Laser generating device and laser system

Abstract

According to the laser generating device and the laser system, the image transmission device is introduced, the object image surface of the image transmission device is accurately overlapped with the two cavity reflectors of the resonant cavity, the important beneficial effects are achieved, the effective transmission distance of light waves between the two cavity reflectors is equivalently eliminated optically, and the laser generating device and the laser system have the advantages of being simple in structure and convenient to use. Therefore, the inherent diffraction effect and the mode selection capability of the resonant cavity are thoroughly inhibited; the direct result is that a large number of laser transverse modes with different orders are allowed to simultaneously meet oscillation conditions and start oscillation in a cavity, and light fields of the multiple transverse modes are combined into a large-mode-field output light beam with the spot size equivalent to the aperture of a gain medium after incoherent superposition. Moreover, the near-field energy distribution is converted from the conventional Gaussian distribution to super Gaussian distribution with a flat top and a steep edge.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more specifically to a laser generating device and a laser system. Background Technology

[0002] A laser generating device is a device that provides optical positive feedback through a resonant cavity, causing photons generated by stimulated emission of the laser gain medium to be amplified back and forth within the cavity, ultimately outputting a coherent laser.

[0003] In related technologies, traditional laser generating devices suffer from the technical problem that their output energy is limited by the damage threshold of optical components due to the small output laser mode field and the Gaussian distribution of near-field energy. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a laser generating device and laser system to solve the technical problem that, in the related technologies, the output energy of traditional laser generating devices is limited by the damage threshold of optical components due to the small output laser mode field and the Gaussian distribution of near-field energy.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a laser generating apparatus, the laser generating apparatus comprising at least: A resonant cavity, which includes at least a first cavity mirror and a second cavity mirror; A laser gain unit is disposed inside the resonant cavity; An image transfer device is disposed inside the resonant cavity, wherein the first cavity mirror and the second cavity mirror are respectively located on the conjugate object plane and image plane of the image transfer device, such that the resonant cavity supports the simultaneous oscillation of multiple transverse modes to output a large mode field super-Gaussian beam.

[0006] Furthermore, the laser generating device further includes: A polarizer is disposed inside the resonant cavity.

[0007] Furthermore, the laser generating device further includes: A pulse modulation device is disposed inside the resonant cavity, and the pulse modulation device and the laser gain unit are located on opposite sides of the polarizer.

[0008] Furthermore, the laser generating device further includes: A phase delay device is disposed inside the resonant cavity, and the phase delay device and the laser gain unit are located on opposite sides of the polarizer.

[0009] Furthermore, the pulse modulation device is an electro-optic Q-switching device, an acousto-optic Q-switching device, or a passive Q-switching device.

[0010] Furthermore, the image transmission device is a 4f imaging system or a single-lens imaging system.

[0011] Furthermore, the laser gain unit is a transmission laser gain module or a reflection laser gain module.

[0012] Furthermore, the resonant cavity includes only a first cavity mirror and a second cavity mirror, and the first cavity mirror and the second cavity mirror constitute a linear resonant cavity.

[0013] Furthermore, the laser generating device further includes a third cavity mirror and a fourth cavity mirror, and the first cavity mirror, the second cavity mirror, the third cavity mirror and the fourth cavity mirror constitute a ring-shaped resonant cavity; The image transfer device includes a first sub-image transfer device and a second sub-image transfer device; wherein, the first sub-image transfer device is disposed between the first cavity mirror and the second cavity mirror, a polarizer and a pulse modulation device are sequentially disposed between the second sub-image transfer device and the third cavity mirror, the second sub-image transfer device is disposed between the third cavity mirror and the fourth cavity mirror, and the laser gain unit is disposed between the fourth cavity mirror and the first cavity mirror.

[0014] Secondly, the present invention provides a laser system, such as the laser generating device described above.

[0015] Beneficial effects: This invention brings significant benefits by introducing an image transfer device and precisely aligning its object-image plane with the two cavity mirrors of the resonant cavity. This configuration optically equivalently eliminates the effective transmission distance of light waves between the two cavity mirrors, thereby completely suppressing the inherent diffraction effect and mode selection capability of the resonant cavity. The direct result is that a large number of laser transverse modes of different orders can simultaneously meet the oscillation conditions and oscillate within the cavity. The incoherent superposition of the optical fields of these multiple transverse modes synthesizes a large mode field output beam with a spot size comparable to the aperture of the gain medium, and its near-field energy distribution changes from a traditional Gaussian distribution to a super-Gaussian distribution with a flat top and steep edges. Attached Figure Description

[0016] Figure 1 This is one of the architectural diagrams of a laser generation device provided in an embodiment of the present invention; Figure 2 This is a second architectural diagram of a laser generation device provided in an embodiment of the present invention; Figure 3 This is the third architectural diagram of a laser generating device provided in an embodiment of the present invention; Figure 4 This is the fourth architectural diagram of a laser generating device provided in an embodiment of the present invention; Figure 5 This is the fifth architectural diagram of a laser generating device provided in an embodiment of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0018] As the core component of a laser system, the performance of the laser generator directly determines the energy, brightness, and beam quality of the output laser. A typical laser generator system environment includes a resonant cavity consisting of at least two cavity mirrors, and a laser gain medium (i.e., a laser gain unit) placed inside the resonant cavity. Under the excitation of the pump source, the gain medium generates spontaneous emission light. This photon propagates back and forth within the resonant cavity, continuously gaining gain amplification through stimulated emission. When the gain is sufficient to overcome the cavity losses, a stable laser oscillation is formed and output. During this process, the geometry of the resonant cavity (e.g., cavity length, mirror curvature) constrains the optical field, generating a specific electromagnetic field distribution, i.e., the laser mode.

[0019] In related technologies, traditional positive feedback resonant cavity laser generators operate based on the principle of mode self-reproduction. Their core characteristic lies in the inherent "mode selection" mechanism of the resonant cavity. Due to the diffraction effect of light, only specific transverse modes (e.g., the fundamental mode TEM00 or a single higher-order mode) whose phase and optical field distribution completely coincide with their own after one round trip within the cavity can oscillate stably, while other modes are suppressed due to destructive interference. While this mechanism can output lasers with high mode purity, it also introduces two interrelated and inherent technical drawbacks: First, the mode field volume is severely limited. Whether it's the fundamental transverse mode or the selected few higher-order transverse modes, their spot size is restricted to a relatively small range. The fundamental mode has the smallest spot size, and the higher-order modes have slightly larger spots, but their mode volume is still very limited compared to the size of the gain medium, resulting in the gain medium's capabilities not being fully utilized.

