A crystal Q-switched solid-state laser with three wavelength conversions

Abstract

The present invention provides a crystal Q-switched solid laser with three wavelength conversions, belonging to the field of laser technology, including: a gold-plated total reflection mirror; a pulse laser output module, arranged behind the gold-plated total reflection mirror, for outputting pump light; a first wavelength laser output module, comprising: a linear polarizer, a second polarization beam splitter, a third polarization beam splitter, and a passive Q-switched crystal; a second wavelength laser output module, comprising: a second electrically controlled optical rotator, an acousto-optic modulator, a first polarization beam splitter, a frequency doubling crystal, and an output mirror; a third wavelength laser output module, comprising: a first electrically controlled optical rotator, a fourth polarization beam splitter, an optical parametric oscillator crystal, and a fourth polarization beam splitter. The device can switch to output pulse lasers of multiple different wavelengths.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers, and in particular relates to a crystal Q-switched solid laser with three wavelength conversions. Background Art

[0002] Lasers are widely used in many fields such as optical medicine, industrial precision machining, environmental monitoring, laser remote sensing and laser communication due to their high brightness, high directivity, high monochromaticity and high coherence. Multi-wavelength pulsed lasers, as one of the hot topics at home and abroad in recent years, play an important role in military applications such as laser detection and confrontation, laser ranging, laser radar, laser guidance and laser weapons.

[0003] Existing approaches to achieve multi-wavelength laser output include the simultaneous output of a fixed-wavelength laser fundamental frequency light and its frequency-converted light, light emitted by a laser based on a broadband emission spectrum of a laser medium, and the use of frequency-selective devices to achieve dual-wavelength or multi-wavelength operation.

[0004] However, although these two methods are relatively mature, the laser output obtained contains other wavelengths in addition to the required wavelength, and the multi-wavelength output energy obtained is low. At the same time, due to the use of different frequency-selective devices and optical elements, the structure of the resonant cavity is complicated and the application scenarios are limited. In order to suppress the oscillation of redundant spectral lines, it is necessary not only to use a multi-cavity mirror structure to increase the intracavity loss of redundant spectral lines, but sometimes it is also necessary to insert a standard device into the cavity to filter out redundant spectral lines.

[0005] In short, the multi-wavelength solid-state lasers in the existing technology generally have the problems of large size, overly complex system, and inability to quickly switch to output a single wavelength, so they cannot be used in actual battlefields. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a crystal Q-switched solid-state laser with three wavelength conversions.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A crystal Q-switched solid-state laser with three wavelength conversions, comprising:

[0009] Gold-plated full reflective mirror;

[0010] A pulse laser output module is arranged behind the gold-plated total reflective mirror and is used to output pump light;

[0011] The first wavelength laser output module comprises:

[0012] A linear polarizer is arranged behind the pulse laser output module; a second polarization beam splitter is arranged behind the linear polarizer, and the angle between the polarizer and the yOz plane is -45 degrees; a third polarization beam splitter is arranged behind the second polarization beam splitter, and the angle between the polarizer and the yOz plane is +45 degrees; a passive Q-switched crystal is arranged behind the third polarization beam splitter;

[0013] The second wavelength laser output module comprises:

[0014] A second electrically controlled optical rotator is disposed between the second polarization beam splitter and the third polarization beam splitter;

[0015] an acousto-optic modulator, disposed between the linear polarizer and the pulse laser output module;

[0016] A first polarization beam splitter is disposed above the third polarization beam splitter, and the angle between the first polarization beam splitter and the yOz plane is -45 degrees; a frequency doubling crystal is disposed in front of the first polarization beam splitter;

[0017] An output mirror, arranged behind the first polarization beam splitter;

[0018] The third wavelength laser output module comprises:

[0019] A first electrically controlled optical rotator is disposed behind the linear polarizer; a fourth polarization beam splitter is disposed below the second polarization beam splitter, and the angle between the fourth polarization beam splitter and the yOz plane is +45 degrees; an optical parametric oscillator crystal is disposed in front of the fourth polarization beam splitter;

[0020] When the acousto-optic modulator is turned off, the first electrically controlled optical rotator is turned off, and the second electrically controlled optical rotator is turned off, the oscillating light output by the pulse laser output module is converted into linear polarized light polarized along the x-axis through the linear polarizer, passes through the second polarization beam splitter and the third polarization beam splitter successively, and then passes through the passive Q-switching crystal for passive Q-switching, and is partially transmitted by the dielectric film layer plated at the rear end of the crystal. The reflected oscillating light returns to the pulse laser output module along the original path. After passing through the pulse laser output module, the light is shot to the right end of the gold-plated total reflection mirror and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light goes back and forth multiple times in the imaging resonant cavity, it outputs a low repetition rate pulse laser with a wavelength of the first wavelength;

