Adjusting device and method for generating strong terahertz radiation by irradiating micron-scale metal wire with laser

Abstract

The invention discloses an adjusting device and method for generating strong terahertz radiation through laser irradiation on a micron-scale metal wire, and belongs to the technical field of optics. One end of the metal wire is installed on an L-shaped multi-wire clamping structure, femtosecond laser is attenuated and focused on the surface of the metal wire through an energy attenuator, and the terahertz radiation is generated; a telescope imaging system is used for monitoring the position and deviation state of laser focused on a metal wire in real time, the spatial position and angle of the metal wire are accurately adjusted and optimized through a high-precision five-dimensional adjusting frame according to the calculated deviation amount of the metal wire, and rapid adjustment and accurate collimation of the metal wire with the micron dimension can be achieved. And necessary conditions are provided for generation of a strong terahertz source by subsequent strong laser irradiation metal wire targeting. Besides, an L-shaped multi-wire clamping structure designed by the device can clamp a plurality of metal wires with different diameters at the same time, rapid wire replacement and efficient and accurate laser targeting can be carried out in a vacuum state, and the device has the advantages of being easy to operate, high in precision, rapid and efficient.

Description

Technical Field

[0001] This invention relates to the field of terahertz radiation generated by the interaction of femtosecond high-intensity lasers with metal wire targets, and in particular to a high-precision and rapid adjustment device and method for generating strong terahertz radiation by laser irradiation of micrometer-scale metal wires. Background Technology

[0002] Terahertz radiation, due to its unique physical properties (peak electric field intensity reaching GV / m, photon energy as low as 4.1 meV@1THz, and sub-picosecond time resolution), has shown revolutionary application potential in fields such as biomedicine (e.g., DNA base-specific recognition), 6G communication (terahertz carrier transmission), and deep space exploration (interstellar molecular spectrum analysis), and has become a core area of ​​global technological competition. However, its large-scale application is limited by the bottleneck in the development of high-performance radiation sources. Recent studies have shown that metal wires in femtosecond lasers (10T) have shown potential in high-performance radiation sources. 18 Under W / cm² irradiation, efficient terahertz radiation (conversion efficiency >1%) and low-loss waveguide transmission (attenuation coefficient <0.1 dB / mm) can be achieved simultaneously. The generated terahertz surface waves have characteristics such as high field strength, wide spectral width, and tunability [Tokita, S., Sakabe, S., Nagashima, T. et al. Strong sub-terahertz surfacewaves generated on a metal wire by high-intensity laser pulses. Scientificreports 5, 8268 (2015); Wang, J., Zhang, Z., Zhou, S. et al. Radiationdynamics and manipulation of extreme terahertz surface wave on a metal wire. Laser&Photonics Reviews 19, 2400954 (2025).] have important applications in terahertz communication, biomedicine, and terahertz sensing.

[0003] The above research indicates that the generation of terahertz radiation sources depends on the interaction between a femtosecond laser and a micrometer-scale metal wire target. The spatial positioning accuracy (≤5μm) and rapid wire-changing efficiency of the metal wire directly affect experimental repeatability and data reliability. To achieve efficient energy conversion of terahertz radiation sources, the spatial position control of the metal wire needs to reach sub-micrometer precision. Traditional laser irradiation of micrometer-scale metal wires often employs three-dimensional adjustment frames that can only achieve linear displacement adjustment (X / Y / Z axes), limiting the accuracy of pitch angle adjustment. ) and yaw angle The control of the target material has significant shortcomings (error > ±0.5°), which easily leads to a decrease in the axial coupling efficiency between the laser beam and the metal wire, thereby affecting the stability and conversion efficiency of terahertz radiation. In addition, existing metal wire clamping structures are usually single-wire designs, and each time the target material is changed, the vacuum environment must be broken, and the re-vacuuming is time-consuming, which seriously restricts the efficiency and continuity of experiments. Frequent vacuum disruption not only increases the instability of the system, but also leads to longer experimental cycles and increased costs, limiting the promotion of this technology in multiple terahertz application scenarios.

[0004] Therefore, there is an urgent need to develop a comprehensive adjustment system with multi-wire rapid switching, high-precision spatial and angle adjustment, and real-time imaging feedback capabilities. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an adjustment device and method for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire. Through a high-precision five-dimensional adjustment frame and a telescope imaging real-time monitoring system, the offset of the metal wire is calculated using trigonometric functions and the law of cosines, achieving three-dimensional spatial positioning of the metal wire (error ≤ 2μm) and adjustment of pitch and yaw angles (accuracy 0.01°). This device supports rapid replacement of multiple metal wires of different diameters (100-500μm) in a vacuum environment, with a replacement time ≤ 5 minutes. Real-time imaging feedback ensures the stability of terahertz radiation generated by laser irradiation of the metal wire (RSD < 3%). This solution significantly improves experimental efficiency, realizes the replacement and adjustment of the metal wire in a vacuum environment, and has the advantages of convenience, high efficiency, high precision, and simple operation.

