Self-triggered dual-pulse synchronized laser

Abstract

Embodiments of the present disclosure disclose a self-triggered dual-pulse synchronous laser. A specific embodiment of the self-triggered dual-pulse synchronous laser comprises a first laser assembly, a second laser assembly, a first pump source, a second pump source, a synchronous control assembly, a first mirror, an optical isolator and a partial mirror, the synchronous control assembly is electrically connected to the first pump source and the second pump source respectively; the light emitting end surface of the first laser assembly faces the first mirror, and the first mirror further faces the optical isolator; the light emitting end surface of the optical isolator faces the partial mirror, and the partial mirror further faces the second laser assembly; the output power of the first pump source is greater than the first light emitting threshold, and the output power of the second pump source is less than the second light emitting threshold. The pulse generated by the first laser assembly triggers the second laser assembly, reducing the dependence of the two pulses on the output energy stability of the two pump sources. The embodiment can improve the output stability of the dual-pulse laser.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the field of laser technology, and more specifically to a self-triggered dual-pulse synchronous laser. Background Technology

[0002] With the development of laser technology, single-pulse lasers can no longer meet the increasingly complex application requirements, leading to the emergence of dual-pulse laser technology. In dual-pulse laser applications, two laser pulses with different pulse widths, energies, or wavelengths are typically required to act on the target sequentially at precise time intervals. Industry data shows that the domestic semiconductor laser dicing equipment market size exceeded 5.63 billion yuan in 2025 and is projected to grow to 10.73 billion yuan by 2030, with a compound annual growth rate of 14.2%; among which, the demand for processing brittle wide-bandgap wafers such as silicon carbide and gallium nitride is growing at a rate exceeding 25%. In mass production lines, dual-pulse lasers, with their controllable layered ablation advantages, have become the preferred light source for low-damage wafer dicing. Stable and consistent dual-pulse output directly determines the yield of single-wafer chips and the production cost for enterprises.

[0003] However, when using the commonly used dual-pulse laser, the following technical problems often arise: Currently used dual-pulse lasers rely on the spontaneous bleaching process of saturable absorbers. The timing of pulse generation is random, leading to instability in the relative delay between the two laser pulses and large fluctuations in the relative delay. Furthermore, the optical path of commonly used dual-pulse lasers is prone to temperature drift and polarization shift, causing trigger energy fluctuations and polarization mismatch, further resulting in poor output stability.

[0004] The information disclosed in this background section is only intended to enhance the understanding of the background of the present disclosure concept, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The summary portion of this disclosure is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description portion. This summary portion is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0006] Some embodiments of this disclosure propose a self-triggered dual-pulse synchronous laser to address one or more of the technical problems mentioned in the background section above.

[0007] Some embodiments of this disclosure provide a self-triggered dual-pulse synchronous laser, which includes a first laser component, a second laser component, a first pump source, a second pump source, a synchronization control component, a first reflector, an optical isolator, and a partial reflector. One output terminal of the synchronization control component is electrically connected to the first pump source, and the other output terminal of the synchronization control component is electrically connected to the second pump source. The pump light output terminal of the first pump source is aligned with the pump end face of the first laser component, and the pump light output terminal of the second pump source is aligned with the pump end face of the second laser component. The light-emitting end of the first laser component... The first reflector faces the first reflector, which also faces the incident surface of the optical isolator; the exit surface of the optical isolator faces the incident surface of the partial reflector, and the incident surface of the partial reflector also faces the emitting surface of the second laser component; the continuous output power of the first pump source is greater than a first emission threshold, and the continuous output power of the second pump source is less than a second emission threshold, wherein the first emission threshold is the emission threshold of the first laser component, and the second emission threshold is the emission threshold of the second laser component; the polarization state of the laser emitted by the first laser component and the polarization state of the laser emitted by the second laser component are orthogonal to each other.

[0008] Optionally, the continuous output power of the second pump source is 90% to 99% of the second light emission threshold.

[0009] Optionally, the reflecting surface of the first reflector forms a 45-degree angle with the output optical axis of the first laser component; the incident surface of the partial reflector forms a 45-degree angle with the output optical axis of the optical isolator, and the incident surface of the partial reflector forms a 45-degree angle with the output optical axis of the second laser component.

[0010] Optionally, both the first laser component and the second laser component are bonded crystals; both the first laser component and the second laser component include a gain medium and a saturable absorber bonded sequentially.

[0011] Optionally, the above-mentioned gain medium is a neodymium-doped yttrium aluminum garnet crystal, and the above-mentioned saturable absorber is a chromium-doped yttrium aluminum garnet crystal.

[0012] Optionally, in the first laser component and the second laser component, a first dielectric film is deposited on both gain media, and a second dielectric film is deposited on both saturable absorbers; the first dielectric film transmits 808 nm wavelength laser light and reflects 1064 nm wavelength laser light; the second dielectric film reflects 808 nm wavelength laser light and partially transmits 1064 nm wavelength laser light, with a transmittance of 10% to 50%.

[0013] Optionally, the first reflector is a planar reflector with a substrate material of fused silica and a reflective film for 1064 nm wavelength lasers coated on its reflective surface; the optical isolator includes an incident polarizer, a Faraday rotator, and an exit polarizer arranged sequentially; the partial reflector is a planar partial reflector with a substrate material of fused silica and antireflective coatings on both optical surfaces; a beam-splitting layer is disposed inside the partial reflector, the beam-splitting layer including alternating layers of silicon dioxide and tantalum pentoxide; the pump end face and the light-emitting end face of the first laser component and the second laser component are both planar; the self-triggered dual-pulse synchronous laser also includes a reflector group and a beam combiner; the reflector group is located on the light-emitting path of the second laser component, and the reflector group is mounted on a translation stage, the translation direction of the translation stage being parallel to the incident light direction of the reflector group or the laser propagation direction inside the reflector group; the beam combiner is located simultaneously on the light-emitting path of the reflector group and the light-emitting path of the first laser component.

