Dual-wavelength lath frequency doubling laser

Abstract

The invention belongs to the technical field of lasers, and relates to a dual-wavelength slab frequency doubling laser which comprises a laser resonant cavity unit and a slab crystal pump unit. The laser resonant cavity unit is provided with a first light path, and a first total reflection mirror, a slab crystal, a first electro-optical Q switch, a first harmonic mirror, a first frequency doubling crystal and a first output mirror are sequentially arranged along the first light path; a second total reflection mirror, a slab crystal, a second electro-optical Q switch, a second harmonic mirror, a second frequency doubling crystal and a second output mirror are sequentially arranged along the second light path; the slab crystal pumping device unit is a side pumping or a large pumping, and comprises a semiconductor laser array and an optical waveguide. The dual-wavelength slab laser has the advantages of high pumping power and high beam quality, and maximum power output is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers, and in particular relates to a dual-wavelength slab frequency-doubling laser. Background Art

[0002] The first dual-wavelength laser was developed by CG Betha et al. of Bell Labs in 1973, who used Nd:YAG crystal in a three-mirror colinear cavity with a Q switch to achieve dual-wavelength pulse operation of 1064nm and 1319nm (CG Betha, IEEEJournal Quantum Electronics, QE-9, 254 (1973)). Since then, reports have been made on the use of other laser crystals to achieve dual-wavelength pulse operation (W. Vollmer, MG Knights et al., Conferences on Laser and Electro-optics, Digest of Technical Papers, 188, 1983, May, 17-21, J.Machan, R. Kurtz et al., Applied Physics Letters, Vol.51, No.17, 1313 (1987), VE Nadtoncheev, OE Nanii, Soviet Journal of Quantum Electronics, Vol.19, No.4, 444 (1991)).

[0003] At this stage, people have reached a general consensus on the wide application value of dual-wavelength lasers. For example, in the civilian field, dual-wavelength lasers can be applied to laser medicine, high-brightness laser color display, laser color printing and other directions; in the military field, dual-wavelength lasers can be applied to differential absorption lidar; at the laboratory level, dual-wavelength lasers can be applied to nonlinear frequency conversion, fine laser spectroscopy, multi-photon distribution ionization of atoms and molecules and other directions. It should be pointed out that compared with gas dual-wavelength lasers, solid dual-wavelength lasers are more valuable for research. In order to obtain stable and more energetic dual-wavelength laser output in solid dual-wavelength lasers, researchers have focused their research directions on the following three aspects: ① Simultaneously output the fundamental frequency light of the laser operating at a fixed wavelength and its frequency conversion light; ② The light emitted by the laser based on the broadband emission spectrum of the laser medium is used to achieve dual-wavelength operation through a frequency-selective device; ③ Dual-wavelength laser output is achieved based on the two emission peaks of the emission spectrum of the laser medium. Among the above three methods of obtaining dual-wavelength laser output, the first two are more mature, but the disadvantage is that other wavelengths are also doped while obtaining dual-wavelength laser output, and the obtained dual-wavelength laser output energy is low. As for the third method of dual-wavelength laser output, because its device structure is relatively simple, the implementation cost is low, and the wavelength band is rich, it has the potential for further exploration; however, for Nd:YAG crystals, there are also some difficulties in the simultaneous output of 1064nm and 1319nm: ① The oscillation effect of suppressing redundant spectral lines such as 1338nm is not good; ② It is difficult to adjust the output power ratio of 1064nm / 1319nm dual-wavelength laser; ③ It is difficult to control the threshold of 1064nm / 1319nm laser to be equal and the laser structure devices are complicated. In addition, based on solid-state laser frequency doubling technology, lithium triborate LiB3O5 (LBO) crystals and potassium titanyl phosphate (KTiOPO4, KTP) crystals are the most commonly used frequency doubling crystals and are widely used in frequency doubling lasers. LBO crystals have the characteristics of wide transmittance range, small breakoff angle, high damage threshold, and wide acceptance angle; KTP crystals have high nonlinearity and are widely used in nonlinear media.