[0021] When the first electrically controlled optical rotator is turned off, the oscillating light output by the pulse laser output module is converted into high repetition rate oscillating light through the acousto-optic modulator, and the high repetition rate oscillating light is converted into linear polarized light polarized along the x-axis through the linear polarizer, and the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis after passing through the second polarization beam splitter and the second electrically controlled optical rotator, and is totally reflected to the lower end face of the first polarization beam splitter after passing through the third polarization beam splitter, and then totally reflected by the first polarization beam splitter P1, and is frequency-doubled by the frequency-doubling crystal to obtain oscillating light with a wavelength of the second wavelength and a fundamental frequency with a wavelength of the first wavelength. The two wavelengths of light are reflected by the gold-plated total reflection mirror and pass through the frequency doubling crystal again. The laser with the second wavelength is transmitted by the first polarization beam splitter and then output through the output mirror. The laser with the first wavelength is totally reflected by the first polarization beam splitter and then returns to the cavity along the original optical path to reach the pulse laser output module. After passing through the pulse laser output module, the light is shot to the right end of the gold-plated total reflection mirror and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light goes back and forth multiple times in the imaging resonant cavity, it outputs a high-repetition-rate pulse laser with the second wavelength.

[0022] When the acousto-optic modulator is turned off, the second electrically controlled optical rotator is turned off, and the oscillating light of the first wavelength output by the pulse laser output module is converted into linear polarized light polarized along the x-axis through the linear polarizer. After passing through the first electrically controlled optical rotator, the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis. After passing through the second polarization beam splitter, it is totally reflected to the upper end surface of the fourth polarization beam splitter, and then totally reflected by the fourth polarization beam splitter. After passing through the optical parametric oscillator crystal, oscillating light with a wavelength of the third wavelength and fundamental frequency light with a wavelength of the first wavelength are obtained. The two wavelengths of light beams are reflected by the gold-plated total reflection mirror and pass through the optical parametric oscillator crystal again. The laser with a wavelength of the third wavelength is transmitted by the fourth polarization beam splitter and then output. The laser with a wavelength of the first wavelength is totally reflected by the fourth polarization beam splitter and then returns to the cavity along the original optical path to reach the pulse laser output module. After passing through the pulse laser output module, the light is shot to the right end of the gold-plated total reflection mirror and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After multiple round trips in the imaging resonant cavity, the oscillating light outputs a low repetition rate pulse laser with a wavelength of the third wavelength.

[0023] Further, the pulse laser output module includes: a laser pump module, which is arranged behind the gold-plated total reflective mirror;

[0024] A gain medium, arranged behind the laser pump module;

[0025] Furthermore, the gain medium is Nd:YAG crystal.

[0026] Further, the laser pump module comprises: a laser pump source, the laser pump source being a quasi-continuous laser diode with a central wavelength of nanometers, for end-face pumping of the laser gain medium;

[0027] Furthermore, the upper end surface of the gold-plated total reflection mirror is plated with a dielectric film that is fully transparent to the first wavelength, and the lower end surface is plated with a dielectric film layer that is fully reflective to the pump wavelength and fully transparent to the first wavelength.

[0028] Furthermore, the frequency doubling crystal is one of potassium dihydrogen phosphate, lithium niobate, β-phase barium metaborate, potassium titanyl phosphate, and polarized lithium niobate crystal.

[0029] Furthermore, the optical parametric oscillator crystal is a KTP crystal.

[0030] Furthermore, the passive Q-switched crystal is a Cr3+:YAG crystal.

[0031] Furthermore, the first electrically-controlled optical rotator includes an electro-optical crystal and a driving power supply, and the output laser wavelength is selected by controlling the driving power supply.

[0032] The crystal Q-switched solid laser with three wavelength conversions provided by the present invention has the following beneficial effects:

[0033] When the acousto-optic modulator is turned off, the first electrically controlled optical rotator is turned off, and the second electrically controlled optical rotator is turned off, the oscillating light output by the pulse laser output module is converted into linear polarized light polarized along the x-axis through the linear polarizer, passes through the second polarization beam splitter and the third polarization beam splitter successively, and then passes through the passive Q-switching crystal for passive Q-switching, and is partially transmitted by the dielectric film layer plated at the rear end of the crystal. The reflected oscillating light returns to the pulse laser output module along the original path. After passing through the pulse laser output module, the light is shot to the right end of the gold-plated total reflection mirror and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light goes back and forth multiple times in the imaging resonant cavity, it outputs a low repetition rate pulse laser with a wavelength of the first wavelength;

