Multi-pulse-width laser

Abstract

The invention discloses a multi-pulse-width laser, which relates to the technical field of medical laser equipment, and structurally comprises a picosecond laser generating unit, a pulse width generating unit, a pulse width generating unit and a pulse width generating unit, the microsecond-nanosecond laser generating unit is used for selectively generating microsecond seed light or nanosecond seed light according to a preset mode; the light beam combining unit is used for combining the laser generated by the picosecond laser generating unit and the microsecond-nanosecond laser generating unit into the same light path; the common amplification unit is arranged behind the light beam combining unit and comprises a first amplifier and a second amplifier which are arranged in parallel, the first amplifier is used for performing double-pass amplification on the picosecond seed light, and the second amplifier is used for performing third-time amplification on the picosecond seed light subjected to double-pass amplification; and the second amplifier is also used for amplifying the microsecond seed light or the nanosecond seed light. According to the invention, the integration of picosecond, nanosecond and microsecond pulse width lasers in a single device is realized, and the device is suitable for various treatment requirements in the field of skin medical cosmetology.

Description

Technical Field

[0001] The invention relates to the technical field of medical picosecond lasers, and in particular to a multi-pulse width laser. Background Art

[0002] In the field of medical skin beauty, lasers with different pulse widths have different working characteristics and application scenarios. Currently, there are three main types of lasers with different pulse widths: Q-switched nanosecond lasers (pulse width of about 3-10 nanoseconds), microsecond lasers (pulse width of about tens to hundreds of microseconds), and picosecond lasers (pulse width of about hundreds of picoseconds).

[0003] However, in actual applications, clinicians usually need to purchase multiple sets of equipment such as nanosecond, picosecond lasers or even microsecond lasers separately, which not only takes up a large space, but also requires medical institutions to pay multiple equipment costs.

[0004] In addition, existing picosecond lasers usually have some technical defects in their design, such as inconsistent spot size and divergence angle at different repetition rates in the non-frequency-divided working state, which affects the consistency and accuracy of treatment. At the same time, the independent configuration of multiple sets of laser equipment also increases the complexity and maintenance cost of the system.

[0005] Therefore, developing a medical laser device that can integrate multiple pulse width output functions to meet diverse clinical needs has important practical value. Summary of the invention

[0006] The present invention discloses a multi-pulse width laser, aiming to solve the technical problems existing in the prior art. The present invention adopts the following technical solutions: An embodiment of the present invention provides a multi-pulse width laser, comprising: A picosecond laser generating unit, used for generating picosecond seed light; A microsecond-nanosecond laser generating unit, used for selectively generating microsecond seed light or nanosecond seed light according to a preset mode; A beam combining unit, used to combine the lasers generated by the picosecond laser generating unit and the microsecond-nanosecond laser generating unit into the same optical path; The common amplification unit is arranged after the beam combining unit, and includes a first amplifier and a second amplifier arranged in parallel. The first amplifier is used to perform double-pass amplification on the picosecond seed light, and the second amplifier is used to perform a third amplification on the picosecond laser after the double-pass amplification. The second amplifier is also used to amplify the microsecond seed light or the nanosecond seed light.

[0007] As a preferred technical solution, the shared amplification unit also includes a first 1 / 4 wave plate and a first 0° total reflection mirror, which are sequentially arranged on the output light path of the first amplifier; the first 0° total reflection mirror is used to totally reflect the picosecond seed light after the first amplification back to the first amplifier; the first 1 / 4 wave plate is used to convert the polarization state of the picosecond seed light after the first amplification.

[0008] As a preferred technical solution, it also includes a beam compensation unit, which is arranged between the first 1 / 4 wave plate and the first 0° total reflection mirror, and is used to compensate the optical characteristics of the laser beam at different repetition frequencies to maintain the consistency of the spot size and divergence angle of the output beam.

[0009] As a preferred technical solution, the beam compensation unit includes a negative lens, which is arranged on a movable bracket and is used to selectively insert or withdraw the light path according to preset repetition frequency parameters to compensate for the differences in optical characteristics of the light beam at different repetition frequencies.

[0010] As a preferred technical solution, the output light path of the picosecond laser generating unit is parallel to the first amplifier, and the output light path of the picosecond laser generating unit is connected to the first amplifier through the first isolation unit, the first 45° reflector and the second 45° reflector in sequence.

