High-power green laser synthesis system based on rotary frequency doubling crystal and multiple beams of infrared pulse laser

Abstract

The invention relates to a high-power green laser synthesis system based on a rotary frequency doubling crystal and multiple beams of infrared pulse laser, and belongs to the technical field of laser. The system comprises a multi-beam pulse infrared laser device, a frequency doubling crystal module, an annular rotating mechanism, a beam combining device, a continuous infrared laser device, a laser frequency regulation and control device and a rotating driving control system. The four beams of pulse infrared laser sources are symmetrically arranged along the circumferential edge, and periodically staggered output is realized through frequency regulation and control; the multiple frequency doubling crystals are distributed along the rotating circular ring at equal intervals and are sequentially aligned with laser pulses under driving of the rotating mechanism, and efficient frequency doubling is achieved. The center continuous infrared laser generates stable green light through frequency doubling of the fixed crystal. Finally, the green light generated by the multiple frequency doubling crystals and the central green light are integrated into a single light beam through a beam combining device to be output. According to the system, the power upper limit and the stability of green laser are remarkably improved through energy sharing of polycrystals, rotary dynamic matching and annular cooling, and the problems that existing green laser is limited in power and serious in heat effect are solved.

Description

Technical Field

[0001] This invention relates to the field of laser technology, specifically to a high-power green laser synthesis system based on a rotating frequency-doubling crystal and multiple infrared pulsed lasers. It falls under the technical category of nonlinear optical frequency conversion and high-power laser output, and is particularly applicable to scenarios requiring high-power green lasers, such as industrial processing, precision measurement, medical treatment, and scientific research. Background Technology

[0002] Green lasers, as a type of laser with a short wavelength and high energy density in the visible light band, are widely used in precision machining, laser displays, medical treatment, optical measurement, and scientific research. In practical applications, obtaining high-power, stable green laser output is of great significance.

[0003] Currently, the main approach to achieving green laser light is to output fundamental frequency light (e.g., 1064nm) from an infrared laser, and then use a nonlinear optical crystal (e.g., KTP, LBO, BBO, etc.) for second harmonic doubling to generate green light with a wavelength of 532nm. However, existing technologies generally suffer from the following shortcomings:

[0004] 1. Power limitation: When the power of a single infrared laser source is increased to several hundred watts or more, it is difficult to further increase the output green light power due to the thermal effect of the laser gain medium, the stability of the resonant cavity, and the damage threshold of the frequency doubling crystal, making it difficult to break through the kilowatt level.

[0005] 2. Significant Crystal Thermal Effects: Energy loss occurs during the frequency doubling process, and the crystal inevitably absorbs some laser energy, resulting in thermal effects. When the incident power is too high, it can easily lead to localized overheating of the crystal, causing phase mismatch, decreased frequency doubling efficiency, or even crystal damage.

[0006] 3. Poor stability: Existing high-power green laser systems usually rely on a single or limited number of infrared laser inputs. The output stability is easily affected by laser fluctuations, phase jitter, or crystal thermal effects, making it difficult to guarantee stable operation over a long period of time.

[0007] 4. Insufficient cooling and energy sharing: Traditional frequency doubling structures usually use fixed crystals and rely on static cooling for heat dissipation. This cannot effectively share the incident energy of multiple high-energy laser beams, resulting in excessive local crystal load, which limits the overall output capability.

[0008] In summary, existing green laser systems still have significant shortcomings in terms of high power output and long-term stable operation. There is an urgent need for a new structure and method to achieve efficient frequency doubling conversion of multiple infrared laser beams, while dispersing the energy burden of the crystal and coordinating with an efficient cooling method, so as to ultimately obtain high-power, long-term stable green laser output. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of existing high-power green laser systems, such as difficulty in achieving high power output, susceptibility to thermal damage to frequency doubling crystals, poor output stability, and insufficient cooling. This invention proposes a high-power green laser synthesis system based on a rotating frequency doubling crystal and multiple infrared pulsed laser beams. This system achieves: joint frequency doubling of multiple infrared pulsed laser beams and continuous infrared laser beams; dynamic energy sharing through a rotating crystal module to avoid overloading of a single crystal; and high-power, high-stability green laser output through optical beam combining.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A high-power green laser synthesis system based on a rotating frequency-doubling crystal and multiple infrared pulsed lasers is characterized in that the system mainly includes: a pulsed infrared laser device (100), a frequency-doubling crystal module (200), a ring-shaped rotating mechanism (300), a beam combining device (400), a continuous infrared laser device (500), a laser frequency control device (600), and a rotation drive control system (700).

