Laser and target debugging device with self-reference light and debugging method thereof
By introducing a self-reference beam that shares the same optical path with the main laser in the laser target firing device, and by using a three-phase switch and a reference beam switch to control the laser path, the problem of mismatch between the self-reference beam and the main laser is solved, achieving efficient and safe target firing debugging results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING RUIDEKANG TECH CO LTD
- Filing Date
- 2023-03-15
- Publication Date
- 2026-05-29
Smart Images
Figure CN116191186B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lasers, and more specifically to a laser and target debugging device with self-reference light and its debugging method. Background Technology
[0002] Since the introduction of chirped laser pulse amplification (CPA), the peak power of lasers has developed by leaps and bounds, with laser pulse peak power reaching several PW (10^6 ppm). 15 W), laser intensity can reach 10 22 W / cm2. This type of strong-field laser is widely used in laser-plasma interactions.
[0003] Common CPA systems such as Figure 1 As shown, a seed source generates an ultrashort pulse (pulse width typically on the order of picoseconds or femtoseconds) as the seed source pulse. This pulse is then time-stretched by a stretcher to obtain a long pulse (pulse width on the order of tens of picoseconds to nanoseconds, the specific stretched pulse width depending on the final energy to be amplified). An amplifier system amplifies the stretched long pulse to obtain a high-energy pulse, where a pump provides energy to the amplifier system. Finally, the high-energy laser pulse is compressed to its minimum time scale (returning to the order of the seed source pulse width) by a compressor, resulting in a high-peak-power, high-field laser pulse. The output pulse is then further transmitted to the target area for firing.
[0004] A self-reference beam is inserted between the target firing point and the compressor. The laser spot size, wavelength, and divergence angle of the self-reference beam are comparable to the main laser output from the compressor. This allows the self-reference beam to be used instead of the main laser for target preparation. However, since the self-reference beam is an independent laser, its wavelength, spot size, and divergence angle can only be matched to the main laser as closely as possible, and cannot be exactly the same. Furthermore, the path taken by the main laser is different from that of the self-reference beam, resulting in different wavefront information. Therefore, especially during focusing, using the self-reference beam to replace the main laser for adjustment is not very meaningful. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention proposes a laser and target debugging device with self-reference light and its debugging method.
[0006] One object of the present invention is to provide a laser and target debugging device with a self-reference beam.
[0007] The laser and target firing adjustment device with self-reference light of the present invention includes: a seed source, a stretcher, a first amplifier, a first pump source, a selection system, a second amplifier, a second pump source, a compressor, a reference light circuit, a reference light switch, and a three-phase switch; wherein, the laser generated by the seed source enters the stretcher and is amplified by the first amplifier, the first pump source provides energy to the first amplifier, the first pump source has a repetition rate of mkHz, and the first amplifier outputs a laser pulse with a repetition rate of mkHz; the mkHz laser pulse output by the first amplifier is selected by the selection system to obtain an nHz laser pulse, where m and n are integers greater than 1 and less than 10, the nHz laser pulse enters the second amplifier for amplification, the second pump source provides energy to the second amplifier, the laser output by the second amplifier enters the compressor for compression, and the output laser is sent to the target area for target firing;
[0008] The selection system selects n laser pulses from m×1000 laser pulses per second as the main laser and sends them to the second amplifier. The remaining m×1000-n laser pulses are output to the selection system. These m×1000-n laser pulses are called self-reference beams. After being output from the selection system, the self-reference beams enter the reference beam circuit. A reference beam switch is added between the output of the self-reference beams from the selection system and the reference beam circuit. The self-reference beams are then transmitted back to the selection system after passing through the subsequent second amplifier and compressor before entering the target area. The reference beam switch and the second pump source are connected to the same power supply through a three-phase switch. The second pump source or the reference beam switch can only operate when the power supply is turned on.
[0009] The three-phase switch has three paths: the first path, the second path, and the third path. Only one path can be selected to be connected at a time. The first path is connected to the reference optical switch, the second path is connected to the second pump source, and the third path is connected to ground.
[0010] When the first path of the three-phase switch is connected and the reference light is powered on, the second pump source is not powered on and cannot be started. The second amplifier has no power supply and no high-energy laser output. This ensures that when the self-reference light is used as the subsequent adjustment optical path, there is no high-energy laser in the subsequent optical path, thus ensuring the safety of the operator.
[0011] When the second path of the three-phase switch is connected and the second pump source is powered on, the reference light switch is not powered on, the reference light switch is closed, the second amplifier is not interfered with by the reference light, and the laser works normally at this time.
[0012] When the third path of the three-phase switch is connected, neither the self-reference light nor the second pump source can work. This state is used as the state when the laser is not running.
