Orthogonal polarization dual-wavelength alternative Q-switched laser and corresponding laser output method

Abstract

The application discloses a kind of orthogonal polarization dual-wavelength alternative Q-switched laser and corresponding laser output method.The laser includes: first laser power supply, first pump source, first laser gain medium, first polarizer, quarter-wave plate, isosceles right-angle prism, second laser power supply, second pump source, second laser gain medium, second polarizer, 45° reflector, electro-optic Q-switching crystal, output mirror, electro-optic Q-switching drive module, power supply timing control device.The application can obtain orthogonal polarization, alternative output dual-wavelength pulsed laser, solves the technical problem of obtaining orthogonal polarization dual-wavelength pulsed laser with high pulse peak power, narrow pulse width and adjustable pulse interval using electro-optic Q-switching technology.

Description

Technical Field

[0001] This invention relates to the field of lasers, and in particular to an orthogonally polarized dual-wavelength alternating Q-switched laser and a corresponding laser output method. Background Technology

[0002] Orthogonally polarized dual-wavelength pulsed lasers are widely used in medical, imaging, communication, detection, and processing research fields due to their unique polarization characteristics. Currently, research on Q-switching technology for orthogonally polarized dual-wavelength lasers mainly focuses on passive Q-switching of dual-wavelength lasers (see reference "YJ Huang, HHCho, and YFChen. Observation of repetition rate locking in an orthogonally-polarized dual-wavelength passively Q-switched hybrid Nd:YVO4 / Nd:YLF Laser. Optical Society of America, 2016"). However, passively Q-switched orthogonally polarized dual-wavelength lasers suffer from many drawbacks, such as large pulse width and low peak power. Furthermore, the resulting orthogonally polarized dual-wavelength pulsed lasers are all output simultaneously (see reference "P. Zhao, S. Ragam, YJ Ding, and IB Zotova. Investigation of terahertz generation from passively Q-switched dual-frequency laser pulses. Optics"). Letters, 2011, 36(24):4818-4820. However, there is an urgent need for an orthogonally polarized dual-wavelength laser source with narrow pulse width, high peak power, and adjustable pulse interval in fields such as laser medicine, laser-induced breakdown spectroscopy, and spectrophotometry. Electro-optic Q-switching has advantages such as high efficiency, fast switching speed, narrow output laser pulse width, and high peak power. However, electro-optic Q-switching combined with a polarizer only adjusts a single polarization state. Therefore, there are few reports on obtaining orthogonally polarized dual-wavelength pulsed lasers using electro-optic Q-switching technology, which ultimately limits the development and application of orthogonally polarized dual-wavelength pulsed lasers and affects the research progress in related fields. Summary of the Invention

[0003] In order to obtain orthogonally polarized dual-wavelength laser output with narrow pulse width, high peak power and adjustable pulse delay, this invention provides an orthogonally polarized dual-wavelength alternating Q-switched laser and a corresponding laser output method.

[0004] According to one aspect of the present invention, an orthogonally polarized dual-wavelength alternating Q-switched laser is provided, the laser comprising: a first laser power supply, a first pump source, a first laser gain medium, a first polarizer, a quarter-wave plate, an isosceles right-angle prism, a second laser power supply, a second pump source, a second laser gain medium, a second polarizer, a 45° mirror, an electro-optic Q-switching crystal, an output mirror, an electro-optic Q-switching drive module, and a power supply timing control device, wherein:

[0005] The first laser power supply is used to power the first pump source, and the two are connected by a cable;

[0006] The first pump source is placed on the side of the first laser gain medium and is parallel to the first laser gain medium, and is used to provide pump light to the first laser gain medium;

[0007] The quarter-wave plate is placed on the other side of the first laser gain medium;

[0008] The first polarizer is placed between the first laser gain medium and the quarter-wave plate;

[0009] The isosceles total reflection prism is placed on the side of the quarter-wave plate away from the first polarizer, and the right-angled surface is perpendicular to the laser transmission direction.