[0020] Second, the near-field energy distribution exhibits a harmful Gaussian distribution. The energy density within the beam range of the laser mode selected by the resonant cavity is not uniformly distributed, but rather decreases sharply from the center to the edge, forming a "bullseye" beam with extremely high energy density at the center and extremely low energy density at the edges. The laser damage threshold of optical components is determined by the maximum energy density (unit: J / cm²) they can withstand. The extremely high energy density at the center of the Gaussian beam becomes the bottleneck of the entire system's output capability. To avoid burning out core components such as the cavity mirror or gain medium, the average output energy of the entire laser must be strictly limited to a low level. This inherently limits the single-pulse energy or continuous power output capability of traditional oscillators (for example, pulse energy is typically only on the order of millijoules).

[0021] To achieve higher output energy, related technologies typically employ a complex "oscillator + multi-stage amplifier" scheme. This involves first outputting a low-energy, Gaussian-distributed seed beam from the oscillator, then using a complex beam expander and spatial filter system to extract the uniform portion in the middle, which is then injected into a multi-stage amplifier chain for energy amplification. This scheme has significant drawbacks: firstly, the low-energy edges of the oscillator output are filtered out, resulting in energy waste and low system efficiency; secondly, the introduction of multi-stage amplifiers significantly increases the system's size, complexity, and cost; and finally, the increased number of optical components reduces the overall reliability and stability of the laser system.

[0022] In summary, traditional laser generating devices suffer from a fundamental technical problem: due to their inherent mode selection mechanism, the output laser mode field is small and the near-field energy exhibits a Gaussian distribution. Consequently, their output energy is limited by the damage threshold of optical components, making it impossible to directly achieve high-energy output.

[0023] This invention aims to fundamentally solve this technical problem. Its core inventive concept lies in: by cleverly introducing an image transfer device into the resonant cavity and precisely positioning two cavity mirrors on the conjugate object-image plane of the device, the mode selection capability of the resonant cavity is optically equivalently eliminated, causing multiple transverse modes to oscillate and superimpose simultaneously, ultimately directly outputting a high-energy laser with a large mode field and an ultra-Gaussian flat near-field distribution.

[0024] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, this embodiment provides a laser generating device, which includes at least: A resonant cavity, which includes at least a first cavity mirror and a second cavity mirror.

[0025] In this embodiment, the resonant cavity may include only the first cavity mirror and the second cavity mirror, or it may include more mirrors in addition to the first cavity mirror and the second cavity mirror.

[0026] In this embodiment, the resonant cavity can be a linear cavity (straight or folded) or a ring cavity.

[0027] In one specific implementation, the resonant cavity is a closed optical feedback path composed of multiple optical mirrors. Its core function is to provide positive optical feedback, allowing light to pass through the laser gain unit multiple times within the cavity, continuously amplifying it and ultimately forming laser oscillation. The resonant cavity includes at least a first cavity mirror and a second cavity mirror. It serves as the carrier for realizing the core idea of ​​this invention (object-image conjugation). Based on this, more cavity mirrors can be flexibly introduced into the resonant cavity to form different cavity structures.

[0028] In order to form an optical path of a specific shape (e.g., a ring cavity) or to achieve other functions (e.g., folding the optical path to reduce volume), the resonant cavity may also include a third cavity mirror, a fourth cavity mirror, or even more cavity mirrors. It is understood that the main function of these mirrors is to change the direction of optical path propagation in order to form a complete closed loop.

[0029] As can be understood, a linear cavity is represented as a straight-through or folded structure in which light travels back and forth in a straight line or within a plane. This linear cavity can consist solely of a first cavity mirror and a second cavity mirror positioned face-to-face.

[0030] It is understandable that a ring cavity can be represented as a structure with a ring-shaped, closed loop of light. Light travels in a single direction (clockwise or counterclockwise) within the cavity.

[0031] In this embodiment, the resonant cavity can also be a figure-eight shaped cavity. That is, its optical path shape resembles the number "8". It can be composed of seven or eight mirrors, dividing the ring into two loops. Light travels unidirectionally along the figure-eight path within the cavity.

[0032] In this embodiment, the resonant cavity can also be a cross-shaped cavity. That is, the optical path is not folded in a plane in space, but has a three-dimensional cross structure. Multiple mirrors can be arranged in three-dimensional space. By designing the mirror mounting angle, the optical path can be made to cross and travel in space, which can greatly compress the cavity volume or achieve special beam superposition.

[0033] In this embodiment, the resonant cavity can also be a V-shaped cavity. That is, the light beam forms a path resembling the letter "V" within the cavity. It can consist of two reflecting mirrors and a guiding mirror, with the light beam reflected from one mirror to another, and then reflected back to the first mirror by the guiding mirror.

[0034] In this embodiment, the resonant cavity can also be a Z-shaped cavity. That is, a Z-shaped cavity is a structure formed by three mirrors, and the optical path is in the shape of the letter "Z". In this structure, the light beam is reflected multiple times, bypassing the middle mirror, and finally returning to the gain medium for gain.

[0035] A laser gain unit is disposed inside the resonant cavity.

[0036] In this embodiment, the laser gain unit provides the necessary optical gain for the laser generating device to generate and amplify laser light. Its core component can be a solid-state laser gain medium with specific doping elements. Under the excitation of an external pump source (e.g., a laser diode array), the particles inside the gain medium undergo population inversion, thereby enabling stimulated emission amplification of incident light of a specific wavelength. The laser gain unit can be constructed as a transmissive structure, that is, both light-transmitting end faces of its gain medium are coated with an optical thin film that reduces the light transmittance of the oscillating laser wavelength, so as to allow the laser beam to pass through with low loss and thus undergo the gain process multiple times.

[0037] In another alternative embodiment, the laser gain unit can also be constructed as a reflective structure, wherein one end face of its gain medium near the pump source is coated with a film that enhances the transmission of pump light and is highly reflective of oscillating laser light, while the other end face is coated with a film that allows partial transmission of oscillating laser light to serve as an output coupling mirror.