[0013] The selection system includes a first polarizing beam splitter, a Pockel cell, and a second polarizing beam splitter. The first and second polarizing beam splitters transmit horizontally polarized lasers and reflect vertically polarized lasers. The Pockel cell is an electro-optic device. In its initial 0-voltage state, the Pockel cell is a half-wave plate. After applying a half-wave voltage, the Pockel cell superimposed on the initial half-wave plate state becomes a full-wave plate. The full-wave plate does not change the polarization state of the light. By controlling the voltage of the Pockel cell, the polarization state of the laser can be adjusted so that the laser is either reflected or transmitted when passing through the second polarizing beam splitter. When the repetition frequency of the half-wave voltage of the Pockel cell is nHz, the input laser can be selected from mkHz to select an nHz repetition frequency laser.
[0014] When the Pockel cell is at 0 voltage, a mkHz laser pulse passes through the Pockel cell, which is then in a half-wave plate state. The polarization changes from horizontal to vertical. The vertically polarized laser pulse is reflected as a self-reference beam when it passes through the second polarization beam splitter. The self-reference beam enters the reference beam circuit, and a reference beam switch is added between the second polarization beam splitter and the reference beam circuit. When a half-wave voltage is applied to the Pockel cell, the mkHz laser pulse passes through the Pockel cell, which is then in a full-wave plate state. The polarization remains horizontal. The horizontally polarized laser pulse is transmitted when it passes through the second polarization beam splitter, ensuring that at least one laser pulse is transmitted through the second polarization beam splitter. The half-wave voltage repetition frequency of the Pockel cell is nHz, enabling the selection of a single nHz repetition frequency laser from the mkHz input laser.
[0015] When the first path is connected and the reference light switch is powered on, the reference light switch opens, and the laser pulse passes through the reference light switch, enters the reference light circuit, and returns to the selection system. At this time, all mkHz laser pulses can enter the second amplifier. The self-reference light is used as a reference for all subsequent optical paths, including the second amplifier, compressor, and target area. When the second path is connected and the reference light switch is powered off, the reference light switch closes, and the laser pulse cannot enter the reference light circuit and return to the selection system. At this time, only the selected nHz laser pulse enters the second amplifier, and the entire laser device works normally and outputs nHz laser pulses.
[0016] There are two ways to implement the reference optical loop.
[0017] In the first implementation, the reference optical circuit includes first and second reflectors and first and second quarter-glass slides. Vertically polarized self-reference light, reflected by a second polarizing beam splitter, is reflected back to the first reflector. A reference light switch and the first quarter-glass slide are placed between the second polarizing beam splitter and the first reflector. The vertically polarized self-reference light becomes circularly polarized after passing through the first quarter-glass slide and is incident on the first reflector at 0°. The first reflector reflects the circularly polarized self-reference light back through the first quarter-glass slide and the reference light switch, at which point the self-reference light becomes horizontally polarized and enters the second polarizing beam splitter, is transmitted through the second polarizing beam splitter, and is incident on the second reflector. A second quarter-glass slide is placed between the second polarizing beam splitter and the second reflector. The horizontally polarized self-reference light becomes circularly polarized after passing through the second quarter-glass slide and is incident on the second reflector at 0°. The second reflector reflects the circularly polarized self-reference light back through the second quarter-glass slide, at which point the self-reference light becomes vertically polarized and enters the second polarizing beam splitter, is reflected, and enters the second amplifier. The self-reference light reflected by the second polarizing beam splitter coincides with the main laser.
[0018] In the second implementation, the reference optical circuit includes third to sixth reflecting mirrors and first and second half-wave plates. Vertically polarized self-reference light, reflected by the second polarizing beam splitter, is reflected at 45° to the third reflecting mirror. A reference light switch is inserted between the second and third reflecting mirrors. The light then propagates to the sixth reflecting mirror. A first half-wave plate is inserted between the third and fourth reflecting mirrors. The vertically polarized self-reference light becomes horizontally polarized after passing through the first half-wave plate. The horizontally polarized self-reference light is incident at 45° to the fourth reflecting mirror and reflected to the first polarizing beam splitter. A beam splitter is used to separate horizontally polarized self-reference light. After being transmitted through the first polarizing beam splitter, the self-reference light is incident at 45° onto the fifth reflecting mirror. The horizontally polarized self-reference light reflected by the fifth reflecting mirror is then incident at 45° onto the sixth reflecting mirror. A second half-wave plate is placed between the fifth and sixth reflecting mirrors. The self-reference light becomes vertically polarized after passing through the second half-wave plate. The vertically polarized self-reference light is reflected by the sixth reflecting mirror and then incident vertically onto the second polarizing beam splitter. It is then reflected by the second polarizing beam splitter and enters the second amplifier. The self-reference light reflected by the second polarizing beam splitter coincides with the main laser.
