Laser linear adjusting system
By incorporating a pump source, frequency doubling crystal, mode selection module, low-pass filter, beam expander, and polarization attenuator into the laser linear adjustment system, linear adjustment of laser energy is achieved. This solves the problem of polarizer damage caused by nonlinear energy changes in existing technologies and extends the service life of the polarizer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 李复云
- Filing Date
- 2025-07-18
- Publication Date
- 2026-05-12
AI Technical Summary
In existing technologies, when laser energy is changed by adjusting the power supply voltage of the pump source, the energy change is nonlinear, which can easily damage the polarizer.
A laser linear adjustment system was designed. By sequentially arranging a pump source, a frequency doubling crystal, a mode selection module, a low-pass filter, a beam expander, and a polarization attenuator along the optical path, the laser energy is linearly varied by expanding the spot diameter using the beam expander and adjusting the polarizer angle of the polarization attenuator.
It extends the lifespan of the polarizer and enables linear adjustment of laser energy, thus avoiding damage to the polarizer.
Smart Images
Figure CN224233131U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of optical technology, and more particularly to a laser linear modulation system. Background Technology
[0002] In related technologies, the energy of the laser emitted by the pump source is changed by adjusting the power supply voltage of the pump source. However, this energy change is nonlinear, and the polarizer is easily burned by high-power lasers due to its low damage resistance threshold. When adjusting the power supply voltage of the pump source, the polarizer is easily damaged due to the nonlinear energy change. Utility Model Content
[0003] This disclosure provides a laser linear adjustment system to at least solve the above-mentioned technical problems existing in the prior art.
[0004] This disclosure provides a laser linear adjustment system, wherein a pump source 1, a frequency doubling crystal 2, a mode selection module 3, a low-pass filter 4, a beam expander 5, and a polarization attenuator 6 are arranged sequentially along the optical path;
[0005] Pump light source 1 generates a first beam of light, which is incident on the frequency doubling crystal 2. The frequency doubling crystal 2 increases the frequency of the first beam of light to obtain a second beam of light.
[0006] The second beam is incident on the mode selection module 3, and a third beam is emitted from the mode selection module 3; the divergence angle of the third beam is smaller than that of the second beam, and the spot diameter of the third beam is smaller than that of the second beam.
[0007] The third beam is incident on the low-pass filter 4, and the fourth beam exits from the low-pass filter 4;
[0008] The fourth beam is incident on the beam expander 5, and the fifth beam is emitted from the beam expander 5; the spot diameter of the fifth beam is larger than the spot diameter of the fourth beam.
[0009] The fourth beam is incident on the polarization attenuator 6, and the fifth beam is emitted from the polarization attenuator 6; in response to the change in the polarizer angle in the polarization attenuator 6, the energy of the fifth beam emitted from the polarization attenuator 6 changes linearly.
[0010] In the above scheme, the pump light source 1 includes a total reflection mirror 7, a Q-switched crystal 8, a polarizer 9, a solid-state laser module 10, and an output mirror 11 along the optical path direction.
[0011] In the above scheme, the distance between the total reflection mirror 7 and the Q-switch crystal 8 is 60mm;
[0012] The distance between the Q-switched crystal 8 and the polarizer 9 is 10 mm;
[0013] The distance between polarizer 9 and solid-state laser module 10 is 50 mm;
[0014] The distance between the solid-state laser module 10 and the output mirror 11 is 70mm.
[0015] In the above scheme, the distance between the pump light source 1 and the frequency doubling crystal 2 is 70mm;
[0016] The distance between the frequency doubling crystal 2 and the mode selection module 3 is 10mm;
[0017] The distance between the mode selection module 3 and the low-pass filter 4 is 20mm;
[0018] The distance between the low-pass filter 4 and the beam expander 5 is 25mm;
[0019] The distance between the beam expander 5 and the polarization attenuator 6 is greater than or equal to 244.4 mm.
[0020] In the above scheme, the mode selection module 3 includes a pinhole aperture;
[0021] In response to the aperture diameter being 1 mm, the light spot mode is the fundamental mode.
[0022] In the above scheme, the frequency doubling crystal 2 is used to increase the frequency of the first beam so that the frequency of the second beam is twice the frequency of the first beam.
[0023] In the above scheme, the low-pass filter 4 is used to filter the fundamental frequency light, allowing light with a wavelength of 532nm to pass through.
[0024] In the above scheme, the beam expander 5 is a plano-concave lens with a working wavelength of 400nm to 700nm.
