passes through the reflector group 6 on the movable guide rail 8, and then enters the image sensor 7 after the optical path is turned. Among them, the spectral filter 2 can be a spectral filter 2 turntable, and different spectral filters 2 can be used by rotating the turntable to eliminate stray spectral components in the laser, and different filters are used for lasers of different wavelength bands. The filter unit 3 includes a first filter 31 and a second filter 32, and the first filter 31 and the second filter 32 are both gradient neutral filters. When the first filter 31 and the second filter 32 are relatively displaced, continuous and stepless adjustment of the laser power density can be achieved. The light shield 4 is used to block light to prevent strong light from entering when not measuring. The achromatic mirror group 5 can eliminate chromatic aberration of broadband light, thereby increasing the accuracy of measuring broadband light. The reflector group 6 is fixed on the slider of the guide rail module, and the movement of the slider is controlled by a high-precision servo motor, thereby changing the optical path between the achromatic mirror group 5 and the image sensor 7 (CCD or CMOS). The optical path is changed to measure the light spots at multiple positions before and after the waist of the focused light beam. When measuring different positions, due to the large moving range, the characteristic parameters of the focused light beam are fitted, and then the beam parameters of the light beam to be measured are calculated.

[0052] In the embodiment of the present invention, the achromatic mirror group 5 satisfies the following relationship equation:

[0053] f / 5<|f1|<|f2|<f / 4

[0054] 6<|R1 / R2|<6.2

[0055] 1.3<|R5 / R4|<1.4

[0056] L1 / L2>3

[0057] L2<L3<L4

[0058] Among them, f1 represents the focal length of the first lens 51, f2 represents the focal length of the second lens 52, f represents the focal length of the achromatic lens group 5, R1 represents the curvature radius of the object side surface of the first lens 51, R2 represents the curvature radius of the image side surface of the first lens 51, R4 represents the curvature radius of the object side surface of the third lens 53, R5 represents the curvature radius of the image side surface of the third lens 53, L1 represents the center thickness of the first lens 51, L2 represents the center thickness of the second lens 52, L3 represents the distance between the second lens 52 and the third lens 53, and L4 represents the center thickness of the third lens 53. The focal length relationship (f / 5<|f1|<|f2|<f / 4) ensures moderate convergence and divergence of the light beam. The curvature ratio of the first lens 51 and the third lens 53 (6<|R1 / R2|<6.2 and 1.3<|R5 / R4|<1.4) optimizes the spherical aberration and aberration correction effects. The specific configuration of lens thickness and spacing (L1 / L2>3 and L2<L3<L4) reasonably controls the optical path difference, so that the optical system has good compensation capability, which not only ensures the feasibility of processing and manufacturing of the optical system, but also realizes precise control of the light beam quality and stable and reliable optical performance.

[0059] For the first lens 51 and the second lens 52 in the achromatic lens group 5 to form a cemented lens, the cemented lens satisfies the following relationship equation:

[0060] 2.5f<f12<3f

[0061] 1.8<f12 / f3<2

[0062] Wherein, f12 represents the focal length of the cemented lens, f represents the focal length of the achromatic lens group 5, and f3 represents the focal length of the third lens 53. By cementing the first lens 51 and the second lens 52, and strictly controlling the focal length range of the cemented lens (2.5f<f12<3f) and the focal length ratio with the third lens 53 (1.8<f12 / f3<2), this specific focal length configuration relationship ensures good optical matching between the cemented lens and the third lens 53, achieves better chromatic aberration correction effect and spherical aberration control ability, and makes the entire achromatic lens group 5 compact, stable and reliable.

[0063] By adopting the achromatic design of the three-piece achromatic lens group 5, the chromatic aberration of light of different wavelengths can be effectively compensated, and the dispersion phenomenon in the optical system is reduced. At the same time, the first lens 51 is set to have positive refractive power, while the second lens 52 has negative refractive power. The combination of the two lenses, one positive and one negative, can be beneficial to correcting the on-axis spherical aberration of the achromatic lens group 5 and bear part of the optical focal length, and the focal length is configured to be f / 5<|f1|<|f2|<f / 4. The combination of the cemented lens and the third lens 53 with positive refractive power is beneficial to balancing the spherical aberration and on-axis chromatic aberration generated by each.