[0038] An image transfer device is disposed inside the resonant cavity, wherein the first cavity mirror and the second cavity mirror are respectively located on the conjugate object plane and image plane of the image transfer device, such that the resonant cavity supports the simultaneous oscillation of multiple transverse modes to output a large mode field super-Gaussian beam.

[0039] In this embodiment, the image transfer device is the core optical component of the laser generating device for realizing the output of a large-mode-field super-Gaussian beam. Its function is to establish a precise optical imaging relationship within the resonant cavity.

[0040] Specifically, the image transmission device can be constructed as a 4f imaging system, which consists of a first lens and a second lens. The first lens and the second lens may have the same focal length f or may not have the same focal length f. In other words, the focal length f of the first lens and the second lens may have a certain difference. Furthermore, the rear focal plane of the first lens coincides with the front focal plane of the second lens, thereby forming an ideal imaging system without aberrations or magnification.

[0041] The reflecting surface of the first cavity mirror is precisely positioned on the front focal plane (i.e., the object plane) of the first lens, while the reflecting surface of the second cavity mirror is precisely positioned on the rear focal plane (i.e., the image plane) of the second lens. With this configuration, the first cavity mirror and the second cavity mirror form a pair of conjugate object and image planes for the 4f imaging system.

[0042] Any light emitted from the first cavity mirror, after passing through the 4f imaging system, will form a precise image point on the second cavity mirror, and vice versa. This makes the transmission of light between the two cavity mirrors equivalent to completing within an infinitesimally small distance, thereby completely suppressing the inherent diffraction effect of the resonant cavity and its resulting mode selection capability. As a result, a large number of higher-order transverse modes, like the fundamental transverse mode, can satisfy the phase condition for oscillation within the resonant cavity, thus achieving simultaneous oscillation of multiple transverse modes.

[0043] These multiple transverse modes that oscillate simultaneously are incoherently superimposed within the cavity, and their optical field distributions are mixed with each other, ultimately synthesizing a large-mode output beam whose spot size fills the entire aperture of the gain medium. Furthermore, its near-field light intensity distribution changes from a traditional Gaussian distribution to a super-Gaussian distribution with a flat top and steep edges, thereby fundamentally solving the technical problem that the output energy is limited by the component damage threshold.

[0044] In an alternative embodiment, the image transfer device can also be implemented by a single lens. By precisely setting the first cavity mirror and the second cavity mirror on the conjugate object plane and image plane of the single lens, the same effect of suppressing mode selection and obtaining a large mode field super-Gaussian beam output can be achieved.

[0045] It is understood that the "laser generating device" described in this embodiment can realize two important laser functions depending on its specific configuration and operating mode: First, the laser generating device can be configured and operated as a laser oscillator. In this mode, its laser oscillation originates entirely from spontaneous emission within the laser gain unit. Excited by an external pump source, the gain medium generates an initial optical field, which propagates back and forth within the resonant cavity, satisfying the aforementioned conditions for simultaneous oscillation of multiple transverse modes. Ultimately, it oscillates and amplifies from spontaneous emission, directly forming and outputting the large-mode-field, super-Gaussian distributed laser. This is a core implementation scheme provided in this embodiment.

[0046] Secondly, this laser generating device can also be configured and function as a laser amplifier, particularly a regenerative amplifier. In this mode, a small-energy laser pulse (i.e., "seed light") from an external seed laser is introduced into the resonant cavity through an additional injection unit (beam splitter or acousto-optic modulator). By controlling the timing of the pulse modulation device (electro-optic Q-switching device), the seed light pulse can be captured within the cavity and amplified multiple times using the energy stored in the laser gain unit. Crucially, because the core structure of this device suppresses mode selection, the amplification process is not the single-mode amplification of a traditional regenerative amplifier, but rather allows multiple transverse modes to participate and superimpose. Therefore, the laser pulse that is ultimately amplified and switched at output has significantly increased energy while perfectly maintaining the characteristics of a large mode field and a super-Gaussian near-field distribution. This provides a novel high-performance amplifier architecture to address the problems of small output mode fields and susceptibility to damage thresholds of optical components in traditional regenerative amplifiers.

[0047] In summary, this embodiment provides a highly versatile core structure for a laser resonator, based on the inventive concept of image transfer conjugation. It also provides a hardware foundation for realizing laser oscillators and regenerative amplifiers with large mode field super-Gaussian output, greatly expanding its application scope and technical value.

[0048] This embodiment fundamentally solves the technical problem of limited output energy in traditional laser generating devices by introducing an image transfer device and configuring it with the cavity mirrors of the resonant cavity in a specific conjugate object-image relationship. Since the first and second cavity mirrors are positioned on the conjugate object and image planes of the image transfer device, the effective optical distance between them is effectively shortened to almost zero from the perspective of light field transmission. This configuration disrupts the diffraction effect upon which traditional resonant cavities rely for mode selection, allowing a large number of different orders of laser transverse modes to simultaneously oscillate within the cavity while meeting the oscillation conditions. The light fields of these multi-transverse modes... Incoherent superposition within the cavity results in a large-mode-field output beam with a spot size comparable to the aperture of the gain medium. Furthermore, its near-field energy distribution transforms from a Gaussian distribution to a uniform and flat super-Gaussian distribution. This super-Gaussian distribution eliminates the highly concentrated hot spots found in traditional Gaussian beams. Consequently, without altering the damage threshold of optical components, the final output energy of the laser is no longer limited by extremely high local energy density but is determined by the average energy density uniformly distributed across the entire spot area. This achieves an order-of-magnitude increase in output energy and eliminates the need for complex and inefficient multi-stage amplification systems.

[0049] In some embodiments, the laser generating apparatus further includes: A polarizer is disposed inside the resonant cavity.

[0050] In one possible and specific implementation, the polarizer can be configured as follows: When the image transfer device is disposed between the laser gain unit and the first cavity mirror, the polarizer can be disposed in the optical path between the image transfer device and the second cavity mirror; when the image transfer device is disposed between the laser gain unit and the second cavity mirror, the polarizer can be disposed in the optical path between the image transfer device and the first cavity mirror.

[0051] In this embodiment, the polarizer can be a single polarizer. The main function of a single polarizer is to allow light components in a certain direction of the incident beam to pass through, while absorbing or reflecting light in other directions. It can be used to selectively transmit laser beams with specific polarization directions, thereby improving beam quality.

