A multi-pulsewidth laser

Abstract

The application discloses a multi-pulse-width laser, and relates to the technical field of medical laser equipment, which comprises a picosecond laser generating unit, a microsecond-nanosecond laser generating unit, a light beam combining unit and a shared amplification unit. The picosecond laser generating unit is used for generating picosecond seed light. 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 shared amplification unit is arranged behind the light beam combining unit and comprises a first amplifier and a second amplifier arranged in parallel. The first amplifier is used for double-pass amplification of the picosecond seed light. The second amplifier is used for third amplification of the double-pass amplified picosecond seed light. The second amplifier is also used for amplification of the microsecond seed light or the nanosecond seed light. The application realizes the integration of picosecond, nanosecond and microsecond three kinds of pulse-width lasers in a single device, and is suitable for various treatment requirements in the field of skin medical cosmetology.

Description

TECHNICAL FIELD

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

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

[0003] However, in actual application, clinicians usually need to purchase multiple sets of devices such as nanosecond, picosecond lasers and even microsecond lasers, which not only occupies a large space, but also makes the medical institutions need to pay multiple device costs.

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

[0005] Therefore, it has important practical value to develop a medical laser device capable of integrating multiple pulse-width output functions to meet diversified clinical needs. SUMMARY

[0006] The present application discloses a multi-pulse-width laser, aiming at solving the technical problems existing in the prior art. The present application adopts the following technical scheme:

[0007] The present application provides a multi-pulse-width laser, comprising:

[0008] A picosecond laser generating unit is configured to generate picosecond seed light.

[0009] A microsecond-nanosecond laser generating unit is configured to selectively generate microsecond seed light or nanosecond seed light according to a preset mode.

[0010] A beam combining unit is configured to combine the laser generated by the picosecond laser generating unit and the microsecond-nanosecond laser generating unit into the same optical path.

[0011] A shared amplification unit is disposed behind the beam combining unit and comprises a first amplifier and a second amplifier arranged in parallel. The first amplifier is configured to perform double-pass amplification on the picosecond seed light, and the second amplifier is configured to perform third amplification on the double-pass amplified picosecond laser. The second amplifier is also configured to amplify the microsecond seed light or the nanosecond seed light.

[0012] As a preferred technical solution, the common amplification unit further comprises a first 1 / 4 wave plate and a first 0° full reflection mirror, which are sequentially arranged on the outgoing light path of the first amplifier; the first 0° full reflection mirror is used for fully reflecting the picosecond seed light after the first amplification back to the first amplifier; and the first 1 / 4 wave plate is used for converting the polarization state of the picosecond seed light after the first amplification.

[0013] As a preferred technical solution, the common amplification unit further comprises a first 1 / 4 wave plate and a first 0° full reflection mirror, which are sequentially arranged on the outgoing light path of the first amplifier; the first 0° full reflection mirror is used for fully reflecting the picosecond seed light after the first amplification back to the first amplifier; and the first 1 / 4 wave plate is used for converting the polarization state of the picosecond seed light after the first amplification.

[0014] As a preferred technical solution, the common amplification unit further comprises a first 1 / 4 wave plate and a first 0° full reflection mirror, which are sequentially arranged on the outgoing light path of the first amplifier; the first 0° full reflection mirror is used for fully reflecting the picosecond seed light after the first amplification back to the first amplifier; and the first 1 / 4 wave plate is used for converting the polarization state of the picosecond seed light after the first amplification.

[0015] As a preferred technical solution, the common amplification unit further comprises a first 1 / 4 wave plate and a first 0° full reflection mirror, which are sequentially arranged on the outgoing light path of the first amplifier; the first 0° full reflection mirror is used for fully reflecting the picosecond seed light after the first amplification back to the first amplifier; and the first 1 / 4 wave plate is used for converting the polarization state of the picosecond seed light after the first amplification.