[0064] In one example, the total focal length of the achromatic lens group 5 is 500 mm, and the length of the achromatic lens group 5 is 16 mm. The refractive index of the first lens 51 is 1.57, the dispersion coefficient of the first lens 51 is 71.3, the radius of curvature of the object side surface of the first lens 51 is 452 mm, the radius of curvature of the image side surface of the first lens 51 is 74 mm, the center thickness of the first lens 51 is 6.7 mm, and the focal length of the first lens 51 is 112 mm. The refractive index of the second lens 52 is 1.61, the dispersion coefficient of the second lens 52 is 55.8, the radius of curvature of the object side surface of the second lens 52 is -74 mm, the center thickness of the second lens 52 is 2 mm, and the focal length of the second lens 52 is -121 mm. The refractive index of the third lens 53 is 1.54, the dispersion coefficient of the third lens 53 is 1.54, the curvature radius of the object side surface of the third lens 53 is 106 mm, the curvature radius of the image side surface of the third lens 53 is 141 mm, the center thickness of the third lens 53 = 3.81 mm, and the focal length of the third lens 53 is 761 mm. The focal length of the cemented lens is 1446 mm.

[0065] like Figure 3 As shown, Figure 3 This is the axial aberration curve of achromatic lens group 5, which shows the chromatic aberration correction effect of the optical system in the wavelength range of 0.486μm to 0.656μm. As can be seen from the figure, the three curves representing different wavelengths intersect near the 0 point, and the curve trend is gentle, indicating that the system has good chromatic aberration correction ability. At the same time, the aberration range is controlled within a small range, and the curve does not fluctuate violently, indicating that the optical system has stable optical performance and good imaging quality. Achromatic lens group 5 achieves effective chromatic aberration control and excellent optical performance.

[0066] like Figure 4 As shown, Figure 4 The light fan diagram of the achromatic lens group 5 shows the light propagation in the ey and ex directions respectively. The figure shows the propagation trajectories of three different wavelengths (0.486μm, 0.563μm and 0.656μm). It can be seen that the blue light presents a large arc distribution, while the red and green light are relatively concentrated. The light fan diagrams in the two directions show similar light distribution characteristics, indicating that the optical system has consistent light control capabilities in different directions. The cross-convergence and distribution of light indicate that the optical system has achieved effective chromatic aberration control, which overall reflects that the achromatic lens group 5 has good beam transmission characteristics and stable optical performance.

[0067] like Figure 5 As shown, Figure 5 This is a dot diagram of achromatic lens group 5, showing the imaging situation of achromatic lens group 5 at 0 degree object plane and 0.000mm image plane position. Figure 5A regular circular spot is shown in the figure, with an Airy spot radius of 35.83μm, an RMS radius of 0.026, and a GEO radius of 0.072. The circular outline is clear and complete, and the center point is clearly marked, indicating that the system has good imaging quality. The light convergence effect of three different wavelengths (0.486133μm, 0.587562μm, and 0.656273μm) is ideal, reflecting that the achromatic lens group 5 has excellent chromatic aberration correction ability and stable optical performance.

[0068] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate quantity restrictions, but indicate the existence of at least one. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A beam quality analyzer, characterized in that: It comprises a light source (1), a spectral filter (2), a filter unit (3), an achromatic mirror group (5), a reflector group (6) and an image sensor (7), wherein: The spectral filter (2), the filter unit (3), the achromatic mirror group (5) and the reflector group (6) are arranged in sequence along the light emitting direction of the light source (1); The laser light emitted by the light source (1) passes through the spectral filter (2), the filter unit (3) and the achromatic mirror group (5) in sequence, the achromatic mirror group (5) outputs an adjusted light beam, and the adjusted light beam is reflected by the reflector group (6) so that the adjusted light beam is transmitted to the image sensor (7); The achromatic lens group (5) comprises a first lens (51), a second lens (52) and a third lens (53) which are arranged in sequence along the light emitting direction of the light source (1); The focal length of the first lens (51) and the focal length of the second lens (52) satisfy: f / 5<|f1|<|f2|<f / 4 Wherein, f1 represents the focal length of the first lens (51), f2 represents the focal length of the second lens (52), and f represents the focal length of the achromatic lens group (5).

