A terahertz wave generation system based on laser coherent synthesis

Abstract

The present invention provides a terahertz wave generation system based on laser coherent synthesis, including: a laser coherent synthesis subsystem, a focal field detection subsystem, a terahertz wave generation subsystem and a numerical control terminal subsystem; by setting the laser coherent synthesis subsystem to amplify and shape the beam of multi-channel lasers, a more powerful, stable and accurate laser beam is obtained to generate a stronger terahertz wave source. Based on the air method to generate a terahertz wave source, the spatial position of the terahertz wave can be selected according to needs, and the pointing, polarization, divergence angle and intensity parameters of the terahertz wave can be regulated. The system is based on a modular design, has a simple structure, is easy to maintain, and can generate different types of special beams and terahertz waves of different intensities and distributions according to actual needs.

Description

Technical Field

[0001] The present invention relates to the fields of terahertz wave technology and laser coherent synthesis technology, and in particular to a terahertz wave generation system based on laser coherent synthesis. Background Art

[0002] The technology of focusing ultrashort laser pulses in the surrounding air to directly generate terahertz waves is also called the "air method". It has a very good application prospect and has attracted widespread attention in recent years because it can generate terahertz waves at a distance (several kilometers away), overcome the strong absorption of terahertz waves in the air, and has the advantages of high peak power and wide spectrum of the generated terahertz waves. However, since the energy utilization efficiency of generating terahertz waves in this way is relatively low, the mechanism of terahertz wave generation has not been fully explained and cannot meet people's needs, people are eager to find a method to improve the energy conversion efficiency of terahertz waves. To this end, technicians in this field have made many attempts to enhance the generation efficiency of terahertz waves by changing the wavelength of the laser, the working medium, and using two-color fields, external bias electric fields, magnetic fields and other methods. In addition, the method of using a spatial light modulator or a phase plate to change the focal field to achieve the control of terahertz wave generation, because the beam modulation device cannot withstand high power, the system has defects that cannot be compensated. Summary of the invention

[0003] In view of this, an embodiment of the present invention provides a terahertz wave generation system based on laser coherent synthesis to eliminate or improve one or more defects existing in the prior art and solve the problem of terahertz wave intensity generated by the beam modulator being unable to withstand high power limitations in the prior art.

[0004] The technical solution of the present invention is as follows:

[0005] Provided is a terahertz wave generation system based on laser coherent synthesis, comprising: a laser coherent synthesis subsystem, a focal field detection subsystem, a terahertz wave generation subsystem and a numerical control terminal subsystem.

[0006] The laser coherent synthesis subsystem comprises a laser, a first beam splitter, a first set number of phase controllers, an optical chopper, a first set number of laser amplifiers and a first set number of laser collimators connected in sequence, each laser collimator is provided with a beam position and orientation controller for adjustment; the laser generates a laser beam, the laser beam is divided into a first set number of sub-beams by the first beam splitter, each sub-beam is respectively introduced into a corresponding phase controller for phase adjustment, modulated to a fixed frequency by an optical chopper, and then introduced into a corresponding laser amplifier for power amplification, and then collimated and emitted by a corresponding laser collimator;

[0007] The focal field detection subsystem includes a second beam splitter, a first focusing lens, a first frequency doubling crystal and a beam analyzer; the sub-beams derived from each laser collimator are divided into two paths by the second beam splitter, a weaker first path of light is obtained by reflection, and a stronger second path of light is obtained by transmission; the first path of photon beams passes through the first focusing lens and the first frequency doubling crystal and is then introduced into the beam analyzer for detecting the focal plane intensity distribution information, laser beam quality factor, phase information and position pointing information of each sub-beam in the first path of light;

[0008] The terahertz wave generating subsystem includes a second focusing lens and a second frequency doubling crystal which are arranged in sequence, the second focusing lens has the same specifications as the first focusing lens, the second frequency doubling crystal has the same specifications as the first frequency doubling crystal, and the distance between the first focusing lens and the first frequency doubling crystal is equal to the distance between the second focusing lens and the second frequency doubling crystal; the sub-beam of the second light passes through the second focusing lens and the second frequency doubling crystal to ionize the air and generate terahertz waves;

[0009] The CNC terminal subsystem includes at least a controller, which is connected to each phase controller, each laser amplifier, each beam position and orientation controller, and the beam analyzer, and is used to regulate the phase, power, position and direction of each sub-beam according to the detection result of the beam analyzer, so that the light intensity of each sub-beam in the second light path is equal and the polarization is consistent.