[0025] In the above scheme, the extinction ratio of the polarizer 6 is greater than 1000:1; the damage threshold is 50mJ / mm2; and the operating wavelength is 400nm to 700nm.
[0026] In the above scheme, the beam expander 5 includes an objective lens and an eyepiece;
[0027] The objective lens has a focal length of 25mm and a diameter of 12.5mm;
[0028] The eyepiece has a focal length of 50mm and a diameter of 12.5mm.
[0029] The laser linear adjustment system provided in this embodiment uses a pump light source 1, a frequency doubling crystal 2, a mode selection module 3, a low-pass filter 4, a beam expander 5, and a polarization attenuator 6 designed along the optical path. This allows the first beam emitted by the pump light source 1 to be transmitted to the polarization attenuator 6 after passing through each optical device. As the angle of the polarizer in the polarization attenuator 6 changes, the energy of the emitted beam changes linearly, thus extending the lifespan of the polarizer when adjusting the power supply voltage of the pump light source.
[0030] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description
[0031] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:
[0032] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.
[0033] Figure 1 A schematic diagram of a first alternative structure of the laser linear modulation system provided in this disclosure embodiment is shown;
[0034] Figure 2 A schematic diagram of a second alternative structure of the laser linear modulation system provided in this disclosure embodiment is shown;
[0035] Figure 3 The diagram shows the energy relationship curves corresponding to the rotation angle of the polarizer from 0 degrees to 90 degrees.
[0036] Figure 4 The graph shows the energy relationship curves corresponding to the rotation angles of the polarizer from 91 degrees to 180 degrees.
[0037] The labels in the diagram are as follows: 1-Pump source, 2-Frequency doubling crystal, 3-Mode selection module, 4-Low-pass filter, 5-Beam expander, 6-Polarization attenuator, 7-Total reflection mirror, 8-Q-switched crystal, 9-Polarizer, 10-Solid-state laser module, and 11-Output mirror. Detailed Implementation
[0038] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0039] Figure 1 A schematic diagram of a first alternative structure of the laser linear adjustment system provided in this disclosure is shown, and will be described in terms of each part.
[0040] like Figure 1 As shown, the system is arranged along the optical path as follows: pump light source 1, frequency doubling crystal 2, mode selection module 3, low-pass filter 4, beam expander 5, and polarization attenuator 6.
[0041] Pump light source 1 generates a first beam of light, which is incident on the frequency doubling crystal 2. The frequency doubling crystal 2 increases the frequency of the first beam of light to obtain a second beam of light.
[0042] The second beam is incident on the mode selection module 3, and a third beam is emitted from the mode selection module 3; the divergence angle of the third beam is smaller than that of the second beam, and the spot diameter of the third beam is smaller than that of the second beam.
[0043] The third beam is incident on the low-pass filter 4, and the fourth beam exits from the low-pass filter 4;
[0044] The fourth beam is incident on the beam expander 5, and the fifth beam is emitted from the beam expander 5; the spot diameter of the fifth beam is larger than the spot diameter of the fourth beam.
[0045] The fourth beam is incident on the polarization attenuator 6, and the fifth beam is emitted from the polarization attenuator 6; in response to the change in the polarizer angle in the polarization attenuator 6, the energy of the fifth beam emitted from the polarization attenuator 6 changes linearly.
[0046] In some embodiments, the beam expander 5 enlarges the spot size of the fourth beam to obtain a fifth beam; ensuring that the power density of the fifth beam is within the safe threshold of the polarizer 6 when it reaches the polarizer. Optionally, the beam expander 5 can enlarge the spot diameter of the fourth beam by a factor of 2, that is, the spot diameter of the fifth beam is twice the spot diameter of the fourth beam.
[0047] In practice, the factor by which the beam expander increases the diameter of the light spot can be determined based on the following formula:
[0048]
[0049] Among them, P 峰值 P represents the peak power of the fourth beam. 安全 The safe power density for a polarizer, i.e., the power density of the incident beam, is represented by P. 安全 In this case, the polarizer will not be burned; M represents the beam expansion ratio, and r represents the fundamental mode radius before beam expansion.
[0050] In some embodiments, the rotation angle of the polarizer of the polarizing attenuator 6 is changed, and the energy of the light beam emitted from the polarizing attenuator 6 changes according to the following formula:
[0051] I = I0cos 2 θ
[0052] Where I0 is the energy of the fifth beam; I is the energy of the beam emitted from polarization attenuator 6; θ is the rotation angle of the polarizer; and I changes linearly with the rotation angle.