[0019] In this configuration, the compressor output is greater than 300 mJ, the spot size is less than 20 mm, and the first amplifier output is greater than 2–5 mJ. In this case, the self-reference can be used in the target area. The self-reference light energy density in the target area is 0.3–1 mJ / cm². 2 To facilitate subsequent operations, the self-reference beam of this invention is used for target area debugging preparation.
[0020] When the self-reference light of this invention is used for debugging the second amplifier, it is applicable to cases where the output energy of the second amplifier is less than 5J. Considering that the size of the light plate of the 5J energy amplifier is less than 30mm, and the output of the first amplifier is greater than 2 to 5mJ, although the spot size is large, the light does not pass through the compressor at this time, and the energy is higher than that of the target area, which facilitates the debugging of the second amplifier.
[0021] A Pockel cell is an electro-optic device, equivalent to a voltage-controlled waveplate. It consists of an electro-optic crystal and a high-voltage power supply. By applying a voltage to the electro-optic crystal, the optical properties exhibited by the photoelectric crystal are controlled. In its zero-voltage state, the Pockel cell is a half-waveplate. When a voltage is applied to the electro-optic crystal, its optical properties are superimposed on its initial state. When the applied voltage changes the optical properties to a half-waveplate state, the applied voltage is a half-wave voltage. Since the Pockel cell's initial zero-voltage state is a half-waveplate, after applying a half-wave voltage, the Pockel cell, superimposed with its initial half-waveplate state, behaves as a full-waveplate, meaning it does not change the polarization state of the light. The starting time t0 for applying the half-wave voltage to the Pockel cell is between two laser pulses of a mkHz laser pulse. The cutoff time of the half-wave voltage is t0 + Δt, where Δt ≤ 1ms, ensuring that only one laser pulse passes through the Pockel cell during the half-wave voltage application period. The repetition frequency of the half-wave voltage is nHz. Applying the half-wave voltage to the Pockel cell ensures that one laser pulse is transmitted through the second polarization beam splitter.
[0022] Another objective of this invention is to provide a debugging method for a laser and target-shooting device with a self-reference beam.
[0023] The debugging method of the laser and target-shooting device with self-reference light of the present invention includes the following steps:
[0024] 1) After the laser generated by the seed source enters the stretcher, it is amplified by the first amplifier. The first pump source provides energy to the first amplifier. The repetition rate of the first pump source is mKHz. The first amplifier outputs a laser pulse with a repetition rate of mKHz.
[0025] The first amplifier outputs mkHz laser pulses to the menu system, where m is an integer greater than 1 and less than 10;
[0026] 2) The selection system selects n laser pulses from m×1000 laser pulses per second as the main laser and sends them to the second amplifier. The remaining m×1000-n laser pulses are output to the selection system. These m×1000-n laser pulses are called the self-reference light, where n is an integer greater than 1 and less than 10.
[0027] In the selection system, when the Pockel cell is at 0 voltage, when a mkHz laser pulse passes through the Pockel cell, the cell is in a half-wave plate state, and its polarization changes from horizontal to vertical. The vertically polarized laser pulse is reflected as a self-reference light when it passes through the second polarization beam splitter, and the self-reference light enters the reference light circuit. A reference light switch is added between the second polarization beam splitter and the reference light circuit. When a half-wave voltage is applied to the Pockel cell, when a mkHz laser pulse passes through the Pockel cell, the cell is in a full-wave plate state, and its polarization remains horizontal. The horizontally polarized laser pulse is transmitted when it passes through the second polarization beam splitter, ensuring that at least one laser pulse is transmitted through the second polarization beam splitter. The half-wave voltage repetition frequency of the Pockel cell is nHz, enabling the selection of an nHz repetition frequency laser from the mkHz input laser.
[0028] 3) Connect the reference light switch and the second pump source to the same power supply via a three-phase switch. The second pump source or the reference light switch can only work when the power supply is turned on. After the reference light is transmitted in the reference light circuit, it is then transmitted back to the selector system to enter the laser light path. The three-phase switch has three paths: the first path, the second path, and the third path. Only one path can be selected at a time. The first path is connected to the reference light switch, the second path is connected to the second pump source, and the third path is connected to ground.
[0029] a) When the first path of the three-phase switch is connected and the reference light is switched on to power, the second pump source is not connected to power and cannot be started. The second amplifier has no power supply and no high-energy laser output. This ensures that when the self-reference light is used as the subsequent adjustment optical path, there is no high-energy laser in the subsequent optical path, thus ensuring the safety of the operator.
