A laser and method for implementing pulse group laser output based on cavity emptying group

Abstract

The present disclosure discloses a kind of laser and method based on cavity emptying group realizes pulse group laser output, in the laser: fast photoelectric detector, first all-reflection mirror, electro-optic switch, quarter-wave plate, polaroid, gain medium, second output mirror are sequentially placed from left to right;Pump source is placed below the gain medium, for using the pump light emitted by it to pump the gain medium, so that gain medium realizes enough particle number inversion;Electro-optic switch voltage waveform controller is electrically connected with the electro-optic switch, for the electro-optic switch power supply, control the voltage of electro-optic crystal inside the electro-optic switch, the electro-optic switch voltage waveform controller is also connected with the fast photoelectric detector, for receiving the electrical signal generated by the fast photoelectric detector, after this signal triggers electro-optic switch voltage waveform controller, output multiple high level as quarter-wave electro-optic crystal voltage square wave signal.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and specifically to a laser and method for realizing pulse group laser output based on cavity emptying group. Background Technology

[0002] Pulsed group lasers have significant application needs in pulsed laser ranging, laser precision machining, and laser-matter interactions. Currently, methods for obtaining pulsed group lasers can be categorized into three types: pulse pumping, Q-switching, and mode-locking. Pulsed pumping primarily utilizes pulse pumping to obtain pulsed lasers, resulting in low pulse frequencies (typically less than 1000 Hz) and wide pulse widths (on the order of microseconds and milliseconds). The second type is Q-switching, which includes pulse-pumped Q-switching and continuous-pump Q-switching. Pulsed-pumped Q-switching addresses the issue of excessively wide pulse widths obtained by pulse pumping, increasing peak power but not the pulse frequency. Continuous-pump Q-switching utilizes continuous pumping and high-frequency Q-switching techniques (such as acousto-optic Q-switching or passive Q-switching) to obtain high-frequency pulses in the 1–500 kHz range. Mode-locking can obtain high-frequency pulses above GHz. While existing pulse group outputs have achieved pulse frequencies from Hz to kHz, kHz, and GHz intervals, techniques for nanosecond interval MHz pulse group outputs are severely lacking. Summary of the Invention

[0003] To address the problem of existing lasers struggling to achieve high-efficiency pulse group output with MHz-interval pulses, this invention provides a laser and method for realizing pulse group laser output based on cavity emptying groups.

[0004] According to one aspect of the present invention, a laser for realizing pulse group laser output based on cavity emptying group is provided, the laser comprising a fast photodetector, a first total reflection mirror, an electro-optic switch, a quarter-wave plate, a polarizer, a gain medium, a second total reflection mirror, a pump source, and an electro-optic switch voltage waveform controller, wherein:

[0005] The fast photodetector, the first total reflection mirror, the electro-optic switch, the quarter-wave plate, the polarizer, the gain medium, and the second output mirror are placed in order from left to right.

[0006] The pump source is placed below the gain medium and is used to pump the gain medium with the pump light emitted by it, so that the gain medium achieves sufficient population inversion.

[0007] The electro-optic switch voltage waveform controller is electrically connected to the electro-optic switch and is used to supply power to the electro-optic switch and control the voltage of the electro-optic crystal inside the electro-optic switch. The electro-optic switch voltage waveform controller is also connected to the fast photodetector and is used to receive the electrical signal generated by the fast photodetector. After being triggered by the electro-optic switch voltage waveform controller, this signal outputs multiple square wave signals with a high level of one-quarter of the electro-optic crystal voltage.

[0008] Optionally, the first total reflection mirror, the electro-optic switch, the quarter-wave plate, the polarizer, the gain medium, and the second total reflection mirror constitute the resonant cavity of the laser.

[0009] Optionally, the first total reflection mirror and the second total reflection mirror are plane mirrors or curved mirrors with curvature.

[0010] Optionally, the polarizer has the characteristics of high transmittance of P-polarized light and high reflectivity of S-polarized light.

[0011] Optionally, the pump source and gain medium are side-pumped structures or end-pumped structures.

[0012] Optionally, the fast photodetector is used to monitor the intracavity laser overflowing from the first total reflection mirror and generate an electrical signal synchronized with the intracavity laser.

[0013] Optionally, the electro-optic switch is made using a transverse electro-optic effect or a longitudinal electro-optic effect.