[0010] The second laser power supply is used to power the second pump source, and the two are connected by a cable;

[0011] The second pump source is placed on the side of the second laser gain medium and is parallel to the second laser gain medium, and is used to provide pump light to the second laser gain medium;

[0012] The second laser gain medium is placed parallel and aligned with the first laser gain medium;

[0013] The second polarizer is located on the other side of the second laser gain medium;

[0014] The 45° reflector is placed on the side of the second polarizer away from the second laser gain medium, and is used to reflect light from the isosceles total internal reflection prism.

[0015] The electro-optic Q-switched crystal and the output mirror are placed sequentially on the side of the 45° reflector away from the second polarizer and perpendicular to the laser output direction;

[0016] The first laser gain medium, the first polarizer, the quarter-wave plate, the isosceles right-angle prism, the 45° reflector, the electro-optic Q-switched crystal, and the output mirror constitute the first laser λ1 resonant cavity;

[0017] The second laser gain medium, the second polarizer, the 45° reflector, the electro-optic Q-switched crystal, and the output mirror constitute the second laser λ2 resonant cavity;

[0018] The electro-optic crystal driving module is connected to the electro-optic Q-switching crystal and is used to apply a common Q-switching bias voltage to the electro-optic Q-switching crystal.

[0019] The power supply timing control device is connected to the electro-optic crystal driving module, the first laser power supply, and the second laser power supply, and is used to control the working timing relationship of the three power supplies.

[0020] In one embodiment of the present invention, the first laser gain medium is Nd:YAG or Nd:YVO4.

[0021] In one embodiment of the present invention, the incident angle of the first laser λ1 onto the inclined surface of the isosceles total internal reflection prism is greater than the Brewster angle.

[0022] In one embodiment of the present invention, the first pump source and the second pump source are semiconductor pump sources, xenon lamps, or krypton lamps.

[0023] In one embodiment of the present invention, the second laser gain medium is Nd:YAG or Nd:YVO4.

[0024] In one embodiment of the present invention, both the first laser gain medium and the second laser gain medium are a-cut, and their c-axis orientations are perpendicular to each other.

[0025] In one embodiment of the present invention, the electro-optic Q-switching crystal is LN, KD*P, KDP or LiNbO3.

[0026] In one embodiment of the present invention, the first laser gain medium is coated with a 1319nm high-reflectivity film and a 1064nm high-transmittance film on the side away from the resonant cavity, and a 1319nm high-transmittance film on the side closer to the resonant cavity; the second laser gain medium is coated with a 1064nm high-reflectivity film on the side away from the resonant cavity, and a 1064nm high-transmittance film on the side closer to the resonant cavity; the 45° reflector is coated with a 1319nm high-transmittance film on the side closer to the second polarizer, and a 1319nm high-transmittance film and a 1064nm high-reflectivity film on the side away from the second polarizer; the output mirror is coated on the side facing the resonant cavity, with a reflectivity of 80% for the 1319nm laser and 25% for the 1064nm laser.

[0027] In one embodiment of the present invention, the first laser λ1 adopts a pressure-adjusted electro-optic Q-switching, and the second laser λ2 adopts a de-adjusted electro-optic Q-switching. The two lasers share the same electro-optic Q-switching crystal. When the first pump source and the second pump source are pumped alternately at equal intervals and a common Q-switching bias voltage is applied, a 1319nm pulsed laser output is obtained; when the common Q-switching bias voltage is removed, a 1064nm pulsed laser output is obtained. By periodically applying / removing the common Q-switching bias voltage, orthogonally polarized and alternately outputting 1064nm & 1319nm dual-wavelength pulsed lasers are obtained.

[0028] According to another aspect of the present invention, a method for outputting laser light using any orthogonally polarized dual-wavelength alternating Q-switched laser is also proposed, the method comprising:

[0029] In step S301, the first laser power supply and the second laser power supply supply power to the first pump source and the second pump source respectively, so that the first pump source and the second pump source provide pulse pump light to the first laser gain medium and the second laser gain medium respectively;

[0030] In step S302, a common Q-switching bias voltage is applied across the electro-optic Q-switching crystal. The second laser λ2 resonator is in a high-loss state, the second laser gain medium is in a population inversion state, and the first laser λ1 resonator is in a low-loss state, thus outputting the first Q-switched laser λ1.

