Ultra- picosecond laser, skin treatment instrument and electronic device

Abstract

The application discloses an ultrashort picosecond laser, a skin treatment instrument and electronic equipment, and belongs to the technical field of lasers, wherein the ultrashort picosecond laser comprises a fundamental frequency laser light source configured to emit fundamental frequency laser light; a first laser resonant cavity configured to perform frequency doubling conversion on the fundamental frequency laser light to form frequency-doubled laser light; a second laser resonant cavity configured to generate 785 nm waveband laser light by taking the frequency-doubled laser light as pump light; and a third laser resonant cavity configured to couple the laser light and output ultrashort picosecond 785 nm waveband laser light. The laser can obtain ultrashort picosecond pulse laser of the 785 nm waveband, has high laser generation efficiency, and enables the ultrashort picosecond laser of the 785 nm waveband to have high single-pulse energy, thereby achieving better curative effect when the laser is used for skin treatment.

Description

Technical Field

[0001] This application belongs to the field of laser technology, specifically relating to an ultra-picosecond laser, a skin treatment instrument, and electronic equipment. Background Technology

[0002] Currently, lasers are widely used in the field of medical aesthetics for tattoo removal, freckle removal and skin rejuvenation, and improvement of fine lines and acne scars. The lasers used are mainly divided into three categories according to their pulse width: microsecond lasers, nanosecond lasers and picosecond lasers.

[0003] Specifically, microsecond-level lasers, due to their relatively wide pulse width (on the order of microseconds), tend to have a longer interaction time with the human body, resulting in a significant photothermal effect. This leads to noticeable heat and pain in the treated area, limiting the therapeutic effect. Summary of the Invention

[0004] The purpose of this application is to provide a picosecond laser, a skin treatment instrument, and an electronic device to solve the problems of limited treatment effects and pain associated with existing laser medical aesthetic instruments.

[0005] According to a first aspect of the embodiments of this application, a picosecond laser is provided, the laser comprising:

[0006] A fundamental frequency laser source, used to emit fundamental frequency laser light;

[0007] The first laser resonant cavity is used to convert the fundamental frequency laser into a frequency-doubled laser.

[0008] The second laser resonator is used to generate 785 nanometer band laser using frequency-doubled laser as pump light;

[0009] The third laser resonator is used to couple the laser and output a picosecond 785 nanometer band laser.

[0010] In some optional embodiments of this application, the first laser resonator is coupled to the second laser resonator, and the second laser resonator is coupled to the third laser resonator.

[0011] In some optional embodiments of this application, the optical cavity lengths of the first laser resonator, the second laser resonator, and the third laser resonator are all equal.

[0012] In some optional embodiments of this application, the first laser resonator is a resonator of a fundamental frequency laser;

[0013] The second laser resonant cavity is a resonant cavity for frequency-doubled lasers;

[0014] The third laser resonant cavity is the resonant cavity of the optical parametric laser and the coupling output cavity of the optical parametric laser.

[0015] In some optional embodiments of this application, the pulse width of the fundamental frequency laser is 100 picoseconds to 500 picoseconds, and the wavelength of the fundamental frequency laser is 1064 nanometers;

[0016] The wavelength of the frequency-doubled laser is 532 nanometers;

[0017] The wavelength range of 785 nm laser is 760 nm to 810 nm.

[0018] The pulse width of the ultra-picosecond 785 nanometer band laser is 100 picoseconds to 500 picoseconds.

[0019] In some optional embodiments of this application, the first laser resonator and the second laser resonator share a set of high-reflection mirrors, a set of beam-splitting mirrors, and a set of frequency-doubling crystals;

[0020] The second and third laser resonators share a set of high-reflection mirrors, a set of beam splitters, and a set of optical parametric crystals.

[0021] In some optional embodiments of this application, it also includes: a high-reflection mirror, a polarizer, a beam shaper, a beam splitter, an electro-optic crystal, a frequency doubling crystal, and an optical parametric crystal;

[0022] There are at least six sets of high-reflection mirrors, at least two sets of polarizers, beam splitters, and electro-optic crystals, and at least three sets of beam shapers.

[0023] According to a second aspect of the embodiments of this application, a method for generating ultra-picosecond 785 nanometer band lasers is provided, the method including:

[0024] Acquire fundamental frequency laser;

[0025] Frequency-doubled laser is obtained by frequency doubling the fundamental frequency laser.

[0026] Using frequency-doubled laser as pump light, a 785 nanometer wavelength laser is generated as the optical parametric laser.

[0027] By coupling a 785 nm wavelength laser, a picosecond 785 nm wavelength laser is obtained.