[0011] As a preferred technical solution, the first isolation unit includes a first 1 / 2 wave plate, a first polarizer, a second 1 / 2 wave plate, a Faraday rotator and a second polarizer arranged in sequence along the optical path. The optical path of the first isolation unit is parallel to the first amplifier. The first 45° reflector is arranged at the output end of the first isolation unit. The second 45° reflector is arranged opposite to the first 45° reflector, and is used to refract the light beam output by the first isolation unit and introduce it into the first amplifier.

[0012] As a preferred technical solution, the beam combining unit includes a third polarizer, a third 1 / 2 wave plate, a third 45° reflector and a fourth 45° reflector arranged in sequence along the optical path; The third polarizer is arranged on the optical path between the first 45° reflector and the second 45° reflector, the third 1 / 2 wave plate is arranged between the third polarizer and the third 45° reflector, the third 45° reflector is used to change the propagation direction of the light beam, and the fourth 45° reflector is arranged opposite to the third 45° reflector, and is used to introduce the light beam refracted by the third 45° reflector into the second amplifier.

[0013] As a preferred technical solution, the output light path of the microsecond-nanosecond laser generating unit is parallel to the second amplifier, and the beam combining unit also includes a fifth 45° reflector, a sixth 45° reflector and a fourth polarizer arranged on the output light path of the microsecond-nanosecond laser generating unit, the fourth polarizer is arranged between the third 45° reflector and the fourth 45° reflector, the fifth 45° reflector and the sixth 45° reflector are arranged relative to each other, and are used to guide the light beam output by the microsecond-nanosecond laser generating unit to the fourth polarizer, and the fourth polarizer is used to reflect the microsecond seed light or the nanosecond seed light to the fourth 45° reflector and enter the second amplifier.

[0014] As a preferred technical solution, an optical shutter is further provided between the microsecond-nanosecond laser generating unit and the fifth 45° reflector, and the optical shutter is used to control the on-off of the output light beam of the microsecond-nanosecond laser generating unit.

[0015] As a preferred technical solution, the microsecond-nanosecond laser generating unit includes a second 0° total reflection mirror, a second 1 / 4 wave plate, a Q switch, a fifth polarizer, a third amplifier and an output mirror arranged in sequence along the optical path; the Q switch is used to control the time characteristics of the laser pulse, and by adjusting the working mode of the Q switch, nanosecond seed light or microsecond seed light can be selectively generated.

[0016] As a preferred technical solution, a second isolation unit is provided after the common amplification unit; the second isolation unit includes a seventh 45° reflector, an eighth 45° reflector and a third 1 / 4 wave plate, the seventh 45° reflector is arranged at the output end of the second amplifier, the eighth 45° reflector is arranged opposite to the seventh 45° reflector, the third 1 / 4 wave plate is arranged on the output optical path of the eighth 45° reflector, and is used to finally output the laser to an external handpiece.

[0017] One embodiment of the above invention has the following advantages or beneficial effects: The present invention mainly provides a multi-pulse width laser, which realizes the integration of three pulse width lasers, namely picosecond, nanosecond and microsecond, in a single device. Seed lights with different pulse widths are generated by a picosecond laser generating unit and a microsecond-nanosecond laser generating unit, and these lasers are combined into the same optical path by a beam combining unit, which greatly reduces the equipment cost and occupied space, so that medical and beauty institutions no longer need to purchase and maintain multiple laser devices with different pulse widths.

[0018] Furthermore, the shared amplification unit in the embodiment of the present invention includes a dual-pump cavity structure arranged in parallel, so that the picosecond seed light can be efficiently amplified in two passes. At the same time, through the optical polarization beam combining scheme, two different types of laser pulses share one amplifier, further improving the integration and resource utilization of the equipment.

[0019] In addition, the embodiment of the present invention also solves the problem of inconsistent laser output characteristics at different repetition frequencies in the non-frequency division state. By setting a beam compensation unit, the optical parameters are automatically adjusted at different repetition frequencies to ensure that the spot size and divergence angle of the output beam remain consistent, thereby improving the stability and reliability of laser treatment in clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings: Figure 1 A structural diagram of a multi-pulse width laser in a preferred implementation manner disclosed in an embodiment of the present invention; Figure 2 This is a structural diagram of a multi-pulse width laser when a beam compensation unit is switched out of the optical path in a preferred implementation manner disclosed in an embodiment of the present invention.