[0031] In step S303, the common Q-switching bias voltage across the electro-optic Q-switching crystal is removed, the first laser λ1 resonator is in a high-loss state, the first laser gain medium is in a population inversion state, the second laser λ2 resonator is in a low-loss state, and the second Q-switched laser λ2 is output.

[0032] In step S304, the voltage-boosting and voltage-de-boosting states of the electro-optic Q-switched crystal are periodically repeated to obtain the first / second laser with orthogonal polarization and alternating output.

[0033] This invention combines boost and deboost electro-optic Q-switching technology, using a common Q-switching bias voltage to alternately Q-switch orthogonally polarized dual-wavelength lasers in a time-division manner: when the common Q-switching bias voltage is applied, the first λ1 pulse laser (e-beam) is output; when the common Q-switching bias voltage is removed, the second λ2 pulse laser (o-beam) is output, ultimately obtaining orthogonally polarized, alternately outputting dual-wavelength pulse lasers. This solves the technical problem of obtaining orthogonally polarized dual-wavelength pulse lasers with high peak power, narrow pulse width, and adjustable pulse interval using electro-optic Q-switching technology. Attached Figure Description

[0034] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings...

[0035] Figure 1 This is a schematic diagram of the structure of an orthogonally polarized dual-wavelength alternating Q-switched laser according to an embodiment of the present invention;

[0036] Figure 2 This is a timing diagram of the loading voltage waveform and each driving signal according to an embodiment of the present invention;

[0037] Figure 3 This is a flowchart of a method for outputting laser light using an orthogonally polarized dual-wavelength alternating Q-switched laser according to an embodiment of the present invention. Detailed Implementation

[0038] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0039] To illustrate the technical solution described in this invention, specific embodiments are described below.

[0040] According to one aspect of the present invention, an orthogonally polarized dual-wavelength alternating Q-switched laser is proposed. Figure 1 This is a schematic diagram of the structure of an orthogonally polarized dual-wavelength alternating Q-switched laser according to an embodiment of the present invention, as shown below. Figure 1 As shown, the laser includes: a first laser power supply 1, a first pump source 2, a first laser gain medium 3, a first polarizer 4, a quarter-wave plate 5, an isosceles right-angle prism 6, a second laser power supply 7, a second pump source 8, a second laser gain medium 9, a second polarizer 10, a 45° reflector 11, an electro-optic Q-switched crystal 12, an output mirror 13, an electro-optic Q-switching drive module 14, and a power timing control device 15, wherein:

[0041] The first laser power supply 1 is used to power the first pump source 2, and the two are connected by a cable;

[0042] The first pump source 2 is placed on the side of the first laser gain medium 3 and is parallel to the first laser gain medium 3, and is used to provide pump light to the first laser gain medium 3;

[0043] In one embodiment of the present invention, the voltage waveform applied to the first pump source 2 is as follows: Figure 2 As shown in V1.

[0044] The quarter-wave plate 5 is placed on the other side of the first laser gain medium 3;

[0045] In one embodiment of the present invention, the first laser gain medium 3 can be a laser crystal such as Nd:YAG or Nd:YVO4.

[0046] The first polarizer 4 is placed between the first laser gain medium 3 and the quarter-wave plate 5;

[0047] The isosceles total reflection prism 6 is placed on the side of the quarter-wave plate 5 away from the first polarizer 4, and the right-angled surface is perpendicular to the laser transmission direction. The incident angle of the first laser λ1 on the inclined surface of the isosceles total reflection prism 6 is greater than the Brewster angle.

[0048] The second laser power supply 7 is used to power the second pump source 8, and the two are connected by a cable;

[0049] The second pump source 8 is placed on the side of the second laser gain medium 9 and is parallel to the second laser gain medium 9, and is used to provide pump light to the second laser gain medium 9;

[0050] In one embodiment of the present invention, the voltage waveform applied to the second pump source 8 is as follows: Figure 2 As shown in V2;

[0051] In one embodiment of the present invention, the first pump source 2 and the second pump source 8 can be semiconductor pump sources, xenon lamps, krypton lamps, etc.