[0010] In some embodiments, the system further comprises a terahertz wave detection subsystem, comprising: a first off-axis parabolic reflector, a silicon chip, a second off-axis parabolic reflector, a filter, and a terahertz intensity and distribution detector;

[0011] The first off-axis parabolic reflector is used to reflect and converge the terahertz wave into a beam of parallel light;

[0012] The silicon chip is used to perform a first filtering on the parallel light;

[0013] The second off-axis parabolic reflector is used to converge the parallel light after filtering by the silicon chip, filter it twice through the filter plate, and transmit it to the terahertz intensity and distribution detector for detection.

[0014] In some embodiments, the controller is also connected to the terahertz intensity and distribution detector to adjust the phase, power, position and direction of each sub-beam according to the terahertz wave intensity and distribution information detected by the terahertz intensity and distribution detector.

[0015] In some embodiments, the laser is a femtosecond pulse laser seed source.

[0016] In some embodiments, the femtosecond pulse laser seed source generates seed light with a pulse width of 50 fs, a pulse repetition rate of 1 KHz, and a line width of 1 GHz.

[0017] In some embodiments, the terahertz intensity and distribution detector uses a pyroelectric detector or a Golay detector to detect the intensity information of the terahertz wave, and uses a terahertz camera or a terahertz wave array sensor to detect the distribution information of the terahertz wave.

[0018] In some embodiments, the frequency of the optical chopper matches the sampling frequency of the detector, and the frequency of the optical chopper is 15-20 Hz.

[0019] In some embodiments, the laser generates a laser beam with a wavelength of 1200-1600 nm, and accordingly, the first beam splitter and the second beam splitter are made of quartz.

[0020] In some embodiments, the CNC terminal subsystem further includes a wireless communication module for remote access and control.

[0021] In some embodiments, the numerical control terminal subsystem further includes a display module for displaying the detection results of the beam analyzer and the terahertz intensity and distribution detector.

[0022] The beneficial effects of the present invention are at least:

[0023] In the terahertz wave generation system based on laser coherent synthesis of the present invention, a laser coherent synthesis subsystem is set to amplify and shape the multi-channel lasers to obtain a more powerful, stable and accurate laser beam to generate a stronger terahertz wave source. Based on the air method to generate a terahertz wave source, the spatial position of the terahertz wave can be selected according to needs, and the pointing, polarization, divergence angle and intensity parameters of the terahertz wave can be regulated. The system is based on modular design, has a simple structure, is easy to maintain, and can generate different types of special beams and terahertz waves of different intensities and distributions according to actual needs.

[0024] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically pointed out in the written description, claims, and drawings.

[0025] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute a limitation of the present invention. In the drawings:

[0027] Figure 1 This is a schematic structural diagram of a terahertz wave generation system based on laser coherent synthesis according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic structural diagram of a terahertz wave generation system based on laser coherent synthesis according to another embodiment of the present invention.

[0029] Description of reference numerals:

[0030] 10: Laser coherent synthesis subsystem; 11: Laser; 12: First beam splitter;

[0031] 13: Phase controller; 14: Optical chopper; 15: Laser amplifier;

[0032] 16: Laser collimator; 17: Beam position and orientation controller; 20: Focal field detection subsystem;

[0033] 21: second beam splitter; 22: first focusing lens; 23: first frequency doubling crystal;

[0034] 24: beam analyzer; 30: terahertz wave generation subsystem; 31: second focusing lens;

[0035] 32: second frequency doubling crystal; 40: numerical control terminal subsystem; 41: controller;

[0036] 50: terahertz wave detection subsystem; 51: first off-axis parabolic reflector; 52: silicon wafer;

[0037] 53: second off-axis parabolic reflector; 54: filter; 55: terahertz intensity and distribution detector. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0039] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0040] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0041] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection with an intermediate.

[0042] Terahertz waves are waves with a frequency of 0.1 to 10 terahertz (1 terahertz = 10 12 The electromagnetic waves of terahertz (Hz) are located between microwaves and infrared in the electromagnetic spectrum and belong to far-infrared electromagnetic waves. Femtosecond pulse laser beams, that is, pulse widths between a few femtoseconds and hundreds of femtoseconds, have ultra-short time characteristics and can produce higher peak power. Femtosecond laser pulses with high pulse energy (pulse energy greater than a few hundred microjoules) interact with gas atoms to excite free ions and electrons and generate plasma. The plasma quickly decays and generates terahertz waves at the same time. This method is called the "air method."