[0053] In some embodiments, the polarizer is used to fix the circularly polarized light emitted from the pump light source 1 as linearly polarized light.
[0054] Thus, through the laser linear adjustment system provided in this embodiment, the power density of the beam incident on the polarization attenuator 6 is kept within the safe range of the polarizer by the beam expander 5, and the rotation angle of the polarizer is adjusted to obtain a laser with linearly changing energy.
[0055] In some embodiments, the frequency doubling crystal 2 can be a KTP frequency doubling crystal, used to increase the frequency of the first beam; after the first beam passes through the frequency doubling crystal 2, the frequency becomes twice, that is, the frequency of the second beam is twice that of the first beam; the wavelength of the second beam is 532nm, that is, green light.
[0056] In some embodiments, the mode selection module 3 can be a pinhole aperture, which can improve the quality of the second beam; the pinhole aperture has a diameter of 1 mm and is used to select the TM00 fundamental mode.
[0057] Specifically, the energy of the TM00 fundamental mode is highly concentrated at the center of the beam, and the transverse intensity distribution is Gaussian (or quasi-Gaussian). The size of the central spot is usually small (less than 1 mm in diameter), so most of the energy in the beam can pass through the pinhole aperture, resulting in less energy loss.
[0058] Optionally, the mode can be changed by adjusting the diameter of the aperture stop, such as higher-order modes like TM01 and TM10. Higher-order modes have a more dispersed energy distribution (which may include a ring structure or side lobes), a lower energy proportion in the central region, and a larger lateral size.
[0059] In some embodiments, the low-pass filter 4 is used to filter out the fundamental frequency light with a wavelength of 1064nm, allowing green light with a wavelength of 532nm to pass through.
[0060] Figure 2 A schematic diagram of a second alternative structure of the laser linear adjustment system provided in this disclosure is shown, and will be described in terms of each part.
[0061] like Figure 2 As shown, the pump source 1 includes a total reflection mirror 7, a Q-switched crystal 8, a polarizer 9, a solid-state laser module 10, and an output mirror 11 arranged along the optical path. The output mirror 11 is the output mirror of the pump source 1.
[0062] In some embodiments, the distance between the total reflection mirror 7 and the Q-switched crystal 8 is 60 mm; the distance between the Q-switched crystal 8 and the polarizer 9 is 10 mm; the distance between the polarizer 9 and the solid-state laser module 10 is 50 mm; and the distance between the solid-state laser module 10 and the output mirror 11 is 70 mm.
[0063] In some embodiments, the maximum energy of the fourth beam reaching the beam expander 5 is 53.5 mJ, therefore the beam expander 5 can be a plano-concave lens with a working wavelength between 400 nm and 700 nm.
[0064] In some embodiments, the polarizer of the polarization attenuator 6 can be a linear polarizer with an extinction ratio greater than 1000:1 and a damage threshold of 50 mJ / mm². 2 The operating wavelength is 400nm-700nm. Optionally, the distance between the eyepiece and the objective lens can be 50mm.
[0065] Furthermore, the P of the fourth beam 峰值 It is 53.5 mJ / mm 2 P 安全 It must be less than or equal to 50 mJ / mm 2 If the magnification M is calculated to be ≥1.17, then the magnification of the beam expander in this embodiment is 2.
[0066] In some embodiments, the beam expander 5 includes an objective lens and an eyepiece; the objective lens has a focal length of 25 mm and a diameter of 12.5 mm; the eyepiece has a focal length of 50 mm and a diameter of 12.5 mm; the beam expansion magnification... Greater than 1.17.
[0067] In this case Less than 50 mJ / mm 2 Therefore, in this embodiment of the present disclosure, selecting a beam expansion ratio of 2 will not damage the polarizer of the polarization attenuator 6.
[0068] Furthermore, the divergence angle half-angle To maintain the uniformity of the light spot at the polarizer of polarization attenuator 6 (diameter variation <5%), the following must be satisfied: minimum distance
[0069] Considering a 30% safety margin, the minimum distance between the beam expander and the polarizer is set to L = (188 + 188 * 0.3) = 244.4 mm; the final distance between the beam expander and the polarizer is set to 300 mm.
[0070] Table 1 shows the correspondence between the laser energy after the polarization attenuator and the rotation angle of the polarizer obtained based on the embodiments of this disclosure.