[0052] The second laser gain medium 9 is placed parallel and aligned with the first laser gain medium 3;

[0053] In one embodiment of the present invention, the second laser gain medium 9 can be a laser crystal such as Nd:YAG or Nd:YVO4.

[0054] In one embodiment of the present invention, both the first laser gain medium 3 and the second laser gain medium 9 are a-cut, and their c-axis orientations are perpendicular to each other.

[0055] The second polarizer 10 is located on the other side of the second laser gain medium 9;

[0056] The 45° reflector 11 is placed on the side of the second polarizer 10 away from the second laser gain medium 9, and is used to reflect light from the isosceles total internal reflection prism 6.

[0057] The electro-optic Q-switched crystal 12 and the output mirror 13 are placed sequentially on the side of the 45° reflector 11 away from the second polarizer 10 and perpendicular to the laser output direction.

[0058] In one embodiment of the present invention, the electro-optic Q-switching crystal 12 can be an electro-optic crystal such as LN, KD*P, KDP, or LiNbO3.

[0059] The first laser gain medium 3, the first polarizer 4, the quarter-wave plate 5, the isosceles right-angle prism 6, the 45° reflector 11, the electro-optic Q-switched crystal 12, and the output mirror 13 constitute the first laser λ1 resonant cavity.

[0060] The second laser gain medium 9, the second polarizer 10, the 45° reflector 11, the electro-optic Q-switched crystal 12, and the output mirror 13 constitute the second laser λ2 resonant cavity;

[0061] The electro-optic crystal driving module 14 is connected to the electro-optic Q-switching crystal 12 and is used to apply a common Q-switching bias voltage to the electro-optic Q-switching crystal 12.

[0062] In one embodiment of the present invention, the waveform of the common Q-switching bias voltage applied to the electro-optic Q-switching crystal 12 is as follows: Figure 2 Chinese V Q As shown.

[0063] The power supply timing control device 15 is connected to the electro-optic crystal driving module 14, the first laser power supply 1, and the second laser power supply 7, and is used to control the working timing relationship of the three power supplies. The timing relationship of the three driving signals is as follows: Figure 2 As shown.

[0064] In one embodiment of the present invention, the value of the common Q-switching bias voltage can be selected between 1200V and 1600V.

[0065] The working principle of the orthogonally polarized dual-wavelength alternating Q-switched laser is as follows: the first laser λ1 uses a pressure-applied electro-optic Q-switching method, and the second laser λ2 uses a de-pressured electro-optic Q-switching method. Both lasers share the same electro-optic Q-switching crystal 12. When the first pump source 2 and the second pump source 8 are pumped alternately at equal intervals, and a shared Q-switching bias voltage is applied, a 1319nm pulsed laser (e-beam) is output; when the shared Q-switching bias voltage is removed, a 1064nm pulsed laser (o-beam) is output. Therefore, by periodically applying / removing the shared Q-switching bias voltage, orthogonally polarized and alternately outputting 1064nm & 1319nm dual-wavelength pulsed lasers can be obtained. Figure 2 As shown in λ.

[0066] In one embodiment of the present invention, the side of the first laser gain medium 3 furthest from the resonant cavity is coated with a 1319nm high-reflectivity film (reflectivity greater than 99%) and a 1064nm high-transmittance film (transmittance greater than 99%). In this case, the end face of the first laser gain medium 3, after coating, is used as a 1319nm laser resonant cavity total reflection mirror, while the side closest to the resonant cavity is coated with a 1319nm high-transmittance film (transmittance greater than 99%). The side of the second laser gain medium 9 furthest from the resonant cavity is coated with a 1064nm high-reflectivity film (reflectivity greater than 99%). In this case, the end face of the second laser gain medium 9, after coating, is used as a 1064nm laser resonant cavity total reflection mirror, while the side closest to the resonant cavity is coated with a 1064nm high-transmittance film (transmittance greater than 99%). The dimensions of both the first laser gain medium 3 and the second laser gain medium 9 are... The 45° reflector 11 is coated with a 1319nm laser high transmittance film (transmittance greater than 99%) on the side closer to the second polarizer 10, and with a 1319nm laser high transmittance film (transmittance greater than 99%) and a 1064nm laser high reflectance film (reflectance greater than 99%) on the side farther away from the second polarizer 10; the electro-optic Q-switched crystal 12 has dimensions of 6mm × 6mm × 20mm; the output mirror 13 is coated on the side facing the resonant cavity, with a 1319nm laser reflectance of 80% and a 1064nm laser reflectance of 25%.