[0004] In the field of laser medical clinical treatment, 532nm and 660nm lasers produced by frequency doubling technology are more easily absorbed by protein tissues than general YAG (1064nm) lasers, have shallow tissue penetration, obvious gasification of tissues, fast cutting speed, less thermal damage to surrounding tissues, clean wounds after gasification and dredging, fewer complications during laser surgery, fast recovery after surgery, and no need for long-term retention of support. Laser clinical experiments and applications have proved that 532nm and 660nm wavelength lasers are ideal light sources for intracavitary interventional treatment. Therefore, frequency-doubled dual-wavelength lasers are better for tear duct dredging and bronchial treatment than general YAG lasers. In clinical trials of human tear duct dredging surgery with 1320nm frequency-doubled laser 660nm, the positive expression of type V collagen in lacrimal duct tissue after surgery was significantly lower than that of 1320nm laser, and the treatment results showed that inflammatory tissues also absorbed 660nm red light well, which is conducive to surgical anti-inflammatory treatment. The 532nm laser after frequency doubling of 1064nm laser is used for laser vaporization, coagulation of caseous and granulation tissue in the bronchus, cutting of adhesion folds, and bronchial dredging. It is found that the caseous tissue of the lesion treated with 532nm laser is completely removed or only left with a trace. Therefore, 532nm green light can be used to treat larger and stubborn granulation tissue.

[0005] Therefore, it is urgent to propose a dual-wavelength slab frequency doubling laser to solve the existing technical problems of suppressing the oscillation of redundant spectral lines such as 1338nm, adjusting the output power ratio of the 1064nm / 1319nm dual-wavelength laser, controlling the thresholds of the 1064nm / 1319nm laser to be equal, and realizing the 1064nm / 1319nm dual-wavelength laser frequency doubling on this basis when realizing the 1064nm / 1319nm dual-wavelength laser output based on the two emission peaks of the emission spectrum of the laser medium. Summary of the invention

[0006] In view of the technical problems in the prior art of suppressing the oscillation of redundant spectral lines such as 1338nm, adjusting the output power ratio of the 1064nm / 1319nm dual-wavelength laser, controlling the thresholds of the 1064nm / 1319nm laser to be equal, and realizing the frequency doubling of the 1064nm / 1319nm dual-wavelength laser on this basis when realizing the 1064nm / 1319nm dual-wavelength laser output based on the two emission peaks of the emission spectrum of the laser medium, the present invention proposes a dual-wavelength slab frequency doubling laser to solve at least one of the above technical problems.

[0007] In a preferred embodiment of the present invention, a dual-wavelength slab frequency-doubled laser is provided, wherein the dual-wavelength slab frequency-doubled laser comprises a laser resonant cavity unit and a slab crystal pump unit; The laser resonant cavity unit comprises: a first optical path, along which a first total reflection mirror, a slab crystal, a first electro-optical Q switch, a first harmonic mirror, a first frequency doubling crystal, and a first output mirror are sequentially arranged; a second optical path, along which a second total reflection mirror, a slab crystal, a second electro-optical Q switch, a second harmonic mirror, a second frequency doubling crystal, and a second output mirror are sequentially arranged; The slab crystal pump unit is side-pumped or large-surface pumped, and the slab crystal pump unit includes a semiconductor laser array and an optical waveguide; wherein, The light apertures of the first electro-optical Q switch and the second electro-optical Q switch are matched to the diameters of the lasers received by the first electro-optical Q switch and the second electro-optical Q switch, respectively; the coating center wavelengths of the first total reflection mirror and the first output mirror are the same, and the coating center wavelengths of the second total reflection mirror and the second output mirror are the same; the coating center wavelengths of the first total reflection mirror and the first output mirror and the coating center wavelengths of the second total reflection mirror and the second output mirror correspond to the wavelengths of the two absorption peaks with the largest and second largest absorption cross sections of the slab crystal, respectively; The shape of the lath crystal is trapezoidal, and the lath crystal is Nd:YAG crystal; The fundamental frequency light of the first optical path and the fundamental frequency light of the second optical path simultaneously complete oscillation along the first direction and conduction along the second direction in the slab crystal; The first frequency doubling crystal and the second frequency doubling crystal are selected from LBO crystal or KTP crystal; The wavelength of the fundamental frequency light of the first optical path is 1064nm, and the wavelength of the fundamental frequency light of the second optical path is 1320nm; The laser wavelengths output by the dual-wavelength slab frequency-doubled laser are 532 nm and 660 nm respectively.