[0052] In this embodiment, the polarizer can be multiple polarizers. Multiple polarizers are combined optical elements composed of multiple layers of polarizers, and can be a superposition of multiple single polarizers, utilizing polarization effects in different directions to provide more precise polarization control.

[0053] In this embodiment, the polarizer may be an adjustable polarizer.

[0054] In some embodiments, by configuring the polarizer inside the resonant cavity in the specific manner, a key beneficial effect is achieved. The polarizer acts as a polarizing element, converting the multi-transverse-mode laser oscillating within the cavity into a single linearly polarized light. This process ensures the consistency of the polarization state of the light wave in the subsequent optical path, laying a crucial foundation for efficient and stable collaborative operation with polarization-sensitive pulse modulation devices (e.g., electro-optic Q-switched crystals). Thus, in addition to the core advantage of achieving large-mode-field super-Gaussian beam output, the laser generating device is further endowed with the ability to generate high-energy pulsed lasers, greatly expanding its application scenarios.

[0055] In some embodiments, the laser generating apparatus further includes: A pulse modulation device is disposed inside the resonant cavity, and the pulse modulation device and the laser gain unit are respectively located on opposite sides of the polarizer.

[0056] In one possible and specific implementation, the pulse modulation device can be configured as follows: When the polarizer is disposed in the optical path between the image transfer device and the second cavity mirror, the pulse modulation device can be disposed in the optical path between the polarizer and the second cavity mirror; when the polarizer can be disposed in the optical path between the image transfer device and the first cavity mirror, the pulse modulation device is disposed in the optical path between the polarizer and the first cavity mirror.

[0057] In this embodiment, the pulse modulation device can be represented as a core active control unit for controlling the laser generating device to operate in pulse mode. It can be constructed as an electro-optic Q-switched crystal, such as a potassium dideuterium phosphate crystal or a lithium niobate crystal. The electro-optic Q-switched crystal can be placed in the optical path downstream of the polarizer and its light transmission direction is aligned with the linear polarization direction of the laser.

[0058] The electro-optic Q-switched crystal and the phase delay device (e.g., a quarter-wave plate) can work together to control the Q-value state of the resonant cavity. For example, when a voltage (e.g., a quarter-wave voltage) is applied to the electro-optic Q-switched crystal, the crystal can be equivalent to a quarter-wave plate. In this state, the crystal and the phase delay device work together to rotate the polarization direction of the one-way linearly polarized light passing through this combination by 90 degrees. The polarized light after rotating 90 degrees is blocked from entering the cavity because its polarization direction is perpendicular to the transmission axis of the upstream polarizer. At this time, the resonant cavity is in a low Q-value (high loss) state, which can suppress laser oscillation and store energy in the laser gain unit. When laser oscillation needs to be established, the voltage applied to the electro-optic Q-switched crystal is changed (e.g., removed), so that the resonant cavity returns to a high Q-value (low loss) state, and the stored energy can be extracted and output as laser. By controlling the voltage on the electro-optic Q-switched crystal, functions such as laser pulse output can be achieved.

[0059] When the gain reaches saturation, the half-wave voltage applied to the crystal is instantly removed through a high-speed switching circuit, and the resonant cavity instantly returns to a high Q value (low loss) state. All the stored energy is released in the form of giant pulses through stimulated emission in a very short time, thereby realizing the output of a large mode field ultra-Gaussian pulse laser with high peak power.

[0060] In alternative embodiments, the pulse modulation device may also be an acousto-optic Q-switching device, which achieves Q-switching by generating periodic diffraction loss through the acousto-optic effect; or it may be a passive Q-switching device, for example, composed of a saturable absorber, which automatically completes the pulse modulation process by utilizing the nonlinear absorption characteristics of the material itself.

[0061] In some embodiments, by configuring the pulse modulation device in the optical path downstream of the polarizer in the specific manner, the pulse modulation device can efficiently perform periodic loss modulation on the linearly polarized laser after polarizer filtering; by periodically changing the Q value of the resonant cavity during laser oscillation, the device can release the huge continuous laser energy with a large mode field and super-Gaussian distribution accumulated in the cavity in the form of a giant pulse in a very short time; thus, while retaining the core advantage of the oscillator directly outputting a high-energy, super-Gaussian beam, a high peak power pulsed laser output is further obtained, greatly expanding the application range of the laser, while avoiding the system complexity and energy loss of traditional schemes that first generate small energy pulses and then cascade amplify them.

[0062] In some embodiments, the laser generating apparatus further includes: A phase delay device is disposed inside the resonant cavity, and the phase delay device and the laser gain unit are located on opposite sides of the polarizer.

[0063] In one possible and specific implementation, the phase delay device can be configured as follows: When the pulse modulation device is disposed in the optical path between the polarizer and the second cavity mirror, the phase delay device can be disposed in the optical path between the pulse modulation device and the second cavity mirror; when the pulse modulation device can be disposed in the optical path between the polarizer and the first cavity mirror, the phase delay device is disposed in the optical path between the pulse modulation device and the first cavity mirror.

[0064] In this embodiment, the phase delay device can be a quarter-wave plate. Specifically, a quarter-wave plate is an optical element capable of changing the polarization state of incident light to circular polarization or reverse circular polarization. It can convert linearly polarized light into circularly polarized light, or reverse the polarization direction of circularly polarized light.

[0065] In this embodiment, the phase delay device can be a half-wave plate. Specifically, a half-wave plate is an optical element that rotates the polarization state of incident light by 90 degrees.

[0066] In this embodiment, the phase delay device may be a birefringent waveplate.

[0067] In this embodiment, the phase delay device may be a rotatable waveplate.

[0068] In this embodiment, the phase delay device may be an electro-optic modulated waveplate.

[0069] In some embodiments, by placing the phase delay device in close proximity to the pulse modulator downstream of the pulse modulator in the specific manner, a key beneficial effect is achieved. The phase delay device, together with the upstream polarizer and pulse modulator (e.g., an electro-optic Q-switching device), constitutes a precise polarization state control system. In the low Q-value state where the voltage is applied by the pulse modulator, it works in conjunction with the modulator to ensure that the laser polarization state is completely blocked. In the high Q-value state where the voltage is removed, it can accurately compensate for polarization errors in the optical path, ensuring that the oscillating laser propagates back and forth in the cavity with low loss and efficiently extracts energy in the optimal linear polarization state. Thus, while achieving high peak power pulse output, it ensures the stability and high efficiency of pulse formation and maximizes the excellent characteristics of large mode field super-Gaussian beam output.