[0016] As a preferred technical solution, the common amplification unit further comprises a first 1 / 4 wave plate and a first 0° full reflection mirror, which are sequentially arranged on the outgoing light path of the first amplifier; the first 0° full reflection mirror is used for fully reflecting the picosecond seed light after the first amplification back to the first amplifier; and the first 1 / 4 wave plate is used for converting the polarization state of the picosecond seed light after the first amplification.

[0017] As a preferred technical solution, the common amplification unit further comprises a first 1 / 4 wave plate and a first 0° full reflection mirror, which are sequentially arranged on the outgoing light path of the first amplifier; the first 0° full reflection mirror is used for fully reflecting the picosecond seed light after the first amplification back to the first amplifier; and the first 1 / 4 wave plate is used for converting the polarization state of the picosecond seed light after the first amplification.

[0018] The third polarization plate is arranged on the light path between the first 45° mirror and the second 45° mirror, the third 1 / 2 wave plate is arranged between the third polarization plate and the third 45° mirror, the third 45° mirror is used for changing the light beam propagation direction, and the fourth 45° mirror is arranged opposite to the third 45° mirror and is used for introducing the light beam refracted by the third 45° mirror into the second amplifier.

[0019] As a preferred technical solution, the exit light path of the microsecond-nanosecond laser generating unit is parallel to the second amplifier, the beam combining unit further comprises a fifth 45° mirror, a sixth 45° mirror and a fourth polarizer arranged on the exit light path of the microsecond-nanosecond laser generating unit, the fourth polarizer is arranged between the third 45° mirror and the fourth 45° mirror, the fifth 45° mirror and the sixth 45° mirror are oppositely arranged, and the fifth 45° mirror and the sixth 45° mirror 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° mirror and into the second amplifier.

[0020] As a preferred technical solution, the microsecond-nanosecond laser generating unit and the fifth 45° mirror are further provided with a light shutter, and the light shutter is used to control the on-off of the light beam output by the microsecond-nanosecond laser generating unit.

[0021] As a preferred technical solution, the microsecond-nanosecond laser generating unit comprises a second 0° total reflector, a second 1 / 4 wave plate, a Q switch, a fifth polarizer, a third amplifier and an output mirror arranged in sequence along the light path; the Q switch is used to control the time characteristic 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.

[0022] As a preferred technical solution, the common amplification unit is further provided with a second isolation unit; the second isolation unit comprises a seventh 45° mirror, an eighth 45° mirror and a third 1 / 4 wave plate, the seventh 45° mirror is arranged at the output end of the second amplifier, the eighth 45° mirror is oppositely arranged with the seventh 45° mirror, and the third 1 / 4 wave plate is arranged on the output light path of the eighth 45° mirror and is used to finally output the laser to an external hand tool.

[0023] The above-mentioned embodiment of the application has the following advantages or beneficial effects:

[0024] The application mainly provides a multi-pulse-width laser, realizes the integration of picosecond, nanosecond and microsecond three kinds of pulse width lasers in a single device, generates seed light of different pulse widths through the picosecond laser generating unit and the microsecond-nanosecond laser generating unit, and combines these lasers into the same light path through the beam combining unit, which greatly reduces the device cost and the occupied space, so that medical and beauty institutions no longer need to purchase and maintain multiple laser devices of different pulse widths.

[0025] Further, the common amplification unit in the embodiment of the application comprises a double-pumping cavity structure arranged in parallel, so that the picosecond seed light can be efficiently amplified in double passes, and through an optical polarization combining scheme, two different types of laser pulses share one amplifier, which further improves the integration degree and resource utilization rate of the device.

[0026] In addition, the embodiment of the present application also solves the problem of inconsistent laser output characteristics at different repetition frequencies in the non-frequency division state, and by setting the light beam compensation unit, the optical parameters are automatically adjusted at different repetition frequencies, so that the spot size and divergence angle of the output light beam are kept consistent, thereby improving the stability and reliability of laser treatment in clinical application. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description, which constitutes a part of the present application. The illustrative embodiments of the present application and the description and explanation thereof do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 The structure diagram of the multi-pulse-width laser in a preferred embodiment disclosed by the present application;

[0029] Figure 2 The structure diagram of the multi-pulse-width laser when the light beam compensation unit is switched out of the optical path in a preferred embodiment disclosed by the present application.