[0014] Optionally, the quarter-wave plate is used to realize the mutual conversion between linearly polarized light incident after passing through the polarizer and other polarization states of light.

[0015] According to another aspect of the present invention, a method for outputting laser light using any of the lasers described above is also provided, the method comprising:

[0016] Step S1: The pump source emits pump light to pump the gain medium;

[0017] In step S2, during the pumping period, the electro-optic switch voltage waveform controller controls the applied voltage of the electro-optic switch to be 0. At this time, the laser resonator is in a high-loss state, the gain medium stores energy, and sufficient population inversion is achieved.

[0018] In step S3, when the pump pulse is at its falling edge, the electro-optic switch voltage waveform controller applies a quarter voltage to the electro-optic switch. At this time, the laser resonator is in a low-loss state, and the spontaneous emission signal light of the gain medium oscillates and strengthens in the resonator to form a laser.

[0019] In step S4, a portion of the laser light spilling from the first total reflection mirror is received by a fast photodetector to generate a synchronous electrical signal. This electrical signal is triggered by an electro-optic switch voltage waveform controller to make the electro-optic switch electro-optic crystal voltage 0.

[0020] Step S5: After the preset time interval, repeat steps S3 and S4 again;

[0021] Step S6 involves repeating the process multiple times to obtain a multi-pulse laser output via a polarizer.

[0022] The beneficial effects of the present invention are as follows: In the prior art, nanosecond pulse interval lasers are obtained by coordinating the output of light through two externally triggered lasers, which is structurally complex. However, the present invention can obtain multi-pulse laser output with adjustable MHz intervals by delay triggering, which not only reduces device costs, but also has the advantages of small footprint and simple structure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a laser that realizes pulse group laser output based on cavity emptying group according to an embodiment of the present disclosure.

[0024] Figure 2 This is a schematic diagram of the pump and crystal voltage waveform timing according to an embodiment of the present disclosure. Detailed Implementation

[0025] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement them. Furthermore, for clarity, portions unrelated to the description of the exemplary embodiments have been omitted from the drawings.

[0026] In embodiments disclosed herein, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, numbers, steps, behaviors, components, portions or combinations thereof disclosed herein, and are not intended to exclude the possibility that one or more other features, numbers, steps, behaviors, components, portions or combinations thereof are present or added.

[0027] It should also be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings and examples.

[0028] Figure 1 This is a schematic diagram of a laser that realizes pulse group laser output based on cavity emptying group according to an embodiment of the present disclosure. Figure 2 This is a schematic diagram of the pump and crystal voltage waveform timing according to an embodiment of the present disclosure, as shown below. Figure 1 and Figure 2 As shown, the laser for pulse group laser output based on cavity emptying group includes: a fast photodetector 1, a first total reflection mirror 2, an electro-optic switch 3, a quarter-wave plate 4, a polarizer 5, a gain medium 6, a second total reflection mirror 7, a pump source 8, and an electro-optic switch voltage waveform controller 9, wherein:

[0029] The fast photodetector 1, the first total reflection mirror 2, the electro-optic switch 3, the quarter-wave plate 4, the polarizer 5, the gain medium 6, and the second output mirror 7 are placed in sequence from left to right;

[0030] The pump source 8 is placed below the gain medium 6 and is used to pump the gain medium 6 with the pump light emitted by it, so that the gain medium 6 achieves sufficient population inversion.

[0031] The electro-optic switch voltage waveform controller 9 is electrically connected to the electro-optic switch 3 and is used to supply power to the electro-optic switch 3 and control the voltage of the electro-optic crystal inside the electro-optic switch 3. The electro-optic switch voltage waveform controller 9 is also connected to the fast photodetector 1 and is used to receive the electrical signal generated by the fast photodetector 1. After being triggered by the electro-optic switch voltage waveform controller 9, this signal outputs multiple square wave signals with a high level of one-quarter of the electro-optic crystal voltage.

[0032] The first total reflection mirror 2, the electro-optic switch 3, the quarter-wave plate 4, the polarizer 5, the gain medium 6, and the second total reflection mirror 7 constitute the resonant cavity of the laser.

[0033] In one embodiment of this disclosure, the fast photodetector 1 is used to monitor the intracavity laser overflowing from the first total reflection mirror 2 and generate an electrical signal synchronized with the intracavity laser.