[0012] 1. Pulsed Infrared Laser Device (100): Includes four infrared pulsed laser sources, evenly distributed along the circumference edge, in an axisymmetric structure, divided into group A and group B (A1, A2, A3 and B1, B2, B3 respectively). Each group contains two laser beams, arranged along the same horizontal plane, with the optical axis perpendicularly incident on the central region of the system, used to periodically generate short pulses of high-energy infrared laser input, thereby providing instantaneous peak power.

[0013] 2. Frequency doubling crystal module (200): Includes multiple nonlinear optical frequency doubling crystals (201), which are mounted at equal intervals on a ring structure to form a ring distribution. During operation, this module receives and converts infrared pulsed laser light, outputting green laser light with half the wavelength. Through the collaborative sharing of energy among multiple crystals, thermal damage caused by excessive energy in a single crystal is avoided, and the overall frequency doubling efficiency and service life are improved.

[0014] 3. Ring-shaped rotating mechanism (300): including a rotating bearing (301) and a support frame (302). The drive motor drives the ring structure and the frequency doubling crystal on it to rotate around the central axis at a constant angular velocity, so that the crystal enters the incident light path of each pulse of infrared laser in sequence during the rotation, thereby realizing the dynamic matching between the laser beam and the crystal and ensuring uniform energy distribution.

[0015] 4. Continuous Infrared Laser Device (500): Located at the geometric center of the system, it includes a continuous infrared laser and a central fixed frequency doubling crystal (202). This device is used to generate a stable continuous infrared laser and achieve continuous frequency doubling output through the central frequency doubling crystal to form a stable power green laser, thereby improving the overall average power and output stability of the system.

[0016] 5. Laser Frequency Control Device (600): Includes a pulse controller, phase adjuster, and synchronization logic module, used to precisely control the emission frequency and phase of infrared pulsed lasers in groups A and B. This device sets a fixed staggered peak relationship between the two laser groups on the time axis and synchronizes it with the rotational angular velocity of the ring crystal, allowing each frequency doubling crystal to sequentially receive energy from different pulse groups, avoiding concentrated heat load or nonlinear mismatch. Simultaneously, the feedback detection unit monitors the intensity of a portion of the emitted green light and performs closed-loop adjustment of the frequency and phase to ensure stable output.

[0017] 6. Beam combiner (400): Includes a mirror assembly, a spatial beam combiner, and an output collimating mirror assembly. The mirror assembly guides the green light from the ring crystal and the central crystal to a common optical path. The spatial beam combiner uses a polarization beam combining structure to achieve efficient superposition of multiple beams. The output collimating mirror assembly further performs wavefront correction and divergence angle control, thereby obtaining a single-direction green light output with high collimation and high beam quality. If necessary, an external beam shaping module can be connected to achieve beam homogenization, energy distribution adjustment, or focusing.

[0018] 7. Rotary drive control system (700): Connected to the ring-shaped rotating mechanism (300), it provides stable drive power and monitors the rotational speed. Feedback control ensures precise matching between the ring's rotational speed and the laser pulse frequency, guaranteeing synchronization between the crystal incident window and the pulsed laser, thus achieving a highly efficient and stable frequency doubling process.