2. The beam quality analyzer according to claim 1, characterized in that: The object side surface of the first lens (51) is convex at the near optical axis, the image side surface of the first lens (51) is convex at the near optical axis, the radius of curvature of the object side surface of the first lens (51) is smaller than the radius of curvature of the image side surface of the first lens (51), the object side surface of the second lens (52) is concave at the near optical axis, the image side surface of the second lens (52) is flat at the near optical axis, the object side surface of the third lens (53) is convex at the near optical axis, the image side surface of the third lens (53) is concave at the near optical axis, the radius of curvature of the object side surface of the third lens (53) is smaller than the radius of curvature of the image side surface of the third lens (53).

3. The beam quality analyzer according to claim 1, characterized in that: The achromatic mirror set (5) meets the following conditions: 6<|R1 / R2|<6.2 1.3<|R5 / R4|<1.4 Wherein, R1 represents the radius of curvature of the object side surface of the first lens (51), R2 represents the radius of curvature of the image side surface of the first lens (51), R4 represents the radius of curvature of the object side surface of the third lens (53), and R5 represents the radius of curvature of the image side surface of the third lens (53).

4. The beam quality analyzer according to claim 1, characterized in that: The achromatic mirror set (5) meets the following conditions: L1 / L2>3 L2<L3<L4 Wherein, L1 represents the center thickness of the first lens (51), L2 represents the center thickness of the second lens (52), L3 represents the distance between the second lens (52) and the third lens (53), and L4 represents the center thickness of the third lens (53).

5. The beam quality analyzer according to claim 1, characterized in that: The first lens (51) and the second lens (52) form a cemented lens, and the focal length of the cemented lens satisfies: 2.5f<f12<3f Wherein, f12 represents the focal length of the cemented lens, and f represents the focal length of the achromatic lens group (5).

6. The beam quality analyzer according to claim 5, characterized in that: The ratio of the focal length of the cemented lens to the focal length of the third lens (53) satisfies: 1.8<f12 / f3<2 Wherein, f12 represents the focal length of the cemented lens, and f3 represents the focal length of the third lens (53).

7. The beam quality analyzer according to claim 1, characterized in that: The refractive index of the first lens (51) is 1.55-1.59, and the dispersion coefficient of the first lens (51) is 68-75; the refractive index of the second lens (52) is 1.6-1.63, and the dispersion coefficient of the second lens (52) is 53-58; the refractive index of the third lens (53) is 1.52-1.56, and the dispersion coefficient of the third lens (53) is 58-62.

8. The beam quality analyzer according to claim 1, characterized in that: It also comprises a movable guide rail (8), the reflector group (6) is fixed on a slider of the movable guide rail (8), and the movable guide rail (8) is used to adjust the distance between the reflector group (6) and the achromatic mirror group (5).

9. The beam quality analyzer according to claim 8, characterized in that: The reflector group (6) comprises a first reflector (61) and a second reflector (62) with an inclination angle of 45°, the first reflector (61) and the second reflector (62) are arranged perpendicular to each other, and the center of the first reflector (61) and the center of the light source (1) are located on the same optical axis.

10. The beam quality analyzer according to claim 9, characterized in that: The filter unit (3), the achromatic mirror group (5), the reflector group (6) and the movable guide rail (8) are all arranged in a packaging shell (9); the spectral filter (2) and the image sensor (7) are arranged outside the packaging shell (9); the spectral filter (2) is arranged between the light source (1) and the filter unit (3); and the image sensor (7) and the second reflector (62) are located on the same optical axis.

Images