[0014] Some embodiments of this disclosure provide a self-triggered dual-pulse synchronous laser, which can improve the output stability of dual-pulse lasers. Specifically, the reason for the poor output stability of most dual-pulse lasers is that currently commonly used dual-pulse lasers employ a structure of two independent passively Q-switched lasers synchronously triggered by the same electrical signal source, and each is directly triggered by its own pump source to generate pulses. However, the pulse generation of passively Q-switched lasers depends on the spontaneous bleaching process of the saturable absorber, which is greatly affected by the output energy fluctuations of the two pump sources. Based on this, some embodiments of this disclosure provide a self-triggered dual-pulse synchronous laser, which includes a first laser component, a second laser component, a first pump source, a second pump source, a synchronization control component, a first mirror, an optical isolator, and a partial mirror. One output terminal of the synchronization control component is electrically connected to the first pump source, and the other output terminal of the synchronization control component is electrically connected to the second pump source. The pump light output terminal of the first pump source is aligned with the pump end face of the first laser component, and the pump light output terminal of the second pump source is aligned with the pump end face of the second laser component. The pump end face of the laser component; the light-emitting end face of the first laser component faces the first reflector, and the first reflector also faces the incident end face of the optical isolator; the light-emitting end face of the optical isolator faces the incident surface of the partial reflector, and the incident surface of the partial reflector also faces the light-emitting end face of the second laser component; the continuous output power of the first pump source is greater than a first light-emitting threshold, and the continuous output power of the second pump source is less than a second light-emitting threshold, wherein the first light-emitting threshold is the light-emitting threshold of the first laser component, and the second light-emitting threshold is the light-emitting threshold of the second laser component. By setting the first laser component to spontaneously generate pulsed laser and setting the pump power of the second laser component to be less than its light-emitting threshold, making it in a critical energy storage state, and then using the partial pulsed laser energy output by the first laser component to trigger the second laser component to release pulsed laser through the partial reflector, the dependence of the two laser pulses on the output energy stability of the two pump sources is reduced. Therefore, the output stability of the dual-pulse laser can be improved. Attached Figure Description

[0015] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0016] Figure 1 This is a three-dimensional structural schematic diagram of a self-triggered dual-pulse synchronous laser according to some embodiments of the present disclosure; Figure 2This is a schematic diagram of the planar structure of a self-triggered dual-pulse synchronous laser according to some embodiments of this disclosure. Detailed Implementation

[0017] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0018] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0019] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0020] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0021] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

[0022] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a three-dimensional structural schematic diagram of a self-triggered dual-pulse synchronous laser according to some embodiments of the present disclosure. Figure 1 It includes a first reflector 1, a first laser assembly 2, a first pump source 3, a synchronization control assembly 4, a second pump source 5, a second laser assembly 6, a beam combiner 7, a reflector group 8, a partial reflector 9, and an optical isolator 10.

[0024] Figure 2 This is a schematic diagram of the planar structure of a self-triggered dual-pulse synchronous laser according to some embodiments of this disclosure. Figure 2 It includes a first reflector 1, a first laser assembly 2, a first pump source 3, a synchronization control assembly 4, a second pump source 5, a second laser assembly 6, a beam combiner 7, a reflector group 8, a partial reflector 9, and an optical isolator 10.

[0025] It needs to be explained that, Figure 1 and Figure 2 The lines with arrows shown represent the optical path of the internal pulses of the laser during operation.

[0026] In some embodiments, the self-triggered dual-pulse synchronous laser may include a first laser component 2, a second laser component 6, a first pump source 3, a second pump source 5, a synchronization control component 4, a first reflector 1, an optical isolator 10, and a partial reflector 9. Both the first pump source 3 and the second pump source 5 can be semiconductor lasers, without specific limitations. Both the first laser component 2 and the second laser component 6 can be bonded crystals. The bonded crystal can be an integral structure formed by bonding two different crystals together through a bonding process. One output terminal of the synchronization control component 4 can be electrically connected to the first pump source 3. The other output terminal of the synchronization control component 4 can be electrically connected to the second pump source 5. The synchronization control component 4 can be a pulse signal generator. The synchronization control component 4 can be used to simultaneously send trigger signals to the first pump source 3 and the second pump source 5, enabling the first pump source 3 and the second pump source 5 to start operating in the same timing sequence. The pump light output terminal of the first pump source 3 can be aligned with the pump end face of the first laser component 2. The aforementioned pump end face can refer to the end face of the first laser component 2 facing the first pump source 3. The first pump source 3 can be an 808 nm wavelength semiconductor laser. The first pump source 3 can generate pump light, which can be incident on the interior of the first laser component 2 to provide energy to the first laser component 2. The pump light output end of the second pump source 5 can be aligned with the pump end face of the second laser component 6. The second pump source 5 can be an 808 nm wavelength semiconductor laser. The second pump source 5 can generate pump light, which can be incident on the interior of the second laser component 6 to provide energy to the second laser component 6. The light-emitting end face of the first laser component 2 can face the first reflector 1. The first laser component 2 can generate pulsed laser under the pumping action of the first pump source 3, and the pulsed laser can be emitted from the light-emitting end face of the first laser component 2. The first reflector 1 can face the incident end face of the optical isolator 10. The first reflecting mirror 1 can be a plane reflecting mirror, and the substrate material of the first reflecting mirror 1 can be fused silica. The first reflecting mirror 1 can change the transmission direction of the pulsed laser emitted from the first laser assembly 2. The exit face of the optical isolator 10 can face the incident face of the partial reflecting mirror 9. For example, the optical isolator 10 can be a free-space optical isolator 10, which is not specifically limited here. The optical isolator 10 can allow the laser to propagate in the direction from the first reflecting mirror 1 to the partial reflecting mirror 9. The incident face of the partial reflecting mirror 9 can also face the exit face of the second laser assembly 6. The second laser assembly 6 can generate pulsed laser under the action of pumping and external trigger light, and the pulsed laser can be emitted from the exit face of the second laser assembly 6. The continuous output power of the first pump source 3 can be greater than the first emission threshold.The aforementioned first emission threshold can be the emission threshold of the first laser component 2. When the output power of the first pump source 3 is greater than the first emission threshold, the first laser component 2 can spontaneously generate pulsed laser. The continuous output power of the second pump source 5 can be less than the second emission threshold. The aforementioned second emission threshold can be the emission threshold of the second laser component 6. When the output power of the second pump source 5 is less than the second emission threshold, the second laser component 6 can be in an energy storage state and cannot spontaneously generate pulsed laser. The polarization state of the laser emitted by the first laser component 2 and the polarization state of the laser emitted by the second laser component 6 can be orthogonal to each other. Setting the output lasers of the two sets of laser components to orthogonal polarization can not only block the crosstalk of the reverse beams between the two resonant cavities, reduce pulse timing and energy jitter, but also reduce the risk of interference fringes after the double pulse beam is combined.