[0043] In the "air method", there is a certain correlation and correspondence between the focal field spot of the focused femtosecond pulse laser beam and the focal field characteristics of the terahertz wave. Under specific focal field conditions, the intensity, distribution characteristics, divergence angle or polarization characteristics of the generated terahertz wave tend to be fixed. Therefore, by reproducing a specific focal field, terahertz waves of specific properties can be generated, that is, the terahertz wave can be controlled by controlling the focal field.

[0044] By focusing a femtosecond pulse laser beam at a distance, terahertz waves can be generated at a distance (several kilometers away), which can overcome the strong absorption of terahertz waves in the air. The terahertz waves generated by this method have the advantages of high peak power and wide spectrum. However, due to the limitation of the beam modulation device on the intensity of the laser source beam, the intensity of the generated terahertz waves also has an upper limit. In order to break through the hardware limitation on the intensity of the laser source beam, the present invention introduces laser coherent synthesis technology in the process of generating terahertz waves to generate a higher intensity laser source and stimulate stronger terahertz waves. At the same time, by detecting the focus field and feedback-regulating the phase, polarization angle, and emission direction of each sub-beam in the laser coherent synthesis subsystem, beam shaping is performed to achieve the acquisition of high-power terahertz waves.

[0045] Specifically, the present invention provides a terahertz wave generation system based on laser coherent synthesis, such as Figure 1 As shown, it includes: a laser coherent synthesis subsystem 10, a focal field detection subsystem 20, a terahertz wave generation subsystem 30 and a numerical control terminal subsystem 40.

[0046] The laser coherent synthesis subsystem 10 includes a laser 11, a first beam splitter 12, a first set number of phase controllers 13 (i.e., phase modulators), an optical chopper 14, a first set number of laser amplifiers 15, and a first set number of laser collimators 16 connected in sequence, each laser collimator 16 is provided with a beam position and orientation controller 17 for adjustment; the laser 11 generates a laser beam, which is divided into a first set number of sub-beams by the first beam splitter 12, and each sub-beam is introduced into a corresponding phase controller 13 for phase adjustment, modulated to a fixed frequency by the optical chopper 14, and then introduced into a corresponding laser amplifier 15 for power amplification, and then collimated and emitted by the corresponding laser collimator 16. In some embodiments, the laser 11 is a femtosecond pulse laser seed source. The femtosecond pulse laser seed source generates seed light with a pulse width of 50fs, a pulse repetition rate of 1KHz, and a line width of 1GHz.

[0047] In this embodiment, the laser coherent synthesis subsystem 10 is used to generate a high-power laser beam as a laser source for exciting terahertz waves. Compared with the traditional one-way laser beam, this embodiment amplifies the power of multiple lasers and performs coherent processing respectively, and finally converges to excite high-intensity terahertz waves at a distance. Specifically, the femtosecond pulse laser seed source emits a beam of seed light, which is divided into a first number of sub-beams by the first beam splitter 12, and transmitted along their respective paths. A phase controller 13 is set on each path to adjust the phase of each sub-beam. The optical chopper 14 is an electronically controlled fan-type blade. At a certain speed, the continuous light is modulated (chopped) into a periodic intermittent light of a certain frequency, and the cut-off time is equal to the light transmission time, changing the constant light source into a variable "square wave" light source. In this embodiment, the frequency of the optical chopper 14 is 15 to 20 Hz. The optical chopper 14 is used to adjust the frequency of the laser beam to make it consistent with the detection frequency of the beam analyzer 24 in the subsequent focal field detection subsystem 20. Next, each sub-beam after chopped is respectively amplified by the laser amplifier 15 for power and optical parameter amplification, and then passes through each laser collimator 16 to obtain a collimated and horizontally polarized Gaussian beam array, and the laser beam array is arrayed and beam pointing is controlled by the beam position and orientation controller 17, and finally the laser coherent synthesis is completed to achieve beam shaping and focal field control. Correspondingly, the control of beam shaping and focal field is mainly based on the detection result of the focal field detection subsystem 20.