[0028] According to a third aspect of the embodiments of this application, a skin treatment device is provided, characterized in that it includes a picosecond laser of any one of the embodiments of the first aspect.

[0029] According to a fourth aspect of the embodiments of this application, an apparatus is provided, characterized in that it includes an ultra-picosecond laser of any one of the embodiments of the first aspect.

[0030] The above-mentioned technical solution of this application has the following beneficial technical effects:

[0031] The laser in this embodiment, by setting up a connected fundamental frequency laser source, a first laser resonant cavity, a second laser resonant cavity, and a third laser resonant cavity, can obtain ultra-picosecond pulsed lasers in the 785 nanometer band, with high laser generation efficiency and high single-pulse energy of the efficiently obtained 785 nanometer band ultra-picosecond laser; this laser can achieve better therapeutic effects when used in skin treatment. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the picosecond laser structure in an exemplary embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the laser structure in a specific embodiment of this application;

[0034] Figure 3 This is a schematic diagram of the laser structure in another specific embodiment of this application.

[0035] Figure reference numerals: 100: Fundamental frequency laser source; 101: First A high-reflection mirror; 102: M electro-optic crystal; 103: Quarter-wave plate; 104: E polarizer; 105: First beam shaper; 106: First beam splitter; 107: Frequency doubling crystal; 108: First B high-reflection mirror; 109: Second A high-reflection mirror; 110: Second beam shaper; 111: Second beam splitter; 112: Optical parametric crystal; 113: Second B high-reflection mirror; 114: Third A high-reflection mirror; 115: Third beam shaper; 116: F polarizer; 117: N electro-optic crystal; 118: Third B high-reflection mirror. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0037] The accompanying drawings illustrate layer structure diagrams according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0038] Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0039] In the description of this application, it should be noted that the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0041] The inventors discovered that lasers with a wavelength of 785 nanometers (760nm~810nm) can be fully absorbed by green and blue tattoos, and also show good absorption against melanin. Furthermore, this wavelength is not affected by hemoglobin in the human body. Compared to lasers with a wavelength of 755 nanometers, green and blue tattoos have a better absorption rate with the 785 nanometer wavelength laser, meaning it is more effective at removing green and blue tattoos. Therefore, the 785 nanometer wavelength laser is more suitable for application in medical fields such as tattoo removal, skin rejuvenation, and improvement of fine lines and acne scars.

[0042] The picosecond laser provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0043] like Figure 1 As shown, in a first aspect of the embodiments of this application, a picosecond laser is provided, which may include:

[0044] A fundamental frequency laser source, used to emit fundamental frequency laser light;

[0045] The first laser resonant cavity is used to convert the fundamental frequency laser into a frequency-doubled laser.

[0046] The second laser resonator is used to generate 785 nanometer band laser using frequency-doubled laser as pump light;

[0047] The third laser resonator is used to couple the laser and output a picosecond 785 nanometer band laser.

[0048] In this embodiment, the laser, by setting up a connected fundamental frequency laser source, a first laser resonant cavity, a second laser resonant cavity, and a third laser resonant cavity, can obtain ultra-picosecond pulsed lasers in the 785 nanometer band, improving laser generation efficiency and ensuring high single-pulse energy of the efficiently obtained 785 nanometer band ultra-picosecond laser; this laser can achieve better therapeutic effects when used in skin treatment.

[0049] In the above embodiments, when the picosecond laser generates ultra-picosecond laser light, a fundamental frequency laser is provided to the first laser resonator through a fundamental frequency laser source. Preferably, the fundamental frequency laser source is capable of generating picosecond-level laser light, and more preferably, a source capable of generating picosecond-level laser light with a wavelength of 1064 nanometers. The fundamental frequency laser is frequency-doubled through the first laser resonator to obtain a frequency-doubled laser. This frequency-doubled laser light is generated by absorbing the fundamental frequency laser light through a frequency-doubled crystal, and the wavelength of the resulting frequency-doubled laser is half the wavelength of the fundamental frequency laser. The frequency-doubled laser light is then used as pump light through the second laser resonator to generate optical parameters. The device utilizes a picosecond laser, specifically a 785 nm wavelength laser, which is generated by absorbing and frequency-doubled laser energy through an optical parametric crystal. This optical parametric laser is coupled through a third laser resonator to output a target picosecond laser, specifically a 785 nm wavelength picosecond laser. The generated 785 nm wavelength picosecond laser has higher single-pulse laser energy. Therefore, devices designed based on this picosecond laser combination can perform laser-related operations more efficiently, especially in medical instruments used for skin treatments, leading to better therapeutic effects.