[0008] Preferably, the semiconductor laser array is a laser diode array.

[0009] Preferably, the slab crystal pump unit is selected from any one of double-sided side pumping, single-sided side pumping, and single-sided large-surface pumping.

[0010] Preferably, the slab crystal pump unit is selected from single-sided large-surface pumping.

[0011] Preferably, the shape of the lath crystal is trapezoidal, the lower base of the Nd:YAG crystal is 69.2 mm, the upper base of the Nd:YAG crystal is 67 mm, the width of the Nd:YAG crystal is 10 mm, the thickness of the Nd:YAG crystal is 2 mm, the bottom angle of the Nd:YAG crystal is 29.2°, the first direction is the height direction of the lath crystal, the second direction is the length direction of the lath crystal, and the first direction is perpendicular to the second direction.

[0012] Preferably, the length of the slab crystal is such that dual-wavelength light can complete an integer number of cycles of oscillation while being transmitted in the slab crystal.

[0013] Preferably, the heat dissipation method of the slat crystal is water cooling.

[0014] Preferably, the first electro-optical Q switch is selected from KD2PO4 crystal.

[0015] Preferably, the second electro-optical Q switch is selected from LiNbO3 crystal.

[0016] Preferably, the first total reflection mirror is coated with a 0°@1064nm total reflection film, the first harmonic mirror is coated with a HR@532nm&AR@1064nm coating, the coating surface faces the first frequency doubling crystal, and the first output mirror is coated with a HR@1064nm&AR@532nm coating; the second total reflection mirror is coated with a 0°@1320nm total reflection film, the second harmonic mirror is coated with a HR@660nm&AR@1320nm coating, the coating surface faces the second frequency doubling crystal, and the second output mirror is coated with a HR@1320nm&AR@660nm coating.

[0017] Compared with the prior art, the present invention can bring at least one of the following beneficial effects: 1) The dual-wavelength slab frequency-doubled laser of the present application adopts a dual-wavelength oscillation resonant cavity type, and forms two different oscillation periods through dual wavelengths, and the oscillation periods are both integer multiples of the dual-wavelength light, thereby fully extracting the upper energy level particles in the slab crystal.

[0018] 2) The dual-wavelength slab frequency-doubled laser of the present application utilizes the advantages of high pump power and high beam quality of the slab laser to achieve maximum power output, which enables the laser to have more application scenarios, thereby broadening the applicability of the laser.

[0019] 3) The dual-wavelength slab frequency-doubled laser of the present application suppresses the oscillation interference of redundant spectral lines by selecting the first electro-optical Q switch from KD2PO4 crystal and the second electro-optical Q switch from LiNbO3 crystal.

[0020] 4) In the dual-wavelength slab frequency-doubled laser of the present application, the first frequency-doubled crystal and the second frequency-doubled crystal are selected from LBO crystals or KTP crystals; the fundamental frequency light wavelength of the first optical path is 1064nm, and the fundamental frequency light wavelength of the second optical path is 1320nm; the laser wavelengths output by the dual-wavelength slab frequency-doubled laser are 532nm and 660nm respectively, and high-quality 532nm / 660nm laser can be obtained based on high-power, high-beam-quality 1064nm / 1319nm laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and their implementation methods.

[0022] Figure 1 It is a side view of a single-side large-surface pumping of the dual-wavelength slab frequency-doubled laser according to a specific embodiment of the present invention; Figure 2 It is a top view of the double-side side pumping of the slab crystal of the dual-wavelength slab frequency-doubled laser according to a specific embodiment of the present invention; Figure 3 It is a top view of the single-side side pumping of the dual-wavelength slab frequency-doubling laser slab crystal according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0023] Various aspects of the present invention are described in further detail below.