[0048] The focal field detection subsystem 20 includes a second beam splitter 21, a first focusing lens 22, a first frequency doubling crystal 23 and a beam analyzer 24; the sub-beams derived from each laser collimator 16 are divided into two paths by the second beam splitter 21, a weaker first path of light is obtained by reflection, and a stronger second path of light is obtained by transmission; the first path of photon beams passes through the first focusing lens 22 and the first frequency doubling crystal 23 and is then introduced into the beam analyzer 24 for detecting the focal plane intensity distribution information, laser beam quality factor, phase information and position pointing information of each sub-beam in the first path of light.

[0049] Specifically, in this embodiment, the focal field detector subsystem is used to detect the focal field information formed by each sub-beam that forms the terahertz wave. The second beam splitter 21 is used to separate the strong and weak paths, the weak one is used for detection, and the strong one is used to generate terahertz waves. It should be emphasized that the second focusing lens 31 is set to have the same specifications as the first focusing lens 22, the second frequency doubling crystal 32 is set to have the same specifications as the first frequency doubling crystal 23, and the spacing between the first focusing lens 22 and the first frequency doubling crystal 23 is equal to the spacing between the second focusing lens 31 and the second frequency doubling crystal 32, so that the focal field information of the first light used for detection and the second light used to generate terahertz waves are consistent.

[0050] The terahertz wave generating subsystem 30 includes a second focusing lens 31 and a second frequency doubling crystal 32 which are arranged in sequence. The second focusing lens 31 has the same specifications as the first focusing lens 22, the second frequency doubling crystal 32 has the same specifications as the first frequency doubling crystal 23, and the spacing between the first focusing lens 22 and the first frequency doubling crystal 23 is equal to the spacing between the second focusing lens 31 and the second frequency doubling crystal 32. The sub-beam of the second light path passes through the second focusing lens 31 and the second frequency doubling crystal 32 to ionize the air and generate terahertz waves.

[0051] The numerical control terminal subsystem 40 at least includes a controller 41, which is connected to each phase controller 13, each laser amplifier 15, each beam position and orientation controller 17, and a beam analyzer 24, and is used to adjust the phase, power, position and direction of each sub-beam according to the detection result of the beam analyzer 24, so that the light intensity of each sub-beam in the second light path is equal, the polarization is consistent, and the phase difference is constant. The controller 41 can use a single-chip microcomputer, a computer processor or other electronic storage medium that can store and run programs. The beam position and orientation controller 17 can use a six-legged parallel pointing mechanism, which includes a first platform, a second platform, and six telescopic parts. The two ends of each telescopic part are connected to the first platform and the second platform respectively through a ball joint; the laser collimator 16 is fixed on the first platform. The telescopic part is a voice coil motor or an electric push rod.

[0052] Based on the "air method", in the process of using a femtosecond pulse laser beam to focus and excite terahertz waves at a distance, there is a corresponding relationship between the focal field of the femtosecond pulse laser beam and the terahertz wave intensity, distribution characteristics, divergence angle, polarization, energy conversion rate (terahertz wave capacity / laser energy) and other properties. Therefore, by detecting the focal field information of the laser beam, it can be used to guide the adjustment of the laser beam that excites the terahertz wave, and by adjusting the phase difference, light intensity, polarization angle and position orientation of each sub-beam to change the focal field, thereby further changing the properties of the terahertz wave.

[0053] Through the existing data, a database of the correspondence between the focal field information and the intensity and distribution information of the terahertz wave is established. Each data item in the database includes at least the attribute information such as the intensity, distribution characteristics, divergence angle, polarization and energy conversion rate of the terahertz wave, as well as the focal field information of the femtosecond pulse laser beam that generates the terahertz wave after being focused and frequency-doubled by the terahertz wave generator. The database of the correspondence between the focal field information and the intensity and distribution information of the terahertz wave can be used to guide the adjustment of the focal field. According to the required terahertz wave properties, the database is searched to obtain the corresponding focal field information, and the phase difference, light intensity, polarization angle and position orientation of each sub-beam are adjusted.

[0054] In some embodiments, Figure 2 As shown, the system further includes a terahertz wave detection subsystem 50 , including: a first off-axis parabolic reflector 51 , a silicon chip 52 , a second off-axis parabolic reflector 53 , a filter 54 , and a terahertz intensity and distribution detector 55 .