[0050] In some embodiments, the first laser resonator is coupled to the second laser resonator, and the second laser resonator is coupled to the third laser resonator. This ensures efficient output of the target picosecond laser. For example, the first laser resonator is a fundamental frequency laser resonator; the second laser resonator is a frequency-doubled laser resonator; and the third laser resonator is both a resonator for an optical parametric laser and a coupled output cavity for the optical parametric laser. Specifically, when the picosecond laser emits light, fundamental frequency laser oscillation occurs in the first laser resonator; frequency-doubled laser oscillation occurs in the second laser resonator; and optical parametric laser oscillation occurs in the third laser resonator. When the optical parametric laser energy reaches its maximum, the optical parametric laser is coupled and output.

[0051] For example, the first laser resonator and the second laser resonator share a set of high-reflection mirrors, a set of beam-shaping mirrors and a set of frequency-doubling crystals; the second laser resonator and the third laser resonator share a set of high-reflection mirrors, a set of beam-shaping mirrors and a set of optical parametric crystals.

[0052] In some embodiments, the optical cavity lengths of the first laser resonator, the second laser resonator, and the third laser resonator are all equal.

[0053] In some embodiments, the first laser resonant cavity is a resonant cavity for a fundamental frequency laser;

[0054] The second laser resonant cavity is a resonant cavity for frequency-doubled lasers;

[0055] The third laser resonant cavity is the resonant cavity of the optical parametric laser and the coupling output cavity of the optical parametric laser.

[0056] In some embodiments, the pulse width of the fundamental frequency laser is 100 picoseconds to 500 picoseconds, and the wavelength of the fundamental frequency laser is 1064 nanometers;

[0057] The wavelength of the frequency-doubled laser is 532 nanometers;

[0058] The wavelength range of 785 nm laser is 760 nm to 810 nm.

[0059] The pulse width of the ultra-picosecond 785 nanometer band laser is 100 picoseconds to 500 picoseconds.

[0060] In some embodiments, the first laser resonator and the second laser resonator share a set of high-reflection mirrors, a set of beam-shaping mirrors, and a set of frequency-doubling crystals;

[0061] The second and third laser resonators share a set of high-reflection mirrors, a set of beam splitters, and a set of optical parametric crystals.

[0062] In some embodiments, it further includes: a high-reflection mirror, a polarizer, a beam shaper, a beam splitter, an electro-optic crystal, a frequency doubling crystal, and an optical parametric crystal;

[0063] There are at least six sets of high-reflection mirrors, at least two sets of polarizers, beam splitters, and electro-optic crystals, and at least three sets of beam shapers.

[0064] In this embodiment, there are six sets of high-reflection mirrors: a first A high-reflection mirror, a first B high-reflection mirror, a second A high-reflection mirror, a second B high-reflection mirror, a third A high-reflection mirror, and a third B high-reflection mirror; two sets of polarizers: an E polarizer and an F polarizer; two sets of beam splitters: a first beam splitter and a second beam splitter; two sets of electro-optic crystals: an M electro-optic crystal and an N electro-optic crystal; and three sets of beam shapers: a first beam shaper, a second beam shaper, and a third beam shaper.

[0065] For example, the first laser resonant cavity includes a first A high-reflectivity mirror, an M electro-optic crystal, an E polarizer, a first beam shaper, a first beam splitter, a frequency doubling crystal, and a first B high-reflectivity mirror arranged in sequence; the second laser resonant cavity includes a first B high-reflectivity mirror, a frequency doubling crystal, a first beam splitter, a second A high-reflectivity mirror, a second beam shaper, a second beam splitter, an optical parametric crystal, and a second B high-reflectivity mirror arranged in sequence; the third laser resonant cavity includes a second B high-reflectivity mirror, an optical parametric crystal, a second beam splitter, a third A high-reflectivity mirror, a third beam shaper, an F polarizer, an N electro-optic crystal, and a third B high-reflectivity mirror arranged in sequence.

[0066] In another example, the first A high-reflection mirror and the first B high-reflection mirror are arranged perpendicularly to each other; the first A high-reflection mirror, the first B high-reflection mirror, the second B high-reflection mirror, and the third B high-reflection mirror are all arranged perpendicularly to their respective optical axes; the first B high-reflection mirror, the second B high-reflection mirror, and the third B high-reflection mirror are arranged parallel to each other; the second A high-reflection mirror, the third A high-reflection mirror, and the E polarizer are arranged parallel to each other; the first beam splitter, the second beam splitter, and the F polarizer are arranged parallel to each other.