[0021] Description of reference numerals: Picosecond laser generating unit 1, first 1 / 2 wave plate 2, first polarizer 3, second 1 / 2 wave plate 4, Faraday rotator 5, second polarizer 6, first 45° reflector 7, third polarizer 8, second 45° reflector 9, first amplifier 10, first 1 / 4 wave plate 11, negative lens 12, first 0° total reflector 13, third 45° reflector 14, fourth polarizer 15, fourth 45° reflector 16, second amplifier 17, seventh 45° reflector 18, eighth 45° reflector 19, third 1 / 4 wave plate 20, light guide arm reflection interface 21, second 0° total reflector 22, second 1 / 4 wave plate 23, Q switch 24, fifth polarizer 25, third amplifier 26, output mirror 27, optical shutter 28, fifth 45° reflector 29, sixth 45° reflector 30, third 1 / 2 wave plate 31. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0023] In the description of the present invention, the terms “first”, “second”, etc. are only used to distinguish the descriptions and should not be understood as indicating or implying relative importance.

[0024] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] refer to Figure 1 The embodiment of the present invention provides a multi-pulse width laser, which includes a picosecond laser generating unit 1, a microsecond-nanosecond laser generating unit, a beam combining unit and a common amplifying unit, wherein the picosecond laser generating unit 1 is used to generate picosecond seed light, the microsecond-nanosecond laser generating unit is used to selectively generate microsecond seed light or nanosecond seed light according to a preset mode, and the output light path of the picosecond laser generating unit 1 and the output light path of the microsecond-nanosecond laser generating unit are arranged in parallel; the beam combining unit is arranged between the picosecond laser generating unit 1 and the output light path of the microsecond-nanosecond laser generating unit, and is used to combine the lasers generated by the picosecond laser generating unit 1 and the microsecond-nanosecond laser generating unit into the same light path; the common amplifying unit is arranged after the beam combining unit, and includes a first amplifier 10 and a second amplifier 17 arranged in parallel, the first amplifier 10 is used to perform double-pass amplification on the picosecond seed light, the second amplifier 17 is used to perform a third amplification on the picosecond laser after the double-pass amplification, or the second amplifier 17 is used to amplify the microsecond seed light or the nanosecond seed light.

[0026] In a preferred embodiment, the picosecond laser generating unit 1 generates picosecond seed light by passive Q-switching principle, and the picosecond seed light can provide a stable short-pulse laser source; the microsecond-nanosecond laser generating unit works by active Q-switching, and can flexibly switch between nanosecond and microsecond pulse width modes by adjusting the working mode of the Q switch 24; the beam combining unit utilizes the polarization characteristics of the laser and adopts polarization combining to combine lasers of different optical paths into the same optical path, so that the picosecond seed light and the nanosecond or microsecond seed light can share the subsequent amplification system; the first amplifier 10 in the shared amplification unit increases the energy of the picosecond seed light by a two-way amplification method, so that the picosecond seed light returns to the original path after the first amplification for the second amplification, and then the picosecond laser can enter the second amplifier 17 for the third amplification; and when the system works in the nanosecond or microsecond mode, the seed light generated by the microsecond-nanosecond laser generating unit directly enters the second amplifier 17 for amplification. Through this shared amplification structure, the integration and resource utilization efficiency of the equipment are greatly improved.

[0027] Those skilled in the art should understand that passive Q-switching is a technology that uses the optical properties of a saturable absorber to automatically modulate the Q value. When the laser intensity in the cavity is lower than the saturation threshold of the saturable absorber, the saturable absorber has a strong absorption of the laser and the Q value in the cavity is low. When the energy in the cavity accumulates to a certain level and the laser intensity exceeds the saturation threshold, the saturable absorber becomes transparent and the Q value of the cavity suddenly increases, thereby outputting ultrashort pulse lasers. This method can generate short pulses on the order of picoseconds.

[0028] Active Q-switching is to actively control the change of the Q value of the cavity by controlling a Q-switch device such as an electro-optic switch or an acousto-optic switch through an external electrical signal. Typically, when the Q-switch 24 is in a low-Q state, the pump energy accumulates in the gain medium, and then the Q-switch 24 switches to a high-Q state, so that the accumulated energy is quickly released to form a pulsed laser. This method can generate nanosecond or microsecond laser pulses as needed by adjusting the control timing of the Q-switch 24.