[0070] In some embodiments, the pulse modulation device is an electro-optic Q-switching device, an acousto-optic Q-switching device, or a passive Q-switching device.

[0071] In this embodiment, the electro-optic Q-switching device is an optical modulator that adjusts the Q-factor of a laser resonant cavity through the electro-optic effect. The electro-optic effect refers to the change in the refractive index of a material under the influence of an electric field. By controlling the refractive index of the material, the output mode of the laser can be controlled, thereby achieving pulsed laser output.

[0072] In this embodiment, the acousto-optic Q-switching device utilizes the acousto-optic effect to control the pulse output of the laser. The acousto-optic effect refers to the periodic refractive index changes that occur in a medium when a sound wave passes through it, thereby affecting the propagation path of the light.

[0073] In this embodiment, the passive Q-switching device is a modulation device that requires no external power supply or control signal. It adjusts the Q-factor of the laser resonator by employing a target material (e.g., a saturable absorber). Its working principle is based on nonlinear optical effects, where laser energy accumulates in the resonator and is released as a laser pulse through the passive Q-switching device at an appropriate time.

[0074] In this embodiment, the pulse modulation device is an electro-optic Q-switched device, an acousto-optic Q-switched device, or a passive Q-switched device. By precisely controlling the pulse characteristics of the laser through different modulation methods, it offers the following advantages: First, electro-optic Q-switched devices can achieve fast and precise pulse modulation, suitable for high-frequency, high-power laser systems, and provide excellent pulse quality. Second, acousto-optic Q-switched devices utilize the acousto-optic effect to achieve efficient pulse modulation, suitable for systems requiring large modulation bandwidth and high stability. Finally, passive Q-switched devices, by self-adjusting the Q factor of the laser generator, make the system simpler and more stable, reducing dependence on external control, while providing high peak power pulse output. Overall, the use of these pulse modulation devices greatly improves the flexibility, pulse control accuracy, and reliability of the laser system, adapting to the laser modulation requirements of different applications.

[0075] In some embodiments, the image transmission device is a 4f imaging system or a single-lens imaging system.

[0076] In this embodiment, the image transmission device is a 4f imaging system or a single-lens imaging system, which has the following advantages: First, the 4f imaging system can provide high-quality optical imaging, ensuring accurate transmission of the laser beam and having good anti-distortion capabilities, making it suitable for applications requiring high-precision beam control. Second, the single-lens imaging system has a simple structure, is easy to adjust and optimize, and is suitable for applications with short beam transmission paths, effectively reducing system complexity and cost. Both can optimize beam propagation within the laser resonant cavity, making the laser mode more stable and improving the quality and efficiency of laser output. Especially in applications requiring precise adjustment of the optical path and image transmission, it enhances the system's flexibility and adaptability.

[0077] In some embodiments, the laser gain unit is a transmissive laser gain module or a reflective laser gain module.

[0078] In this embodiment, the transmissive laser gain module can be represented as a laser module that provides gain through a gain medium (e.g., solid, gas, liquid, or optical fiber), where the laser beam is amplified as it passes through the gain medium. In such a module, the laser beam passes through the gain medium and gains energy amplification therefrom, ultimately outputting an amplified laser beam. In a transmissive laser gain module, the laser beam enters the gain medium (e.g., a neodymium-doped laser crystal, optical fiber, or gas) from a gain source (e.g., a pump laser or spontaneous emission source). The laser beam propagates in the gain medium and amplifies its energy through stimulated emission. The gain process of the laser beam is often accompanied by the action of a pump source, providing sufficient energy to excite particles or molecules in the gain medium. As the laser beam passes through the gain medium, the particles in the gain medium release additional light energy, thereby increasing the intensity of the laser beam.

[0079] In this embodiment, the reflective laser gain module can be represented as a module that amplifies the laser beam through a gain medium. In this module, the laser beam passes through the gain medium and is reflected back, thereby increasing the amplification effect of the light through multiple round trips. The reflective gain module includes at least one mirror or other reflective optical element for changing the propagation path of the laser and increasing its interaction with the gain medium.

[0080] In a reflective laser gain module, after the laser beam enters the gain medium, the medium amplifies the energy of the laser beam. Then, the beam is reflected back into the gain medium by a mirror or reflective optics, allowing the laser beam to travel back and forth multiple times within the gain medium, continuing to amplify. This reflection process allows the laser beam to remain in the gain medium for a longer period, thus achieving higher gain and resulting in a higher intensity laser output.

[0081] In this embodiment, the laser gain unit is either a transmissive laser gain module or a reflective laser gain module, which has the following advantages: First, the transmissive laser gain module can directly transmit the laser beam through the gain medium, resulting in lower optical loss and higher beam quality, making it suitable for high-efficiency laser output. Second, the reflective laser gain module increases the optical path through reflection, allowing the laser to be amplified more in the gain medium, which helps to improve output power and enhance system stability. The two gain module designs can be flexibly selected as needed to optimize the laser's output characteristics, improve the overall system efficiency and reliability, and adapt to the different application requirements for laser output power and quality.

[0082] In some embodiments, the resonant cavity includes only a first cavity mirror and a second cavity mirror, and the first cavity mirror and the second cavity mirror constitute a linear resonant cavity.

[0083] In this embodiment, the resonant cavity includes only a first cavity mirror and a second cavity mirror, forming a linear resonant cavity. This has the following advantages: First, the linear resonant cavity has a simple structure, lower design and manufacturing costs, and reduces system complexity, thereby improving overall reliability and stability. Second, the linear resonant cavity has high beam transmission efficiency, reducing losses in the optical path, making it suitable for high-efficiency energy amplification laser systems. Furthermore, the linear resonant cavity design enables better mode control, resulting in a more stable laser output mode, suitable for various laser applications. Overall, this simplified design not only improves system performance but also enhances the applicability and economy of the laser.

[0084] In some embodiments, the laser generating device further includes a third cavity mirror and a fourth cavity mirror, wherein the first cavity mirror, the second cavity mirror, the third cavity mirror, and the fourth cavity mirror constitute a ring-shaped resonant cavity; The image transfer device includes a first sub-image transfer device and a second sub-image transfer device; wherein, the first sub-image transfer device is disposed between the first cavity mirror and the second cavity mirror, a polarizer and a pulse modulation device are sequentially disposed between the second sub-image transfer device and the third cavity mirror, the second sub-image transfer device is disposed between the third cavity mirror and the fourth cavity mirror, and the laser gain unit is disposed between the fourth cavity mirror and the first cavity mirror.