[0067] Optionally, the first A high-reflectivity mirror is coated with a high-reflectivity film for fundamental frequency lasers; the first beam splitter is coated with a high-transmittance film for fundamental frequency lasers and a high-reflectivity film for frequency-doubled lasers; the first B high-reflectivity mirror is coated with a high-reflectivity film for fundamental frequency lasers and a high-reflectivity film for frequency-doubled lasers; the second A high-reflectivity mirror is coated with a high-reflectivity film for frequency-doubled lasers; the second beam splitter is coated with a high-transmittance film for frequency-doubled lasers and a high-reflectivity film for optical parametric lasers; the second B high-reflectivity mirror is coated with a high-reflectivity film for frequency-doubled lasers and a high-reflectivity film for optical parametric lasers; the third A high-reflectivity mirror is coated with a high-reflectivity film for optical parametric lasers; and the third B high-reflectivity mirror is coated with a high-reflectivity film for optical parametric lasers.

[0068] Optionally, the picosecond laser also includes a quarter-wave plate, which is disposed in the first laser resonant cavity.

[0069] Optionally, the picosecond laser also includes a connected high-speed photodetector, an oscilloscope, and a controller, wherein the high-speed photodetector is located outside the third laser resonant cavity.

[0070] For example, in the picosecond laser of the present invention, the frequency doubling crystal is an LBO crystal or a KTP crystal; the optical parametric crystal is any one of an LBO crystal, a BBO crystal, a KTP crystal, and a KTA crystal.

[0071] The polarizer, beam splitter, and electro-optic crystal are each provided in at least two sets, and the beam shaper is provided in at least three sets. Correspondingly, at least three sets of high-reflection mirrors, one set of beam shaper, and one set of beam splitters are provided in each of the first, second, and third laser resonant cavities. At least one set of polarizers and one set of electro-optic crystals are provided in each of the first and third laser resonant cavities, respectively. More preferably, the picosecond laser also includes a quarter-wave plate, which is disposed in the first laser resonant cavity to ensure more efficient high-power output of the target picosecond laser.

[0072] In some embodiments of this application, to ensure that the coupled target picosecond laser has high energy, preferably, the picosecond laser further includes a high-speed photoelectric probe, an oscilloscope, and a controller connected in series, wherein the high-speed photoelectric probe is disposed outside the third laser resonant cavity; more preferably, the high-speed photoelectric probe is disposed outside the high-reflectivity mirror at the end of the third laser resonant cavity. Specifically, during the generation of the target picosecond laser by the picosecond laser, the high-speed photoelectric probe detects the optical parametric laser transmitted through the third laser resonant cavity in real time and converts it into an electrical signal, which is then transmitted to the oscilloscope for display; the controller receives the signal displayed on the oscilloscope and controls the electro-optic crystal in the third laser resonant cavity according to the signal; when the signal displayed on the oscilloscope reaches its maximum, a high voltage is applied to the electro-optic crystal in the third laser resonant cavity, so that the polarized light generated by the polarizer in the third laser resonant cavity has the same direction, and then the polarized light with the same direction is coupled together and reflected by the polarizer in the third laser resonant cavity before being output; thereby realizing the coupling and output of the optical parametric laser with the maximum energy, and obtaining the target picosecond laser with the maximum energy. Preferably, the high voltage applied to the electro-optic crystal in the third laser resonant cavity is a quarter-wave voltage. Specifically, the value of the quarter-wave voltage is set according to the specific working conditions of the electro-optic crystal in the third laser resonant cavity, so as to ensure that the maximum energy is stably and efficiently output after optical parametric laser coupling.

[0073] In other embodiments of this application, based on the above settings, in order to efficiently achieve high-energy, high-power target picosecond laser output with optimized combination settings, preferably, as follows: Figure 2 or Figure 3 As shown, there are six sets of high-reflection mirrors: first A high-reflection mirror 101, first B high-reflection mirror 108, second A high-reflection mirror 109, second B high-reflection mirror 113, third A high-reflection mirror 114, and third B high-reflection mirror 118; two sets of polarizers: E polarizer 104 and F polarizer 116; two sets of beam splitters: first beam splitter 106 and second beam splitter 111; two sets of electro-optic crystals: M electro-optic crystal 102 and N electro-optic crystal 117; and three sets of beam shapers: first beam shaper 105, second beam shaper 110, and third beam shaper 115. Preferably, to more efficiently achieve high-energy, high-power target picosecond laser output, such as... Figure 3 As shown, the picosecond laser also includes a quarter-wave plate 103, which is disposed in the first laser resonant cavity.