[0029] By combining the above two Q-switching methods, the multi-pulse width laser of the embodiment of the present invention can realize the generation and output of three different pulse width lasers: picosecond, nanosecond and microsecond in a single device.

[0030] In a preferred embodiment, the picosecond laser generating unit 1 is used to output picosecond seed light with an energy of 0.4-0.5 mJ and a pulse width of 250-900 PS. In this embodiment, the pulse width is preferably 300 PS.

[0031] Optionally, the picosecond laser generating unit 1 may be a semiconductor laser, a fiber laser, or other types of lasers capable of generating ultrashort pulses, which are not specifically limited in this embodiment.

[0032] In a preferred embodiment, the output light path of the picosecond laser generating unit 1 is parallel to the first amplifier 10, that is, the output light path of the picosecond laser generating unit 1, the output light path of the microsecond-nanosecond laser generating unit, the light path where the first amplifier 10 is located, and the light path where the second amplifier 17 is located are all arranged in parallel to shorten the axial length of the entire multi-pulse width laser.

[0033] Preferably, the output optical path of the picosecond laser generating unit 1 is connected to the first amplifier 10 through the first isolation unit, the first 45° reflector 7 and the second 45° reflector 9 in sequence, and the first isolation unit is used to suppress the self-excitation between the picosecond laser generating unit 1 and the first amplifier 10; preferably, the first isolation unit includes a first 1 / 2 wave plate 2, a first polarizer 3, a second 1 / 2 wave plate 4, a Faraday rotator 5 and a second polarizer 6 arranged in sequence along the optical path, the optical path of the first isolation unit is parallel to the first amplifier 10, the first 45° reflector 7 is arranged at the output end of the first isolation unit, and the second 45° reflector 9 is arranged opposite to the first 45° reflector 7, and is used to refract the light beam output by the first isolation unit and introduce it into the first amplifier 10.

[0034] Specifically, the first 1 / 2 wave plate 2 is used to adjust the polarization direction of the incident laser so that it is consistent with the transmission polarization direction of the first polarizer 3, thereby improving the transmission efficiency; the first polarizer 3 is used to filter the light with a specific polarization direction, and only allows the light consistent with its polarization direction to pass; the second 1 / 2 wave plate 4 is used to adjust the polarization direction of the light beam so that it is suitable for the working requirements of the subsequent Faraday rotator 5; the Faraday rotator 5 is the core component of the first isolation unit, which can cause the light to produce irreversible polarization rotation in the propagation direction under the action of an external magnetic field. The polarization direction of the forward propagating light will rotate by a certain angle, while the polarization direction of the reverse propagating light will continue to rotate in the same direction. Instead of returning to the original state, in this embodiment, the Faraday rotator 5 is preferably a Faraday rotator 5 of 2-5 mm; the second polarizer 6 works in conjunction with the first polarizer 3. Due to the irreversible optical rotation characteristics of the Faraday rotator 5, the forward propagating light can pass through the second polarizer 6 after being processed by the Faraday rotator 5, while the reverse propagating light cannot match the first polarizer 3 after passing through the second polarizer 6 and the Faraday rotator 5, so it is blocked, thereby realizing the unidirectional transmission function of light, effectively preventing the reverse light in the first amplifier 10 from returning to the picosecond laser generating unit 1, thereby suppressing the self-excitation of the system and protecting the picosecond seed light source.

[0035] Those skilled in the art should understand that self-excitation, or self-lasing, refers to the formation of a resonant cavity by certain optical elements and gain media within the laser, causing part of the laser beam to reflect back and forth and be amplified without control, thereby forming an uncontrolled laser. This self-lasing will interfere with the expected laser output, affect the therapeutic / cosmetic effect, and pose a safety hazard.

[0036] In a preferred embodiment, the shared amplification unit is configured as a single-lamp dual-rod pump cavity, in which a xenon lamp and two parallel YAG crystals are provided, and the two YAG crystals are the first amplifier 10 and the second amplifier 17. In this embodiment, the crystal diameter of the first amplifier 10 is 6 mm. Those skilled in the art should understand that since a xenon lamp provides pump energy for two parallel YAG crystals at the same time, the energy loss that may be caused by multiple independent pump light sources is reduced, and the power consumption of the system is reduced; secondly, the single-lamp dual-rod structure enables the two amplification rods to obtain relatively uniform and synchronous pumping conditions, which helps to maintain the consistency and stability of each optical path amplification, improves the overall output beam quality, and since the single-lamp dual-rod pump cavity has a more compact structure, it is particularly suitable for application scenarios such as medical cosmetology that require high equipment space.