[0055] The first off-axis parabolic reflector 51 is used to reflect and converge the terahertz wave into a beam of parallel light. The silicon wafer 52 is used to filter the parallel light for the first time. The second off-axis parabolic reflector 53 is used to converge the parallel light filtered by the silicon wafer 52, filter it twice through the filter 54, and transmit it to the terahertz intensity and distribution detector 55 for detection. In this embodiment, a part of the terahertz wave is collected by the terahertz wave detection subsystem 50 for property detection. After the first off-axis parabola converges to obtain a beam of parallel light, the laser and the terahertz wave are mixed and the intensity is high, which cannot be used directly for detection. Therefore, it is first filtered by the silicon wafer 52. The silicon wafer 52 is a single crystal silicon wafer 52, which can withstand a high-intensity beam. The size and thickness can be set according to the actual application scenario. After the silicon wafer 52 is filtered, it is further converged by the second off-axis parabolic reflector 53, filtered again by the filter 54, and then introduced into the terahertz intensity and distribution detector 55 for detection. The filter 54 may be a terahertz filter 54 , which is mainly divided into low-pass and band-pass filters. Different filters 54 are made of different materials. This embodiment uses a low-pass filter 54 , which may be made of PE (polyethylene) or PC (polycarbonate) material.

[0056] In this embodiment, a terahertz wave detection subsystem 50 is added to detect and verify the properties of the formed terahertz wave, including terahertz wave intensity, distribution characteristics, divergence angle, polarization, and energy conversion rate. On this basis, the controller 41 is also connected to a terahertz intensity and distribution detector 55 to adjust the phase, power, position, and direction of each sub-beam according to the terahertz wave intensity and distribution information detected by the terahertz intensity and distribution detector 55. This is an adjustment made in combination with the properties of the terahertz wave actually formed, to ensure the effect in the actual operation process.

[0057] In some embodiments, the terahertz intensity and distribution detector 55 uses a pyroelectric detector or a Golay detector to detect the intensity information of the terahertz wave, and uses a terahertz camera or a terahertz wave array sensor to detect the distribution information of the terahertz wave.

[0058] In some embodiments, the laser 11 generates a laser beam with a wavelength of 1200-1600 nm, and accordingly, the first beam splitter 12 and the second beam splitter 21 are made of quartz.

[0059] In some embodiments, the CNC terminal subsystem 40 further includes a wireless communication module for remote access and control.

[0060] In some embodiments, the numerical control terminal subsystem 40 further includes a display module for displaying the detection results of the beam analyzer 24 and the terahertz intensity and distribution detector 55 .

[0061] The present invention is described below in conjunction with a specific embodiment:

[0062] This embodiment provides a system for generating terahertz waves using laser coherent synthesis technology. The system monitors beam pointing, phase information, delay information, laser power, laser wavelength, focal field information, terahertz wave intensity and its distribution in real time, and realizes real-time focal field control and terahertz wave intensity and distribution adjustment.

[0063] like Figure 2 As shown, the system for generating terahertz waves using laser coherent synthesis technology described in this embodiment includes a laser coherent synthesis subsystem 10, a focal field detection subsystem 20, a terahertz wave generation subsystem 30, a terahertz wave detection subsystem 50 and a numerical control terminal subsystem 40;

[0064] The laser coherent synthesis subsystem 10 includes a laser 11, a first beam splitter 12, a first set number of phase controllers 13, an optical chopper 14, a first set number of laser amplifiers 15 and a first set number of laser collimators 16, which are sequentially arranged on the optical path. The laser collimator 16 is adjusted by a beam position and orientation controller 17. A femtosecond pulse laser seed source emits a beam of seed light, and the first beam splitter 12 is used to divide the beam into several beams. A phase controller 13 is used to perform phase control on each optical path. Then the beam is chopped by the optical chopper 14, and the laser power and optical parameters are amplified by the laser amplifier 15. A collimated and horizontally polarized Gaussian beam array is obtained by the laser collimator 16, and the laser beam array is arrayed and the beam pointing is controlled by the beam position and orientation controller 17, and finally the laser coherent synthesis is completed to achieve beam shaping and focal field control.