[0074] In the above embodiments, preferably, as follows: Figure 2As shown, the first laser resonant cavity includes a first A high-reflection mirror 101, an M electro-optic crystal 102, an E polarizer 104, a first beam shaper 105, a first beam splitter 106, a frequency doubling crystal 107, and a first B high-reflection mirror 108 arranged sequentially; the second laser resonant cavity includes a first B high-reflection mirror 108, a frequency doubling crystal 107, a first beam splitter 106, a second A high-reflection mirror 109, a second beam shaper 110, a second beam splitter 111, an optical parametric crystal 112, and a second B high-reflection mirror 113 arranged sequentially; the third laser resonant cavity includes a second B high-reflection mirror 113, an optical parametric crystal 112, a second beam splitter 111, a third A high-reflection mirror 114, a third beam shaper 115, an F polarizer 116, an N electro-optic crystal 117, and a third B high-reflection mirror 118 arranged sequentially. Preferably, as shown... Figure 3 As shown, the first laser resonator also includes a quarter-wave plate 103, which is disposed between the M electro-optic crystal 102 and the E polarizer 104. Thus, fundamental frequency laser oscillation is achieved through the first laser resonator between the first A high-reflection mirror 101 and the first B high-reflection mirror 108; frequency-doubled laser oscillation is achieved through the second laser resonator between the first B high-reflection mirror 108 and the second B high-reflection mirror 113; and optical parametric laser oscillation is achieved through the third laser resonator between the second B high-reflection mirror 113 and the third B high-reflection mirror 118. When the optical parametric laser energy reaches its maximum, the optical parametric laser is coupled and output to obtain the target picosecond laser.

[0075] In the above embodiments, to ensure efficient acquisition of high-power, high-energy target picosecond lasers, such as Figure 2 or Figure 3As shown, preferably, the first A high-reflection mirror 101 and the first B high-reflection mirror 108 are arranged perpendicularly to each other; the first A high-reflection mirror 101, the first B high-reflection mirror 108, the second B high-reflection mirror 113, and the third B high-reflection mirror 118 are all arranged perpendicularly to their respective optical axes; the first B high-reflection mirror 108, the second B high-reflection mirror 113, and the third B high-reflection mirror 118 are arranged parallel to each other; the second A high-reflection mirror 109, the third A high-reflection mirror 114, and the E polarizer 104 are arranged parallel to each other; the first beam splitter 106, the second beam splitter 111, and the F polarizer 116 are arranged parallel to each other. Preferably, the first A high-reflectivity mirror 101 is coated with a high-reflectivity film for fundamental frequency lasers; the first beam splitter 106 is coated with a high-transmittance film for fundamental frequency lasers and a high-reflectivity film for frequency-doubled lasers; the first B high-reflectivity mirror 108 is coated with a high-reflectivity film for fundamental frequency lasers and a high-reflectivity film for frequency-doubled lasers; the second A high-reflectivity mirror 109 is coated with a high-reflectivity film for frequency-doubled lasers; the second beam splitter 111 is coated with a high-transmittance film for frequency-doubled lasers and a high-reflectivity film for optical parametric lasers; the second B high-reflectivity mirror 113 is coated with a high-reflectivity film for frequency-doubled lasers and a high-reflectivity film for optical parametric lasers; the third A high-reflectivity mirror 114 is coated with a high-reflectivity film for optical parametric lasers; and the third B high-reflectivity mirror 118 is coated with a high-reflectivity film for optical parametric lasers. To ensure the high-power, efficient, and stable output of the target picosecond laser, preferably, the reflectivity of the first A high-reflectivity mirror 101 and the first B high-reflectivity mirror 108 for the fundamental frequency laser is 99.5%–99.8%, the transmittance of the first beam splitter 106 for the fundamental frequency laser is 98.25%–99.6%, the reflectivity of the first beam splitter 106, the first B high-reflectivity mirror 108, the second A high-reflectivity mirror 109, and the second B high-reflectivity mirror 113 for the frequency-doubled laser is 99.5%–99.8%, the transmittance of the second beam splitter 111 for the frequency-doubled laser is 98.25%–99.6%, and the reflectivity of the second beam splitter 111, the second B high-reflectivity mirror 113, the third A high-reflectivity mirror 114, and the third B high-reflectivity mirror 118 for the optical parametric laser is 99.5%–99.8%.