[0019] Frequency-doubling crystals can be made of KTP, LBO, or BBO materials, exhibiting high nonlinear coefficients and high laser damage thresholds. The crystals can be fabricated into rectangular or cylindrical transparent structures, with dual-wavelength anti-reflective coatings deposited on both the incident and exit surfaces to reduce losses. During crystal mounting, the optical axis angle is precisely adjusted to maintain optimal phase matching with the incident infrared light, thereby maximizing frequency doubling efficiency.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention achieves an effective combination of pulsed peak power and continuous stable output by employing a synergistic design of multiple pulsed infrared lasers and a central continuous infrared laser, combined with a ring-shaped rotating frequency doubling crystal module and precise laser frequency control. This not only significantly improves the overall output power of the green laser but also avoids damage caused by single crystal overheating, extending the crystal's lifespan. Simultaneously, the system can improve frequency doubling efficiency and output stability through synchronous control of pulses and rotation, and achieve high-beam-quality green light output using spatial beam combining and collimation correction. Furthermore, the system features feedback control and polycrystalline material compatibility, ensuring robustness and adaptability for long-term operation, meeting the demands of high-power, long-life, and high-quality green laser applications. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a high-power green laser synthesis system based on a rotating frequency-doubling crystal and multiple infrared pulsed lasers provided by the present invention;

[0023] Figure 2 This is a schematic diagram of a frequency doubling crystal module for a high-power green laser synthesis system based on a rotating frequency doubling crystal and multiple infrared pulsed lasers, provided by the present invention.

[0024] Figure 3 This is a schematic diagram of a beam combining device for a high-power green laser combining system based on a rotating frequency doubling crystal and multiple infrared pulsed lasers, provided by the present invention.

[0025] Figure 4 This is a schematic diagram of a pulsed laser module of a high-power green laser synthesis system based on a rotating frequency doubling crystal and multiple infrared pulsed lasers provided by the present invention.

[0026] The numbers in the diagram are explained as follows: 100, pulsed infrared laser; 201, ring frequency doubling crystal; 202, center frequency doubling crystal; 301, rotary bearing; 302, support frame; 401, reflector; 407, spatial beam combiner; 408, output collimating lens group; 500, continuous infrared laser; 600, laser frequency control system; 700, rotary drive control system. Detailed Implementation

[0027] This invention relates to a high-power green laser synthesis system based on a rotating frequency-doubling crystal and multiple infrared pulsed laser beams. The invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] This invention provides a high-power green laser combining system based on a rotating frequency-doubling crystal and multiple infrared pulsed laser beams. The system mainly consists of a pulsed infrared laser device, a continuous infrared laser device, a ring-shaped frequency-doubling crystal module, a rotation drive mechanism, a laser frequency control system, and a beam combining device. Four pulsed infrared laser sources, divided into groups A and B, are symmetrically arranged along the circumference and incident perpendicularly onto the ring-shaped frequency-doubling crystal. A continuous infrared laser source and a fixed frequency-doubling crystal are positioned in the center to form a stable green light reference output. The frequency-doubling crystal module maintains a constant angular velocity rotation through a rotation drive control system, achieving dynamic matching between the multiple crystals and the pulsed laser beams.

[0029] During operation, the laser frequency control system adjusts the emission frequency and phase of the pulsed lasers in groups A and B, staggering their output periods and matching the crystal rotation angle. This ensures that the pulsed lasers are sequentially incident on different crystals, preventing energy concentration on a single crystal. The infrared pulsed laser undergoes second harmonic conversion in the rotating crystal, yielding a peak-value green laser output. Simultaneously, the central continuous infrared laser is converted into stable green light by a fixed frequency-doubled crystal, working in conjunction with the pulsed frequency-doubled green light to form a high-power composite output.