[0030] Explanation of reference signs:

[0031] Picosecond laser generation 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° mirror 7, third polarizer 8, second 45° mirror 9, first amplifier 10, first 1 / 4 wave plate 11, negative lens 12, first 0° total reflection mirror 13, third 45° mirror 14, fourth polarizer 15, fourth 45° mirror 16, second amplifier 17, seventh 45° mirror 18, eighth 45° mirror 19, third 1 / 4 wave plate 20, light guide arm reflection interface 21, second 0° total reflection mirror 22, second 1 / 4 wave plate 23, Q switch 24, fifth polarizer 25, third amplifier 26, output mirror 27, shutter 28, fifth 45° mirror 29, sixth 45° mirror 30, third 1 / 2 wave plate 31. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will combine the specific embodiments of the present application and the corresponding drawings to clearly and completely describe the technical solutions of the present application. In the description of the present application, it should be noted that the term “or” is generally used in the sense of including “and / or”, unless the content is explicitly indicated otherwise.

[0033] In the description of the present application, the terms “first”, “second” and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0034] Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0035] Reference Figure 1 The embodiment of the present application provides a multi-pulse-width laser, which comprises a picosecond laser generating unit 1, a microsecond-nanosecond laser generating unit, a beam combining unit and a shared amplification unit. The picosecond laser generating unit 1 is used for generating picosecond seed light, the microsecond-nanosecond laser generating unit is used for selectively generating microsecond seed light or nanosecond seed light according to a preset mode, and the exit light paths of the picosecond laser generating unit 1 and the microsecond-nanosecond laser generating unit are arranged in parallel. The beam combining unit is arranged between the exit light paths of the picosecond laser generating unit 1 and the microsecond-nanosecond laser generating unit, and is used for combining the laser generated by the picosecond laser generating unit 1 and the microsecond-nanosecond laser generating unit into the same light path. The shared amplification unit is arranged after the beam combining unit, and comprises a first amplifier 10 and a second amplifier 17 arranged in parallel. The first amplifier 10 is used for double-pass amplification of the picosecond seed light, and the second amplifier 17 is used for third amplification of the double-pass amplified picosecond laser, or the second amplifier 17 is used for amplification of the microsecond seed light or the nanosecond seed light.

[0036] In a preferred embodiment, the picosecond laser generating unit 1 generates picosecond seed light through the passive Q-switching principle, and the picosecond seed light can provide a stable short-pulse laser source. The microsecond-nanosecond laser generating unit works in an active Q-switching mode, and through adjustment of the working mode of the Q-switch 24, the microsecond-nanosecond laser generating unit can be flexibly switched between the nanosecond and microsecond pulse width modes. The beam combining unit uses the polarization characteristics of laser to combine the laser in different light paths into the same light path through polarization beam combining, 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 improves the energy of the picosecond seed light through double-pass amplification, so that the picosecond seed light returns to the original path for second amplification after first amplification, and then the picosecond laser can enter the second amplifier 17 for third amplification. 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 the shared amplification structure, the integration degree and resource utilization efficiency of the equipment are greatly improved.

[0037] Those skilled in the art should understand that passive Q-switching is a technology that automatically modulates the Q value by using the optical characteristics of a saturable absorber. When the intracavity laser intensity is lower than the saturation threshold of the saturable absorber, the saturable absorber has strong absorption to the laser, and the intracavity Q value is low. When the intracavity energy accumulates to a certain extent, 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 laser. This way can produce picosecond short pulses.

[0038] Active Q-switching is to control the Q-switching device such as electro-optical switch or acousto-optical switch by external electrical signal, to actively control the Q value change of the cavity. 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 pulsed laser. This way can produce nanosecond or microsecond laser pulses according to the need by adjusting the control timing of the Q-switch 24.