[0034] When the first electrically controlled optical rotator is turned off, the oscillating light output by the pulse laser output module is converted into high repetition rate oscillating light through the acousto-optic modulator, and the high repetition rate oscillating light is converted into linear polarized light polarized along the x-axis through the linear polarizer, and the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis after passing through the second polarization beam splitter and the second electrically controlled optical rotator, and is totally reflected to the lower end face of the first polarization beam splitter after passing through the third polarization beam splitter, and then totally reflected by the first polarization beam splitter P1, and is frequency-doubled by the frequency-doubling crystal to obtain oscillating light with a wavelength of the second wavelength and a fundamental frequency with a wavelength of the first wavelength. The two wavelengths of light are reflected by the gold-plated total reflection mirror and pass through the frequency doubling crystal again. The laser with the second wavelength is transmitted by the first polarization beam splitter and then output through the output mirror. The laser with the first wavelength is totally reflected by the first polarization beam splitter and then returns to the cavity along the original optical path to reach the pulse laser output module. After passing through the pulse laser output module, the light is shot to the right end of the gold-plated total reflection mirror and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light goes back and forth multiple times in the imaging resonant cavity, it outputs a high-repetition-rate pulse laser with the second wavelength.

[0035] When the acousto-optic modulator is turned off, the second electrically controlled optical rotator is turned off, and the oscillating light of the first wavelength output by the pulse laser output module is converted into linear polarized light polarized along the x-axis through the linear polarizer. After passing through the first electrically controlled optical rotator, the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis. After passing through the second polarization beam splitter, it is totally reflected to the upper end surface of the fourth polarization beam splitter, and then totally reflected by the fourth polarization beam splitter. After passing through the optical parametric oscillator crystal, oscillating light with a wavelength of the third wavelength and fundamental frequency light with a wavelength of the first wavelength are obtained. The two wavelengths of light beams are reflected by the gold-plated total reflection mirror and pass through the optical parametric oscillator crystal again. The laser with a wavelength of the third wavelength is transmitted by the fourth polarization beam splitter and then output. The laser with a wavelength of the first wavelength is totally reflected by the fourth polarization beam splitter and then returns to the cavity along the original optical path to reach the pulse laser output module. After passing through the pulse laser output module, the light is shot to the right end of the gold-plated total reflection mirror and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After multiple round trips in the imaging resonant cavity, the oscillating light outputs a low repetition rate pulse laser with a wavelength of the third wavelength. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 The schematic diagram is a structural diagram of a crystal Q-switched solid-state laser with three wavelength conversions according to an embodiment of the present invention.

[0038] Figure 2This is a schematic diagram of the optical path structure for outputting a first wavelength laser according to an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the optical path structure for outputting a second wavelength laser according to an embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the optical path structure for outputting a third wavelength laser according to an embodiment of the present invention.

[0041] Description of reference numerals:

[0042] 1-gold-plated total reflection mirror; 2-laser pump mode; 3-gain medium; 4-acousto-optic modulator; 5-linear polarizer; 6-passive Q-switched crystal; 7-frequency doubling crystal; 8-output mirror; 9-optical parametric oscillator crystal; P1-first polarization beam splitter; P2-second polarization beam splitter; P3-third polarization beam splitter; P4-fourth polarization beam splitter; D1-first electrically controlled optical rotator; D2-second electrically controlled optical rotator. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0044] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0046] Example:

[0047] The present invention provides a crystal Q-switched solid laser with three wavelength conversions, specifically: Figure 1-4 As shown, it includes: a gold-plated total reflection mirror 1; a pulse laser output module, which is arranged behind the gold-plated total reflection mirror 1 and is used to output pump light; a first wavelength laser output module, which includes: a linear polarizer 5, which is arranged behind the pulse laser output module; a second polarization beam splitter P2, which is arranged behind the linear polarizer 5 and has an angle of -45 degrees with the yOz plane; a third polarization beam splitter P3, which is arranged behind the second polarization beam splitter P2 and has an angle of +45 degrees with the yOz plane; and a passive Q-switched crystal 6, which is arranged behind the third polarization beam splitter.

[0048] The second wavelength laser output module comprises: a second electrically controlled optical rotator D2, arranged between the second polarization beam splitter P2 and the third polarization beam splitter P3; an acousto-optic modulator 4, arranged between the linear polarizer 5 and the pulse laser output module; a first polarization beam splitter P1, arranged above the third polarization beam splitter P3, and having an angle of -45 degrees with the yOz plane; a frequency doubling crystal 7, arranged in front of the first polarization beam splitter P1; an output mirror 8, arranged behind the first polarization beam splitter

[0049] The third wavelength laser output module comprises:

[0050] The first electrically controlled optical rotator D1 is arranged behind the linear polarizer 5; the fourth polarization beam splitter P4 is arranged below the second polarization beam splitter P2, and the angle between it and the yOz plane is +45 degrees; the optical parametric oscillator crystal 9 is arranged in front of the fourth polarization beam splitter.