[0034] In one embodiment of this disclosure, the first total reflection mirror 2 and the second total reflection mirror 7 are plane mirrors or curved mirrors with curvature, which have a high reflectivity to laser light.

[0035] In one embodiment of this disclosure, the electro-optic switch 3 can be made using either a transverse electro-optic effect or a longitudinal electro-optic effect.

[0036] In one embodiment of this disclosure, the quarter-wave plate 4 is used to realize the mutual conversion between linearly polarized light incident after passing through the polarizer 5 and other polarization states of light.

[0037] In one embodiment of this disclosure, the polarizer 5 has the characteristics of high transmittance of P-polarized light and high reflectance of S-polarized light. It can be a Brewster plate, a Glan prism, or even a PBS beam splitter. When the polarizer 5 is a Glan prism or a PBS beam splitter, its light-transmitting surface needs to be coated with a high-transmittance film.

[0038] In one embodiment of the present invention, the gain medium 6 is a gain medium used to achieve particle inversion.

[0039] In one embodiment of the present invention, the pump source 8 and the gain medium 6 are side-pumped structures, but the present invention is not limited to this type of pumping structure. The pump source 8 and the gain medium 6 can also be end-pumped structures, that is, the direction of the pump light generated by the pump source 8 is consistent with or parallel to the optical path direction of the laser.

[0040] In one embodiment of the present invention, the pump source 8 is a device for providing pump light, and its type is not limited. It can be a flash lamp pump, an LD pump, or other devices that provide pump light.

[0041] Based on the above scheme, when the laser is working, the pump source 8 emits pump light to pump the gain medium 6. During pumping, the electro-optic switch voltage waveform controller 9 controls the applied voltage of the electro-optic switch 3 to be 0. At this time, the laser resonant cavity is in a high-loss state, and the gain medium 6 stores energy to achieve sufficient population inversion. When the pump light pump pulse is at its falling edge, the electro-optic switch voltage waveform controller 9 applies a quarter voltage to the electro-optic switch 3. At this time, the laser resonant cavity is in a low-loss state, and the spontaneous emission signal light of the gain medium 6 (the laser gain medium 6 causes a certain number of population inversion distributions under the excitation of the pump source, and the particles at high energy levels are unstable and generate spontaneous emission light) quickly oscillates and strengthens in the resonant cavity to form laser light. At the same time, a portion of the laser light overflowing from the first total reflection mirror 2 (since the total reflection mirror cannot achieve 100% laser transmission, a very small portion of the laser light will overflow) is received by the fast photodetector 1 to generate a synchronous electrical signal. This electrical signal is triggered by the electro-optic switch voltage waveform controller 9, making the electro-optic crystal voltage of the electro-optic switch 3 0.

[0042] After a preset time interval, the process is repeated: the electro-optic switch voltage waveform controller 9 applies a quarter voltage to the electro-optic switch 3; the laser resonator is in a low-loss state; the spontaneous emission signal light from the gain medium 6 quickly oscillates and strengthens within the resonator to form laser light; a portion of the laser light overflowing from the first total reflection mirror 2 is received by the fast photodetector 1, generating a synchronous electrical signal; this electrical signal triggers the electro-optic switch 3 to have its electro-optic crystal voltage set to zero via the electro-optic switch voltage waveform controller 9. After multiple repetitions of this process, a multi-pulse laser output via polarizer 5 is obtained. The pulse interval within the pulse group is determined by a preset time interval, and the number of pulses is determined by the number of repetitions of the steps. Using this method, a multi-pulse laser output with adjustable MHz frequency intervals can be achieved.

[0043] The present invention also provides a method for outputting laser light using the above-mentioned laser, the method comprising the following steps:

[0044] Step S1: Pump source 8 emits pump light to pump the gain medium 6;

[0045] In step S2, during the pumping period, the electro-optic switch voltage waveform controller 9 controls the applied voltage of the electro-optic switch 3 to be 0. At this time, the laser resonator cavity is in a high-loss state, the gain medium 6 stores energy, and sufficient population inversion is achieved.