[0030] Multiple green laser beams output from crystals are guided and superimposed onto the same optical path by optical mirrors and spatial beam combiners. They then undergo wavefront correction and collimation by a collimating lens group to obtain high-quality green laser output. A feedback detection unit monitors the output power in real time and adjusts pulse parameters and rotation speed to ensure the system's stability and efficiency under long-term operating conditions. This implementation not only significantly improves the output power and beam quality of the green laser but also enhances the system's reliability and lifespan.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A high-power green laser synthesis system based on a rotating frequency-doubling crystal and multiple infrared pulsed laser beams, characterized in that, It mainly includes a pulsed infrared laser device (100), a frequency doubling crystal module (200), a ring-shaped rotating mechanism (300), a beam combining device (400), a continuous infrared laser device (500), a laser frequency control system (600), and a rotation drive control system (700). The pulsed infrared laser device (100) includes four infrared pulsed laser sources, which are evenly distributed along the circumference edge and have an axisymmetric structure. They are divided into group A and group B (A1, A2, A3 and B1, B2, B3, respectively). Each group contains two laser beams, which are arranged along the same horizontal plane. The output direction of each laser beam is kept perpendicular to the central region of the system. This is used to periodically generate short pulses and high-energy infrared laser outputs to provide laser input with high instantaneous peak power. The frequency doubling crystal module (200) includes multiple nonlinear optical frequency doubling crystals. The frequency doubling crystals (201) are installed on a ring structure at equal intervals to form a ring distribution. They are used to receive and convert the infrared pulse laser to output green laser with half the wavelength. By working together with multiple crystals, the excessive energy load of a single crystal is avoided, which would cause the crystal to overheat. This improves the overall frequency conversion efficiency and service life. The ring-shaped rotating mechanism (300) includes a rotating bearing (301) and a support frame (302). The drive motor drives the ring structure and the frequency doubling crystal on it to rotate around the central axis at a constant angular velocity, so that each crystal enters the incident position of each pulse infrared laser in sequence during the rotation, realizing the dynamic matching between the pulse laser beam and the crystal, and ensuring uniform energy distribution. The laser frequency control system (600) includes a pulse controller, a phase adjuster, and a synchronization logic module, which are used to precisely control the emission frequency and phase of the infrared pulse laser sources of group A and group B, so that the output cycles of the two groups of pulses form a fixed staggered relationship in time, thereby matching the crystal rotation angular velocity, ensuring that each frequency doubling crystal receives the energy of different pulse groups in sequence, and avoiding multiple laser beams acting on the same crystal at the same time, which would cause heat load concentration or nonlinear mismatch. The continuous infrared laser device (500) is located at the geometric center of the system and includes a continuous infrared laser and a central fixed frequency doubling crystal (202) for generating stable output infrared laser and continuously converting it into a stable power green laser beam as a supplementary output, effectively improving the overall average output power and stability of the system. The beam combining device (400) includes multiple mirrors (401, 402, 403, 404, 405, 406), a spatial beam combining mirror (407), and an output collimating mirror group (408), which correspond to the green light output optical paths of the ring-distributed frequency doubling crystal and the central frequency doubling crystal, respectively. It is used to guide green lasers output from different directions to a common optical path, and realize the combination of multiple beams into a high beam quality and good collimation green laser output through spatial integration, thereby improving the final effective output power density of the system. The rotary drive control system (700) is connected to the ring-shaped rotary mechanism (300) to provide stable rotary drive power and monitor the rotation speed. Through feedback control, it ensures that the rotation speed of the ring structure is precisely matched with the laser pulse frequency, thereby achieving synchronous alignment between the crystal incident window and the laser pulse and ensuring stable frequency doubling efficiency.

2. The high-power green laser synthesis system according to claim 1, wherein the frequency doubling crystal is a KTP, LBO, or BBO crystal, and the crystal material has a high nonlinear coefficient and a high laser damage threshold; the frequency doubling crystal is prepared as a rectangular or cylindrical transparent structure, and a dual-wavelength antireflection coating is formed on the incident and exit surfaces through an antireflection coating process to reduce the energy loss of infrared and green light on the crystal surface; the installation angle of the frequency doubling crystal is precisely adjusted so that its optical axis maintains optimal phase matching with the incident infrared laser, thereby improving the frequency doubling efficiency.