[0030] b) When the second path of the three-phase switch is connected and the second pump source is powered on, the reference light switch is not powered on, the reference light switch is closed, the second amplifier is not interfered with by the reference light, and the laser works normally at this time.
[0031] c) When the third path of the three-phase switch is connected, neither the reference light switch nor the second pump source can work. This is used as the state when the laser is not running.
[0032] 4) When the first path is connected and the reference light switch is powered on, the reference light switch opens, and the laser pulse returns to the menu system after passing through the reference light circuit via the reference light switch. At this time, all the mKHz laser pulses can enter the second amplifier. The self-reference light is used as a reference for all subsequent optical paths, including the second amplifier, compressor and target area.
[0033] When the second path is connected and the reference light switch is de-energized, the reference light switch is closed. The laser pulse cannot enter the reference light circuit through the reference light switch and return to the selection system. At this time, only the selected nHz laser pulse enters the second amplifier, and the entire laser device works normally and outputs nHz laser pulse.
[0034] 5) The nHz laser pulse enters the second amplifier for amplification. The second pump source provides energy to the second amplifier. The laser output from the second amplifier enters the compressor for compression. The output laser is sent to the target area to strike the target.
[0035] Advantages of this invention:
[0036] This invention eliminates the need for an external reference beam, making it more economical. The self-reference beam has the same beam quality as the main laser, including spot size, divergence angle, and wavelength, enabling it to accurately replace the original laser for subsequent target-shooting system debugging, with results comparable to those achieved using the main laser. The addition of a reference beam switch increases safety and prevents accidents caused by misoperation. The mkHz laser has a high repetition rate, making it easy for the human eye to observe and very convenient to use as a self-reference beam for subsequent adjustments. In contrast, the nHz laser of the main laser has a very low repetition rate, making it difficult for the human eye to observe directly. Attached Figure Description
[0037] Figure 1 This is a structural block diagram of a CPA system in the prior art;
[0038] Figure 2 This is a block diagram of the overall structure of the laser and target debugging device with self-reference light of the present invention;
[0039] Figure 3 This is a structural block diagram of the menu system of the laser and target debugging device with self-reference light of the present invention;
[0040] Figure 4 This is a structural block diagram of a first implementation of the reference light circuit of the laser and target debugging device with self-reference light according to the present invention;
[0041] Figure 5 This is a structural block diagram of a second implementation of the reference light circuit of the laser and target debugging device with self-reference light according to the present invention. Detailed Implementation
[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0043] like Figure 2As shown, the laser and target calibration device with self-reference light in this embodiment includes: a seed source, a stretcher, a first amplifier, a first pump source, a selection system, a second amplifier, a second pump source, a compressor, a reference light circuit, a reference light switch, and a three-phase switch. The laser generated by the seed source enters the stretcher and is amplified by the first amplifier. The first pump source provides energy to the first amplifier, which has a repetition rate of mkHz. The first amplifier outputs a laser pulse with a repetition rate of mkHz. The mkHz laser pulse output by the first amplifier is selected by the selection system to obtain an nHz laser pulse, where m and n are integers greater than 1 and less than 10. The nHz laser pulse enters the second amplifier for amplification, and the second pump source provides energy to the second amplifier. The laser output by the second amplifier is compressed by the compressor, and the output laser is sent to the target area for target firing.
[0044] The selection system selects n laser pulses from m×1000 laser pulses per second as the main laser and sends them to the second amplifier. The remaining m×1000-n laser pulses are output to the selection system. These m×1000-n laser pulses are called self-reference beams. After being output from the selection system, the self-reference beams enter the reference beam circuit. A reference beam switch is added between the output of the self-reference beams from the selection system and the reference beam circuit. The self-reference beams are then transmitted back to the selection system after passing through the subsequent second amplifier and compressor before entering the target area. The reference beam switch and the second pump source are connected to the same power supply through a three-phase switch. The second pump source or the reference beam switch can only operate when the power supply is turned on.
[0045] The three-phase switch has three paths: the first path, the second path, and the third path. Only one path can be selected to be connected at a time. The first path is connected to the reference optical switch, the second path is connected to the second pump source, and the third path is connected to ground.
[0046] When the first path of the three-phase switch is connected and the reference light is powered on, the second pump source is not powered on and cannot be started. The second amplifier has no power supply and no high-energy laser output. This ensures that when the self-reference light is used as the subsequent adjustment optical path, there is no high-energy laser in the subsequent optical path, thus ensuring the safety of the operator.