[0024] Unless otherwise defined or indicated, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the method of the present invention.

[0025] Unless otherwise clearly specified and limited, the "or" mentioned in the present invention includes the relationship of "and". The "and" is equivalent to the Boolean logic operator "AND", the "or" is equivalent to the Boolean logic operator "OR", and "AND" is a subset of "OR".

[0026] It is to be understood that although the terms "first", "second", etc. may be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, the first element may be referred to as the second element without departing from the teachings of the present invention.

[0027] In the present invention, the terms "consisting mainly of" and "consisting of" are included in the terms "containing", "including" or "comprising".

[0028] Unless otherwise clearly specified and limited, the terms "connected", "connected" and "connection" in the present invention should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] For example, if an element (or component) is referred to as being on, coupled to, or connected to another element, the element may be directly formed on, coupled to, or connected to the other element, or there may be one or more intervening elements between them. In contrast, if the expressions "directly on," "directly coupled to," and "directly connected to" are used herein, then no intervening elements are indicated. Other words used to describe the relationship between elements should be similarly interpreted, such as "between" and "directly between," "attached" and "directly attached," "adjacent" and "directly adjacent," etc.

[0030] It should also be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the drawings. The words "inner" and "outer" used refer to directions toward or away from the geometric center of a particular component, respectively. It can be understood that these terms are used here to describe the relationship of one element, layer or region relative to another element, layer or region as shown in the drawings. In addition to the orientations described in the drawings, these terms should also include other orientations of the device.

[0031] Other aspects of the present invention will be apparent to those skilled in the art in view of the disclosure herein.

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0033] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show the components related to the present application and are not drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout may also be more complicated. For example, the thickness of the components in the drawings may be exaggerated for the sake of clarity.

[0034] See attached Figure 1-3 , in a preferred embodiment of the present invention, a dual-wavelength slab frequency-doubled laser is provided, the dual-wavelength slab frequency-doubled laser comprising a laser resonant cavity unit and a slab crystal pump unit; The laser resonant cavity unit comprises: a first optical path, along which a first total reflection mirror 1, a slab crystal 2, a first electro-optical Q switch 3, a first harmonic mirror 12, a first frequency doubling crystal 10, and a first output mirror 4 are sequentially arranged; a second optical path, along which a second total reflection mirror 5, a slab crystal 2, a second electro-optical Q switch 6, a second harmonic mirror 13, a second frequency doubling crystal 11, and a second output mirror 7 are sequentially arranged; The slab crystal pump unit is side-pumped or large-surface pumped, and the slab crystal pump unit includes a semiconductor laser array 9 and an optical waveguide 8; wherein, The light apertures of the first electro-optical Q switch 3 and the second electro-optical Q switch 6 are matched to the diameters of the lasers received by the first electro-optical Q switch 3 and the second electro-optical Q switch 6, respectively; the coating center wavelengths of the first total reflection mirror 1 and the first output mirror 4 are the same, and the coating center wavelengths of the second total reflection mirror 5 and the second output mirror 7 are the same; the coating center wavelengths of the first total reflection mirror 1 and the first output mirror 4 and the coating center wavelengths of the second total reflection mirror 5 and the second output mirror 7 correspond to the wavelengths of the two absorption peaks with the largest and second largest absorption cross sections of the slab crystal, respectively; The shape of the lath crystal 2 is trapezoidal, and the lath crystal 2 is Nd:YAG crystal; The fundamental frequency light of the first optical path and the fundamental frequency light of the second optical path simultaneously complete oscillation along the first direction and conduction along the second direction in the slab crystal 2; The first frequency doubling crystal 10 and the second frequency doubling crystal 11 are selected from LBO crystal or KTP crystal; The wavelength of the fundamental frequency light of the first optical path is 1064nm, and the wavelength of the fundamental frequency light of the second optical path is 1320nm; The laser wavelengths output by the dual-wavelength slab frequency-doubled laser are 532 nm and 660 nm respectively.