[0027] Optionally, the continuous output power of the second pump source 5 can be 90% to 99% of the second light-emitting threshold. This range of 90% to 99% allows the second laser component 6 to accumulate near-saturated energy, enabling it to quickly generate pulsed laser light upon receiving external trigger light. If the continuous output power of the second pump source 5 is below 90%, the energy storage of the second laser component 6 is insufficient, requiring more trigger light energy to generate pulsed laser light. If the power is above 99%, the second laser component 6 can spontaneously generate pulsed laser light, losing the synchronization effect of external triggering.

[0028] Optionally, such as Figure 2 As shown, the reflecting surface of the first reflector 1 can form a 45-degree angle with the output optical axis of the first laser component 2. The first reflector 1 can change the vertically propagating pulsed laser emitted from the first laser component 2 to a horizontally propagating pulsed laser. The incident surface of the partial reflector 9 can form a 45-degree angle with the output optical axis of the optical isolator 10, and the incident surface of the partial reflector 9 can also form a 45-degree angle with the output optical axis of the second laser component 6. The partial reflector 9 can change a portion of the horizontally propagating pulsed laser emitted from the first laser component 2 to a vertically propagating pulsed laser, which then enters the interior of the second laser component 6.

[0029] Optionally, such as Figure 1 and Figure 2 As shown, both the first laser component 2 and the second laser component 6 can be bonded crystals. The bonded crystal can be an integral structure formed by bonding two different crystals together using a bonding process. Both the first laser component 2 and the second laser component 6 can include a gain medium and a saturable absorber bonded sequentially. The gain medium can be used to absorb the energy of the pump light and generate laser light. The saturable absorber can be used to achieve Q-switching, generating ultrashort pulse laser light.

[0030] Optionally, the gain medium can be a neodymium-doped yttrium aluminum garnet crystal. This neodymium-doped yttrium aluminum garnet crystal can absorb pump light at a wavelength of 808 nm and generate laser light at a wavelength of 1064 nm. The saturable absorber can be a chromium-doped yttrium aluminum garnet crystal. This chromium-doped yttrium aluminum garnet crystal exhibits saturable absorption characteristics for laser light at a wavelength of 1064 nm.

[0031] Optionally, in the first laser component 2 and the second laser component 6, a first dielectric film can be deposited on both gain media, and a second dielectric film can be deposited on both saturable absorbers. The first dielectric film can be a multilayer dielectric film, composed of alternating layers of silicon dioxide and tantalum pentoxide. The first dielectric film can transmit 808 nm wavelength laser light and reflect 1064 nm wavelength laser light. The first dielectric film allows pump light to enter the interior of the gain media while reflecting the 1064 nm wavelength laser light generated by the gain media back into the bonded crystal. The second dielectric film can also be a multilayer dielectric film, composed of alternating layers of silicon dioxide and tantalum pentoxide. The second dielectric film can reflect 808 nm wavelength laser light and partially transmit 1064 nm wavelength laser light, with a transmittance of 10% to 50%. This transmittance range of 10% to 50% allows the bonded crystal to form suitable resonant cavity losses, resulting in stable Q-switched pulse output. If the transmittance is below 10%, the resonant cavity loss will be too low, resulting in excessively high peak pulse power and potential damage to the crystal. If the transmittance is above 50%, the resonant cavity loss will be too high, increasing the laser's output threshold and reducing output efficiency. The second dielectric film can reflect pump light not absorbed by the gain medium back into the gain medium, while simultaneously allowing some 1064 nm wavelength laser light to exit from the interior of the bonded crystal.