[0006] The technical solution of the present invention is as follows: A device for regulating strong terahertz radiation generated by laser irradiation of a micrometer-scale metal wire, characterized in that it includes: The vacuum chamber has a laser incident window, an observation window, and a terahertz emission window on its walls. The target assembly, disposed inside the vacuum cavity, includes a multi-wire clamping structure for simultaneously fixing multiple metal wires, and a high-precision five-dimensional adjustment frame for driving the multi-wire clamping structure to move. An optical focusing component is disposed inside the vacuum cavity. After the femtosecond laser beam is focused through the laser incident window, it points to the target component and is used to focus the femtosecond laser pulse onto the surface of the metal wire to form a laser focus. A telescope imaging real-time monitoring system is positioned opposite the observation window to perform two-dimensional shadow imaging of the metal filament and laser focus, so as to provide real-time collimation status feedback. The high-precision five-dimensional adjustment frame is configured to receive feedback signals from the telescope imaging real-time monitoring system and drive the multi-wire clamping structure to perform three-dimensional linear displacement and at least two-dimensional angular deflection based on the feedback signals, thereby realizing the collimation adjustment of the metal wires.

[0007] Furthermore, the high-precision five-dimensional adjustment frame enables angle deflection in at least two dimensions: pitch angle and yaw angle.

[0008] Furthermore, the telescope imaging real-time monitoring system includes a commercial telescope and a scientific-grade CCD camera, the signal output of which is connected to a computer; the telescope imaging real-time monitoring system is configured to quantitatively calculate the offset of the metal wire by analyzing the position and shape changes of the laser spot on the computer screen when the laser is focused on the surface of the metal wire and moves.

[0009] Furthermore, the quantitative calculation of the wire offset includes: Based on the horizontal variation of the light spot l 1 and vertical change l 2. According to the formula Calculate the elevation offset angle; Based on the light spot position offset distance l 3. Change in wire length l 4. The off-axis angle α of the optical focusing component is determined using a geometric model and the law of cosines, according to the formula... Calculate the left and right offset angles.

[0010] Furthermore, the multi-wire clamping structure is an L-shaped structure, with multiple micro-holes pre-formed on its upright section for inserting and clamping metal wires, and its horizontal section is fixedly connected to the drive end of the five-dimensional adjustment frame.

[0011] Furthermore, the high-precision five-dimensional adjustment frame is sealed to the wall of the vacuum chamber through a vacuum flange, and its drive end extending into the vacuum chamber is fixedly connected to the L-shaped multi-wire clamping structure, which can realize linear displacement in the X, Y, and Z axis directions, as well as pitch angle adjustment around the Y axis and yaw angle adjustment around the Z axis.

[0012] Furthermore, the optical focusing assembly includes, in sequence along the optical path, a femtosecond laser, a laser energy attenuator, and an off-axis parabolic mirror.

[0013] Furthermore, the laser energy attenuator is a set of detachable attenuation plates with adjustable attenuation factor, used to attenuate the focused intensity of the laser to prevent the metal wire from being ablated by the focused laser during collimation and target alignment, thus avoiding damage to the target material.

[0014] Furthermore, the off-axis angle of the off-axis parabolic reflector is... focal length is mm, which can focus the incident laser onto the surface of the metal wire.

[0015] Second, the present invention also provides a method for adjusting the generation of strong terahertz radiation by laser irradiation of a micrometer-scale metal wire, characterized in that: Step S1: Initial focus marking: Turn on the femtosecond laser. After the laser pulse passes through the laser energy attenuator and the off-axis parabolic mirror in sequence, it forms a filamentary white light focus in the air. The position of this white light focus is observed and marked as point P on the computer screen through the telescope imaging real-time monitoring system. Step S2: Target introduction and pre-alignment: The L-shaped multi-wire clamping structure is driven by a high-precision five-dimensional adjustment frame to move the target wire among the pre-installed multiple metal wires so that its image coincides with point P on the computer display screen. Step S3: Precise collimation based on imaging feedback: Keep the laser energy attenuator in working condition, and observe the shape and position of the laser focus spot on the surface of the metal wire in real time through the telescope imaging real-time monitoring system; adjust the vertical and horizontal offsets sequentially through the high-precision five-dimensional adjustment frame until the laser focus spot remains the smallest, roundest and most stable at different length positions of the metal wire, thus completing the collimation; Step S4: Terahertz radiation generation: Remove or adjust the laser energy attenuator so that the femtosecond laser irradiates the collimated metal wire with the energy required for the experiment, thereby generating terahertz radiation; Step S5: The terahertz radiation generated by the terahertz radiation detection is emitted through the terahertz emission window and collected and its energy measured by the terahertz radiation collection and detection system.

[0016] Furthermore, the adjustment of the high and low offset in step S3 specifically involves: Adjust the Y-axis dimension of the high-precision five-dimensional adjustment frame to change the laser irradiation point on the metal wire, and record the horizontal change l1 and vertical change l2 when the light spot moves from point a to point b on the computer screen. According to the formula The offset in the vertical direction is calculated. ; Based on the offset in the vertical direction The Z-axis dimension and pitch angle of the high-precision five-dimensional adjustment frame are adjusted synchronously to eliminate deviations in the vertical direction.