[0085] In some embodiments, by employing the ring cavity structure and configuring two sub-image transfer devices, the following beneficial effects are achieved: the ring cavity structure allows the laser to propagate in a unidirectional traveling wave manner within the cavity, thereby significantly improving the energy extraction efficiency and output power stability of the laser gain medium; by precisely configuring the first and second sub-image transfer devices in two opposite optical paths composed of four cavity mirrors, and setting corresponding cavity mirrors (e.g., the first and second cavity mirrors, the third and fourth cavity mirrors) on their conjugate image planes, two regions with infinitely small equivalent cavity lengths are created in the entire ring optical path, thus perfectly maintaining the core advantages of suppressing diffraction mode selection and achieving simultaneous oscillation of multiple transverse modes even in complex cavity shapes; at the same time, this symmetrical structure provides an optimal layout for concentrating control elements such as polarizers and pulse modulation devices in a free optical path (e.g., between the second sub-transfer device and the third cavity mirror), ensuring both high efficiency of pulse modulation and maintaining the super-Gaussian distribution characteristics of the beam, ultimately realizing a ring cavity oscillator with a compact structure, optimized thermal management, and the ability to output high-quality, high-energy lasers.

[0086] This embodiment provides a laser system, including: the laser generating device described above.

[0087] In this embodiment, the laser system can be a laser system for industrial processing. The laser system can be an industrial-grade laser processing platform for macroscopic material processing, the core of which includes the aforementioned large mode field laser generation device as a seed source or directly as a high-power output source; the system utilizes the uniform energy distribution and absence of central hot spots of the large mode field and super-Gaussian flat-top beam output by the oscillator to perform laser welding, surface cladding, or macroscale additive manufacturing on workpieces such as metals and composite materials.

[0088] In this embodiment, the laser system can be a laser system used in the field of medical aesthetics. The laser system can be a laser treatment device used for surface treatment in the medical or aesthetic field, which integrates the large-area laser generating device as a treatment light source.

[0089] In this embodiment, the laser system can be a laser system used in scientific research scenarios. The laser system can be a scientific experimental device for physical, chemical, or optical research, which uses the large-mode-field laser generator as a pump source or a driving light source for nonlinear optical experiments.

[0090] In one specific implementation, a large-area laser generation device is provided.

[0091] In related technologies, current laser generating devices all rely on the principle of positive feedback resonance to achieve free-form oscillation of the light field within the resonant cavity, thereby realizing Gaussian laser output. Their characteristics include either a fundamental transverse mode or a single higher-order transverse mode. However, both cases suffer from drawbacks such as uneven near-field energy distribution, small mode volume, and limitations in output energy (continuous or single-pulse energy) due to the influence of device damage threshold. Furthermore, to obtain higher energy output, the laser output from the generating device is typically expanded, shaped by taking the middle flat-top region, and then amplified. This process has several drawbacks: firstly, it wastes the energy output from the oscillator, resulting in low laser efficiency; secondly, it necessitates the use of multi-stage laser amplifiers to achieve higher energy output; and thirdly, the increased number of components increases laser cost and reduces operational reliability.

[0092] To address the shortcomings of existing laser generation devices and solve the aforementioned problems, this embodiment provides a large-mode-field laser generation device. This large-mode-field oscillator allows multiple transverse laser modes to oscillate simultaneously within the resonant cavity. A large energy output is obtained through a single oscillator, and the superposition of multiple transverse modes results in a super-Gaussian distribution in the laser near-field. This laser generation device features a compact structure, high efficiency, low cost, high reliability, and good applicability.

[0093] This implementation scheme uses an image transfer device to infinitely reduce the distance of the cavity mirror within the laser resonant cavity. This results in the laser transmission distance being insufficient to effectively filter the laser mode when the laser reaches the oscillation emission threshold, causing multiple modes to oscillate simultaneously within the cavity. Theoretically, this can achieve a laser mode field that is identical to the confined element within the cavity and has a super-Gaussian near-field distribution, thereby obtaining a greater energy output within a limited damage threshold range.

[0094] This implementation scheme overcomes the shortcomings of commonly used oscillators, such as small modulus volume and uneven laser near-field distribution. It is suitable for most laser systems that require a specific laser near-field, and is especially suitable for high-repetition-rate, high-energy systems.

[0095] Understandably, in traditional oscillators, the gain medium generates spontaneous emission light under the excitation of the pump source. This spontaneous emission light then passes through the gain medium to produce stimulated emission light. This stimulated emission light is transmitted back and forth between cavity mirror one and cavity mirror two, allowing it to be amplified with sufficient energy to form a laser. However, lasers have modes, which are selected by the resonant cavity. Some oscillate with the fundamental transverse mode, while others oscillate with higher-order transverse modes. But after mode selection by the resonant cavity, only a few modes can oscillate. Even the mode volume of higher-order modes is only slightly larger than that of the fundamental transverse mode, and is still volume-limited. At the same time, the near field of the beam has a Gaussian distribution, with the energy density at the center of the beam being much higher than at the edges, like a target. The energy is strong at the center and weaker towards the edges. However, optical components are limited by the damage threshold, and the energy density or power density they can withstand is limited. Therefore, the output energy is very limited with a small mode volume. For example, a pulsed laser may only have a few millijoules.

[0096] The image transfer device used in this implementation differs from the common practice of embedding it within the resonant cavity to improve beam quality. Instead, we place the resonant cavity and mirror two on a conjugate image plane. From the perspective of laser transmission, the two reflective surfaces are phase-conjugate, equivalent to zero transmission distance. This eliminates the need for resonant cavity mode selection, allowing all transverse modes to oscillate within the cavity. The near-fields of multiple transverse modes are superimposed, preventing the formation of Gaussian modes. Instead, the beam aperture is comparable to the aperture of the gain medium or cavity mirror, resulting in a large-mode-field laser output with a beam diameter reaching the centimeter level. Furthermore, the near-field of this large-mode-field laser exhibits a super-Gaussian morphology, avoiding the issue of high energy in the center and low energy at the edges of a Gaussian beam. Therefore, at the same energy or power density, a significantly higher energy output can be achieved, reaching hundreds of millijoules or even several joules.