[0035] It should be noted that the dual-wavelength slab frequency-doubling laser has a simple structure and does not use a large number of redundant optical devices, thereby reducing the manufacturing cost. In addition, the coating center wavelengths of the first total reflection mirror 1 and the first output mirror 4 and the coating center wavelengths of the second total reflection mirror 5 and the second output mirror 7 correspond to the wavelengths of the two absorption peaks with the largest and second largest absorption cross sections of the slab crystal 2, respectively. The wavelengths with the largest and second largest absorption cross sections are selected as the oscillation light wavelengths of the first optical path and the second optical path, and are also used as the coating center wavelengths of the first total reflection mirror 1 and the first output mirror 4 on the first optical path and the second total reflection mirror 5 and the second output mirror 7 on the second optical path. Moreover, the light apertures of the first electro-optical Q switch 3 and the second electro-optical Q switch 6 are matched to the laser diameters received by the first electro-optical Q switch 3 and the second electro-optical Q switch 6, respectively, which is conducive to obtaining the best Q-switching efficiency.

[0036] It should be noted that, as a preferred embodiment, the shape of the slab crystal 2 is trapezoidal, the lower base of the Nd:YAG crystal is 69.2 mm, the upper base of the Nd:YAG crystal is 67 mm, the width of the Nd:YAG crystal is 10 mm, the thickness of the Nd:YAG crystal is 2 mm, the bottom angle of the Nd:YAG crystal is 29.2°, the first direction is the height direction of the slab crystal 2, the second direction is the length direction of the slab crystal 2, and the first direction is perpendicular to the second direction. The length of the slab crystal 2 along the Z direction satisfies that the two oscillation wavelengths of the first optical path and the second optical path can complete the conduction of a complete number of cycles, and the laser oscillates in the Y direction of the slab crystal 2.

[0037] As a preferred embodiment, the semiconductor laser array 9 is a laser diode array.

[0038] As a preferred embodiment, the slab crystal pump unit is selected from any one of double-sided side pumping, single-sided side pumping, and single-sided large-surface pumping.

[0039] It should be noted that in double-sided side pumping, the pump light is injected from another plane perpendicular to the cooling surface and the laser propagation plane, which increases the absorption length of the pump light and improves the utilization rate.

[0040] As a preferred embodiment, the slab crystal pump unit is selected from single-sided large-surface pumping.

[0041] It should be noted that the large-surface pump injects more energy and is more suitable for high-power solid-state dual-wavelength lasers.

[0042] As a preferred embodiment, the length of the slab crystal 2 is sufficient to allow dual-wavelength light to complete an integer number of cycles of oscillation while being transmitted in the slab crystal 2 .

[0043] As a preferred embodiment, the heat dissipation method of the lath crystal 2 is water cooling.

[0044] It should be noted that by adopting a water-cooling cooling method, the pump surface and the cooling surface are separated, simplifying the design of the laser head.

[0045] As a preferred embodiment, the first electro-optical Q switch 3 is selected from KD2PO4 crystal.

[0046] As a preferred embodiment, the second electro-optical Q switch 6 is selected from LiNbO3 crystal.

[0047] As a preferred embodiment, the first total reflection mirror 1 is coated with a 0°@1064nm total reflection film, the first harmonic mirror 12 is coated with a HR@532nm&AR@1064nm coating, the coating surface faces the first frequency doubling crystal 10, and the first output mirror 4 is coated with a HR@1064nm&AR@532nm coating; the second total reflection mirror 5 is coated with a 0°@1320nm total reflection film, the second harmonic mirror 13 is coated with a HR@660nm&AR@1320nm coating, the coating surface faces the second frequency doubling crystal 11, and the second output mirror 7 is coated with a HR@1320nm&AR@660nm coating.