[0032] Optionally, the first reflecting mirror 1 can be a planar reflecting mirror, the substrate material can be fused silica, and the reflecting surface can be coated with a reflective film for 1064nm wavelength laser. The fused silica substrate has high optical transmittance and good thermal stability. The reflective film can be a multilayer dielectric film, which can be composed of alternating layers of silicon dioxide and tantalum pentoxide. The reflective film can improve the reflectivity of the first reflecting mirror 1 for 1064nm wavelength laser. The optical isolator 10 can include an incident polarizer, a Faraday rotator, and an exit polarizer arranged sequentially. Both the incident polarizer and the exit polarizer can be Glan prisms, without specific limitations. Both the incident polarizer and the exit polarizer can allow laser with a specific polarization direction to pass through. The Faraday rotator can rotate the polarization direction of the passing laser. The optical isolator 10 can be used to block the back propagation of laser. The partial reflecting mirror 9 can be a planar partial reflecting mirror 9, the substrate material can be fused silica, and both optical surfaces can be coated with an anti-reflection film. The aforementioned antireflection coating can be a multilayer dielectric film. This antireflection coating can reduce the reflection loss of the optical surface of the partially reflecting mirror 9 to 1064nm wavelength laser light. A beam-splitting film layer can be disposed inside the partially reflecting mirror 9, which may include alternately deposited silicon dioxide and tantalum pentoxide layers. The total number of beam-splitting film layers can be 15 to 25 layers, without specific limitation. If the number of layers is less than 15, the spectral bandwidth of the beam-splitting film layer is narrow, and the beam-splitting characteristics for lasers of different wavelengths and incident angles vary significantly. If the number of layers is more than 25, the fabrication difficulty and cost of the beam-splitting film layer increase. Since the silicon dioxide and tantalum pentoxide layers have different refractive indices, different transmittance and reflectance can be obtained by adjusting the thickness and number of layers. The pump end face and light-emitting end face of both the first laser component 2 and the second laser component 6 can be planar. Planar end faces facilitate the coating and installation of the first laser component 2 and the second laser component 6. The aforementioned self-triggered dual-pulse synchrotron laser may further include a mirror assembly 8 and a beam combiner 7. The mirror assembly 8 may include two mirrors, and these mirrors may have the same structure and material as the first mirror 1. (See reference...) Figure 1Two reflectors can be arranged with their reflective surfaces facing each other, allowing the pulsed laser beam output from the second laser component 6 to reach the beam combiner 7. The reflector group 8 can be located in the output optical path of the second laser component 6. The reflector group 8 can change the transmission direction of the pulsed laser emitted from the second laser component 6. The reflector group can be mounted on a translation stage. The translation direction of the translation stage is parallel to the incident light direction of the reflector group or the laser propagation direction inside the reflector group. The translation stage can be used to adjust the delay interval of the pulsed lasers emitted by the two laser components. The translation stage can be an electrically driven stage, and no specific limitation is made here. The beam combiner 7 can be located simultaneously in the output optical path of the reflector group 8 and the output optical path of the first laser component 2. The beam combiner 7 can combine the pulsed lasers emitted from the first laser component 2 and the second laser component 6 into a single beam, which is then transmitted along the same optical axis.

[0033] In addressing the technical problems mentioned above using technical solutions, and considering the application scenario—high-precision dual-pulse laser micro / nano processing, such as precision dicing of brittle wafers—the following technical issues often arise: fluctuations in injection trigger energy and polarization mismatch lead to degradation of dual-pulse output consistency, making it difficult to meet the yield requirements of precision processing. Considering the following requirements for this application scenario: adaptability to low-damage precision dicing of brittle wafers, stability of micron-level linewidth uniform etching processes, and matching requirements for dual-pulse synergistic ablation process parameters, we have decided to adopt the following solution: A polarization locking component and an energy calibration beam splitter component can be sequentially arranged on the optical path between the optical isolator 10 and the partial reflector 9. The polarization locking component may include a half-wave plate and a polarization beam splitter arranged coaxially along the optical path. The half-wave plate can be configured to rotate around the optical axis. The transmission polarization direction of the polarization beam splitter can be parallel to the intrinsic polarization direction of the resonant cavity of the second laser component 6. The half-wave plate can be an optical element that changes the polarization state of light, adjusting the polarization direction of the incident light to match the polarization direction of subsequent components. For example, the half-wave plate can be a quartz half-wave plate, without specific limitation. The polarization beam splitter can be a prism that separates light rays with different polarization states, transmitting light rays with a specific polarization direction and reflecting light rays with orthogonal polarization directions to maintain the consistency of the polarization direction of the injected trigger light. For example, the polarization beam splitter can be a Wollaston prism, without specific limitation. The aforementioned polarization locking component, through the cooperation of a half-wave plate and a polarization beam splitter, can calibrate the polarization direction of the trigger light emitted by the first laser component 2, matching it with the intrinsic polarization direction of the resonant cavity of the second laser component 6. This reduces effective trigger energy fluctuations caused by polarization mismatch and improves the stability of the triggering process. The aforementioned synchronization control component 4 can be communicatively connected to the aforementioned energy calibration beam splitter component. The aforementioned energy calibration beam splitter component can include a flat beam splitter with a beam splitting ratio of 1:99 and a photodetector. The flat beam splitter can be arranged at a 45-degree angle along the incident light path, and the reflected light path of the flat beam splitter can be directly facing the photosensitive surface of the photodetector. Here, 1:99 means that 1% of the incident light energy is reflected to the photodetector for sampling, and 99% is transmitted for further transmission. The reflected light energy from the 1% weak light sampling is low, making it less likely to cause saturation or damage to the photodetector; 99% of the trigger light is delivered to the second laser component to ensure sufficient trigger energy and avoid trigger instability due to beam splitting loss. The planar beam splitter is arranged at a 45° angle, allowing the reflected light path to be perpendicular to the incident light path. This results in a neat optical path arrangement and convenient assembly. Furthermore, 45° beam splitters are standard optical components on the market, with stable beam splitting ratios due to their coatings. Using other angles, such as 40°, could lead to beam deflection angles causing beam splitting ratio shifts and inaccurate sampling calculations. Additionally, non-standard lenses are more expensive. The aforementioned planar beam splitter can be a planar optical lens with a beam splitting coating. Its function is to proportionally split the incident beam into a transmitted beam and a reflected beam. The transmitted beam can continue along the original optical path, while the reflected beam can be used for energy sampling. For example, the planar beam splitter can be a beam splitter flat plate with a K9 glass substrate; no specific limitation is made here. The aforementioned photodetector can be a device that converts optical signals into electrical signals. Its function is to collect the light energy signal from the reflected light path and transmit the signal to the aforementioned synchronization control component 4. For example, the aforementioned photodetector can be a PIN photodiode; no specific limitation is made here.