[0039] Through the combination of the above two Q-switching methods, the multi-pulse-width laser of the embodiment of the present application can realize the generation and output of picosecond, nanosecond and microsecond lasers with different pulse widths in a single device.

[0040] 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 the present embodiment, the pulse width is preferably 300 PS.

[0041] Alternatively, the picosecond laser generating unit 1 can select a semiconductor laser, a fiber laser or other types of lasers that can generate ultrashort pulses, which are not specifically limited in the present embodiment.

[0042] In a preferred embodiment, the exit light path of the picosecond laser generating unit 1 is parallel to the first amplifier 10, that is, the exit light path of the picosecond laser generating unit 1, the exit 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, so as to shorten the axial length of the entire multi-pulse-width laser.

[0043] Preferably, the exit light path of the picosecond laser generating unit 1 is connected with the first amplifier 10 in sequence through the first isolation unit, the first 45° mirror 7 and the second 45° mirror 9, and the first isolation unit is used to suppress the self-excitation occurring between the picosecond laser generating unit 1 and the first amplifier 10; preferably, the first isolation unit comprises the first 1 / 2 wave plate 2, the first polarizer 3, the second 1 / 2 wave plate 4, the Faraday rotator 5 and the second polarizer 6 arranged along the light path in sequence, the light path of the first isolation unit is parallel to the first amplifier 10, the first 45° mirror 7 is arranged at the exit end of the first isolation unit, and the second 45° mirror 9 is arranged opposite to the first 45° mirror 7 and used to refract the light beam output by the first isolation unit and then introduce it into the first amplifier 10.

[0044] Specifically, the first 1 / 2 wave plate 2 is used to adjust the polarization direction of the incident laser light so as to make it 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 of a specific polarization direction and only allow the light with the consistent polarization direction to pass through; the second 1 / 2 wave plate 4 is used to adjust the polarization direction of the light beam so as to make it suitable for the working requirements of the subsequent Faraday rotator 5; the Faraday rotator 5 is the core element of the first isolation unit, which can make the light produce irreversible polarization rotation in the propagation direction under the action of an external magnetic field, and the polarization direction of the forward propagating light will rotate by a certain angle, while the polarization direction of the backward propagating light will continue to rotate in the same direction instead of returning to the original state, in the embodiment, the Faraday rotator 5 is preferably a Faraday rotator 5 with a length of 2-5 mm; the second polarizer 6 works in cooperation with the first polarizer 3, and 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 backward propagating light cannot match the first polarizer 3 after passing through the second polarizer 6 and the Faraday rotator 5, and thus is blocked, so that the one-way transmission function of the light is realized, the backward light in the first amplifier 10 is effectively prevented from returning to the picosecond laser generating unit 1, and thus the self-excitation of the system is suppressed and the picosecond seed light source is protected.

[0045] It should be understood by those skilled in the art that the self-excitation, or self-laser, refers to that some optical elements and gain medium in the laser form a resonant cavity, so that part of the laser beam is reflected back and forth and amplified without control, thereby forming an uncontrolled laser, which will interfere with the expected laser output, affect the treatment / beautifying effect, and exist safety hazards.

[0046] In a preferred embodiment, the common amplification unit is configured as a single-lamp double-rod pumping cavity, which is provided with one xenon lamp and two parallel YAG crystals, i.e., 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 one xenon lamp simultaneously provides pumping energy for two parallel YAG crystals, the energy loss caused by multiple independent pumping light sources is reduced, and the power consumption of the system is reduced. In addition, the single-lamp double-rod structure enables the two amplification rods to obtain relatively uniform and synchronous pumping conditions, which helps to maintain the consistency and stability of the amplification of each light path, improves the beam quality of the overall output, and since the single-lamp double-rod pumping cavity has a more compact structure, it is particularly suitable for applications such as medical beauty that have higher requirements for device space.