[0048] It should be noted that the slab crystal of the dual-wavelength slab frequency-doubled laser is Nd:YAG, the fundamental frequency of the oscillating light of the first optical path is a wavelength of 1064nm, and after being frequency-doubled by the first frequency-doubled crystal 10 (KTP or Class II LBO), 532nm green light is output, and the fundamental frequency of the oscillating light of the second optical path is a wavelength of 1320nm, and after being frequency-doubled by the second frequency-doubled crystal 11 (KTP or Class II LBO), 660nm red light is output.

[0049] Embodiment 1: See attached Figure 1 The dual-wavelength slab frequency-doubled laser has a slab crystal 2 which is a Nd:YAG trapezoidal crystal with a doping concentration of 1%, a size of 67 mm×10 mm×2 mm, and a bottom angle of 29.2°.

[0050] The slab crystal 2 is Nd:YAG, the fundamental frequency of the oscillating light of the first optical path is 1064nm wavelength, after being frequency-doubled by the first frequency-doubling crystal 10 (KTP or Class II LBO), 532nm green light is output, and the fundamental frequency of the oscillating light of the second optical path is 1320nm wavelength, after being frequency-doubled by the second frequency-doubling crystal 11 (KTP or Class II LBO), 660nm red light is output.

[0051] The second electro-optical Q switch 6 crystal uses LIN (lithium niobate) crystal, which has a much smaller absorption coefficient in the 1320nm band than KDP crystal. After coating, its transmittance in the 1320nm band is higher than 98%, and its insertion loss does not exceed 1%, which is more conducive to the oscillation of 1320nm laser. The first electro-optical Q switch crystal uses KD2PO4 (potassium dideuterium phosphate), which is used for electro-optical Q switching of 1064nm laser optical path in this embodiment. A semiconductor laser array 9 is used for single-sided large-surface pumping. After waveguide 8 shaping, the spot size is 65×9mm, which is evenly irradiated on the large surface of the slat-shaped crystal. A water-cooled heat sink device is welded on the other large surface opposite to the semiconductor pump. In the optical path of this scheme, the 1064nm wavelength adopts a straight-through cavity structure along the optical path 1, and is oscillated and transmitted in the resonant cavity optical path composed of the first total reflection mirror 1, the slab crystal 2, the first electro-optical Q switch 3, and the first output mirror 4. Since the emission cross section of Nd:YAG is the largest in the 1064nm band, the output power of the 1064nm laser is also relatively high. According to calculations, the 1064nm wavelength light has 4 complete oscillation cycles in the slab. The 1320nm laser propagates along the second optical path, with the second total reflection mirror 5, the slab crystal 2, the second electro-optical Q switch 6, and the second output mirror 7. The 1320nm laser is incident on the slab crystal 2 at an angle of 46.6° with the incident surface of the slab, oscillates along the Y axis in the slab crystal 2, and propagates along the Z axis. According to calculations, there are 8 complete cycles. Among them, the oscillation period of the 1320nm wavelength in the crystal is twice the number of periods of the 1064nm wavelength, and the output power is also improved, further reducing the power difference of the dual-wavelength output power.

[0052] Embodiment 2: See attached Figure 2 The slab crystal 2 is pumped on both sides by two semiconductor laser arrays 9. After being shaped by the waveguide 8, the spot size is 9 mm×1.5 mm, which is evenly irradiated on the side of the slab crystal. This method has high pumping power density and long absorption distance of double-sided pumping light, effectively reducing the influence of temperature gradient on the slab crystal, and the output laser beam quality is better. This solution welds water-cooled heat sinks on both sides of the slab crystal for heat dissipation, and the rest is referred to Example 1.