[0034] The aforementioned synchronization control component can be configured to perform the following steps: The first step is to obtain the actual energy value of the injected trigger light through a photodetector. The injected trigger light can refer to the laser beam output from the first laser component, transmitted along the main optical path to the second laser component, and used to trigger it to generate a pulse. The actual energy value can refer to the quantized energy value corresponding to a single pulse of injected trigger light. In practice, the synchronization control component can read the voltage signal of the photodetector, convert it to digital to obtain the pulse energy value incident on the photodetector, and then divide it by the beam splitting ratio of the planar beam splitter to obtain the actual energy value of the injected trigger light. For example, when the beam splitting ratio of the planar beam splitter is 1:99, it means that the planar beam splitter can direct 1% of the energy of the incident injected trigger light along the reflected optical path to the photodetector, and the remaining 99% of the energy can continue to be transmitted to the second laser component along the transmitted optical path. If the reflected light pulse energy obtained by the photodetector after analog-to-digital conversion is 0.1 microjoules, the synchronization control component can divide this reflected light energy value by the 1% beam splitting ratio to calculate the actual energy value of the injected trigger light as 10 microjoules. It should be noted that the split ratio used as the divisor can be preset by the user.

[0035] The second step is to determine the energy deviation based on the actual energy value and a reference energy threshold. The reference energy threshold can refer to a pre-stored reference energy value, which corresponds to a preset triggering state of the second laser component. The energy deviation can be the calculated result of subtracting the actual energy value from the reference energy threshold. In practice, the synchronization control component can call upon the internally stored reference energy threshold and calculate the difference between it and the currently sampled and converted actual energy value to determine the energy deviation. When the actual energy value is higher than the reference energy threshold, the energy deviation can be positive; when the actual energy value is lower than the reference energy threshold, the energy deviation can be negative.

[0036] The third step involves adjusting the output power of the second pump source drive circuit based on the energy deviation. The second pump source drive circuit refers to the circuit unit that provides operating current to the second pump source. The magnitude of its output current can vary according to the input control signal, thereby changing the output optical power of the second pump source. In practice, the synchronization control component can generate a corresponding power adjustment signal based on the absolute value and sign of the energy deviation and send it to the second pump source drive circuit. When the energy deviation is positive, the output power of the drive circuit can be reduced accordingly; when the energy deviation is negative, the output power of the drive circuit can be increased accordingly. For example, for every 1 microjoule deviation, the output current of the second pump source drive circuit is adjusted by 0.2 milliamps. A positive energy deviation indicates that the actual energy of the injected trigger light is higher than the reference energy threshold. In this case, the synchronization control component can output a control signal to lower the current, thereby reducing the continuous output power of the second pump source. A negative energy deviation indicates that the actual energy of the injected trigger light is lower than the reference energy threshold. In this case, the synchronization control component can output a control signal to raise the current, thereby increasing the continuous output power of the second pump source.

[0037] The above-mentioned optional embodiments, as an inventive point of this disclosure, solve the technical problem of "deterioration in the consistency of dual-pulse output caused by injection trigger energy fluctuations and polarization mismatch". The specific factors leading to the deterioration of dual-pulse output consistency caused by injection trigger energy fluctuations and polarization mismatch are as follows: During long-term high-repetition-rate operation of brittle wafer dicing, the polarization state of the trigger light is prone to shift, and polarization mismatch significantly reduces the effective trigger energy; simultaneously, optical path loss causes continuous drift of the injected trigger light energy. When the second laser component operates within the threshold critical range, even small energy fluctuations directly change the energy ratio and pulse timing of the output dual pulses, ultimately resulting in uneven wafer dicing depth and inconsistent line width, reducing the yield of the finished product. Solving these factors can achieve the effect of stabilizing the dual-pulse output parameters and improving the uniformity of precision dicing of brittle wafers. To achieve this effect, this disclosure also provides a device for polarization calibration and energy closed-loop adjustment. On the one hand, the polarization locking component matches the intrinsic polarization of the trigger light and the second laser resonator in real time, weakening the trigger energy attenuation caused by polarization drift. On the other hand, by relying on the energy calibration beam splitter component and the synchronization control component to build a pulse-by-pulse energy closed-loop adjustment, the output power of the second pump source is dynamically corrected to offset the trigger light energy drift caused by the optical path and the environment. This achieves the effect of stabilizing the dual-pulse output parameters and improving the uniformity of precision dicing of brittle wafers.

[0038] In addressing the technical challenges of inconsistent dual-pulse output caused by injection trigger energy fluctuations and polarization mismatch, the following technical issues often arise in the application scenarios: high-repetition-rate continuous dual-pulse laser micro / nano fabrication, such as silicon carbide wafer dicing and glass substrate micro-groove fabrication lines. These issues are often accompanied by pulse energy drift caused by the superposition of optical cavity temperature changes and crystal heating. Considering the following requirements for this application scenario—namely, adaptability to constant temperature control during long-term high-repetition-rate continuous processing, adaptation to optical cavity environment temperature change compensation, adaptation to stable light emission under low crystal thermal stress, and adaptation to dual-pulse matching for low-damage, uniform wafer ablation—we have decided to adopt the following solution: Optionally, both the first laser component 2 and the second laser component 6 can be encapsulated in a thermoelectric cooling heat sink with a built-in temperature sensor. The thermoelectric cooling heat sink can be a mounting base that combines heat conduction and temperature control functions, serving to support the laser components and regulate their operating temperature. For example, the thermoelectric cooling heat sink can be a TEC-cooled copper heat sink, without specific limitations. The signal output terminal of the temperature sensor can be connected to the synchronous control component 4. For example, the temperature sensor can be a platinum resistance thermometer (PT100), without specific limitations. The thermoelectric cooling heat sink can use an oxygen-free copper substrate. Both the first laser component 2 and the second laser component 6 can be bonded and fixed to the positioning groove on the top of the thermoelectric cooling heat sink using thermally conductive insulating adhesive. The positioning groove can be an integrally formed recessed cavity on the top surface of the thermoelectric cooling heat sink, with the groove's outline dimensions matching the crystal shape of the first laser component 2 and the second laser component 6. The thermally conductive insulating adhesive can be an adhesive medium with both thermal conductivity and insulation properties, serving to fix the laser components while transferring heat. For example, the aforementioned thermally conductive insulating adhesive can be an epoxy resin-based thermally conductive adhesive, without specific limitations. A thermoelectric cooling element can be attached to the bottom heat dissipation surface of the aforementioned thermoelectric cooling heat sink. The aforementioned thermoelectric cooling element can be a temperature control element based on the Peltier effect, which can achieve cooling or heating effects by changing the magnitude and direction of the driving current. For example, the aforementioned thermoelectric cooling element can be a semiconductor cooling element, without specific limitations. The aforementioned synchronous control component can be configured to adjust the driving current of the aforementioned thermoelectric cooling element through the following steps: The first step involves real-time acquisition of the actual operating temperature of the thermoelectric cooling heat sink using a temperature sensor. This temperature sensor is fixedly mounted inside a pre-drilled temperature-measuring hole on the side of the positioning groove on the top of the thermoelectric cooling heat sink, allowing it to closely contact the surface of the oxygen-free copper substrate to collect the heat sink's body temperature. The actual operating temperature refers to the temperature value detected by the thermoelectric cooling heat sink in real time during operation, which indirectly reflects the operating temperature of the internally bonded laser crystal. In practice, the synchronous control component can read the analog signal output by the temperature sensor at a fixed sampling period (e.g., every 20 milliseconds), convert it into a temperature value through analog-to-digital conversion, and obtain the actual operating temperature.