[0046] In step S3, when the pump pulse is at its falling edge, the electro-optic switch voltage waveform controller 9 applies a quarter voltage to the electro-optic switch 3. At this time, the laser resonant cavity is in a low-loss state, and the spontaneous emission signal light of the gain medium 6 oscillates and strengthens in the resonant cavity to form a laser.

[0047] In step S4, a portion of the laser light spilling from the first total reflection mirror 2 is received by the fast photodetector 1 to generate a synchronous electrical signal. This electrical signal is triggered by the electro-optic switch voltage waveform controller 9, causing the electro-optic switch 3 electro-optic crystal voltage to be 0.

[0048] Step S5: After the preset time interval, repeat steps S3 and S4 again;

[0049] Step S6: After multiple repetitions, a multi-pulse laser output is obtained via polarizer 5.

[0050] The meaning and explanation of the technical features in the method are the same as those in the laser described above, and will not be repeated here.

[0051] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A laser that achieves pulse group laser output based on cavity reversal, characterized in that, The laser includes a fast photodetector, a first total reflection mirror, an electro-optic switch, a quarter-wave plate, a polarizer, a gain medium, a second total reflection mirror, a pump source, and an electro-optic switch voltage waveform controller, wherein: The fast photodetector, the first total reflection mirror, the electro-optic switch, the quarter-wave plate, the polarizer, the gain medium, and the second total reflection mirror are placed in order from left to right. The pump source is placed below the gain medium and is used to pump the gain medium with the pump light emitted therefrom, so that the gain medium achieves sufficient population inversion. The electro-optic switch voltage waveform controller is electrically connected to the electro-optic switch and is used to supply power to the electro-optic switch and control the voltage of the electro-optic crystal inside the electro-optic switch. The electro-optic switch voltage waveform controller is also connected to the fast photodetector and is used to receive the electrical signal generated by the fast photodetector. This electrical signal is triggered by the electro-optic switch voltage waveform controller to make the voltage of the electro-optic crystal of the electro-optic switch 0. After being triggered by the electro-optic switch voltage waveform controller, this signal outputs multiple high-level square wave signals with a voltage of one-quarter of the electro-optic crystal voltage. At this time, the laser resonator cavity is in a low-loss state.

2. The laser according to claim 1, characterized in that, The first total reflection mirror, the electro-optic switch, the quarter-wave plate, the polarizer, the gain medium, and the second total reflection mirror constitute the resonant cavity of the laser.

3. The laser according to claim 1 or 2, characterized in that, The first and second total reflection mirrors are plane mirrors or curved mirrors with curvature.

4. The laser according to claim 3, characterized in that, The polarizer has the characteristics of high transmittance of P-polarized light and high reflectivity of S-polarized light.

5. The laser according to claim 4, characterized in that, The pump source and gain medium are either side-pumped or end-pumped structures.

6. The laser according to claim 5, characterized in that, The fast photodetector is used to monitor the intracavity laser overflowing from the first total reflection mirror and generate an electrical signal synchronized with the intracavity laser.

7. The laser according to claim 6, characterized in that, The electro-optic switch is made using either the transverse electro-optic effect or the longitudinal electro-optic effect.

8. The laser according to claim 7, characterized in that, The quarter-wave plate is used to realize the mutual conversion between linearly polarized light incident after passing through the polarizer and other polarization states of light.

9. A method for outputting laser light using any one of the lasers described in claims 1-8, characterized in that, The method includes: Step S1: The pump source emits pump light to pump the gain medium; In step S2, during the pumping period, the electro-optic switch voltage waveform controller controls the applied voltage of the electro-optic switch to be 0. At this time, the laser resonator is in a high-loss state, the gain medium stores energy, and sufficient population inversion is achieved. In step S3, when the pump pulse is at its falling edge, the electro-optic switch voltage waveform controller applies a quarter voltage to the electro-optic switch. At this time, the laser resonator is in a low-loss state, and the spontaneous emission signal light of the gain medium oscillates and strengthens in the resonator to form a laser. In step S4, a portion of the laser light spilling from the first total reflection mirror is received by a fast photodetector to generate a synchronous electrical signal. This electrical signal is triggered by an electro-optic switch voltage waveform controller to make the electro-optic switch electro-optic crystal voltage 0. Step S5: After a preset time interval, repeat steps S3 and S4 again; Step S6 involves repeating the process multiple times to obtain a multi-pulse laser output via a polarizer.

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