[0067] According to another aspect of the present invention, a method for outputting laser light using the above-described orthogonally polarized dual-wavelength alternating Q-switched laser is also proposed, such as... Figure 3 As shown, the method includes steps S301-S304:

[0068] In step S301, the first laser power supply 1 and the second laser power supply 7 supply power to the first pump source 2 and the second pump source 8 respectively, so that the first pump source 2 and the second pump source 8 provide pulsed pump light to the first laser gain medium 3 and the second laser gain medium 9 respectively.

[0069] In step S302, a common Q-switching bias voltage is applied across the electro-optic Q-switching crystal 12. The second laser λ2 resonator is in a high-loss state, the second laser gain medium 9 is in a population inversion state, and the first laser λ1 resonator is in a low-loss state, outputting the first Q-switched laser λ1 (e-beam).

[0070] In step S303, the common Q-switching bias voltage across the electro-optic Q-switching crystal 12 is removed, the first laser λ1 resonator is in a high-loss state, the first laser gain medium 3 is in a population inversion state, the second laser λ2 resonator is in a low-loss state, and the second Q-switched laser λ2 (o-light) is output.

[0071] In step S304, the voltage-boosting and voltage-de-boosting states of the electro-optic Q-switching crystal 12 are periodically repeated to obtain the first / second laser with orthogonal polarization and alternating output.

[0072] This invention combines boost and deboost electro-optic Q-switching technology, using a common Q-switching bias voltage to alternately Q-switch orthogonally polarized dual-wavelength lasers in a time-division manner: when the common Q-switching bias voltage is applied, the first λ1 pulse laser (e-beam) is output; when the common Q-switching bias voltage is removed, the second λ2 pulse laser (o-beam) is output, ultimately obtaining orthogonally polarized, alternately outputting dual-wavelength pulse lasers. This solves the technical problem of obtaining orthogonally polarized dual-wavelength pulse lasers with high peak power, narrow pulse width, and adjustable pulse interval using electro-optic Q-switching technology.

[0073] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. An orthogonally polarized dual-wavelength alternating Q-switched laser, characterized in that, The laser includes: a first laser power supply, a first pump source, a first laser gain medium, a first polarizer, a quarter-wave plate, an isosceles right-angle prism, a second laser power supply, a second pump source, a second laser gain medium, a second polarizer, a 45° reflector, an electro-optic Q-switched crystal, an output mirror, an electro-optic Q-switching drive module, and a power timing control device, wherein: The first laser power supply is used to power the first pump source, and the two are connected by a cable; The first pump source is placed on the side of the first laser gain medium and is parallel to the first laser gain medium, and is used to provide pump light to the first laser gain medium; The quarter-wave plate is placed on the other side of the first laser gain medium; The first polarizer is placed between the first laser gain medium and the quarter-wave plate; The isosceles right-angle prism is placed on the side of the quarter-wave plate away from the first polarizer, and the right-angle surface is perpendicular to the laser transmission direction; The second laser power supply is used to power the second pump source, and the two are connected by a cable; The second pump source is placed on the side of the second laser gain medium and is parallel to the second laser gain medium, and is used to provide pump light to the second laser gain medium; The second laser gain medium is placed parallel and aligned with the first laser gain medium; The second polarizer is located on the other side of the second laser gain medium; The 45° reflector is placed on the side of the second polarizer away from the second laser gain medium, and is used to reflect light from the isosceles right-angle prism. The electro-optic Q-switched crystal and the output mirror are placed sequentially on the side of the 45° reflector away from the second polarizer and perpendicular to the laser output direction; The first laser gain medium, the first polarizer, the quarter-wave plate, the isosceles right-angle prism, the 45° reflector, the electro-optic Q-switched crystal, and the output mirror constitute the first laser λ1 resonant cavity; The second laser gain medium, the second polarizer, the 45° reflector, the electro-optic Q-switched crystal, and the output mirror constitute the second laser λ2 resonant cavity; The electro-optic Q-switching drive module is connected to the electro-optic Q-switching crystal and is used to apply a common Q-switching bias voltage to the electro-optic Q-switching crystal. The power supply timing control device is connected to the electro-optic Q-switching drive module, the first laser power supply, and the second laser power supply, and is used to control the working timing relationship of the three power supplies. Both the first and second laser gain media are a-cut, and their c-axis orientations are perpendicular to each other. The first laser λ1 uses a pressure-adjusted electro-optic Q-switching method, and the second laser λ2 uses a de-adjusted electro-optic Q-switching method. Both lasers share the same electro-optic Q-switching crystal. When the first pump source and the second pump source are pumped alternately at equal intervals and a common Q-switching bias voltage is applied, a 1319nm pulsed laser output is obtained; when the common Q-switching bias voltage is removed, a 1064nm pulsed laser output is obtained. By periodically applying and removing the common Q-switching bias voltage, orthogonally polarized and alternately outputting 1064nm & 1319nm dual-wavelength pulsed lasers are obtained.

