High-uniformity area array pumping source based on novel balsaming lens and use method of high-uniformity area array pumping source

Abstract

The invention discloses a high-uniformity area array pumping source based on a novel balsaming lens and a use method, and belongs to the technical field of semiconductor lasers. The area array pumping source comprises a laser emitting module, a bonding lens and a macro-channel cooling water channel, the balsaming lens comprises a triangular prism, a rectangular lens and a conical lens, the triangular prism is arranged on one side of the laser emitting module, the rectangular lens is connected to the side, away from the laser emitting module, of the triangular prism in a glued mode, and the conical lens is connected to the side, away from the triangular prism, of the rectangular lens in a glued mode. According to the area array pumping source, light output by the two bar arrays is subjected to beam shaping in the fast axis direction and the slow axis direction, high light spot uniformity and light spot modulation degree are further achieved, and the system structure can be simplified fundamentally.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, and in particular to a highly uniform area array pump source based on a novel cemented lens and its usage method. Background Technology

[0002] High-power semiconductor lasers, especially arrays built from laser diode bars, have become a core power source in advanced manufacturing. They play an irreplaceable role in applications such as metal cladding, surface hardening, welding, and as pump sources for solid-state lasers. A single laser diode bar can output hundreds of watts of power over a cavity length of about 1 cm, while arrays formed by stacking multiple diode bars vertically are the standard technical approach to achieve power output of several kilowatts or even tens of thousands of watts.

[0003] To achieve efficient and reliable integration of the light emitted from each laser bar into a single, uniformly distributed beam, a discrete lens group and spatial beam combining scheme are typically used. This involves equipping each laser bar with an independent fast-axis collimator (FAC) and slow-axis collimator (SAC), and then using complex spatial optical elements (such as mirrors and prisms) to translate and arrange the beams from each laser bar along the slow axis to fill the dark areas. This shaping method has significant drawbacks. The optical system is extremely complex, containing dozens of degrees of freedom requiring precise adjustment. The assembly and adjustment process is time-consuming, labor-intensive, and costly. The system is highly sensitive to vibration and thermal drift, resulting in poor long-term reliability. Furthermore, it is bulky, and its structural complexity leads to an exponential increase in manufacturing costs and susceptibility to environmental instability, ultimately limiting the power level and industrial applications of the laser. Summary of the Invention

[0004] To address the shortcomings of existing technologies and solve the aforementioned problems, this invention proposes a high-uniformity area array pump source based on a novel cemented lens and its usage method. This invention performs beam shaping on the output light from two bar arrays along both the fast and slow axes, thereby achieving high beam uniformity and beam modulation, and fundamentally simplifies the system structure.

[0005] Terminology Explanation: Slow axis direction: refers to the X-axis direction.

[0006] Fast axis direction: refers to the Y-axis direction.

[0007] The technical solution of the present invention is as follows: A highly uniform area array pump source based on a novel cemented lens includes: The laser emitting module is used to emit pump light; A cemented lens, located on one side of the laser emitting module, is used to shape the spot of the output light from the laser emitting module in both the fast and slow axes. The macro-channel cooling water channel, located below the laser emitting module, is used to dissipate heat from the laser emitting module; The cemented lens includes a triangular prism, a rectangular lens, and a conical lens. The triangular prism is disposed on one side of the laser emitting module. A rectangular lens is cemented to the side of the triangular prism away from the laser emitting module, and a conical lens is cemented to the side of the rectangular lens away from the triangular prism.