[0053] Based on this application, it should be understood by those skilled in the art that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0054] It should be noted that the above embodiments can be freely combined as needed. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

[0055] All documents mentioned in the present invention are cited as references in this application, just as each document is cited as reference separately. In addition, it should be understood that after reading the above content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A dual-wavelength slab frequency-doubling laser, characterized in that: The dual-wavelength slab frequency-doubling laser comprises a laser resonant cavity unit and a slab crystal pump unit; The laser resonant cavity unit comprises: a first optical path, along which a first total reflection mirror, a slab crystal, a first electro-optical Q switch, a first harmonic mirror, a first frequency doubling crystal, and a first output mirror are sequentially arranged; a second optical path, along which a second total reflection mirror, a slab crystal, a second electro-optical Q switch, a second harmonic mirror, a second frequency doubling crystal, and a second output mirror are sequentially arranged; The slab crystal pump unit is side-pumped or large-surface pumped, and the slab crystal pump unit includes a semiconductor laser array and an optical waveguide; wherein, The light apertures of the first electro-optical Q switch and the second electro-optical Q switch are matched to the diameters of the lasers received by the first electro-optical Q switch and the second electro-optical Q switch, respectively; the coating center wavelengths of the first total reflection mirror and the first output mirror are the same, and the coating center wavelengths of the second total reflection mirror and the second output mirror are the same; the coating center wavelengths of the first total reflection mirror and the first output mirror and the coating center wavelengths of the second total reflection mirror and the second output mirror correspond to the wavelengths of the two absorption peaks with the largest and second largest absorption cross sections of the slab crystal, respectively; The shape of the lath crystal is trapezoidal, and the lath crystal is Nd:YAG crystal; The fundamental frequency light of the first optical path and the fundamental frequency light of the second optical path simultaneously complete oscillation along the first direction and conduction along the second direction in the slab crystal; The first frequency doubling crystal and the second frequency doubling crystal are selected from LBO crystal or KTP crystal; The wavelength of the fundamental frequency light of the first optical path is 1064nm, and the wavelength of the fundamental frequency light of the second optical path is 1320nm; The laser wavelengths output by the dual-wavelength slab frequency-doubled laser are 532 nm and 660 nm respectively.

2. A dual-wavelength slab frequency-doubled laser according to claim 1, characterized in that: The semiconductor laser array is a laser diode array.

3. A dual-wavelength slab frequency-doubled laser according to claim 1, characterized in that: The slab crystal pump unit is selected from any one of double-sided side pumping and single-sided side pumping.

4. A dual-wavelength slab frequency-doubled laser according to claim 1, characterized in that: The slab crystal pump unit is selected from single-sided large-area pumping.

5. A dual-wavelength slab frequency-doubled laser according to claim 4, characterized in that: The shape of the lath crystal is trapezoidal, the lower base of the Nd:YAG crystal is 69.2 mm, the upper base of the Nd:YAG crystal is 67 mm, the width of the Nd:YAG crystal is 10 mm, the thickness of the Nd:YAG crystal is 2 mm, the bottom angle of the Nd:YAG crystal is 29.2°, the first direction is the height direction of the lath crystal, the second direction is the length direction of the lath crystal, and the first direction is perpendicular to the second direction.

6. A dual-wavelength slab frequency-doubled laser according to claim 5, characterized in that: The length of the slab crystal is such that dual-wavelength light can complete an integer number of cycles of oscillation while being transmitted in the slab crystal.

7. A dual-wavelength slab frequency-doubled laser according to claim 6, characterized in that: The heat dissipation method of the slat crystal is water cooling.

8. The dual-wavelength slab frequency-doubled laser according to claim 1, characterized in that: The first electro-optical Q switch is selected from KD2PO4 crystal.

9. The dual-wavelength slab frequency-doubled laser according to claim 1, characterized in that: The second electro-optical Q switch is selected from LiNbO3 crystal.

10. The dual-wavelength slab frequency-doubled laser according to claim 9, characterized in that: The first total reflection mirror is coated with a 0°@1064nm total reflection film, the first harmonic mirror is coated with a HR@532nm&AR@1064nm coating, the coated surface faces the first frequency doubling crystal, and the first output mirror is coated with a HR@1064nm&AR@532nm coating; the second total reflection mirror is coated with a 0°@1320nm total reflection film, the second harmonic mirror is coated with a HR@660nm&AR@1320nm coating, the coated surface faces the second frequency doubling crystal, and the second output mirror is coated with a HR@1320nm&AR@660nm coating.

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