[0065] The focal field detection subsystem 20 separates a weak light beam from the main optical path through the second beam splitter 21, passes through the first lens and the first frequency doubling crystal 23 in sequence, and obtains the focal field information through the beam analyzer 24. In order to ensure that the detected focal field information is consistent with the focal field information of the generated terahertz wave, the system needs to use the same lens and frequency doubling crystal in the focal field detection subsystem 20 and the terahertz wave generation subsystem 30, and keep the spacing between the lens and the frequency doubling crystal the same.

[0066] The terahertz wave generating subsystem 30 includes a second lens and a second frequency doubling crystal 32 sequentially arranged on the optical path. After the monochromatic femtosecond pulse laser beam is focused and frequency doubling by the second lens and the second frequency doubling crystal 32, the air plasma is excited to induce terahertz wave radiation.

[0067] The terahertz wave detection subsystem 50 includes a first off-axis parabolic reflector 51, a silicon chip 52, a second off-axis parabolic reflector 53, a filter 54 and a terahertz wave intensity and distribution detector. The first off-axis parabolic reflector 51 converges the terahertz wave to form a parallel light beam, which is filtered by the silicon chip 52 and projected onto the second off-axis parabolic reflector 53. Then, it is filtered by the filter 54 and incident on the terahertz wave intensity and distribution detector to detect the intensity and distribution state.

[0068] The numerical control terminal subsystem 40 controls and processes information such as beam pointing, phase information, delay information, laser power, laser wavelength, focal field information, terahertz wave intensity and its distribution in real time through the data processing terminal, thereby realizing information interconnection among the laser coherent synthesis subsystem 10, the focal field detection subsystem 20 and the terahertz wave detection subsystem 50.

[0069] In this embodiment, the terahertz wave detection subsystem 50 uses a Golay detector, and the frequency of the optical chopper 14 is 15-20 Hz.

[0070] In this embodiment, the phase difference of each sub-beam is constant, and the polarization direction is horizontal.

[0071] In this embodiment, the laser wavelength is 1550 nm, and the materials of the first beam splitter 12, the first focusing lens 22, the second beam splitter 21 and the second focusing lens 31 are all quartz-made components selected according to the laser wavelength and pulse width in the actual system.

[0072] In this embodiment, the terahertz wave intensity and distribution detector is divided into a terahertz wave intensity detector and a terahertz wave distribution detector. The terahertz wave intensity detector is a pyroelectric detector or a Golay detector, and the terahertz wave distribution detector is a terahertz camera or a terahertz wave array sensor.

[0073] Compared with the traditional method, the present invention provides a method for achieving higher terahertz waves by realizing focal field control through laser coherent synthesis technology. The technological innovations that can be achieved are as follows:

[0074] (1) This embodiment realizes the generation of terahertz waves through laser coherent synthesis technology. This embodiment realizes beam shaping of a strong laser beam, thereby obtaining a stronger terahertz wave source.

[0075] (2) This embodiment can give full play to the advantages of the "air method" terahertz wave source, and can select the spatial position of generating terahertz waves as needed, and can control the direction, polarization, divergence angle, intensity and other parameters of the terahertz waves.

[0076] (3) The system for generating terahertz waves using laser coherent synthesis technology provided in this embodiment has a modular design, simple structure, and is easy to maintain. It can generate different types of special light beams and terahertz waves of different intensities and distributions according to actual needs, filling the gap in the current field of high-intensity terahertz wave generation technology and has strong scientific research and practical application value.

[0077] Those skilled in the art can understand that the modules in the device in this embodiment can be distributed in the device in the embodiment according to the description of the embodiment, or can be changed accordingly and located in one or more devices different from the embodiment. The modules in the above embodiments can be combined into one module, or can be further divided into multiple sub-modules.

[0078] In summary, in the terahertz wave generation system based on laser coherent synthesis of the present invention, a laser coherent synthesis subsystem is set to amplify and shape the multi-channel lasers to obtain a more powerful, stable and accurate laser beam to generate a stronger terahertz wave source. Based on the air method to generate a terahertz wave source, the spatial position of the terahertz wave can be selected according to needs, and the pointing, polarization, divergence angle and intensity parameters of the terahertz wave can be regulated. The system is based on modular design, has a simple structure, is easy to maintain, and can generate different types of special beams and terahertz waves of different intensities and distributions according to actual needs.

[0079] It should also be noted that the exemplary embodiments mentioned in the present invention describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiments, or in a different order from the embodiments, or several steps can be performed simultaneously.