[0047] When the second path of the three-phase switch is connected and the second pump source is powered on, the reference light switch is not powered on, the reference light switch is closed, the second amplifier is not interfered with by the reference light, and the laser works normally at this time.
[0048] When the third path of the three-phase switch is connected, neither the self-reference light nor the second pump source can work. This state is used as the state when the laser is not running.
[0049] like Figure 3As shown, the selection system includes a first polarizing beam splitter, a Pockel cell, and a second polarizing beam splitter. The first and second polarizing beam splitters transmit horizontally polarized lasers and reflect vertically polarized lasers. The Pockel cell is an electro-optic device. In its initial 0-voltage state, the Pockel cell is a half-wave plate. After applying a half-wave voltage, the Pockel cell superimposed with the initial half-wave plate state becomes a full-wave plate. The full-wave plate does not change the polarization state of the light. By controlling the voltage of the Pockel cell, the polarization state of the laser can be adjusted so that the laser is either reflected or transmitted when passing through the second polarizing beam splitter. When the repetition frequency of the half-wave voltage of the Pockel cell is nHz, the input laser can be selected from mkHz to select an nHz repetition frequency laser.
[0050] A Pockel cell is an electro-optic device, essentially a voltage-controlled waveplate. It consists of an electro-optic crystal and a high-voltage power supply. By applying a voltage to the electro-optic crystal, the optical properties exhibited by the crystal are controlled. In its zero-voltage state, the Pockel cell is a half-wave plate. When a voltage is applied to the electro-optic crystal, its optical properties are superimposed on its initial state. When the applied voltage changes the optical properties to a half-wave plate state, the applied voltage is a half-wave voltage. Since the initial zero-voltage state of the Pockel cell is a half-wave plate, applying a half-wave voltage superimposed on the initial half-wave plate state results in a full-wave plate state, meaning there is no change in the polarization state of the light. By controlling the Pockel cell... The voltage of the Pockel cell is used to control the polarization state of the laser, so that the laser is either reflected or transmitted when it passes through the second polarization beam splitter. When the voltage repetition frequency of the Pockel cell is nHz, a single nHz repetition frequency laser is selected from the mkHz laser. The start time t0 of the half-wave voltage applied by the Pockel cell is between two laser pulses of the mkHz laser pulse, and the cutoff time of the half-wave voltage is t0+Δt, where Δt≤1ms, ensuring that only one laser pulse passes through the Pockel cell during the application of the half-wave voltage. The half-wave voltage repetition frequency of the Pockel cell is nHz. Applying the half-wave voltage to the Pockel cell ensures that one laser pulse is transmitted through the second polarization beam splitter.
[0051] When the Pockel cell is at 0 voltage, a mkHz laser pulse passes through the Pockel cell, which is then in a half-wave plate state. The polarization changes from horizontal to vertical. The vertically polarized laser pulse is reflected as a self-reference beam when it passes through the second polarization beam splitter. The self-reference beam enters the reference beam circuit, and a reference beam switch is added between the second polarization beam splitter and the reference beam circuit. When a half-wave voltage is applied to the Pockel cell, the mkHz laser pulse passes through the Pockel cell, which is then in a full-wave plate state. The polarization remains horizontal. The horizontally polarized laser pulse is transmitted when it passes through the second polarization beam splitter, ensuring that at least one laser pulse is transmitted through the second polarization beam splitter. The half-wave voltage repetition frequency of the Pockel cell is nHz, enabling the selection of a single nHz repetition frequency laser from the mkHz input laser.
[0052] When the first path is connected and the reference light switch is powered on, the reference light switch opens, and the laser pulse passes through the reference light switch, enters the reference light circuit, and returns to the selection system. At this time, all mkHz laser pulses can enter the second amplifier. The self-reference light is used as a reference for all subsequent optical paths, including the second amplifier, compressor, and target area. When the second path is connected and the reference light switch is powered off, the reference light switch closes, and the laser pulse cannot enter the reference light circuit and return to the selection system. At this time, only the selected nHz laser pulse enters the second amplifier, and the entire laser device works normally and outputs nHz laser pulses.
[0053] like Figure 4 As shown, in a first implementation of the reference optical circuit, the reference optical circuit includes first and second reflectors and first and second quarter-glass slides; vertically polarized self-reference light, reflected by a second polarizing beam splitter, is reflected from the second polarizing beam splitter to the first reflector; a reference optical switch and the first quarter-glass slide are added between the second polarizing beam splitter and the first reflector; the vertically polarized self-reference light becomes circularly polarized light after passing through the first quarter-glass slide and is incident on the first reflector at 0°; the first reflector reflects the circularly polarized self-reference light back along its original path through the first quarter-glass slide and the reference optical switch. At this point, the self-reference light becomes horizontally polarized and enters the second polarizing beam splitter, then passes through it and is incident on the second reflecting mirror. A second quarter-glass slide is placed between the second polarizing beam splitter and the second reflecting mirror. The horizontally polarized self-reference light becomes circularly polarized after passing through the second quarter-glass slide and is incident on the second reflecting mirror at 0°. The second reflecting mirror reflects the circularly polarized self-reference light back through the second quarter-glass slide, at which point the self-reference light becomes vertically polarized and enters the second polarizing beam splitter, then is reflected into the second amplifier. The self-reference light reflected by the second polarizing beam splitter coincides with the main laser.