2. The laser according to claim 1, characterized in that, The first laser gain medium is Nd:YAG or Nd:YVO4.

3. The laser according to claim 1 or 2, characterized in that, The incident angle of the first laser λ1 onto the inclined plane of the isosceles right prism is greater than the Brewster angle.

4. The laser according to claim 1 or 2, characterized in that, The first pump source and the second pump source are semiconductor pump sources, xenon lamps, or krypton lamps.

5. The laser according to claim 1 or 2, characterized in that, The second laser gain medium is Nd:YAG or Nd:YVO4.

6. The laser according to claim 1 or 2, characterized in that, The electro-optic Q-switching crystal is LN, KD*P, KDP, or LiNbO3.

7. The laser according to claim 1 or 2, characterized in that, The first laser gain medium has a 1319nm high-reflectivity film and a 1064nm high-transmittance film deposited on the side away from the resonant cavity, and a 1319nm high-transmittance film deposited on the side closer to the resonant cavity; the second laser gain medium has a 1064nm high-reflectivity film deposited on the side away from the resonant cavity, and a 1064nm high-transmittance film deposited on the side closer to the resonant cavity; the 45° reflector has a 1319nm high-transmittance film deposited on the side closer to the second polarizer, and a 1319nm high-transmittance film and a 1064nm high-reflectivity film deposited on the side away from the second polarizer; the output mirror has a film deposited on the side facing the resonant cavity, with a 1319nm laser reflectivity of 80% and a 1064nm laser reflectivity of 25%.

8. A method for outputting laser light using any one of the orthogonally polarized dual-wavelength alternating Q-switched lasers according to claims 1-6, characterized in that, The method includes: In step S301, the first laser power supply and the second laser power supply supply power to the first pump source and the second pump source respectively, so that the first pump source and the second pump source provide pulse pump light to the first laser gain medium and the second laser gain medium respectively; In step S302, a common Q-switching bias voltage is applied across the electro-optic Q-switching crystal. The second laser λ2 resonator is in a high-loss state, the second laser gain medium is in a population inversion state, and the first laser λ1 resonator is in a low-loss state, thus outputting the first Q-switched laser λ1. In step S303, the common Q-switching bias voltage across the electro-optic Q-switching crystal is removed, the first laser λ1 resonator is in a high-loss state, the first laser gain medium is in a population inversion state, the second laser λ2 resonator is in a low-loss state, and the second Q-switched laser λ2 is output. In step S304, the voltage-boosting and voltage-de-boosting states of the electro-optic Q-switched crystal are periodically repeated to obtain the first / second laser with orthogonal polarization and alternating output.

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