[0008] In this invention, a triangular prism refracts the light emitted by the laser emitting module, asymmetrically focusing the beam along the slow axis. The beveled structure of the triangular prism introduces a controllable optical path difference, achieving initial focusing and pointing adjustment along the slow axis. Simultaneously, the beveled surface of the triangular prism helps eliminate stray reflections, thereby eliminating the uneven beam pattern present in the slow axis direction of the laser emitting module. A rectangular lens, serving as the optical framework of the cemented lens, provides refractive power for the beam in both the fast and slow axes, undertaking basic imaging or focusing functions, and correcting overall aberrations for pre-shaping the beam. The rectangular lens also maintains the system's... The optical path is stable, ensuring that the beam can efficiently enter the conical lens after being processed by the triangular prism. The rectangular cross-section is conducive to mechanical packaging and integration, and facilitates matching with subsequent optical systems. The conical lens is used for beam homogenization in the fast axis direction. The conical cross-section redistributes the light intensity distribution in the fast axis direction through the gradient refraction effect, eliminating the non-uniformity of strong light in the center and weak light at the edge of the spot. At the same time, the conical lens homogenizes the beam in the slow axis direction, and finally outputs a rectangular spot with optimized uniformity. The triangular prism, rectangular lens and conical lens are cemented together as a whole, so that the cemented lens as a whole shapes the beam in both the fast axis and slow axis directions.

[0009] According to a preferred embodiment of the present invention, the laser emitting module includes two bar arrays, which are arranged in parallel along the slow axis direction, and each bar array contains a plurality of laser bars arranged along the fast axis direction.

[0010] According to a preferred embodiment of the present invention, the triangular prism, rectangular lens, and conical lens are all made of fused silica. Fused silica has a high damage threshold and thermal conductivity, a near-zero thermo-optic coefficient over a wide temperature range, and a low coefficient of thermal expansion, which can effectively suppress thermally induced focusing shift and wavefront distortion.

[0011] According to a preferred embodiment of the present invention, an optical adhesive is used for the bonding process, wherein the optical adhesive is a UV-curable silicone-based optical adhesive or a high-temperature epoxy resin.

[0012] The curing shrinkage rate of the two optical adhesives in this invention is less than 0.5%, and their elastic modulus matches that of fused silica, thereby avoiding interfacial debonding or microcracks caused by differences in thermal expansion and contraction. These two optical adhesives have undergone anti-ultraviolet radiation aging treatment, and their polymer chain structure has self-healing potential, which can maintain the bonding strength under cyclic thermal loads and extend the service life of triangular prisms, rectangular lenses and conical lenses.

[0013] According to a preferred embodiment of the present invention, the two light-incident surfaces of the triangular prism near the laser emitting module and the light-outceasing surface of the conical lens away from the rectangular lens are all provided with anti-reflection coatings; the anti-reflection coating is a multilayer stacked structure of oxides, and more preferably, the anti-reflection coating is a stacked structure of SiO2 layers / Ta2O5 layers.

[0014] In this invention, the antireflective coating dynamically compensates for changes in the laser incident angle, especially for changes in the angle of the conical lens's inclined surface, ensuring a reflectivity of less than 0.2% in both the fast and slow axes of the beam. The coating material uses a multilayer stacked oxide structure, whose rigid properties can withstand wear caused by cleaning and wiping, while also possessing heat diffusion capabilities to assist in heat dissipation for the triangular prism and conical lens.

[0015] According to a preferred embodiment of the present invention, a coolant flows through the macrochannel cooling water channel; preferably, the coolant is deionized water.

[0016] The present invention also provides a method for using the above-mentioned high-uniformity array pump source based on a novel cemented lens.

[0017] A method for using a highly uniform area array pump source based on a novel cemented lens includes the following steps: After the macro channel cooling water is circulated, the laser emitting module is powered to emit light. The beam is refracted by a triangular prism, then pre-shaped by a rectangular lens, and finally homogenized by a conical lens in the fast and slow axis directions to output a rectangular light spot.

[0018] Technical features and beneficial effects of the present invention: 1. High uniformity of light spot: This invention eliminates the "dead zone" between bars through active optical design, achieving high uniformity and high light spot modulation that are difficult to achieve with traditional solutions, thus significantly improving processing quality.

[0019] 2. Excellent structural stability: This invention integrates a complex multi-lens spatial beamforming system into a single cemented lens, eliminating the need for adjustment of dozens of degrees of freedom. The cemented structure is naturally resistant to vibration and thermal imbalance, significantly improving the long-term reliability of the system.