[0080] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A terahertz wave generation system based on laser coherent synthesis, characterized in that: include: A laser coherent synthesis subsystem, comprising a laser, a first beam splitter, a first set number of phase controllers, an optical chopper, a first set number of laser amplifiers and a first set number of laser collimators connected in sequence, each laser collimator being provided with a beam position and orientation controller for adjustment; the laser generates a laser beam, the laser beam is divided into a first set number of sub-beams by the first beam splitter, each sub-beam is respectively introduced into a corresponding phase controller for phase adjustment, modulated to a fixed frequency by an optical chopper, and then introduced into a corresponding laser amplifier for power amplification, and then collimated and emitted by a corresponding laser collimator; A focal field detection subsystem includes a second beam splitter, a first focusing lens, a first frequency doubling crystal and a beam analyzer; the sub-beams derived from each laser collimator are divided into two paths by the second beam splitter, a weaker first path of light is obtained by reflection, and a stronger second path of light is obtained by transmission; the first path of photon beams passes through the first focusing lens and the first frequency doubling crystal and is then introduced into the beam analyzer for detecting focal plane intensity distribution information, laser beam quality factor, phase information and position pointing information of each sub-beam in the first path of light; A terahertz wave generating subsystem comprises a second focusing lens and a second frequency doubling crystal which are arranged in sequence, wherein the second focusing lens has the same specifications as the first focusing lens, the second frequency doubling crystal has the same specifications as the first frequency doubling crystal, and the spacing between the first focusing lens and the first frequency doubling crystal is equal to the spacing between the second focusing lens and the second frequency doubling crystal; a sub-beam of the second light path passes through the second focusing lens and the second frequency doubling crystal to ionize air and generate terahertz waves; The numerical control terminal subsystem at least includes a controller, which is connected to each phase controller, each laser amplifier, each beam position and orientation controller, and the beam analyzer, and is used to adjust the phase, power, position and direction of each sub-beam according to the detection result of the beam analyzer.

2. The terahertz wave generation system based on laser coherent synthesis according to claim 1, characterized in that: The system also includes a terahertz wave detection subsystem, including: a first off-axis parabolic reflector, a silicon chip, a second off-axis parabolic reflector, a filter, and a terahertz intensity and distribution detector; The first off-axis parabolic reflector is used to reflect and converge the terahertz wave into a beam of parallel light; The silicon chip is used to perform a first filtering on the parallel light; The second off-axis parabolic reflector is used to converge the parallel light after filtering by the silicon chip, filter it twice through the filter plate, and transmit it to the terahertz intensity and distribution detector for detection.

3. The terahertz wave generation system based on laser coherent synthesis according to claim 2, characterized in that: The controller is also connected to the terahertz intensity and distribution detector to adjust the phase, power, position and direction of each sub-beam according to the terahertz wave intensity and distribution information detected by the terahertz intensity and distribution detector.

4. The terahertz wave generation system based on laser coherent synthesis according to claim 1, characterized in that: The laser is a femtosecond pulse laser seed source.

5. The terahertz wave generation system based on laser coherent synthesis according to claim 4, characterized in that: The femtosecond pulse laser seed source generates seed light with a pulse width of 50 fs, a pulse repetition rate of 1 KHz, and a line width less than 10 GHz.

6. The terahertz wave generation system based on laser coherent synthesis according to claim 2, characterized in that: The terahertz intensity and distribution detector uses a pyroelectric detector or a Golay detector to detect the intensity information of the terahertz wave, and uses a terahertz camera or a terahertz wave array sensor to detect the distribution information of the terahertz wave.

7. The terahertz wave generation system based on laser coherent synthesis according to claim 1, characterized in that: The frequency of the optical chopper matches the sampling frequency of the detector, and the frequency of the optical chopper is 15-20 Hz.

8. The terahertz wave generation system based on laser coherent synthesis according to claim 1, characterized in that: The laser generates a laser beam with a wavelength of 1200-1600 nm, and correspondingly, the first beam splitter and the second beam splitter are made of quartz material.

9. The terahertz wave generation system based on laser coherent synthesis according to claim 1, characterized in that: The numerical control terminal subsystem also includes a wireless communication module for remote access and control.

10. The terahertz wave generation system based on laser coherent synthesis according to claim 6, characterized in that: The numerical control terminal subsystem also includes a display module for displaying the detection results of the beam analyzer and the terahertz intensity and distribution detector.

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