[0051] Specifically, in this embodiment:

[0052] Specifically, the laser pump module includes a laser pump source and a plane reflector. The laser pump source includes a continuous / quasi-continuous / pulsed laser diode, which is used to output pump light of a pump wavelength to excite the laser gain medium. Side pumping or end pumping can be used. The plane reflector has an angle of +45 degrees with the xOz plane where the three optical paths are located, and is used to guide the pump light into the optical path.

[0053] Preferably, the laser pump source adopts quasi-continuous pumping and adopts end-face pumping mode;

[0054] Preferably, the upper end surface of the plane reflector is coated with a dielectric film that is fully transparent to the first wavelength, and the lower end surface is coated with a dielectric film layer that is fully reflective to the pump wavelength and fully transparent to the first wavelength;

[0055] Specifically, the gain medium may be any medium capable of generating laser light, including single crystal gain medium, laser ceramic gain medium, laser glass gain medium, etc.;

[0056] Preferably, the gain medium uses Nd:YAG crystal to achieve pulsed laser output of the first wavelength;

[0057] Specifically, the imaging structure resonant cavity includes a straight cavity structure, a ring cavity structure and an inner cavity structure. The straight cavity structure is used to obtain a first wavelength light beam, the ring cavity structure is used to obtain a second wavelength light beam after passing through a frequency doubling crystal, and the inner cavity structure is used to obtain a third wavelength light beam after passing through an optical parametric oscillator. The imaging structure resonant cavity adopts a uniform gold-plated total reflection mirror as an input mirror to achieve a total reflection effect for various wavelengths.

[0058] Specifically, the Q-switching module includes an acousto-optic modulator and a passive Q-switching crystal. Different Q-switching modes correspond to lasers of different wavelengths. By controlling the incident ultrasonic power of the acousto-optic modulator, the imaging structure resonant cavity can obtain pulsed lasers with different repetition frequencies.

[0059] Preferably, the acousto-optic modulator is used to output laser pulses of a second wavelength with a high repetition rate;

[0060] Preferably, the passive Q-switching crystal adopts Cr3+:YAG crystal to realize Q modulation of the oscillating light of the first wavelength, and the right end of the crystal is plated with a dielectric film layer with a reflectivity of ≥80% for the first wavelength as an output mirror of the straight cavity structure;

[0061] Specifically, the frequency doubling crystal can be any nonlinear optical crystal used for frequency doubling effect to achieve wavelength conversion of oscillating light, and the frequency doubling crystal is any one of potassium dihydrogen phosphate (KDP), lithium niobate, β-phase barium borate (BBO), potassium titanyl phosphate (KTP), and polarized lithium niobate (PPLN) crystals;

[0062] Preferably, the frequency doubling crystal is a KDP crystal to achieve nonlinear conversion of the first wavelength and output a pulsed laser of the second wavelength;

[0063] Specifically, the polarization beam splitter includes a first polarization beam splitter, a second polarization beam splitter, a third polarization beam splitter and a fourth polarization beam splitter, and two end faces of the polarization beam splitter are respectively coated with dielectric film layers with different reflectivity for different wavelengths, and are used to transmit or reflect light beams of different wavelengths or different polarization states, so that the optical paths of the wavelengths after passing through different polarization beam splitters are different, so that the laser only outputs pulsed lasers of one wavelength;

[0064] Specifically, the first polarization beam splitter has an angle of -45 degrees with the yOz plane, the second polarization beam splitter has an angle of -45 degrees with the yOz plane, the third polarization beam splitter has an angle of +45 degrees with the yOz plane, the fourth polarization beam splitter has an angle of +45 degrees with the yOz plane, the first polarization beam splitter is aligned and placed parallel to the x-axis, the second polarization beam splitter is aligned and placed parallel to the fourth polarization beam splitter along the x-axis, and the second polarization beam splitter is coaxially placed with the third polarization beam splitter along the z-axis;

[0065] Preferably, the lower end surface of the first polarization beam splitter is coated with a film that fully reflects light polarized along the y-axis direction of the first wavelength and fully transmits light of the second wavelength, and the upper end surface is coated with a film layer that fully transmits light of the second wavelength;

[0066] Preferably, the lower end surface of the second polarization beam splitter is coated with a fully transparent film for polarized light of the first wavelength along the x-axis direction, and the upper end surface is coated with a fully transparent film layer for light of the first wavelength;