[0047] In a preferred embodiment, the common amplification unit further includes a first 1 / 4 wave plate 11 and a first 0° total reflection mirror 13, which are sequentially arranged on the outgoing light path of the first amplifier 10. The first 0° total reflection mirror 13 is used to totally reflect the first amplified picosecond seed light back to the first amplifier 10. The first 1 / 4 wave plate 11 is used to convert the polarization state of the first amplified picosecond seed light.

[0048] Preferably, after the picosecond seed light passes through the first amplifier 10 for the first time, the output laser has a spot diameter of 6 mm, an energy of about 30 mJ, and a horizontal polarization state. The first amplified laser returns to the first amplifier 10 via the first 0° total reflection mirror 13 for the second time, i.e., double-pass amplification. The laser passes through the first 1 / 4 wave plate 11 twice in the double-pass light path, and its horizontal polarization state is converted to a vertical polarization state. The second amplified output laser has a spot diameter of 8 mm and an energy of about 80 mJ.

[0049] In a preferred embodiment, the picosecond laser generation unit 1 adopts a non-frequency division mode when working, which means that the laser produces only one pulse each time, rather than dividing the energy into a sequence of multiple lower-energy pulses. In the non-frequency division mode, the peak power of the laser output is higher, but the thermal effect in the gain medium is different at different repetition frequencies, which in turn affects 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 intensifies, and the thermal effect is more pronounced, resulting in changes in the beam quality parameters.

[0050] To solve the problem of inconsistent 1-10 Hz 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 for the optical properties of the laser beam at different repetition frequencies, so as to maintain the consistency of the spot size and divergence angle of the output beam.

[0051] In a preferred embodiment, the light beam compensation unit is configured as a negative lens 12, which is arranged on the movable support and is used to selectively insert or withdraw from the light path according to the preset repetition frequency parameter, so as to compensate for the difference in optical characteristics of the light beam at different repetition frequencies.

[0052] Preferably, when the picosecond laser generating unit 1 is working at a high repetition frequency, the negative lens 12 can be inserted into the light path to compensate for the change of the light beam caused by the thermal effect through its negative refraction ability; when the picosecond laser generating unit 1 is working at a low repetition frequency, the negative lens 12 can be automatically withdrawn from the light path to maintain the original light beam characteristics.

[0053] Preferably, when the repetition frequency is greater than or equal to 6Hz, the negative lens 12 is inserted into the light path for compensation, as shown in FIG. 2B. Figure 1 When the repetition frequency is less than 5Hz, the negative lens 12 is withdrawn from the light path, as shown in FIG. 2A. Figure 2 .

[0054] In a preferred embodiment, the light beam combining unit comprises a third polarizer 8, a third 1 / 2 wave plate 31, a third 45° mirror 14 and a fourth 45° mirror 16 arranged in sequence along the light path; the third polarizer 8 is arranged on the light path between the first 45° mirror 7 and the second 45° mirror 9, the third 1 / 2 wave plate 31 is arranged between the third polarizer 8 and the third 45° mirror 14, and is used to convert the light beam in a vertical polarization state into a horizontal polarization state, the third 45° mirror 14 is used to change the propagation direction of the light beam, and the fourth 45° mirror 16 is arranged opposite to the third 45° mirror 14, and is used to introduce the light beam refracted by the third 45° mirror 14 into the second amplifier 17 of the shared amplification unit, so that the third amplification of the picosecond seed light is realized, and the output laser has a spot diameter of 9mm and an energy of about 500mJ.

[0055] In a preferred embodiment, a second isolation unit is further arranged between the shared amplification unit and the external handpiece, and the second isolation unit is used to suppress self-excitation generated by the external handpiece of the multi-pulse-width laser. Preferably, the second isolation unit comprises a seventh 45° mirror 18, an eighth 45° mirror 19 and a third 1 / 4 wave plate 20, the seventh 45° mirror 18 is arranged at the output end of the second amplifier 17, the eighth 45° mirror 19 is arranged opposite to the seventh 45° mirror 18, and the third 1 / 4 wave plate 20 is arranged on the output light path of the eighth 45° mirror 19 and is used to finally output the laser to the external handpiece.