[0037] In a preferred embodiment, the shared amplification unit also includes a first 1 / 4 wave plate 11 and a first 0° total reflection mirror 13, which are sequentially arranged on the output light path of the first amplifier 10; the first 0° total reflection mirror 13 is used to totally reflect the picosecond seed light after the first amplification back to the first amplifier 10; the first 1 / 4 wave plate 11 is used to convert the polarization state of the picosecond seed light after the first amplification.

[0038] Preferably, after the picosecond seed light passes through the first amplifier 10 for the first time, the spot diameter of the output laser is 6mm, the energy is about 30mJ, and the polarization state is horizontal. The laser after the first amplification returns to the first amplifier 10 through the first 0° total reflection mirror 13 for the second amplification, that is, double-pass amplification. The laser passes through the first 1 / 4 wave plate 11 twice in the double-pass optical path, and its horizontal polarization state is converted to a vertical polarization state. The spot diameter of the output laser after the second amplification is 8mm and the energy is about 80mJ.

[0039] In a preferred embodiment, the picosecond laser generating unit 1 adopts a non-frequency division mode when working, which means that the laser only generates one pulse each time it discharges, rather than dividing the energy into multiple pulse sequences with lower energy for output. In the non-frequency division mode, the peak power of the laser output is higher, but the thermal effect in the gain medium will be different at different repetition frequencies, thereby affecting the optical properties of the beam, such as the divergence angle, spot size and other parameters. Specifically, when the repetition frequency is low, the gain medium has enough time to cool down, and the thermal effect is weak; when the repetition frequency is high, the heat accumulation in the gain medium is aggravated, and the thermal effect is more significant, resulting in changes in the beam quality parameters.

[0040] In order to solve the problem of inconsistent 1-10Hz light spot and divergence angle caused by non-frequency division, a beam compensation unit is provided between the first 1 / 4 wave plate 11 and the first 0° total reflection mirror 13, which is used to compensate the optical characteristics of the laser beam at different repetition frequencies to maintain the consistency of the spot size and divergence angle of the output light beam.

[0041] In a preferred embodiment, the beam compensation unit is configured as a negative lens 12, which is disposed on a movable bracket and is used to selectively insert or withdraw the light path according to preset repetition frequency parameters to compensate for differences in optical properties of the light beam at different repetition frequencies.

[0042] Preferably, when the picosecond laser generating unit 1 operates at a high repetition frequency, the negative lens 12 can be inserted into the optical path to compensate for the beam changes caused by thermal effects through its negative refractive ability; when the picosecond laser generating unit 1 operates at a low repetition frequency, the negative lens 12 can be automatically withdrawn from the optical path to maintain the original beam characteristics.

[0043] Preferably, when the repetition rate is ≥ 6 Hz, the negative lens 12 is cut into the optical path for compensation, such as Figure 1 When the repetition rate is ≤5 Hz, the negative lens 12 cuts out the light path, such as Figure 2 .

[0044] In a preferred embodiment, the beam combining unit includes a third polarizer 8, a third 1 / 2 wave plate 31, a third 45° reflector 14 and a fourth 45° reflector 16 arranged in sequence along the optical path; the third polarizer 8 is arranged on the optical path between the first 45° reflector 7 and the second 45° reflector 9, the third 1 / 2 wave plate 31 is arranged between the third polarizer 8 and the third 45° reflector 14, and is used to convert a vertically polarized light beam into a horizontal polarization state, the third 45° reflector 14 is used to change the propagation direction of the light beam, and the fourth 45° reflector 16 is arranged opposite to the third 45° reflector 14, and is used to introduce the light beam refracted by the third 45° reflector 14 into the second amplifier 17 of the common amplification unit, at which time the third amplification of the picosecond seed light is realized, and the spot diameter of the output laser is 9mm and the energy is about 500mJ.

[0045] In a preferred embodiment, a second isolation unit is further provided between the common amplification unit and the external handpiece, and the second isolation unit is used to suppress the self-excitation generated by the external handpiece of the multi-pulse width laser. Preferably, the second isolation unit includes a seventh 45° reflector 18, an eighth 45° reflector 19 and a third 1 / 4 wave plate 20, the seventh 45° reflector 18 is arranged at the output end of the second amplifier 17, the eighth 45° reflector 19 is arranged opposite to the seventh 45° reflector 18, and the third 1 / 4 wave plate 20 is arranged on the output optical path of the eighth 45° reflector 19, and is used to finally output the laser to the external handpiece.