[0039] The second step is to determine the temperature deviation based on the actual operating temperature and the reference operating temperature. The reference operating temperature can be a target constant temperature value pre-stored in the aforementioned synchronous control component, such as 25°C, without specific limitations. The temperature deviation can be obtained by calculating the difference between the real-time acquired actual operating temperature and the reference operating temperature. In practice, the aforementioned synchronous control component can retrieve the locally stored reference operating temperature and calculate the difference between it and the currently acquired and converted actual operating temperature to obtain the corresponding temperature deviation. When the actual operating temperature is higher than the reference operating temperature, the temperature deviation can be positive; when the actual operating temperature is lower than the reference operating temperature, the temperature deviation can be negative.

[0040] The third step involves adjusting the drive current of the thermoelectric cooler based on the temperature deviation. The thermoelectric cooler is attached to the bottom heat dissipation surface of the thermoelectric heat sink. The magnitude and direction of the drive current control the operating power and the cooling / heating mode, respectively. In practice, the synchronous control component outputs a corresponding adjustment signal to the thermoelectric cooler drive circuit based on the sign and absolute value of the temperature deviation. When the temperature deviation is positive, indicating that the crystal's operating temperature is too high, the synchronous control component increases the drive current in the cooling direction; when the temperature deviation is negative, indicating that the crystal's operating temperature is too low, the synchronous control component switches to the heating current direction, while maintaining a constant current magnitude. For example, it can be preset that for every 0.5°C deviation of the actual operating temperature from the reference operating temperature, the thermoelectric cooler drive current is adjusted by 0.1A. This adjustment coefficient can be pre-stored within the synchronous control component.

[0041] The aforementioned synchronization control component can be communicatively connected to an ambient temperature acquisition device. The temperature probe of this ambient temperature acquisition device can be positioned within the optical cavity region of the self-triggered dual-pulse synchronous laser housing. The optical cavity region can refer to the sealed optical path space through which all laser beams propagate within the laser housing, for example, the interior of two sets of laser resonant cavities. The ambient temperature acquisition device can be a device for acquiring ambient temperature, its function being to sense changes in the ambient temperature within the optical cavity of the laser. The ambient temperature acquisition device can be a digital temperature sensor, without specific limitations. The aforementioned synchronization control component can be configured to dynamically correct the aforementioned reference energy threshold through the following steps: The first step is to acquire the real-time ambient temperature of the optical cavity region using an ambient temperature acquisition device. This real-time ambient temperature refers to the temperature value inside the optical cavity during continuous laser processing. In practice, the aforementioned synchronization control component can acquire the real-time ambient temperature of the optical cavity region through the ambient temperature acquisition device at a fixed temperature sampling period (e.g., once every 100 milliseconds).

[0042] The second step involves generating a reference energy threshold adapted to the current environment based on the real-time ambient temperature. This reference energy threshold can refer to the one used in the step of determining the energy deviation based on the actual energy value and the reference energy threshold. In practice, after acquiring the real-time ambient temperature, the synchronization control component can retrieve an internally stored temperature-threshold mapping data table to match the reference energy threshold corresponding to the current real-time ambient temperature. This temperature-threshold mapping data table records the mapping relationships between different temperature ranges and different reference energy thresholds. For example, assuming the real-time ambient temperature is 40℃, falling within the 30~60℃ operating temperature range, a preset reference energy threshold of 10 microjoules can be used; if the real-time ambient temperature is 25℃, falling within the 15~30℃ temperature range, a preset reference energy threshold of 9 microjoules can be used; and if the real-time ambient temperature is 10℃, falling within the -10~15℃ temperature range, a preset reference energy threshold of 8 microjoules can be used. No specific limitations are made here. Among them, for the endpoint values ​​that overlap between adjacent intervals, the benchmark energy threshold corresponding to the interval with the higher temperature value in the adjacent interval can be taken, so as to avoid the judgment conflict caused by matching two sets of thresholds at the same temperature point.