[0056] Specifically, since the folding light path structure can be formed between the seventh 45° mirror 18 and the eighth 45° mirror 19, the possible reflected light can be blocked from directly returning to the common amplification unit. In addition, when the forward propagating laser passes through the third 1 / 4 wave plate 20, the polarization state thereof is converted from the horizontal polarization state to the circular polarization state. If there is a reflective surface in the external hand tool, part of the light returns. After the returned light passes through the third 1 / 4 wave plate 20 again, the polarization state is converted again to the vertical polarization state. Since the common amplification unit has different amplification efficiencies for light with different polarization states, the change in the polarization state can significantly reduce the possibility of the returned light being amplified again in the second amplifier 17, thereby effectively suppressing the self-oscillation phenomenon.

[0057] In a preferred embodiment, the light beam combining unit further comprises a fifth 45° mirror 29 and a sixth 45° mirror 30 disposed on the outgoing light path of the microsecond-nanosecond laser generating unit, and a fourth polarizer 15 disposed between the third 45° mirror 14 and the fourth 45° mirror 16. The fifth 45° mirror 29 and the sixth 45° mirror 30 are oppositely disposed to guide the light beams output by the microsecond-nanosecond laser generating unit to the fourth polarizer 15. Optionally, other optical elements such as corresponding lenses can be further disposed between the fifth 45° mirror 29 and the sixth 45° mirror 30 as needed. The microsecond seed light or the nanosecond seed light is configured in a vertical polarization state. 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° mirror 16 and into the second amplifier 17. Meanwhile, the fourth polarizer 15 has high transmission characteristics for picosecond laser with different polarization states. Since the picosecond laser has been converted to a horizontal polarization state after passing through the third 1 / 2 wave plate 31, the normal transmission of the picosecond laser between the third 45° mirror 14 and the fourth 45° mirror 16 is not hindered or significantly affected.

[0058] In this embodiment, the light beam combining method based on polarization control avoids the energy loss caused by the use of a beam splitter, and ensures the energy utilization efficiency of each of the two different pulse width lasers. In addition, the layout of the light beam combining unit also ensures that the two lasers with different pulse widths can strictly propagate coaxially after being combined, and share the same amplification light path, thereby ensuring that the two lasers output by the system have almost completely the same beam characteristics and spatial distribution, greatly improving the operation convenience and consistency of the treatment effect of the system in actual application.

[0059] In a preferred embodiment, the microsecond-nanosecond laser generating unit comprises, sequentially arranged along the optical path, 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; 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 core elements for realizing pulse width regulation. 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 pumped cavity. Further, a light shutter 28 is arranged between the microsecond-nanosecond laser generating unit and the fifth 45° reflection mirror 29, and the light shutter 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 light shutter 28 can block the laser output to prevent accidental irradiation caused by incorrect operation.

[0060] In a preferred embodiment, when the microsecond-nanosecond laser generating unit outputs nanosecond laser pulses, the Q switch 24 works in a conventional Q-switched mode, i.e., a high-speed switching state, resulting in rapid release of energy in the resonant cavity. The output is 200-400 mJ of laser with a pulse width of 3 ns and a vertical polarization state. After one amplification by the second amplifier 17, the output is a laser pulse with a pulse width of 3 ns and an energy of 800 mJ-1 J. When the microsecond-nanosecond laser generating unit outputs microsecond laser pulses, the Q switch 24 works in a corresponding modulation mode. By accurately controlling the Q value change process of the resonant cavity, the energy is released at a relatively slow rate. The output is a local oscillator light with a pulse width of 120 μs and an energy of 300-500 mJ. After one amplification, the output is a microsecond laser with a pulse width of 120 μs and an energy of 1 J.