[0046] Specifically, since a folded optical path structure can be formed between the seventh 45° reflector 18 and the eighth 45° reflector 19, it is possible to block the reflected light from directly returning to the common amplifier unit. Secondly, when the forward-propagating laser passes through the third 1 / 4 wave plate 20, its polarization state changes from a horizontal polarization state to a circular polarization state. If there is a reflective surface in the external handpiece that causes part of the light to return, the polarization state of the returned light will change again after passing through the third 1 / 4 wave plate 20 again, becoming a vertical polarization state. Since the common amplifier unit has different amplification efficiencies for light in different polarization states, this change in polarization state will significantly reduce the possibility of the returned light being amplified again in the second amplifier 17, thereby effectively suppressing the self-excitation phenomenon.

[0047] In a preferred embodiment, the beam combining unit further includes a fifth 45° reflector 29, a sixth 45° reflector 30 and a fourth polarizer 15 arranged on the output light path of the microsecond-nanosecond laser generating unit, the fourth polarizer 15 is arranged between the third 45° reflector 14 and the fourth 45° reflector 16, the fifth 45° reflector 29 and the sixth 45° reflector 30 are arranged relative to each other, and are used to guide the light beam output by the microsecond-nanosecond laser generating unit to the fourth polarizer 15, and optionally, the fifth 45° reflector 29 and the sixth 45° reflector 30 can be further arranged as needed. Other optical elements are further arranged, such as corresponding lenses; the microsecond seed light or the nanosecond seed light is configured to be in a vertical polarization state, and the fourth polarizer 15 is used to reflect the microsecond seed light or the nanosecond seed light in the vertical polarization state to the fourth 45° reflector 16 and enter the second amplifier 17. At the same time, the fourth polarizer 15 exhibits high transmission characteristics for picosecond lasers in different polarization states. Since the picosecond laser has been converted into a horizontal polarization state after passing through the third 1 / 2 wave plate 31, it will not hinder or significantly affect the normal transmission of the picosecond laser between the third 45° reflector 14 and the fourth 45° reflector 16.

[0048] In this embodiment, the beam combining method based on polarization control avoids the energy loss that may be caused by the use of a beam splitter, and ensures the energy utilization efficiency of the two lasers with different pulse widths. In addition, the layout of the beam combining unit also ensures that the two lasers with different pulse widths can strictly propagate coaxially after beam combining and share the same amplification optical path, thereby ensuring that the two lasers output by the system have almost exactly the same beam characteristics and spatial distribution, greatly improving the system's operational convenience in practical applications and the consistency of treatment effects.

[0049] In a preferred embodiment, the microsecond-nanosecond laser generating unit includes a second 0° total reflection mirror 22, a second 1 / 4 wave plate 23, a Q switch 24, a fifth polarizer 25, a third amplifier 26 and an output mirror 27 arranged in sequence along the optical path; wherein, the second 0° total reflection mirror 22 and the output mirror 27 form a basic resonant cavity, and the second 1 / 4 wave plate 23, the Q switch 24, the fifth polarizer 25 and the third amplifier 26 are the core components for realizing pulse width control, and the Q switch 24 is used to control the time characteristics of the laser pulse, and by adjusting the working mode of the Q switch 24, nanosecond seed light or microsecond seed light can be selectively generated. Preferably, the third amplifier 26 is a single lamp single rod pump cavity; further, an optical gate 28 is also provided between the microsecond-nanosecond laser generating unit and the fifth 45° reflection mirror 29, and the optical gate 28 is used to control the on-off of the output beam of the microsecond-nanosecond laser generating unit. When the microsecond-nanosecond laser generating unit needs to switch the working mode or perform internal debugging, the optical gate 28 can block the laser output to prevent accidental irradiation caused by erroneous operation.