[0071] Table 1
[0072]
[0073]
[0074] Using the rotation angle as the x-axis and laser energy as the y-axis, a curve was determined based on the data in Table 1, resulting in... Figure 3 and Figure 4 .
[0075] Figure 3 The graph shows the energy relationship curves corresponding to the rotation angle of the polarizer from 0 degrees to 90 degrees.
[0076] Figure 4 The graph shows the energy relationship curves corresponding to the rotation angles of the polarizer from 91 degrees to 180 degrees.
[0077] Depend on Figure 3 Can Figure 4 It can be concluded that the rotation angle of the polarizer is linearly related to the laser energy after passing through the polarization attenuator. That is, when the rotation angle of the polarizer is adjusted, the laser energy after passing through the polarization attenuator is also linearly adjusted.
[0078] Thus, the laser linear adjustment system provided in this embodiment can control the energy of the beam incident on the polarization attenuator to 17 mJ / mm². 2 This allows the polarizer's lifespan to exceed 30,000 pulses. In addition to extending the polarizer's lifespan, the rotation angle of the polarizer can also be adjusted to obtain lasers with linearly changing energy.
[0079] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this disclosure can be achieved, and this is not limited herein.
[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.
[0081] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A laser linear adjustment system, characterized in that, The system is configured along the optical path as follows: pump light source (1), frequency doubling crystal (2), mode selection module (3), low-pass filter (4), beam expander (5) and polarization attenuator (6); A pump light source (1) generates a first beam, which is incident on the frequency doubling crystal (2). The frequency doubling crystal (2) increases the frequency of the first beam to obtain a second beam. The second beam is incident on the mode selection module (3), and a third beam is emitted from the mode selection module (3); the divergence angle of the third beam is smaller than that of the second beam, and the spot diameter of the third beam is smaller than that of the second beam. The third beam is incident on the low-pass filter (4), and the fourth beam exits from the low-pass filter (4); The fourth beam is incident on the beam expander (5), and the fifth beam is emitted from the beam expander (5); the spot diameter of the fifth beam is larger than the spot diameter of the fourth beam. The fourth beam is incident on the polarization attenuator (6), and the fifth beam is emitted from the polarization attenuator (6); in response to the change in the polarizer angle in the polarization attenuator (6), the energy of the fifth beam emitted from the polarization attenuator (6) changes linearly.
2. The system according to claim 1, characterized in that, The pump light source (1) includes a total reflection mirror (7), a Q-switched crystal (8), a polarizer (9), a solid-state laser module (10), and an output mirror (11) along the optical path.
3. The system according to claim 2, characterized in that, The distance between the total reflection mirror (7) and the Q-switched crystal (8) is 60 mm; The distance between the Q-switched crystal (8) and the polarizer (9) is 10 mm; The distance between the polarizer (9) and the solid-state laser module (10) is 50 mm; The distance between the solid-state laser module (10) and the output mirror (11) is 70 mm.
4. The system according to claim 1, characterized in that, The distance between the pump light source (1) and the frequency doubling crystal (2) is 70 mm; The distance between the frequency doubling crystal (2) and the mode selection module (3) is 10mm; The distance between the mode selection module (3) and the low-pass filter (4) is 20mm; The distance between the low-pass filter (4) and the beam expander (5) is 25 mm; The distance between the beam expander (5) and the polarization attenuator (6) is greater than or equal to 244.4 mm.
5. The system according to claim 1, characterized in that, The mode selection module (3) includes a pinhole aperture; In response to the aperture diameter being 1 mm, the light spot mode is the fundamental mode.
6. The system according to claim 1, characterized in that, The frequency doubling crystal (2) is used to increase the frequency of the first beam so that the frequency of the second beam is twice the frequency of the first beam.
7. The system according to claim 1, characterized in that, The low-pass filter (4) is used to filter the fundamental frequency light, allowing the light beam with a wavelength of 532nm to pass through.
8. The system according to claim 1, wherein the beam expander (5) is a plano-concave lens with a working wavelength of 400 nm to 700 nm.
9. The system according to claim 1, characterized in that, The extinction ratio of the polarizer (6) is greater than 1000:1; the damage threshold is 50 mJ / mm. 2 The operating wavelength is 400nm to 700nm.
10. The system according to claim 1, characterized in that, The beam expander (5) includes an objective lens and an eyepiece; The objective lens has a focal length of 25mm and a diameter of 12.5mm; The eyepiece has a focal length of 50mm and a diameter of 12.5mm.