[0067] Preferably, the third polarization beam splitter has a lower end surface coated with a fully transparent film for light of the first wavelength, an upper end surface coated with a fully reflective film for light of the first wavelength polarized along the y-axis direction, and a fully transparent film for light of the first wavelength polarized along the x-axis direction;

[0068] Preferably, a film that fully reflects light of the first wavelength polarized along the y-axis direction and fully transmits light of the third wavelength is coated on the fourth polarization beam splitter;

[0069] Specifically, a linear polarizer is used to convert fundamental frequency oscillation light into linear polarized light;

[0070] Specifically, the electrically controlled optical rotator module includes a first electrically controlled optical rotator and a second electrically controlled optical rotator, the electrically controlled optical rotator includes an electro-optical crystal and a driving power supply, and the output laser wavelength is selected by controlling the driving power supply;

[0071] Specifically, an optical parametric oscillator crystal is used for an optical parametric oscillation effect, and the optical parametric oscillator crystal outputs a pulse of a third wavelength. The basic requirements of the optical parametric oscillator crystal are the same as those of the frequency doubling crystal.

[0072] Preferably, the optical parametric oscillator crystal adopts a KTP crystal to achieve nonlinear transformation of the first wavelength and realize pulse laser output of the third wavelength.

[0073] On the basis of the above technical solution, the optical path for transmitting the first wavelength light beam formed by the laser pump source, the gain medium, the linear polarizer, the second polarization beam splitter, the fourth polarization beam splitter, and the passive Q-switched crystal is the first optical path;

[0074] An optical path for transmitting a second wavelength light beam formed by a laser pump source, a gain medium, an acousto-optic modulator, a linear polarizer, a second polarization beam splitter, a second electrically-controlled optical rotator, a fourth polarization beam splitter and a first polarization beam splitter is a second optical path, and an optical path for transmitting a third wavelength light beam formed by a laser pump source, a gain medium, a linear polarizer, a first electrically-controlled optical rotator, a second polarization beam splitter, an optical parametric oscillator crystal and a fourth polarization beam splitter is a third optical path.

[0075] The following is a specific implementation of the present invention:

[0076] See also Figure 1 As shown, an embodiment of the present invention provides a multi-wavelength solid-state laser, including a laser pump module, a plane reflector, a gain medium, an imaging structure resonant cavity, a Q-switching module, a frequency doubling crystal, a polarization beam splitter, a linear polarizer, an electrically controlled optical rotator module, and an optical parametric oscillator crystal.

[0077] The laser pump module 2 includes a laser pump source and a plane reflector; the laser pump source includes a quasi-continuous laser diode with a central wavelength of 808 nanometers, which is used to perform end-face pumping on the laser gain medium; the plane reflector is at an angle of 45 degrees to the plane where the three optical paths are located, and is used to guide the pump light into the optical path; the upper end face of the plane reflector is coated with a 1064nm fully transparent dielectric film, and the lower end face is coated with a 808nm fully reflective and 1064nm fully transparent dielectric film layer;

[0078] The gain medium uses Nd:YAG crystal to achieve the first wavelength pulse laser output;

[0079] The imaging structure resonant cavity includes a straight cavity structure, a ring cavity structure and an inner cavity structure; the straight cavity structure is used to obtain a first wavelength light beam with a wavelength of 1064nm; the ring cavity structure is used to obtain a second wavelength light beam with a wavelength of 532nm after passing through a frequency doubling crystal; the inner cavity structure is used to obtain a third wavelength light beam with a wavelength of 1.57μm after passing through an optical parametric oscillation; the imaging structure resonant cavity adopts a uniform gold-plated total reflection mirror 1 as an input mirror to achieve a total reflection effect for various wavelengths;

[0080] The Q-switching module includes an acousto-optic modulator and a Cr:YAG crystal as a passive Q-switching crystal; the acousto-optic modulator is used to output a high-repetition-rate 532nm pulsed laser; the Cr:YAG crystal is used to realize Q-modulation of the 1064nm oscillating light; the right end of the Cr:YAG crystal is plated with a dielectric film layer with a reflectivity of ≥80% for the 1064nm wavelength as an output mirror of the straight cavity structure;

[0081] The frequency doubling crystal uses KDP crystal to achieve nonlinear transformation of the first wavelength and realize pulse laser output of the second wavelength;