[0020] 3. Cost and size advantages: This invention significantly reduces the number of optical components and assembly time, thereby lowering manufacturing costs. Simultaneously, the system structure is very compact, which is beneficial for the miniaturization of the entire laser device. Attached Figure Description

[0021] Figure 1 This is a bottom view of the high-uniformity array pump source based on a novel cemented lens according to the present invention. Figure 2 This is a schematic diagram of the laser emitting module of the present invention; Figure 3 This is a schematic diagram of the cemented lens of the present invention; Figure 4 This is a test image of the light spot of the highly uniform area array pump source based on the novel cemented lens in Example 1; Figure 5 The image shows the light spot test pattern of the area array pump source in Comparative Example 1. Among them: 1. Bar array, 2. Cemented lens, 3. Macro channel cooling water channel, 4. Front shell, 5. Rear shell; 21. Triangular prism; 22. Rectangular lens; 23. Conical lens. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments and accompanying drawings, but is not limited thereto. The described embodiments are some embodiments of the present invention. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and should not be construed as limiting this invention.

[0024] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Unless otherwise specified in the embodiments of the present invention, all techniques existing in the art can be used.

[0025] Example 1 like Figures 1-3 As shown, a high-uniformity array pump source based on a novel cemented lens 2 includes a laser emitting module, a cemented lens 2, and a macrochannel cooling water channel 3; a rear shell 5 is provided on the rear side of the laser emitting module, a front shell 4 is provided on the front side of the laser emitting module, the cemented lens 2 is disposed on one side of the laser emitting module through the front shell 4, and the macrochannel cooling water channel 3 is disposed below the laser emitting module.

[0026] The laser emitting module consists of two bar arrays 1 with a spacing of 2.5 mm between them. Each bar array 1 includes 12 bars arranged along the Y-axis with a spacing of 2.2 mm between adjacent bars. Each bar integrates 49 light-emitting units and has an output power of 100W.

[0027] The cemented lens 2 includes a triangular prism 21, a rectangular lens 22, and a conical lens 23. The triangular prism 21 is positioned on one side of the laser emitting module. The rectangular lens 22 is cemented to the side of the triangular prism 21 away from the laser emitting module, and the conical lens 23 is cemented to the side of the rectangular lens 22 away from the triangular prism 21. The triangular prism 21, the rectangular lens 22, and the conical lens 23 are all made of fused silica and are cemented together as a single unit using UV-curable silicone-based optical adhesive. The triangular prism 21 measures 30mm × 24mm × 1mm, and the rectangular lens 23... Mirror 22 measures 31mm × 26mm × 11.4mm. The conical lens 23 has an entrance aperture of 31mm × 26mm and an exit aperture of 25mm × 20mm. The length of the conical lens 23 is 28.6mm. The length and width of the triangular prism 21 are smaller than those of the rectangular lens 22, facilitating the assembly of the rectangular lens 22. Anti-reflection coatings are applied to the two entrance surfaces of the triangular prism 21 near the laser emission module and to the exit surface of the conical lens 23 away from the rectangular lens 22. These anti-reflection coatings are stacked SiO2 / Ta2O5 layers. To ensure the complete realization of the beam shaping module's design functions, an optical installation coordinate system must be established, using the physical center of the laser's exit aperture or the light-emitting chip as a reference. The positioning and fixing of the cemented lens 2 must ensure that its optical center (defined by the curvature centers of each sub-lens and the prism's inclined surface) is aligned with the origin of this reference coordinate system, thus forming the primary assembly reference for the entire optical path.

[0028] Deionized water flows through the macro channel cooling water channel 3.