[0097] In short, the two characteristics of a large-mode-field laser generator are: first, the oscillator output beam has a large aperture; and second, the near-field energy distribution is super-Gaussian, thus enabling the output of high energy. In contrast, traditional oscillators have limited mode volume and small aperture; their near-field distribution is Gaussian, with strong energy at the center, and their output energy is limited by the component damage threshold.

[0098] The difference between super-Gaussian and Gaussian distributions is that when the beam energy density is the same, the energy density of a super-Gaussian beam is almost uniform in the near field, while the Gaussian distribution has an average energy density. The energy density at the center of the beam is several times the average energy density, while the energy density at the edge of the beam is very low. Therefore, the energy density at the center determines the upper limit of the average energy density.

[0099] In one specific implementation, a linear large-mode-field laser generating device is provided, including a cavity mirror one, a laser head, a 4f image transfer device, a polarizer, a Q-switching element, a waveplate, and a cavity mirror two.

[0100] The laser head emits spontaneous emission light under pump excitation. The light can propagate to the left or the right. Taking leftward propagation as an example, the spontaneous emission light is transmitted to cavity mirror one, reflected, and then passes through the laser head again. It then passes through the image transfer device and polarizer in sequence. Due to the polarization effect of the polarizer, only P-polarized light can pass through. Then it passes through the Q-switching element and waveplate in sequence, and reaches cavity mirror two. It is reflected by cavity mirror two to form positive feedback. Then it passes through the waveplate, Q-switching element, polarizer, image transfer device, and laser head in sequence to reach cavity mirror one. This process repeats to form oscillation. At this point, cavity mirror one and cavity mirror two are located on the object plane and image plane of the image transmission device, respectively. Theoretically, the cavity length of the resonant cavity is infinitely close to zero, which allows high-order transverse modes transmitted at large angles to oscillate within the resonant cavity. Therefore, multiple transverse modes oscillate simultaneously within the resonant cavity. The Q-switching element is an electro-optic Q-switch. A 1 / 4 voltage is applied during oscillation, which cancels out the effect of the 1 / 4 waveplate, allowing the P-polarized laser to oscillate continuously within the cavity. By removing the voltage on the electro-optic Q-switch, a laser output with a large mode field, high energy, and super-Gaussian morphology can be obtained.

[0101] In this implementation scheme, the Q-switching device is used to achieve pulsed laser output by combining Q-switching elements, waveplates, polarizers, etc. when the oscillator has pulsed laser output. The Q-switching elements can be active Q-switching devices such as electro-optic Q-switching and acousto-optic Q-switching, or passive Q-switching devices such as saturable absorbers.

[0102] In this implementation scheme, the large mode field oscillator can output laser light through cavity mirror one or cavity mirror two, or by adding a polarizer inside the cavity or adding a partial mirror in the middle as an output coupling mirror. In this embodiment, the resonant cavity formed by cavity mirror one and cavity mirror two can be a linear cavity (straight or folded) or a ring cavity.

[0103] In this embodiment, the order of the device positions between cavity mirror one and cavity mirror two can be adjusted as needed.

[0104] In this embodiment, the laser head can be either transmissive or reflective.

[0105] In this embodiment, the image transmission device can be a 4f imaging system or a single-lens imaging system.

[0106] This implementation scheme may include the following workflow: Step S1: Under the excitation of an external pump source, population inversion occurs in the laser gain unit and spontaneous emission light is generated. This spontaneous emission light is emitted from the laser gain unit in various directions within the resonant cavity.

[0107] Step S2: The spontaneous emission light generated in step S1 propagates within the resonant cavity composed of the first cavity mirror and the second cavity mirror. Part of the spontaneous emission light first passes through an image transfer device, which, based on its object-image conjugate characteristics, precisely images the light field distribution of the first cavity mirror located on its object plane onto the second cavity mirror located on its image plane. Subsequently, the beam continues to propagate and passes through a Q-switching device, which is subjected to voltage during the oscillation setup phase and is in a high-loss state to suppress laser oscillation and store energy in the laser gain unit. Step S3: The beam is finally transmitted to the second cavity mirror and reflected by it, and then transmitted in the opposite direction along the original optical path; the beam transmitted in the opposite direction passes through the Q-switching device and the image transfer device again, and finally reaches the first cavity mirror and is reflected by it, thus completing a complete round-trip propagation and forming positive feedback. Step S4: Since the first cavity mirror and the second cavity mirror are precisely located on the conjugate object plane and image plane of the image transfer device, respectively, from the perspective of light field transmission, the effective optical distance between them is equivalently shortened to almost zero. Under this condition, the light wave cannot undergo sufficient diffraction evolution during the propagation process between the two reflections, causing the resonant cavity to lose its inherent mode selection capability.

[0108] Step S5: Therefore, a large number of higher-order transverse modes and fundamental transverse modes of different orders can satisfy the phase condition of oscillation, and at the same time, they oscillate in the resonant cavity and participate in gain competition; the optical fields of these multiple transverse modes are incoherently superimposed in the cavity, and their synthesis effect finally forms a large-mode field output beam with a spot size comparable to the aperture of the gain medium, and its near-field energy distribution presents a super-Gaussian morphology with a flat top and steep edges.

[0109] Step S6: When the energy stored in the laser gain unit reaches saturation, the voltage applied to the Q-switching device is removed, causing it to instantly switch to a low-loss state. The huge energy accumulated in the cavity is released and output in the form of a giant pulse, ultimately obtaining a high-energy pulsed laser with a large mode field and a super-Gaussian near-field distribution.

[0110] In one specific implementation, a ring-shaped large-mode-field laser generating device is provided, including cavity mirror one, image transfer device one, cavity mirror two, polarizer, Q-switching element, cavity mirror three, image transfer device two, cavity mirror four, and laser head.