[0076] Based on such Figure 2The picosecond laser described above, specifically, in the picosecond laser generation method, in the first laser resonant cavity, polarized laser is obtained by polarizing the fundamental frequency laser provided by the fundamental frequency laser source 100 through an E-polarizer 104. The obtained polarized laser includes a first P-polarized light and a first S-polarized light, wherein the first P-polarized light is the fundamental frequency laser polarized parallel to the incident plane, and the first S-polarized light is the fundamental frequency laser polarized perpendicular to the incident plane. The E-polarizer 104 has high transmission for the first P-polarized light and high reflection for the first S-polarized light. The fundamental frequency laser transmitted through the E-polarizer 104 is incident on the first A high-reflection mirror 101 after its polarization direction is changed by the M-electro-optic crystal 102. After being reflected by the first A high-reflection mirror 101, it is again incident on the E-polarizer 104 after its polarization direction is changed by the M-electro-optic crystal 102. The fundamental frequency laser reflected by the E-polarizer 104 then sequentially passes through the first... A beam shaper 105, a first beam splitter 106, and a frequency doubling crystal 107 are incident on a first B high-reflection mirror 108. High voltage is input to both ends of an M-electro-optic crystal 102 to change the polarization direction of the fundamental frequency laser passing through it. The fundamental frequency laser is highly reflected by a first A high-reflection mirror 101. The first beam shaper 105 shapes the input fundamental frequency laser beam, and the shaped laser is injected into the frequency doubling crystal 107. The frequency doubling crystal 107 performs frequency doubling on the injected laser, generating a frequency-doubled laser. The first beam splitter 106 separates the fundamental frequency laser and the frequency-doubled laser, where the first beam splitter 106 provides high transmission for the fundamental frequency laser and high reflection for the frequency-doubled laser. The first B high-reflection mirror 108 provides high reflection for both the fundamental frequency laser and the frequency-doubled laser. Specifically, the fundamental frequency laser is preferably a picosecond laser with a wavelength of 1064 nm, and the pulse width of the fundamental frequency laser is preferably 100 picoseconds to 500 picoseconds. The frequency-doubled laser obtained by frequency doubling based on the fundamental frequency laser is a laser with a wavelength of 532 nm. Preferably, the fundamental frequency laser, after its polarization direction is changed by the M-electro-optic crystal 102, is incident on the E-polarizer 104 perpendicularly to the E-polarizer 104. More preferably, the high voltage input at both ends of the M-electro-optic crystal 102 is preferably a half-wave voltage. The specific value of the half-wave voltage is set according to the specific working conditions of the material of the M-electro-optic crystal 102, so as to ensure that the optical parametric laser coupling outputs maximum energy stably and efficiently.

[0077] Based on such Figure 3 The picosecond laser shown above generates picosecond lasers using a method similar to that described above. Figure 2The method for generating ultra-picosecond lasers shown is basically the same, except that in the first laser resonant cavity, the polarization direction of the fundamental frequency laser passing through the quarter-wave plate 103 is changed. Specifically, the fundamental frequency laser passing through the E polarizer 104 is incident on the first A high-reflection mirror 101 after its polarization direction is changed by the quarter-wave plate 103 and the M electro-optic crystal 102, after being reflected by the first A high-reflection mirror 101, and then incident on the E polarizer 104 again after its polarization direction is changed by the M electro-optic crystal 102 and the quarter-wave plate 103. Preferably, as shown... Figure 3 As shown, the fundamental frequency laser, after its polarization direction has been changed by the M-electro-optic crystal 102 and the quarter-wave plate 103, is incident again on the E-polarizer 104 perpendicular to the E-polarizer 104. Preferably, as... Figure 3 As shown, the high voltage input at both ends of the M-electro-optic crystal 102 is preferably a quarter-wave voltage to change the polarization direction of the fundamental frequency laser passing through the M-electro-optic crystal 102; wherein, the specific value of the quarter-wave voltage is set according to the specific working conditions of the material of the M-electro-optic crystal 102, so as to ensure that the optical parametric laser coupling is performed with the maximum energy stable and efficient output as the standard.

[0078] In the above embodiments, such as Figure 2 or Figure 3 As shown, preferably, in the second laser resonant cavity, the frequency-doubled laser reflected by the first beam splitter 106 is incident on the second A high-reflection mirror 109. After being reflected by the second A high-reflection mirror 109, it passes sequentially through the second beam shaper 110, the second beam splitter 111, and the optical parametric crystal 112 before being incident on the second B high-reflection mirror 113. The second beam shaper 110 shapes the input frequency-doubled laser beam, and the shaped frequency-doubled laser is injected into the optical parametric crystal 112. The optical parametric crystal 112 absorbs the injected frequency-doubled laser shaped by the second beam shaper 110, generating an optical parametric laser. The second beam splitter 111 separates the frequency-doubled laser and the optical parametric laser, wherein the second beam splitter 111 provides high transmission for the frequency-doubled laser and high reflection for the optical parametric laser. The second B high-reflection mirror 113 provides high reflection for both the frequency-doubled laser and the optical parametric laser.