[0061] In the present embodiment, for picosecond laser, its optical path starts from picosecond laser generating unit 1, the picosecond seed light generated by the unit first passes through first isolation unit, first 45° mirror 7, second 45° mirror 9 in turn, and then enters first amplifier 10 in the shared amplification unit. After the first amplification, the light beam propagates to first 1 / 4 wave plate 11 with horizontal polarization state, 6mm spot diameter and about 30mJ energy, and then is reflected by first 0° total reflection mirror 13. In the process, the light beam characteristics can be adjusted by passing through the beam compensation unit. The reflected light beam passes through first 1 / 4 wave plate 11 again, and the polarization state is converted to vertical polarization. The light beam passes through first amplifier 10 again for the second amplification, and the light beam parameters are improved to 8mm spot diameter and about 80mJ energy. Subsequently, the picosecond laser passes through third polarizer 8, third 1 / 2 wave plate 31, third 45° mirror 14 in turn, and then passes through fourth polarizer 15 to reach fourth 45° mirror 16, and is guided to second amplifier 17 for the third amplification. The amplified high-energy picosecond laser is turned by seventh 45° mirror 18 and eighth 45° mirror 19, and finally output to light guide arm reflection interface 21 after passing through third 1 / 4 wave plate 20.

[0062] In the present embodiment, for nanosecond laser, its path starts from microsecond-nanosecond laser generating unit. The Q switch 24 in the unit works in Q-switched mode. The nanosecond seed light with 3ns pulse width and 200-400mJ energy is generated through the resonant cavity composed of second 0° total reflection mirror 22, second 1 / 4 wave plate 23, Q switch 24, fifth polarizer 25, third amplifier 26 and output mirror 27. After passing through optical shutter 28, the nanosecond laser is guided to fourth polarizer 15 by fifth 45° mirror 29 and sixth 45° mirror 30. Due to the polarization characteristics, the nanosecond laser is reflected by fourth polarizer 15, turns to fourth 45° mirror 16, and then enters second amplifier 17 for amplification. The output parameters are improved to 3ns pulse width and 800mJ-1J energy. Subsequently, the nanosecond laser shares the latter part of the optical path with the picosecond laser, and also passes through seventh 45° mirror 18, eighth 45° mirror 19 and third 1 / 4 wave plate 20, and finally output to light guide arm reflection interface 21.

[0063] The optical path of microsecond laser is the same as that of nanosecond laser, and only the working mode of Q switch 24 in microsecond-nanosecond laser generating unit is different to generate microsecond seed light. Subsequently, the microsecond laser is transmitted along the same path as the nanosecond laser to the final output. In the present embodiment, the structure will not be described again.

[0064] It should be noted that the invention point of the present embodiment is the redesign and layout of the optical path structure in the laser, rather than the improvement of a certain component. Any component described in the present embodiment can be directly purchased, and the structure will not be described again in the present embodiment.

[0065] Those skilled in the art will appreciate that the format of a specification, including the claims, abstract and figures accompanying it, can be used for providing any combination of features disclosed therein, except where such combinations are mutually exclusive, as well as all processes or units of any method or apparatus so disclosed. Unless explicitly stated otherwise, each feature disclosed in the specification, including the claims, abstract and figures accompanying it, can be replaced by alternative features providing the same, equivalent or similar functionality.

Claims

1. A multi-pulsewidth laser, characterized by, The application relates to a laser device, comprising: an independently arranged picosecond laser generating unit for generating picosecond seed light; an independently arranged microsecond-nanosecond laser generating unit for selectively generating microsecond seed light or nanosecond seed light according to a preset mode; wherein the picosecond seed light output by the picosecond laser generating unit is configured to always pass through the microsecond-nanosecond laser generating unit; a light beam combining unit for combining the laser generated by the picosecond laser generating unit and the microsecond-nanosecond laser generating unit into the same light path; an independently arranged shared amplification unit arranged after the light beam combining unit, comprising a first amplifier and a second amplifier arranged in parallel, the first amplifier being used for double-pass amplification of the picosecond seed light, the second amplifier being used for third amplification of the double-pass amplified picosecond laser, and the second amplifier also being used for amplification of the microsecond seed light or the nanosecond seed light; the seed light generated by the microsecond-nanosecond laser generating unit directly enters the second amplifier for amplification, and the exit light path is parallel to but not coaxial with the first amplifier and the second amplifier; a light beam compensation unit arranged on the exit light path of the first amplifier, which can be selectively inserted into or withdrawn from the light path, and is used for compensating the optical properties of the laser beam at different repetition frequencies to maintain the consistency of the spot size and the divergence angle of the output light beam; first and second 45-degree mirrors are arranged in sequence between the picosecond laser generating unit and the first amplifier; the light beam combining unit comprises third, fourth, fifth and sixth 45-degree mirrors and third and fourth quarter-wave plates arranged in sequence along the light path; the fifth and sixth 45-degree mirrors are arranged on the exit light path of the microsecond-nanosecond laser generating unit; the third quarter-wave plate is arranged between the first and second 45-degree mirrors; and the fourth quarter-wave plate is used for reflecting the light beam to the fourth 45-degree mirror and into the second amplifier.