3. The high-power green laser synthesis system according to claim 1, wherein the laser frequency control system comprises: (a) A pulse control unit, used to control the emission timing of infrared pulse lasers in groups A and B; (b) Phase adjuster: finely adjusts the phase of the laser pulse using a high-speed electronic modulator or optical delay line to ensure precise synchronization between the pulse and the incident window of the rotating frequency doubling crystal; (c) Synchronization logic module: receives the angle signal output by the rotation drive control system in real time, and automatically adjusts the emission frequency of the two sets of lasers according to the rotational angular velocity of the ring to maintain a fixed staggered peak relationship on the time axis; (d) Feedback detection unit: monitors the intensity and stability of part of the emitted green light through a photodetector and feeds the signal back to the pulse control unit to achieve closed-loop control of the laser frequency and phase.

4. The high-power green laser combining system according to claim 1, wherein the beam combining and output device comprises: (a) Multiple sets of first reflectors are respectively set in the optical path of the green light output direction of each frequency doubling crystal to guide green laser light from different directions to a common beam combining region; (b) Spatial beam combiner, which adopts a polarization beam combiner structure to efficiently superimpose green laser light from multiple directions onto the same optical axis; (c) Output collimating lens group, including a combination of convex lenses, concave lenses or cylindrical lenses, is used to perform wavefront correction and divergence angle control on the combined green light to make the output beam have high collimation and high beam quality; (d) External beam shaping module, which can further realize beam spot homogenization, energy distribution adjustment or focusing functions as needed to adapt to different industrial processing or scientific research application scenarios.

5. The high-power green laser synthesis system based on a rotating frequency-doubling crystal and multiple infrared pulsed lasers according to claim 1, its usage method includes the following steps: Step 1: Start the rotary drive control system (700) to make the ring-shaped rotary mechanism (300) drive the frequency doubling crystal module (200) to operate stably at a constant angular velocity; adjust the optical axis direction of each pulse infrared laser device (100) to ensure that the four laser beams are all perpendicularly pointed to the central area of ​​the system and precisely aligned with the incident window of the frequency doubling crystal; calibrate the optical path of the central continuous infrared laser device (500) to ensure that the laser beam is incident positively on the central frequency doubling crystal. Step 2: Set the emission frequency of infrared pulse lasers of group A and group B through the laser frequency control device (600); start the pulse controller to ensure that the output cycles of the two groups of lasers are staggered so that the pulses of group A and group B do not overlap on the time axis. The phase adjuster is activated, and the phase of the laser pulse is finely adjusted according to the angle signal fed back by the rotation drive control system, so that each pulse can be accurately incident when the crystal rotates to the specified position. The feedback detection unit is activated to monitor the intensity of the emitted green light in real time. If output fluctuations are detected, the pulse phase and frequency are automatically adjusted to maintain system synchronization and stability. Step 3: When infrared pulse lasers from groups A and B are sequentially incident on the frequency doubling crystal module (200), the crystal will perform second harmonic conversion on the input infrared light and output a high-peak green laser with half the wavelength. As the ring continues to rotate, each crystal will receive the energy of different pulse lasers in sequence, achieving dynamic energy sharing and avoiding damage to a single crystal due to excessive energy. At the same time, the central continuous infrared laser device (500) will stably output an infrared beam, which will be continuously frequency-doubled by the fixed frequency doubling crystal to form a stable green light reference output. Step 4: The green laser output from multiple frequency-doubling crystals is first reflected by the first set of mirrors and guided to the common beam combining region; the spatial beam combining mirror superimposes the green beams from multiple directions onto the same optical axis; the output collimating mirror group performs wavefront correction and collimation on the combined beam to form a high-quality green light output in a single direction; the continuous green light generated by the central crystal and the green light generated by pulse frequency doubling simultaneously enter the beam combining optical path to achieve a combination of high power and high stability output. Step 5: Adjust the laser power output according to application requirements. This can be done by adjusting the pulse frequency, laser energy, or beam combining optical elements. During operation, the feedback control system automatically maintains stability, ensuring that the green laser output does not experience intensity fluctuations or beam distortion under long-term operation. When it is necessary to stop working, first turn off the pulsed infrared laser and the continuous infrared laser, and then turn off the rotating mechanism to ensure that the crystal cools down under no-light conditions and avoids thermal shock damage.

Images