[0054] like Figure 5As shown, in a second implementation of the reference optical circuit, the reference optical circuit includes third to sixth reflecting mirrors and first and second half-wave plates. Vertically polarized self-reference light, reflected by the second polarizing beam splitter, is reflected at 45° to the third reflecting mirror. A reference light switch is added between the second and third reflecting mirrors. The light then propagates to the sixth reflecting mirror. A first half-wave plate is added between the third and fourth reflecting mirrors. The vertically polarized self-reference light becomes horizontally polarized after passing through the first half-wave plate. The horizontally polarized self-reference light is incident at 45° to the fourth reflecting mirror and reflected... The horizontally polarized self-reference light is transmitted through the first polarizing beam splitter and then incident at 45° onto the fifth reflecting mirror. The horizontally polarized self-reference light reflected by the fifth reflecting mirror is then incident at 45° onto the sixth reflecting mirror. A second half-wave plate is placed between the fifth and sixth reflecting mirrors. The self-reference light becomes vertically polarized after passing through the second half-wave plate. The vertically polarized self-reference light is reflected by the sixth reflecting mirror and then incident vertically onto the second polarizing beam splitter, where it is reflected into the second amplifier. The self-reference light reflected by the second polarizing beam splitter coincides with the main laser.
[0055] In this configuration, the compressor output is greater than 300 mJ, the spot size is less than 20 mm, and the first amplifier output is greater than 2–5 mJ. In this case, the self-reference can be used in the target area. The self-reference light energy density in the target area is 0.3–1 mJ / cm². 2 To facilitate subsequent operations, the self-reference beam of this invention is used for target area debugging preparation.
[0056] When the self-reference light of this invention is used for debugging the second amplifier, it is applicable to cases where the output energy of the second amplifier is less than 5J. Considering that the size of the light plate of the 5J energy amplifier is less than 30mm, and the output of the first amplifier is greater than 2 to 5mJ, although the spot size is large, the light does not pass through the compressor at this time, and the energy is higher than that of the target area, which facilitates the debugging of the second amplifier.
[0057] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.
Claims
1. A laser and target calibration device with a self-reference beam, characterized in that, The laser and target-setting adjustment device with self-reference light includes: a seed source, a stretcher, a first amplifier, a first pump source, a selection system, a second amplifier, a second pump source, a compressor, a reference light circuit, a reference light switch, and a three-phase switch. The laser generated by the seed source enters the stretcher and is amplified by the first amplifier. The first pump source provides energy to the first amplifier, which has a repetition rate of mkHz. The first amplifier outputs a laser pulse with a repetition rate of mkHz. The mkHz laser pulse output by the first amplifier is selected by the selection system to obtain an nHz laser pulse, where m and n are integers greater than 1 and less than 10. The nHz laser pulse enters the second amplifier for amplification, and the second pump source provides energy to the second amplifier. The laser output by the second amplifier is compressed by the compressor, and the output laser is sent to the target area for target firing. The selection system selects n laser pulses from m×1000 laser pulses per second as the main laser and sends them to the second amplifier. The remaining m×1000-n laser pulses are output to the selection system. These m×1000-n laser pulses are called self-reference beams. After being output from the selection system, the self-reference beams enter the reference beam circuit. A reference beam switch is added between the output of the self-reference beams from the selection system and the reference beam circuit. The self-reference beams are then transmitted back to the selection system after passing through the subsequent second amplifier and compressor before entering the target area. The reference beam switch and the second pump source are connected to the same power supply through a three-phase switch. The second pump source or the reference beam switch can only operate when the power supply is turned on. The three-phase switch has three paths: the first path, the second path, and the third path. Only one path can be selected to be connected at a time. The first path is connected to the reference optical switch, the second path is connected to the second pump source, and the third path is connected to ground. When the first path of the three-phase switch is connected and the reference light is powered on, the second pump source is not powered on and cannot be started. The second amplifier has no power supply and no high-energy laser output. This ensures that when the self-reference light is used as the subsequent adjustment optical path, there is no high-energy laser in the subsequent optical path, thus ensuring the safety of the operator. When the second path of the three-phase switch is connected and the second pump source is powered on, the reference light switch is not powered on, the reference light switch is closed, the second amplifier is not interfered with by the reference light, and the laser works normally at this time. When the third path of the three-phase switch is connected, neither the self-reference light nor the second pump source can work. This state is used as the state when the laser is not running. The selection system includes a first polarizing beam splitter, a Pockel cell, and a second polarizing beam splitter. The first and second polarizing beam splitters allow horizontally polarized lasers to pass through