[0111] The laser head emits spontaneous emission light under pump excitation. The light can propagate to either cavity mirror one or cavity mirror four. Taking propagation to cavity mirror one as an example, the spontaneous emission light is transmitted to cavity mirror one and reflected, then passes through image transfer device one, cavity mirror two, and polarizer in sequence. Due to the polarization effect of the polarizer, only P-polarized light can pass through. Then, it passes through Q-switching element, cavity mirror three, image transfer device two, cavity mirror four, and laser head in sequence, thus completing positive feedback. This process repeats to form oscillation. At this point, the object plane of image transfer device one coincides with the image plane of image transfer device two, and the image plane of image transfer device one coincides with the object plane of image transfer device two. Theoretically, the cavity length of the resonant cavity is infinitely close to zero, which allows high-order transverse modes transmitted at large angles to oscillate within the resonant cavity. Therefore, multiple transverse modes oscillate simultaneously within the resonant cavity. The Q-switching element is an electro-optic Q-switch. During oscillation, a voltage of 1 / 2 is applied, allowing the P-polarized laser to oscillate continuously within the cavity. By removing the voltage on the electro-optic Q-switch, a laser output with a large mode field, high energy, and super-Gaussian morphology can be obtained.

[0112] It should be noted that the core structure of the laser generation device described in this embodiment is also suitable for constructing a high-performance regenerative amplifier. It is understood that the laser resonator, after configuring a seed light injection unit and employing corresponding timing control logic, can achieve regenerative amplification. Specifically, by controlling the state of the pulse modulation device (electro-optic Q-switching device), a weak seed laser pulse injected externally can be captured within the resonant cavity, and multi-pass cyclic amplification is performed using the cavity laser gain unit. Because the core structure of this embodiment suppresses the cavity's mode selection capability, this amplification process does not only amplify the fundamental mode as in traditional regenerative amplifiers, but allows multiple transverse modes to participate in amplification simultaneously and undergo incoherent superposition. Therefore, the final output is a high-energy laser pulse that has been efficiently amplified and possesses a large mode field and a super-Gaussian near-field distribution.

[0113] In an alternative embodiment, the laser generating device provided is not limited to use as a self-oscillating oscillator. Its unique physical structure, which suppresses diffraction mode selection, makes it well-suited for construction as a regenerative amplifier.

[0114] When used as a regenerative amplifier, in addition to all the optical components described in the foregoing embodiments (i.e., resonant cavity, laser gain unit, image transfer device, and optional polarizer, pulse modulation device, and phase delay device), a sub-light injection unit (e.g., composed of a beam splitter, electro-optic isolator, or acousto-optic modulator) needs to be added and connected to the controller. The function of the controller is to synchronize with the external seed light source and precisely control the operating state of the pulse modulation device (e.g., electro-optic Q-switching switch).

[0115] In a specific implementation plan, the workflow may be: When the laser gain unit is pumped to saturation gain, the pulse modulator is set to a high-loss state by the controller to suppress spontaneous emission oscillations within the cavity. At this time, a weak pulse from an external seed laser is introduced into the resonant cavity through the seed light injection unit. The instant the seed pulse fully enters the cavity, the controller drives the pulse modulator to rapidly change its state (e.g., by removing the voltage applied to the electro-optic crystal), switching the Q value of the resonant cavity from low to high, thereby trapping the seed pulse within the cavity.

[0116] The captured seed pulse will cycle dozens to hundreds of times within a resonant cavity with an equivalent cavity length of nearly zero. Each cycle amplifies the energy through the laser gain unit. The amplification process does not filter the laser transverse modes; the seed light excites a large number of transverse modes during amplification and incoherently superimposes them. Therefore, the pulse energy and spot size increase synchronously, and its near-field intensity distribution always maintains a super-Gaussian shape.

[0117] When the pulse energy is amplified to a predetermined value, the controller controls the pulse modulation device to change its state again (e.g., reapply voltage), instantly reducing the Q value of the resonant cavity, thereby "switching" the fully amplified laser pulse out of the cavity and completing one amplification process.

[0118] Ultimately, the system outputs a laser pulse with significantly enhanced energy while perfectly preserving its ultra-large mode field and ultra-Gaussian flat-top distribution characteristics. This demonstrates that the present invention is not only a novel oscillator, but its core concept also represents a completely new regenerative amplifier architecture capable of simultaneously improving output pulse energy and beam quality, possessing extremely broad application prospects.

[0119] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0120] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0121] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0122] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0123] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A laser generating device, characterized in that, The laser generating device includes at least: A resonant cavity, which includes at least a first cavity mirror and a second cavity mirror; A laser gain unit is disposed inside the resonant cavity; An image transfer device is disposed inside the resonant cavity, wherein the first cavity mirror and the second cavity mirror are respectively located on the conjugate object plane and image plane of the image transfer device, such that the resonant cavity supports the simultaneous oscillation of multiple transverse modes to output a large mode field super-Gaussian beam.

2. The laser generating apparatus according to claim 1, characterized in that, The laser generating device further includes: A polarizer is disposed inside the resonant cavity.

3. The laser generating apparatus according to claim 2, characterized in that, The laser generating device further includes: A pulse modulation device is disposed inside the resonant cavity, and the pulse modulation device and the laser gain unit are located on opposite sides of the polarizer.

4. The laser generating apparatus according to claim 3, characterized in that, The laser generating device further includes: A phase delay device is disposed inside the resonant cavity, and the phase delay device and the laser gain unit are located on opposite sides of the polarizer.

5. The laser generating apparatus according to claim 3, characterized in that, The pulse modulation device is an electro-optic Q-switching device, an acousto-optic Q-switching device, or a passive Q-switching device.

6. The laser generating apparatus according to claim 1, characterized in that, The image transmission device is a 4f imaging system or a single-lens imaging system.

7. The laser generating apparatus according to claim 1, characterized in that, The laser gain unit is either a transmission laser gain module or a reflection laser gain module.

8. The laser generating apparatus according to claim 1, characterized in that, The resonant cavity includes only a first cavity mirror and a second cavity mirror, and the first cavity mirror and the second cavity mirror constitute a linear resonant cavity.

9. The laser generating apparatus according to claim 1, characterized in that, The laser generating device further includes a third cavity mirror and a fourth cavity mirror, and the first cavity mirror, the second cavity mirror, the third cavity mirror and the fourth cavity mirror constitute a ring-shaped resonant cavity. The image transfer device includes a first sub-image transfer device and a second sub-image transfer device; wherein, the first sub-image transfer device is disposed between the first cavity mirror and the second cavity mirror, a polarizer and a pulse modulation device are sequentially disposed between the second sub-image transfer device and the third cavity mirror, the second sub-image transfer device is disposed between the third cavity mirror and the fourth cavity mirror, and the laser gain unit is disposed between the fourth cavity mirror and the first cavity mirror.

10. A laser system, characterized in that... include: A laser generating apparatus as described in any of claims 1-9.

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