[0082] The polarization beam splitter comprises a first polarization beam splitter, a second polarization beam splitter, a third polarization beam splitter and a fourth polarization beam splitter, wherein the lower end surface of the first polarization beam splitter is plated with a film that fully reflects light polarized along the y-axis direction of 1064 nm, and a film that fully transmits light of 532 nm, and the upper end surface is plated with a film layer that fully transmits light of 532 nm; the lower end surface of the second polarization beam splitter is plated with a film that fully transmits light polarized along the x-axis direction of 1064 nm, and the upper end surface is plated with a film layer that fully transmits light of 532 nm; the lower end surface of the third polarization beam splitter is plated with a film that fully reflects light polarized along the y-axis direction of 1064 nm, and the upper end surface is plated with a film layer that fully transmits light polarized along the x-axis direction of 1064 nm; the upper end surface of the fourth polarization beam splitter is plated with a film that fully reflects light polarized along the y-axis direction of 1064 nm, and a film layer that fully transmits light of 1.57 μm;

[0083] Linear polarizers are used to convert fundamental frequency oscillating light into linear polarized light;

[0084] The electrically controlled optical rotator module includes a first electrically controlled optical rotator and a second electrically controlled optical rotator; the electrically controlled optical rotator includes an electro-optical crystal and a driving power supply, and the output laser wavelength is selected by controlling the driving power supply;

[0085] The optical parametric oscillator crystal uses KTP crystal to achieve nonlinear conversion of 1064nm fundamental frequency light and realize 1.57μm pulse laser output.

[0086] See also Figure 2 As shown, when the acousto-optic modulator 4 is turned off, the first electrically-controlled optical rotator D1 is turned off, and the second electrically-controlled optical rotator D2 is turned off, the pump light with a central wavelength of 808 nm output by the laser pump module 2 is incident on the left end face of the Nd:YAG crystal 3, and the oscillation light with a central wavelength of 1064 nm obtained by stimulated radiation is converted into linear polarized light polarized along the x-axis through the linear polarizer 5, and then passes through the second polarization beam splitter P2 and the third polarization beam splitter P3 successively, and then passes through the Cr:YAG crystal 6 for passive Q switching, and is partially transmitted by the dielectric film layer with a reflectivity of 1064 nm wavelength ≥80% plated on the rear end of the crystal, and the reflected oscillation light with a wavelength of 1064 nm returns to the laser pump module 2 along the original path, passes through the plane reflector with a 1064 nm fully transparent film plated on the lower end face of the module, and then is incident on the right end of the gold-plated total reflection mirror 1 and is totally reflected, completing a round trip in the laser resonant cavity, and the oscillation light outputs a low repetition rate pulse laser with a wavelength of 1064 nm after multiple round trips in the imaging resonant cavity;

[0087] See also Figure 3As shown, when the electrically controlled optical rotator D1 is turned off, the pump light with a central wavelength of 808 nm output by the laser pump module 2 is incident on the left end face of the Nd:YAG crystal 3, and the oscillation light with a central wavelength of 1064 nm obtained by stimulated radiation is converted into high repetition rate oscillation light through the acousto-optic modulator 4, and is converted into linear polarized light polarized along the x-axis through the linear polarizer 5. After passing through the second polarization beam splitter P2 and the second electrically controlled optical rotator D2, the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis. After passing through the third polarization beam splitter P3, it is totally reflected to the lower end face of the first polarization beam splitter P1, and then totally reflected by the first polarization beam splitter P1. After being frequency-doubled by the KDP frequency-doubling crystal 7, a wavelength of 1064 nm is obtained. The oscillating light of 532nm and the fundamental frequency light of 1064nm are reflected by the gold-plated total reflection mirror 1 and pass through the KDP crystal 7 again. The laser with a wavelength of 532nm is transmitted by the first polarization beam splitter P1 and then output through the output mirror 8. The laser with a wavelength of 1064nm is totally reflected by the first polarization beam splitter P1 and then returns to the cavity along the original optical path to reach the laser pump module 2. After passing through the plane reflection mirror with a 1064nm fully transparent film plated on the lower end face of the module, it is incident on the right end of the gold-plated total reflection mirror 1 and is totally reflected, completing a round trip in the laser resonant cavity. After multiple round trips in the imaging resonant cavity, the oscillating light outputs a high-repetition-rate pulsed laser with a wavelength of 532nm.