and vertically polarized lasers to be reflected. The Pockel cell is an electro-optic device. Initially, the Pockel cell is a half-wave plate when it has zero voltage. After applying a half-wave voltage, the Pockel cell becomes a full-wave plate, which does not change the polarization state of the light. By controlling the voltage of the Pockel cell, the polarization state of the laser can be adjusted so that the laser is either reflected or transmitted when it passes through the second polarizing beam splitter. When the Pockel cell is at 0 voltage, a mkHz laser pulse passes through the Pockel cell, which is then in a half-wave plate state. The polarization changes from horizontal to vertical. The vertically polarized laser pulse is reflected as a self-reference beam when it passes through the second polarization beam splitter. The self-reference beam enters the reference beam circuit, and a reference beam switch is added between the second polarization beam splitter and the reference beam circuit. When a half-wave voltage is applied to the Pockel cell, the mkHz laser pulse passes through the Pockel cell, which is then in a full-wave plate state. The polarization remains horizontal. The horizontally polarized laser pulse is transmitted when it passes through the second polarization beam splitter, ensuring that at least one laser pulse is transmitted through the second polarization beam splitter. The half-wave voltage repetition frequency of the Pockel cell is nHz, enabling the selection of a single nHz repetition frequency laser from the mkHz input laser. When the first path is connected and the reference light switch is powered on, the reference light switch opens, and the laser pulse passes through the reference light switch, enters the reference light circuit, and returns to the selection system. At this time, all mkHz laser pulses can enter the second amplifier. The self-reference light is used as a reference for all subsequent optical paths, including the second amplifier, compressor, and target area. When the second path is connected and the reference light switch is powered off, the reference light switch closes, and the laser pulse cannot enter the reference light circuit and return to the selection system. At this time, only the selected nHz laser pulse enters the second amplifier, and the entire laser device works normally and outputs nHz laser pulses.
2. The laser and target adjustment device with self-reference light as described in claim 1, characterized in that, The start time t0 of the half-wave voltage applied to the Pockel cell is between two laser pulses of the mKHz laser pulse, and the cutoff time of the half-wave voltage is t0+Δt, where Δt≤1ms, ensuring that only one laser pulse passes through the Pockel cell during the application of the half-wave voltage.
3. The laser and target adjustment device with self-reference light as described in claim 1, characterized in that, The reference optical circuit includes first and second reflectors and first and second quarter-glass slides. Vertically polarized self-reference light, reflected by the second polarizing beam splitter, is reflected back to the first reflector. A reference light switch and the first quarter-glass slide are placed between the second polarizing beam splitter and the first reflector. The vertically polarized self-reference light becomes circularly polarized after passing through the first quarter-glass slide and is incident on the first reflector at 0°. The first reflector reflects the circularly polarized self-reference light back through the first quarter-glass slide and the reference light switch, at which point the self-reference light becomes horizontally polarized and enters the second polarizing beam splitter, is transmitted through the second polarizing beam splitter, and is incident on the second reflector. A second quarter-glass slide is placed between the second polarizing beam splitter and the second reflector. The horizontally polarized self-reference light becomes circularly polarized after passing through the second quarter-glass slide and is incident on the second reflector at 0°. The second reflector reflects the circularly polarized self-reference light back through the second quarter-glass slide, at which point the self-reference light becomes vertically polarized and enters the second polarizing beam splitter, is reflected, and enters the second amplifier. The self-reference light reflected by the second polarizing beam splitter coincides with the main laser.
4. The laser and target adjustment device with self-reference light as described in claim 1, characterized in that, The reference optical circuit includes third to sixth reflecting mirrors and first and second half-wave plates; the vertically polarized self-reference light reflected by the second polarizing beam splitter is reflected at 45° to the third reflecting mirror, and a reference light switch is added between the second polarizing beam splitter and the third reflecting mirror. The light is then transmitted to the sixth mirror; a first half-wave plate is placed between the third and fourth mirrors; the vertically polarized self-reference light becomes horizontally polarized after passing through the first half-wave plate; the horizontally polarized self-reference light is incident on the fourth mirror at 45° and reflected to the first polarizing beam splitter; the horizontally polarized self-reference light is transmitted through the first polarizing beam splitter and then incident on the fifth mirror at 45°; the horizontally polarized self-reference light reflected by the fifth mirror is incident on the sixth mirror at 45°; a second half-wave plate is placed between the fifth and sixth mirrors; the self-reference light becomes vertically polarized after passing through the second half-wave plate. The vertically polarized self-reference light is reflected by the sixth mirror and then incident vertically on the second polarizing beam splitter, where it is reflected into the second amplifier; the self-reference light reflected by the second polarizing beam splitter coincides with the main laser.