[0043] The above-mentioned optional embodiments, as an inventive point of this disclosure, solve the technical problem of "the superposition of crystal temperature rise and optical cavity ambient temperature change leading to double-pulse energy drift and poor processing consistency". The specific factors causing double-pulse energy drift and poor processing consistency are as follows: During long-term pumping operation of the laser component, the gain crystal continuously generates heat. Without a precise isostatic structure, lattice temperature drift will occur, altering the laser output energy. Simultaneously, the ambient temperature of the workshop causes fluctuations in the optical cavity ambient temperature, resulting in synchronous changes in optical path loss and crystal absorption coefficient. This leads to deviations in the fixed trigger energy determination standard, causing a continuous shift in the double-pulse ratio and an increase in wafer processing defects. Solving these factors can suppress pulse energy fluctuations caused by crystal temperature rise and optical cavity ambient temperature changes, stabilize double-pulse output parameters, reduce brittle wafer dicing edge chipping and uneven scribe line defects, and improve the yield of precision-processed finished products. To achieve this effect, this disclosure also provides a device that coordinates crystal closed-loop isostatic control with cavity temperature adaptive threshold adjustment. On the one hand, relying on a thermoelectric cooling heat sink with positioning grooves combined with synchronous temperature control logic, real-time closed-loop temperature control is achieved for the gain crystals of the first and second laser components, reducing crystal temperature drift caused by pump heating and stabilizing the basic single-pulse output energy. On the other hand, an optical cavity ambient temperature acquisition device is added to dynamically correct the energy threshold for energy determination based on the cavity temperature. This achieves the effect of suppressing pulse energy fluctuations caused by crystal temperature rise and optical cavity ambient temperature changes, stabilizing dual-pulse output parameters, reducing the defect rate of brittle wafers, and improving the yield of precision-machined finished products.

[0044] In addressing the aforementioned technical challenges by employing technical solutions, and considering the application scenario—high-precision micro-machining of hard and brittle materials, such as sapphire wafer dicing and drilling, and stealth dicing of silicon carbide substrates—the following technical problems often arise: insufficient focal depth of conventional beams makes it difficult to simultaneously and efficiently process both the surface and deeper layers of the material, and concentrated thermal effects can easily lead to processing defects such as edge chipping and microcracks. To meet the following requirements for this application scenario: adjustable focal depth to accommodate materials of varying thicknesses, low thermal damage under high energy density, and optical path integration within confined workspaces, we have decided to adopt the following solution: Optionally, the output end of the aforementioned self-triggered dual-pulse synchrotron laser may also be coaxially equipped with a Bessel beam shaper. The Bessel beam shaper can be an optical component that converts a Gaussian beam into a Bessel beam, generating a focused spot with a long depth of focus. The Bessel beam shaper may include a conical lens and a flat-field focusing lens arranged sequentially along the output optical axis. The conical surface of the conical lens may face the incident light path, and the object-side focal point of the flat-field focusing lens may coincide with the apex of the exit conical surface of the conical lens. The conical lens can be an optical lens with a conical structure, converting incident parallel light into a ring-shaped diverging beam. For example, the conical lens may be an axial cone, without specific limitation. The conical lens may use a fused silica substrate, and the half-cone angle of the conical surface may be set to 0.8° to 1.5°. The flat-field focusing lens can be a focusing lens that forms a uniform flat-field spot on the focal plane, focusing the ring beam into a Bessel spot with a long depth of focus. A ring stop may be coaxially arranged between the conical lens and the flat-field focusing lens. The aforementioned annular aperture can be a central light-blocking, edge-passing aperture element, capable of filtering out higher-order sidelobe components of the beam and increasing the energy ratio of the central spot. The aforementioned conical lens, annular aperture, and plan-focusing lens can all be mounted inside the same Invar alloy lens barrel. The aforementioned Invar alloy lens barrel can be a mounting barrel made of a low-expansion alloy material, capable of fixing the optical elements and maintaining their coaxiality. For example, the aforementioned Invar alloy lens barrel can be a 4J36 Invar alloy lens barrel, without specific limitation. The inner wall of the aforementioned Invar alloy lens barrel can be pre-set with positioning steps, and the aforementioned conical lens, annular aperture, and plan-focusing lens can be axially pressed and fixed together by a metal spacer. The aforementioned positioning steps can be step-shaped protrusions pre-set on the inner wall of the aforementioned Invar alloy lens barrel, and the protruding parts can be used to fix the aforementioned conical lens, annular aperture, and plan-focusing lens. The aforementioned metal spacer can be an annular metal gasket, capable of limiting the axial spacing between the optical elements. For example, the aforementioned metal spacer can be an aluminum alloy spacer, without specific limitation. The tail end of the aforementioned Invar alloy lens barrel can be connected to the mounting flange at the laser output end via an external thread structure.

[0045] The above-mentioned optional embodiments, as an inventive point of this disclosure, solve the technical problem of "insufficient focal depth of conventional beams leading to limited processing depth of hard and brittle materials, and frequent chipping and microcrack defects." The specific factors leading to insufficient focal depth of conventional beams and thus limited processing depth of hard and brittle materials, as well as frequent chipping and microcrack defects, are as follows: After focusing, the focal depth of a Gaussian beam decreases sharply with increasing numerical aperture. When processing high-hardness transparent materials such as sapphire and silicon carbide, a single pulse cannot penetrate the entire thickness of the material, requiring layer-by-layer scanning and stacking, resulting in low processing efficiency. Simultaneously, the energy at the center of the Gaussian beam is highly concentrated, while the energy at the edges decays rapidly, forming localized overheating on the material surface, causing irreversible defects such as chipping, microcracks, and even material fragmentation. Solving these factors can improve processing efficiency in high-precision micro-machining scenarios of hard and brittle materials, while controlling the heat-affected zone to the sub-micron level and significantly reducing chipping rate and microcrack density. To achieve this effect, this disclosure also provides a long focal depth laser processing device based on a Bessel beam. On the one hand, a combination of a conical lens and a flat-field focusing lens converts the Gaussian beam into a Bessel beam with a long depth of focus. On the other hand, an annular aperture filters out higher-order sidelobe components, increasing the energy ratio of the central main lobe. Combined with the low expansion characteristics of the Invar alloy lens barrel, this ensures the thermal stability of the optical path during long-term continuous processing, thereby reducing the heat-affected zone. Thus, in high-precision micro-machining scenarios involving hard and brittle materials, this achieves improved processing efficiency while controlling the heat-affected zone to the sub-micron level and significantly reducing edge chipping rate and microcrack density.