[0050] In a preferred embodiment, when the microsecond-nanosecond laser generating unit outputs nanosecond laser pulses, the Q switch 24 operates in a conventional Q-switching mode, i.e., a high-speed switching state, resulting in rapid release of energy in the resonant cavity, and the local oscillator outputs 200-400mJ, a pulse width of 3ns, and a vertically polarized laser. After amplification by the second amplifier 17, a 3ns, 800mJ-1J laser pulse is output; when the microsecond-nanosecond laser generating unit outputs microsecond laser pulses, the Q switch 24 operates in a corresponding modulation mode, and by precisely controlling the Q value change process of the resonant cavity, the energy is released at a slower rate, and a local oscillator light with a pulse width of 120μs and an energy of 300-500mJ is output. After amplification, a microsecond laser with a pulse width of 120μs and an energy of 1J is output.

[0051] In this embodiment, for picosecond laser, its optical path starts from the picosecond laser generating unit 1. The picosecond seed light generated by the unit first passes through the first isolation unit, the first 45° reflector 7, and the second 45° reflector 9 in sequence, and then enters the first amplifier 10 in the common amplification unit. After the first amplification, the light beam is propagated to the first 1 / 4 wave plate 11 with a horizontal polarization state, a 6mm spot diameter, and an energy of about 30mJ, and then is reflected by the first 0° total reflection mirror 13. During this process, the light beam characteristics may be adjusted by the beam compensation unit. The reflected light beam passes through the first 1 / 4 wave plate 11 again, and the polarization state is converted to vertical polarization at this time. It is amplified for the second time by the first amplifier 10 again, and the beam parameters are increased to 8mm spot diameter and about 80mJ energy. Subsequently, the picosecond laser passes through the third polarizer 8, the third 1 / 2 wave plate 31, and the third 45° reflector 14 in sequence, and then passes through the fourth polarizer 15 to reach the fourth 45° reflector 16, and is guided to the second amplifier 17 for the third amplification. The amplified high-energy picosecond laser is redirected by the seventh 45° reflector 18 and the eighth 45° reflector 19, and finally passes through the third 1 / 4 wave plate 20 and is output to the light guide arm reflection interface 21.

[0052] In this embodiment, for nanosecond laser, its path starts from the microsecond-nanosecond laser generating unit, in which the Q switch 24 works in the Q-switching mode, and generates a nanosecond seed light with a pulse width of 3ns and an energy of 200-400mJ through a resonant cavity composed of a second 0° total reflection mirror 22, a second 1 / 4 wave plate 23, a Q switch 24, a fifth polarizer 25, a third amplifier 26 and an output mirror 27. After passing through the optical gate 28, this nanosecond laser is guided to the fourth polarizer 15 through the fifth 45° reflection mirror 29 and the sixth 45° reflection mirror 30. Due to the polarization characteristics, the nanosecond laser is reflected by the fourth polarizer 15, turned to the fourth 45° reflection mirror 16, and then enters the second amplifier 17 for amplification, and the output parameters are increased to a pulse width of 3ns and an energy of 800mJ-1J. Thereafter, the nanosecond laser and the picosecond laser share the rear optical path, and also pass through the seventh 45° reflector 18 , the eighth 45° reflector 19 and the third 1 / 4 wave plate 20 , and are finally output to the light guide arm reflection interface 21 .

[0053] The optical path of the microsecond laser is the same as that of the nanosecond laser, except that the operating mode of the Q switch 24 inside the microsecond-nanosecond laser generating unit is different to generate microsecond seed light, which is then transmitted to the final output along the same path as the nanosecond laser, which will not be repeated in this embodiment.

[0054] It should be noted that the invention of this embodiment lies in the redesign and layout of the optical path structure in the laser, rather than the improvement of a certain component. Any component described in this embodiment can be purchased directly, and their structures will not be described one by one in this embodiment.

[0055] Those skilled in the art will understand that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstract and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise explicitly stated, each feature disclosed in this specification (including the accompanying claims, abstract and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

Claims

1. A multi-pulse width laser, characterized in that: include: A picosecond laser generating unit, used for generating picosecond seed light; A microsecond-nanosecond laser generating unit, used for selectively generating microsecond seed light or nanosecond seed light according to a preset mode; A beam combining unit, used for combining the lasers generated by the picosecond laser generating unit and the microsecond-nanosecond laser generating unit into the same optical path; A common amplification unit is arranged after the beam combining unit, and includes a first amplifier and a second amplifier arranged in parallel, wherein the first amplifier is used to perform double-pass amplification on the picosecond seed light, and the second amplifier is used to perform a third amplification on the picosecond laser after the double-pass amplification, and the second amplifier is also used to amplify the microsecond seed light or the nanosecond seed light.