5. The laser and target adjustment device with self-reference light as described in claim 1, characterized in that, The compressor outputs more than 300 mJ, the spot size is less than 20 mm, and the first amplifier outputs more than 2 to 5 mJ.
6. A debugging method for a laser and target debugging device with self-reference light as described in claim 1, characterized in that, The debugging method includes the following steps: 1) After the laser generated by the seed source enters the stretcher, it is amplified by the first amplifier. The first pump source provides energy to the first amplifier. The repetition rate of the first pump source is mKHz. The first amplifier outputs a laser pulse with a repetition rate of mKHz. The first amplifier outputs mkHz laser pulses to the menu system, where m is an integer greater than 1 and less than 10; 2) The selection system selects n laser pulses from m×1000 laser pulses per second as the main laser and sends them to the second amplifier. The remaining m×1000-n laser pulses are output to the selection system. These m×1000-n laser pulses are called the self-reference light, where n is an integer greater than 1 and less than 10. In the selection system, when the Pockel cell is at 0 voltage, a mkHz laser pulse passing through the Pockel cell is in a half-wave plate state, and its polarization changes from horizontal to vertical. The vertically polarized laser pulse is reflected as a self-reference beam when it passes through the second polarization beam splitter, and this self-reference beam enters the reference light circuit. A reference light switch is added between the second polarization beam splitter and the reference light circuit. When a half-wave voltage is applied to the Pockel cell, the mkHz laser pulse passing through the Pockel cell is in a full-wave plate state, and its polarization remains horizontal. The horizontally polarized laser pulse is transmitted when it passes through the second polarization beam splitter, ensuring that at least one laser pulse is transmitted through the second polarization beam splitter. The half-wave voltage repetition frequency of the Pockel cell is nHz, enabling the input laser to be selected from mkHz as a single nHz repetition frequency laser. 3) Connect the reference light switch and the second pump source to the same power supply via a three-phase switch. The second pump source or the reference light switch can only work when the power supply is turned on. After the reference light is transmitted in the reference light circuit, it is then transmitted back to the selector system to enter the laser light path. The three-phase switch has three paths: the first path, the second path, and the third path. Only one path can be selected at a time. The first path is connected to the reference light switch, the second path is connected to the second pump source, and the third path is connected to ground. a) When the first path of the three-phase switch is connected and the reference light is switched on to power, the second pump source is not connected to power and cannot be started. The second amplifier has no power supply and no high-energy laser output. This ensures that when the self-reference light is used as the subsequent adjustment optical path, there is no high-energy laser in the subsequent optical path, thus ensuring the safety of the operator. b) When the second path of the three-phase switch is connected and the second pump source is powered on, the reference light switch is not powered on, the reference light switch is closed, the second amplifier is not interfered with by the reference light, and the laser works normally at this time. c) When the third path of the three-phase switch is connected, neither the reference light switch nor the second pump source can work. This is used as the state when the laser is not running. 4) When the first path is connected and the reference light switch is powered on, the reference light switch is open. The laser pulse passes through the reference light switch and the reference light circuit before returning to the selection system. At this time, all mkHz laser pulses can enter the second amplifier. The self-reference light is used as a reference for all subsequent optical paths, including the second amplifier, compressor, and target area. When the second path is connected and the reference light switch is powered off, the reference light switch is closed. The laser pulse cannot pass through the reference light switch and return to the selection system after entering the reference light circuit. At this time, only the selected nHz laser pulse enters the second amplifier, and the entire laser device works normally and outputs nHz laser pulses. 5) The nHz laser pulse enters the second amplifier for amplification. The second pump source provides energy to the second amplifier. The laser output from the second amplifier enters the compressor for compression. The output laser is sent to the target area to strike the target.
7. The debugging method as described in claim 6, characterized in that, In step 2), the starting time t0 of the half-wave voltage applied by the Pockel cell is between two laser pulses of the mKHz laser pulse, and the cutoff time of the half-wave voltage is t0+Δt, where Δt≤1ms, ensuring that only one laser pulse passes through the Pockel cell during the application of the half-wave voltage.