[0029] In use, first connect the inlet and outlet of the macro channel cooling water channel 3 to the corresponding pipes of the water chiller. Set the water chiller temperature to 20°C to dissipate heat for the laser emission module. After completing the water flow operation, power the laser emission module to emit light. The beam is refracted by the triangular prism 21, then pre-shaped by the rectangular lens 22, and finally homogenized by the conical lens 23 in the fast axis and slow axis directions. A rectangular spot of 24mm×20mm is output at a distance of 45mm from the light-emitting surface of the array pump source, and the energy distribution uniformity of the spot is 90% at this distance (the formula for calculating the uniformity of the spot is: [1 - (Imax - Imin) / (Imax + Imin)]×100%, where Imax represents the maximum light intensity value and Imin represents the minimum light intensity value).

[0030] Comparative Example 1 As described in Example 1, the difference is: The cemented lens 2 is replaced with a conical lens. The light inlet size of the conical lens is 31mm×26mm, the light outlet size is 25mm×20mm, and the length of the conical lens is 40mm.

[0031] The other steps and conditions are the same as in Example 1.

[0032] Test case The beam pattern of the area pump source in Example 1 and Comparative Example 1 was tested, and the test results are as follows: Figure 4 , Figure 5 As shown.

[0033] Depend on Figure 4 It was found that the spot size was compressed simultaneously along the fast and slow axes, ultimately forming a rectangular spot of 24mm × 20mm, with an energy distribution uniformity of 90% and a peak output power of 2400W; Figure 5 It was found that the light spot in the slow axis direction has a large spectral depression and uneven energy distribution; this indicates that the energy of the output light spot of the area array pump source of the present invention is more uniform, and the cemented lens 2 has a better light spot shaping effect, thereby achieving higher light spot uniformity and light spot modulation.

Claims

1. A highly uniform planar array pump source based on a novel cemented lens, characterized in that, include: The laser emitting module is used to emit pump light; A cemented lens, located on one side of the laser emitting module, is used to shape the spot of the output light from the laser emitting module in both the fast and slow axes. The macro-channel cooling water channel, located below the laser emitting module, is used to dissipate heat from the laser emitting module; The cemented lens includes a triangular prism, a rectangular lens, and a conical lens. The triangular prism is disposed on one side of the laser emitting module. A rectangular lens is cemented to the side of the triangular prism away from the laser emitting module, and a conical lens is cemented to the side of the rectangular lens away from the triangular prism.

2. The high-uniformity array pump source based on a novel cemented lens according to claim 1, characterized in that, The laser emitting module includes two bar arrays, which are arranged in parallel along the slow axis, and each bar array contains multiple laser bars arranged along the fast axis.

3. The high-uniformity array pump source based on a novel cemented lens according to claim 1, characterized in that, The triangular prism, rectangular lens, and conical lens are all made of fused silica.

4. The high-uniformity array pump source based on a novel cemented lens according to claim 1, characterized in that, Optical adhesives are used for the bonding process.

5. The high-uniformity array pump source based on a novel cemented lens according to claim 4, characterized in that, The optical adhesive is a UV-curable silicone-based optical adhesive or a high-temperature epoxy resin.

6. The high-uniformity array pump source based on a novel cemented lens according to claim 1, characterized in that, The two light-incident surfaces of the triangular prism near the laser emitting module and the light-out surface of the conical lens away from the rectangular lens are all provided with anti-reflection coatings, which are multilayer stacked oxide structures.

7. The high-uniformity array pump source based on a novel cemented lens according to claim 6, characterized in that, The antireflective film has a stacked structure of SiO2 layers / Ta2O5 layers.

8. The high-uniformity array pump source based on a novel cemented lens according to claim 1, characterized in that, Coolant flows through the macrochannel cooling water channel.

9. The high-uniformity array pump source based on a novel cemented lens according to claim 8, characterized in that, The coolant is deionized water.

10. A method for using a high-uniformity area array pump source based on a novel cemented lens, comprising the high-uniformity area array pump source based on a novel cemented lens as described in claim 1, characterized in that... Including the following steps: After the macro channel cooling water is circulated, the laser emitting module is powered to emit light. The beam is refracted by a triangular prism, then pre-shaped by a rectangular lens, and finally homogenized by a conical lens in the fast and slow axis directions to output a rectangular light spot.

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