2. The multi-pulse width laser according to claim 1, characterized in that: The common amplification unit also includes a first 1 / 4 wave plate and a first 0° total reflection mirror, which are sequentially arranged on the output light path of the first amplifier; the first 0° total reflection mirror is used to totally reflect the picosecond seed light after the first amplification back to the first amplifier; the first 1 / 4 wave plate is used to convert the polarization state of the picosecond seed light after the first amplification.

3. The multi-pulse width laser according to claim 2, characterized in that: It also includes a beam compensation unit, which is arranged between the first 1 / 4 wave plate and the first 0° total reflection mirror and is used to compensate the optical characteristics of the laser beam at different repetition frequencies to maintain the consistency of the spot size and divergence angle of the output beam.

4. The multi-pulse width laser according to claim 3, characterized in that: The beam compensation unit comprises a negative lens, which is arranged on a movable bracket and is used to selectively insert into or withdraw from the optical path according to preset repetition frequency parameters to compensate for the difference in optical characteristics of the beam at different repetition frequencies.

5. The multi-pulse width laser according to claim 1, characterized in that: The outgoing light path of the picosecond laser generating unit is parallel to the first amplifier, and the outgoing light path of the picosecond laser generating unit is connected to the first amplifier through the first isolation unit, the first 45° reflector and the second 45° reflector in sequence.

6. The multi-pulse width laser according to claim 5, characterized in that: The first isolation unit includes a first 1 / 2 wave plate, a first polarizer, a second 1 / 2 wave plate, a Faraday rotator and a second polarizer which are sequentially arranged along the optical path. The optical path of the first isolation unit is parallel to the first amplifier. The first 45° reflector is arranged at the output end of the first isolation unit. The second 45° reflector is arranged opposite to the first 45° reflector, and is used to refract the light beam output by the first isolation unit and introduce it into the first amplifier.

7. The multi-pulse width laser according to claim 6, characterized in that: The beam combining unit comprises a third polarizer, a third 1 / 2 wave plate, a third 45° reflector and a fourth 45° reflector which are sequentially arranged along the optical path; The third polarizer is arranged on the optical path between the first 45° reflector and the second 45° reflector, the third 1 / 2 wave plate is arranged between the third polarizer and the third 45° reflector, the third 45° reflector is used to change the propagation direction of the light beam, and the fourth 45° reflector is arranged opposite to the third 45° reflector, and is used to introduce the light beam refracted by the third 45° reflector into the second amplifier.

8. The multi-pulse width laser according to claim 7, characterized in that: The output light path of the microsecond-nanosecond laser generating unit is parallel to the second amplifier. The beam combining unit also includes a fifth 45° reflector, a sixth 45° reflector and a fourth polarizer arranged on the output light path of the microsecond-nanosecond laser generating unit. The fourth polarizer is arranged between the third 45° reflector and the fourth 45° reflector. The fifth 45° reflector and the sixth 45° reflector are arranged opposite to each other and are used to guide the light beam output by the microsecond-nanosecond laser generating unit to the fourth polarizer. The fourth polarizer is used to reflect the microsecond seed light or the nanosecond seed light to the fourth 45° reflector and enter the second amplifier.

9. The multi-pulse width laser according to claim 8, characterized in that: An optical shutter is also provided between the microsecond-nanosecond laser generating unit and the fifth 45° reflecting mirror, and the optical shutter is used to control the on-off of the output light beam of the microsecond-nanosecond laser generating unit.

10. The multi-pulse width laser according to claim 1, characterized in that: The microsecond-nanosecond laser generating unit includes a second 0° total reflection mirror, a second 1 / 4 wave plate, a Q switch, a fifth polarizer, a third amplifier and an output mirror arranged in sequence along the optical path; the Q switch is used to control the time characteristics of the laser pulse, and by adjusting the working mode of the Q switch, the nanosecond seed light or the microsecond seed light can be selectively generated.

11. The multi-pulse width laser according to any one of claims 1 to 10, characterized in that: A second isolation unit is also provided after the common amplification unit; the second isolation unit includes a seventh 45° reflector, an eighth 45° reflector and a third 1 / 4 wave plate, the seventh 45° reflector is arranged at the output end of the second amplifier, the eighth 45° reflector is arranged opposite to the seventh 45° reflector, the third 1 / 4 wave plate is arranged on the output optical path of the eighth 45° reflector, and is used to finally output the laser to an external handpiece.

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