2. The multi-pulsewidth laser of claim 1, wherein, The shared amplification unit further comprises a first quarter-wave plate and a first 0-degree total reflection mirror, which are arranged in sequence on the exit light path of the first amplifier; the first 0-degree total reflection mirror is used for totally reflecting the first-amplified picosecond seed light back to the first amplifier; and the first quarter-wave plate is used for converting the polarization state of the first-amplified picosecond seed light.

3. The multi-pulsewidth laser of claim 2, wherein, The light beam compensation unit is arranged between the first quarter-wave plate and the first 0-degree total reflection mirror, and comprises a negative lens arranged on a movable support, which is used for selectively inserting into or withdrawing from the light path according to a preset repetition frequency parameter to compensate the optical property difference of the light beam at different repetition frequencies.

4. The multi-pulsewidth laser of claim 1, wherein, The exit light path of the picosecond laser generating unit is parallel to the first amplifier, and the exit light path of the picosecond laser generating unit is connected with the first amplifier through a first isolation unit, the first 45-degree mirror and the second 45-degree mirror in sequence.

5. The multi-pulsewidth laser of claim 4, wherein, The first isolation unit comprises 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 an optical path, the optical path of the first isolation unit is parallel to the first amplifier, the first 45° mirror is arranged at the exit end of the first isolation unit, and the second 45° mirror is arranged opposite to the first 45° mirror and used to refract the light beam output by the first isolation unit and introduce the light beam into the first amplifier.

6. The multi-pulse-width laser of claim 5, wherein, The third 1 / 2 wave plate is arranged between the third polarizer and the third 45° mirror, the third 45° mirror is used to change the direction of propagation of the light beam, and the fourth 45° mirror is arranged opposite to the third 45° mirror and used to introduce the light beam refracted by the third 45° mirror into the second amplifier.

7. The multi-pulsewidth laser of claim 6, wherein, The fourth polarizer is arranged between the third 45° mirror and the fourth 45° mirror, the fifth 45° mirror and the sixth 45° mirror are arranged opposite to each other and 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° mirror and into the second amplifier.

8. The multi-pulsewidth laser of claim 7, wherein, An optical shutter is further arranged between the microsecond-nanosecond laser generating unit and the fifth 45° mirror, and the optical shutter is used to control the on-off of the light beam output by the microsecond-nanosecond laser generating unit.

9. The multi-pulsewidth laser of claim 1, wherein, The microsecond-nanosecond laser generating unit comprises a second 0° mirror, a second 1 / 4 wave plate, a Q switch, a fifth polarizer, a third amplifier and an output mirror arranged in sequence along an 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.

10. The multi-pulsewidth laser of any of claims 1-9, wherein, A second isolation unit is further arranged behind the common amplification unit, the second isolation unit comprises a seventh 45° mirror, an eighth 45° mirror and a third 1 / 4 wave plate, the seventh 45° mirror is arranged at the output end of the second amplifier, the eighth 45° mirror is arranged opposite to the seventh 45° mirror, and the third 1 / 4 wave plate is arranged on the output optical path of the eighth 45° mirror and used to finally output the laser to an external hand tool.

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