[0088] See also Figure 4 As shown, when the acousto-optic modulator 4 is turned off, the second electrically-controlled optical rotator D2 is turned off, and the pump light with a central wavelength of 808 nm output by the laser pump module 2 is incident on the left end face of the Nd:YAG crystal 3. The oscillation light with a central wavelength of 1064 nm obtained by stimulated radiation is converted into linear polarized light polarized along the x-axis through the linear polarizer 5. After passing through the first electrically-controlled optical rotator D1, the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis. After passing through the second polarization beam splitter P2, it is totally reflected to the upper end face of the fourth polarization beam splitter P4, and then totally reflected by the fourth polarization beam splitter P4. After passing through the KTP optical parametric oscillator crystal 9, a linear polarized light with a wavelength of 1.57 μm is obtained. The oscillating light and the fundamental frequency light with a wavelength of 1064nm are reflected by the gold-plated total reflection mirror 1, and then pass through the KTP crystal 9 again. The laser with a wavelength of 1.57μm is transmitted by the fourth polarization beam splitter P4 and then output. The laser with a wavelength of 1064nm is totally reflected by the fourth polarization beam splitter P4 and then returns to the cavity along the original optical path to reach the laser pump module 2. After passing through the plane reflector with a 1064nm fully transparent film coated on the lower end face of the module, it is incident on the right end of the gold-plated total reflection mirror 1 and is totally reflected, completing a round trip in the laser resonance cavity. After multiple round trips in the imaging resonance cavity, the oscillating light outputs a low repetition rate pulse laser with a wavelength of 1.57μm.

[0089] In the embodiments of the present invention, pulsed lasers with different wavelengths and different repetition rates can be realized, which is convenient for selecting different wavelengths for application according to different distances, different energies and different functions in laser military systems; and the structure is compact, the volume is small and the cost is low.

[0090] Compared with the prior art, the advantages of the present invention are:

[0091] 1) The multi-wavelength solid-state laser of the present invention can switch to output pulsed lasers of multiple different wavelengths, and theoretically can achieve laser output of more wavelengths, with a wide range of applications;

[0092] 2) The multi-wavelength solid-state laser of the present invention can realize the selection of pulse repetition frequency by using acousto-optic Q-switching, passive Q-switching and polarization beam splitter, and has certain practical value;

[0093] 3) The present invention adopts a unified gold-plated total reflection mirror as the input mirror of the imaging resonant cavity to achieve spontaneous collimation of light paths output at different wavelengths, avoids the introduction of other collimation elements, simplifies the laser structure, and makes the laser structure compact and smaller in size.

[0094] The embodiments described above are only preferred specific implementation modes of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. A crystal Q-switched solid laser with three wavelength conversions, characterized in that: include: Gold-plated full-reflective mirror (1); A pulse laser output module, arranged behind the gold-plated total reflective mirror (1), for outputting pump light; The first wavelength laser output module comprises: A linear polarizing plate (5) is arranged behind the pulse laser output module; a second polarizing beam splitter (P2) is arranged behind the linear polarizing plate (5) and has an angle of -45 degrees with the yOz plane; a third polarizing beam splitter (P3) is arranged behind the second polarizing beam splitter (P2) and has an angle of +45 degrees with the yOz plane; and a passive Q-switched crystal (6) is arranged behind the third polarizing beam splitter; The second wavelength laser output module comprises: A second electrically controlled optical rotator (D2) is disposed between the second polarization beam splitter (P2) and the third polarization beam splitter (P3); an acousto-optic modulator (4), arranged between the linear polarizer (5) and the pulse laser output module; A first polarization beam splitter (P1) is arranged above the third polarization beam splitter (P3), and the angle between the first polarization beam splitter and the yOz plane is -45 degrees; a frequency doubling crystal (7) is arranged in front of the first polarization beam splitter (P1); An output mirror (8), arranged behind the first polarization beam splitter; The third wavelength laser output module comprises: A first electrically controlled optical rotator (D1) is arranged behind the linear polarizer (5); a fourth polarization beam splitter (P4) is arranged below the second polarization beam splitter (P2), and the angle between the fourth polarization beam splitter and the yOz plane is +45 degrees; an optical parametric oscillator crystal (9) is arranged in front of the fourth polarization beam splitter; When the acousto-optic modulator (4) is turned off, the first electrically controlled optical rotator (D1) is turned off, and the second electrically controlled optical rotator (D2) is turned off, the oscillating light output by the pulse laser output module is converted into linear polarized light along the x-axis through the linear polarizer (5), and then passes through the second polarization beam splitter (P2) and the third polarization beam splitter (P3) successively, and then passes through the passive Q-switching crystal (6) for passive Q-switching, and is partially transmitted by the dielectric film layer plated on the rear end of the crystal. The reflected oscillating light returns to the pulse laser output module along the original path, and after passing through the pulse laser output module, the light is projected to the right end of the gold-plated total reflection mirror (1) and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light has made multiple round trips in the imaging resonant cavity, it outputs a low repetition rate pulse laser with a wavelength of the first wavelength; When the first electrically controlled optical rotator (D1) is closed, the oscillating light output by the pulse laser output module is converted into high repetition rate oscillating light through the acousto-optic modulator (4), and the high repetition rate oscillating light is converted into linear polarized light polarized along the x-axis through the linear polarizing plate (5). After passing through the second polarization beam splitter (P2) and the second electrically controlled optical rotator (D2), the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis. After passing through the third polarization beam splitter (P3), the linear polarized light is totally reflected to the lower end face of the first polarization beam splitter (P1), and then totally reflected by the first polarization beam splitter (P1). After being frequency-doubled by the frequency-doubling crystal (7), the oscillating light having a wavelength of the second wavelength and the linear polarized light having a wavelength of The fundamental frequency light of the first wavelength, the light beams of the two wavelengths are reflected by the gold-plated total reflection mirror (1), and then pass through the frequency doubling crystal (7). The laser light of the second wavelength is transmitted by the first polarization beam splitter (P1) and then output through the output mirror. The laser light of the first wavelength is totally reflected by the first polarization beam splitter (P1) and then returns to the cavity along the original optical path to reach the pulse laser output module. After the light passes through the pulse laser output module, it is projected to the right end of the gold-plated total reflection mirror (1) and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light makes multiple round trips in the imaging resonant cavity, a high repetition rate pulse laser light of the second wavelength is output; When the acousto-optic modulator (4) is turned off and the second electrically controlled optical rotator (D2) is turned off, the oscillating light of the first wavelength output by the pulse laser output module is converted into linear polarized light polarized along the x-axis through the linear polarizer (5), and after passing through the first electrically controlled optical rotator (D1), the linear polarized light polarized along the x-axis is converted into linear polarized light polarized along the y-axis, and after passing through the second polarization beam splitter (P2), it is totally reflected to the upper end face of the fourth polarization beam splitter (P4), and then totally reflected by the fourth polarization beam splitter (P4), and after passing through the optical parametric oscillator crystal (9), an oscillating light with a wavelength of the third wavelength and a fundamental frequency light with a wavelength of the first wavelength are obtained. The light beam of the first wavelength is reflected by the gold-plated total reflection mirror (1), and passes through the optical parametric oscillator crystal (9) again. The laser beam of the third wavelength is transmitted by the fourth polarization beam splitter (P4) and then output. The laser beam of the first wavelength is totally reflected by the fourth polarization beam splitter (P4) and then returns to the cavity along the original optical path to reach the pulse laser output module. After the light beam passes through the pulse laser output module, it is projected to the right end of the gold-plated total reflection mirror (1) and is totally reflected back to the pulse laser output module, completing a round trip in the laser resonant cavity. After the oscillating light makes multiple round trips in the imaging resonant cavity, a low repetition rate pulse laser beam of the third wavelength is output.