[0079] In the above embodiments, such as Figure 2 or Figure 3As shown, preferably, in the third laser resonant cavity, the parametric laser light reflected by the second beam splitter 111 is incident on the third A high-reflection mirror 114. After being reflected by the third A high-reflection mirror 114, it passes sequentially through the third beam shaper 115, the F polarizer 116, and the N electro-optic crystal 117 before being incident on the third B high-reflection mirror 118. The input parametric laser light is shaped by the third beam shaper 115, and the parametric laser light shaped by the second beam shaper 110 is incident on the F polarizer 116. The F polarizer 116, the N electro-optic crystal 117, and the third B high-reflection mirror 118 jointly achieve the coupling and output of the target picosecond laser light. The wavelength range of the obtained target picosecond laser light is 760 nm to 810 nm, and the pulse width is 100 picoseconds to 500 picoseconds.

[0080] In the above embodiments, to ensure stable output of the target picosecond laser, more preferably, as follows: Figure 2 or Figure 3 As shown, after the optical parametric laser is incident on the F polarizer 116, it generates third P-polarized light and third S-polarized light through the F polarizer 116. The third S-polarized light is output after coupling. When no voltage is applied to the N electro-optic crystal 117, the third P-polarized light is confined and oscillates in the third laser resonant cavity. When a quarter-wave voltage is applied to the N electro-optic crystal 117, the third P-polarized light is changed to the same direction as the third S-polarized light, and after coupling together with the third S-polarized light, it is reflected by the F polarizer 116 and output. The specific value of the quarter-wave voltage is set according to the material and other specific operating conditions of the N electro-optic crystal 117 to ensure that the optical parametric laser outputs stable and efficient maximum energy after coupling.

[0081] In the above embodiments, when the fundamental frequency laser and the frequency-doubled laser oscillate in the first and second laser resonant cavities respectively, the first and second laser resonant cavities have equal optical cavity lengths, allowing the fundamental frequency laser and the frequency-doubled laser to be synchronously incident on the frequency-doubled crystal 107 to achieve phase matching. After an appropriate number of oscillations or delays, the energy of the frequency-doubled laser continuously increases. Correspondingly, when the frequency-doubled laser and the optical parametric laser oscillate in the second and third laser resonant cavities respectively, the second and third laser resonant cavities have equal optical cavity lengths, allowing the frequency-doubled laser and the optical parametric laser to be synchronously incident on the optical parametric crystal 112. After an appropriate number of oscillations or delays, the energy of the optical parametric laser reaches its maximum. At this point, the optical parametric laser is coupled and output, thereby ensuring the acquisition of a single pulse of high-energy target picosecond laser. Preferably, the number of oscillations experienced by the frequency-doubled laser and the optical parametric laser is less than one hundred, and the delay experienced by the frequency-doubled laser and the optical parametric laser is less than one hundred. The delay time is selected to be within 1 microsecond, thus ensuring both the high energy of the target picosecond laser output and the overall efficient operation of the picosecond laser. More preferably, the specific value of the delay time of the optical parametric laser can be determined by the following method: A high-speed photodetector is set behind the third B high-reflection mirror 118. When the optical parametric laser oscillates in the third resonant cavity, a very small portion of the optical parametric laser will be transmitted at the third B high-reflection mirror 118. The high-speed photodetector detects the optical parametric laser transmitted through the third B high-reflection mirror 118 in real time and converts it into an electrical signal, which is then transmitted to an oscilloscope for display. The controller receives the signal displayed on the oscilloscope and controls the N electro-optic crystal 117 according to the signal. When the signal displayed on the oscilloscope reaches its maximum, that is, when the optical parametric laser energy reaches its maximum, a quarter-wave voltage is immediately applied to the N electro-optic crystal 117, so that the third P polarized light is changed to the same direction as the third S polarized light, and after coupling together with the third S polarized light, it is reflected by the F polarizer 116 and output. Therefore, the output of the target picosecond laser can be effectively controlled, and the high energy of each single pulse of the target picosecond laser can be efficiently ensured. More preferably, such as Figure 2 or Figure 3 As shown, to ensure the acquisition of a target ultra-picosecond laser with a wavelength of 785 nm and a pulse width of 100 picoseconds to 500 picoseconds, a fundamental frequency laser with a wavelength of 1064 nm and a single pulse energy of 500 mJ to 1000 mJ is preferably used. The frequency-doubled laser with a wavelength of 532 nm generated by the frequency-doubled crystal 107 that absorbs the fundamental frequency laser has a single pulse energy of 250 mJ to 800 mJ, thereby effectively ensuring that the single pulse energy of the target ultra-picosecond laser reaches 100 mJ to 500 mJ.