[0046] Some embodiments of this disclosure provide a self-triggered dual-pulse synchronous laser, which can improve the output stability of dual-pulse lasers. Specifically, the reason for the poor output stability of most dual-pulse lasers is that currently commonly used dual-pulse lasers employ a structure of two independent passively Q-switched lasers synchronously triggered by the same electrical signal source, and each is directly triggered by its own pump source to generate pulses. However, the pulse generation of passively Q-switched lasers depends on the spontaneous bleaching process of the saturable absorber, which is greatly affected by the output energy fluctuations of the two pump sources. Based on this, some embodiments of this disclosure provide a self-triggered dual-pulse synchronous laser, which includes a first laser component, a second laser component, a first pump source, a second pump source, a synchronization control component, a first mirror, an optical isolator, and a partial mirror. One output terminal of the synchronization control component is electrically connected to the first pump source, and the other output terminal of the synchronization control component is electrically connected to the second pump source. The pump light output terminal of the first pump source is aligned with the pump end face of the first laser component, and the pump light output terminal of the second pump source is aligned with the pump end face of the second laser component. The pump end face of the laser component; the light-emitting end face of the first laser component faces the first reflector, and the first reflector also faces the incident end face of the optical isolator; the light-emitting end face of the optical isolator faces the incident surface of the partial reflector, and the incident surface of the partial reflector also faces the light-emitting end face of the second laser component; the continuous output power of the first pump source is greater than a first light-emitting threshold, and the continuous output power of the second pump source is less than a second light-emitting threshold, wherein the first light-emitting threshold is the light-emitting threshold of the first laser component, and the second light-emitting threshold is the light-emitting threshold of the second laser component. By setting the first laser component to spontaneously generate pulsed laser and setting the pump power of the second laser component to be less than its light-emitting threshold, making it in a critical energy storage state, and then using the partial pulsed laser energy output by the first laser component to trigger the second laser component to release pulsed laser through the partial reflector, the dependence of the two laser pulses on the output energy stability of the two pump sources is reduced. Therefore, the output stability of the dual-pulse laser can be improved.

[0047] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A self-triggered dual-pulse synchronous laser, characterized in that, The self-triggered dual-pulse synchronous laser includes a first laser component, a second laser component, a first pump source, a second pump source, a synchronization control component, a first reflector, an optical isolator, and a portion of the reflectors, wherein... One output terminal of the synchronization control component is electrically connected to the first pump source, and the other output terminal of the synchronization control component is electrically connected to the second pump source; The pump light output end of the first pump source is aligned with the pump end face of the first laser component, and the pump light output end of the second pump source is aligned with the pump end face of the second laser component. The light-emitting end face of the first laser component faces the first reflector, and the first reflector also faces the incident end face of the optical isolator; The output end face of the optical isolator faces the incident surface of the partial reflector, and the incident surface of the partial reflector also faces the output end face of the second laser component. The continuous output power of the first pump source is greater than the first light-emitting threshold, and the continuous output power of the second pump source is less than the second light-emitting threshold, wherein the first light-emitting threshold is the light-emitting threshold of the first laser component, and the second light-emitting threshold is the light-emitting threshold of the second laser component. The polarization state of the laser emitted by the first laser component is orthogonal to the polarization state of the laser emitted by the second laser component.

2. The self-triggered dual-pulse synchronous laser according to claim 1, characterized in that, The continuous output power of the second pump source is 90% to 99% of the second light emission threshold.

3. The self-triggered dual-pulse synchronous laser according to claim 1, characterized in that, The reflecting surface of the first reflector forms a 45-degree angle with the light-emitting optical axis of the first laser component; The incident surface of the partial reflector forms a 45-degree angle with the output optical axis of the optical isolator, and the incident surface of the partial reflector forms a 45-degree angle with the output optical axis of the second laser component.

4. The self-triggered dual-pulse synchronous laser according to claim 1, characterized in that, Both the first laser component and the second laser component are bonded crystals; Both the first laser component and the second laser component include a gain medium and a saturable absorber bonded together in sequence.

5. The self-triggered dual-pulse synchronous laser according to claim 4, characterized in that, The gain medium is neodymium-doped yttrium aluminum garnet crystal, and the saturable absorber is chromium-doped yttrium aluminum garnet crystal.

6. The self-triggered dual-pulse synchronous laser according to claim 4, characterized in that, In the first laser component and the second laser component, a first dielectric film is deposited on both gain media and a second dielectric film is deposited on both saturable absorbers. The first dielectric film transmits 808 nm wavelength laser light and reflects 1064 nm wavelength laser light. The second dielectric film reflects 808 nm wavelength laser light and partially transmits 1064 nm wavelength laser light, with a transmittance of 10% to 50%.

7. The self-triggered dual-pulse synchronous laser according to claim 1, characterized in that, The first reflector is a plane reflector with a substrate material of fused silica and a reflective film for 1064 nanometer wavelength lasers coated on the reflective surface. The optical isolator includes an incident polarizer, a Faraday rotator, and an outgoing polarizer arranged in sequence. The partial reflector is a planar partial reflector with a substrate material of fused silica and both optical surfaces coated with an anti-reflection film. The interior of the partially reflective mirror is provided with a beam-splitting film layer, which includes alternating layers of silicon dioxide and tantalum pentoxide. The pump end face and the light-emitting end face of both the first laser component and the second laser component are planar; The self-triggered dual-pulse synchronous laser also includes a mirror assembly and a beam combiner. The reflector group is located in the light output path of the second laser component, and the reflector group is mounted on a translation stage. The translation direction of the translation stage is parallel to the incident light direction of the reflector group or the laser propagation direction inside the reflector group. The beam combiner is located in both the light output path of the reflector group and the light output path of the first laser component.

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