2. A crystal Q-switched solid-state laser with three wavelength conversions according to claim 1, characterized in that: The pulse laser output module comprises: a laser pump module (2), which is arranged behind the gold-plated total reflection mirror (1); The gain medium (3) is arranged behind the laser pump module (2).

3. The crystal Q-switched solid laser with three wavelength conversions according to claim 2, characterized in that: The gain medium is Nd:YAG crystal.

4. The crystal Q-switched solid-state laser with three wavelength conversions according to claim 2, characterized in that: The laser pump module (2) comprises: a laser pump source, which is a quasi-continuous laser diode with a central wavelength of 808 nanometers, and is used for end-face pumping of a laser gain medium; The plane reflector, which forms an angle of +45 degrees with the xOz plane where the three optical paths are located, is used to guide the pump light into the optical path.

5. The crystal Q-switched solid-state laser with three wavelength conversions according to claim 1, characterized in that: The upper end surface of the gold-plated total reflection mirror (1) is plated with a dielectric film that is fully transparent to the first wavelength, and the lower end surface is plated with a dielectric film layer that is fully reflective to the pump wavelength and fully transparent to the first wavelength.

6. The crystal Q-switched solid laser with three wavelength conversions according to claim 1, characterized in that: The frequency doubling crystal (7) is one of potassium dihydrogen phosphate, lithium niobate, beta-phase barium metaborate, potassium titanyl phosphate, and polarized lithium niobate crystal.

7. The crystal Q-switched solid laser with three wavelength conversions according to claim 1, characterized in that: The optical parametric oscillator crystal (9) is a KTP crystal.

8. The crystal Q-switched solid laser with three wavelength conversions according to claim 1, characterized in that: The passive Q-switching crystal (6) is a Cr3+:YAG crystal.

9. The crystal Q-switched solid laser with three wavelength conversions according to claim 1, characterized in that: The first electrically-controlled optical rotator comprises: an electro-optical crystal; a driving power supply; and the wavelength of the laser output by the first electrically-controlled optical rotator is selected by controlling the driving power supply.

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