[0082] Compared with the existing traditional single-pass frequency conversion technology, the picosecond laser provided by the above embodiments of this application breaks through the traditional concept and adopts solid-state laser frequency conversion technology for the first time. For the first time, it sets up the laser resonator involving the fundamental frequency laser, the frequency doubling laser and the optical parametric laser to be mutually coupled, and uses this coupling structure to couple the optical parametric laser to output, so as to achieve the purpose of higher efficiency and higher frequency conversion, thereby obtaining a 785-nanometer picosecond laser with higher single pulse energy. The obtained picosecond 785-nanometer band laser has a wavelength range of 760 nanometers to 810 nanometers and the pulse width can be controlled to be 100 picoseconds to 500 picoseconds. Based on the picosecond laser provided in the embodiments of this application, it can be used to manufacture equipment that requires the application of a 785-nanometer picosecond laser source, especially to manufacture medical instruments for skin treatment. In the field of skin treatment, the provided picosecond 785-nanometer band laser can be well absorbed by melanin and can be widely used for tattoo removal, freckle and mole removal, skin rejuvenation, and improvement of fine lines and acne scars. In particular, in the removal of tattoos, the 785-nanometer picosecond pulsed laser can be fully absorbed by green and blue tattoos and is not affected by human hemoglobin, so as to obtain better treatment results with almost no heat and pain.

[0083] According to a second aspect of the embodiments of this application, a method for generating ultra-picosecond 785 nanometer band lasers is provided, the method including:

[0084] Acquire fundamental frequency laser;

[0085] Frequency-doubled laser is obtained by frequency doubling the fundamental frequency laser.

[0086] Using frequency-doubled laser as pump light, a 785 nanometer wavelength laser is generated as the optical parametric laser.

[0087] By coupling a 785 nm wavelength laser, a picosecond 785 nm wavelength laser is obtained.

[0088] According to a third aspect of the embodiments of this application, a skin treatment device is provided, characterized in that it includes a picosecond laser of any one of the embodiments of the first aspect.

[0089] According to a fourth aspect of the embodiments of this application, an apparatus is provided, characterized in that it includes the picosecond laser described in any one of the embodiments of the first aspect.

[0090] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A picosecond laser, characterized in that, include: A fundamental frequency laser source, used to emit fundamental frequency laser light; The first laser resonant cavity is used to perform frequency doubling conversion on the fundamental frequency laser to form a frequency-doubled laser; The second laser resonant cavity is used to generate 785 nanometer band laser using the frequency-doubled laser as pump light; A third laser resonant cavity is used to couple the laser beam and output a picosecond 785 nanometer wavelength laser. The optical cavity lengths of the first laser resonant cavity, the second laser resonant cavity, and the third laser resonant cavity are all equal. The first laser resonant cavity is the resonant cavity of the fundamental frequency laser; The second laser resonant cavity is the resonant cavity of the frequency-doubled laser; The third laser resonant cavity is both the resonant cavity of the optical parametric laser and the coupled output cavity of the optical parametric laser; The first laser resonant cavity and the second laser resonant cavity share a set of high-reflection mirrors, a set of beam-splitting mirrors, and a set of frequency-doubling crystals; The second laser resonator and the third laser resonator share a set of high-reflection mirrors, a set of beam mirrors, and a set of optical parametric crystals.

2. The picosecond laser according to claim 1, characterized in that, The first laser resonant cavity is coupled to the second laser resonant cavity, and the second laser resonant cavity is coupled to the third laser resonant cavity.

3. The picosecond laser according to claim 1, characterized in that, The pulse width of the fundamental frequency laser is 100 picoseconds to 500 picoseconds, and the wavelength of the fundamental frequency laser is 1064 nanometers. The wavelength of the frequency-doubled laser is 532 nanometers; The wavelength range of the 785 nm band laser is 760 nm to 810 nm. The pulse width of the ultra-picosecond 785 nanometer band laser is 100 picoseconds to 500 picoseconds.

4. The picosecond laser according to claim 1, characterized in that, Also includes: High-reflection mirrors, polarizers, beam shapers, beam splitters, electro-optic crystals, frequency doubling crystals, and optical parametric crystals; The high-reflectivity mirror has at least six sets, the polarizer, the beam splitter and the electro-optic crystal each have at least two sets, and the beam shaper has at least three sets.

5. A skin treatment device, characterized in that, Includes the picosecond laser according to any one of claims 1 to 4.

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