[0017] Furthermore, the adjustment of the left and right offset in step S3 specifically involves: Adjust the X-axis dimension of the high-precision five-dimensional adjustment frame to find and mark the position O where the laser forms the roundest and brightest spot on the metal wire surface; Adjust the Y-axis dimension of the high-precision five-dimensional adjustment frame, change the length of the metal wire l4, and observe the distance l3 from point O to point O' of the light spot position; Combining the off-axis angle of the off-axis parabolic mirror By constructing a geometric model and applying the law of cosines, according to the formula The offset angles in the left and right directions are calculated. ; Based on the offset angle in the left and right directions The X-axis dimension and yaw angle of the high-precision five-dimensional adjustment frame are adjusted synchronously to eliminate the offset in the left and right directions.

[0018] Furthermore, when it is necessary to replace the metal wire target, the other pre-installed metal wire on the L-shaped multi-wire clamping structure is moved to the position of point P by operating the high-precision five-dimensional adjustment frame. The entire process maintains a vacuum degree of 10 in the vacuum chamber. -5 Completed under the condition of Pa.

[0019] Compared with the prior art, the present invention has the following features and effects: 1. Ease of operation and high efficiency: This invention designs an L-shaped multi-wire clamping structure, as shown in the schematic diagram below. Figure 2 As shown, by designing multiple micrometer-scale holes, installing metal wires in the holes, and finally covering them with a small plate, it is possible to quickly switch between multiple metal wires (diameter 100-500μm, length 1-10cm). Compared with the traditional clamping method, this clamping method shortens the target changing time to within 5 minutes and improves efficiency by 40 times compared with the traditional single-wire structure.

[0020] 2. Innovative L-shaped multi-wire clamping structure: Supports pre-loading of metal wires of different specifications, operating in a vacuum environment (leakage rate <1×10⁻⁶). -9 Pa·m 3 / s) No need to break the vacuum to change the target, optimized compatibility: Titanium alloy material (TC4) and bellows interface design, which takes into account both mechanical strength and vacuum sealing.

[0021] 3. Through the synergistic innovation of mechanical-optical-control system, this invention achieves precise control of laser energy density (error <5%), shortens the experimental cycle by 80%, and improves long-term operational stability, significantly enhancing the standardization and repeatability of high-energy laser experiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the femtosecond laser pulse irradiation metal wire target structure of the present invention; Figure 2 Schematic diagram of L-shaped multi-wire clamping structure; Figure 3 This is a schematic diagram of the metal wire adjustment method; Figure 4 The metal wire and the target position for imaging by the telescope imaging system. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but should not be construed as limiting the scope of protection of the present invention. In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "high," "low," "left," "right," "front," "rear," "tilt," "left-handed," or "right-handed" indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms describing positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0024] Please refer to the following first. Figure 1 , Figure 1 This invention provides a high-precision, rapid adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire. The device comprises the following components: a femtosecond laser, a laser energy attenuator, an off-axis parabolic mirror, a vacuum cavity, a metal wire, an L-shaped multi-wire clamping structure, a high-precision five-dimensional adjustment frame, a commercially available telescope (magnification × objective lens diameter of 8 × 42), a scientific-grade CCD camera, an illumination source, a computer display screen, a first and second collecting parabolic mirror, and a terahertz energy detector.

[0025] One of the pulse duration (FWHM) femtosecond laser pulses, with a duration of 30 fs, 800 nm, and a pulse size of 10 mJ, enters the vacuum cavity with an incident window along the optical path and then irradiates the off-axis angle of... On an off-axis parabolic mirror with a focal length of 200 mm, white light is filamentated in the air along the focusing light path. The filamentation position is the laser focal point position. The filamentation white light is then observed through a telescope imaging real-time monitoring system, and the position P is marked on the computer screen at this moment. Multiple metal wires of different diameters and lengths are pre-installed on an L-shaped multi-wire clamping structure. The L-shaped multi-wire clamping structure is installed on a high-precision five-dimensional adjustment frame. By adjusting the height (Z-axis), left and right (X-axis), and front and back (Y-axis) of the high-precision five-dimensional adjustment frame, a certain metal wire that needs to be adjusted is adjusted to the marked position P on the computer display screen of the above-mentioned telescope imaging real-time monitoring system. Before adjusting the collimation of the metal wire, a laser energy attenuator with an attenuation factor of 40 is needed to reduce the intensity of the focused spot to prevent the metal wire from being ablated by the focused laser during the collimation process, which would damage the target material. After completing the above preparations, the next step is to monitor the state of the metal wire in real time using a telescope imaging real-time monitoring system. To adjust the alignment of the metal wire, its spatial position and angle need to be considered, namely its height and lateral movement. The degree of deviation is adjusted using a high-precision five-dimensional adjustment frame, controlling its height (Z-axis), lateral movement (X-axis), forward / backward movement (Y-axis), pitch (pitch angle (θ)), and rotation (yaw angle (φ)) to achieve alignment. This mainly involves two steps: Step 1: Adjust the height and position offset of the metal wire. Figure 3 (a) is a schematic diagram of adjusting the spatial position of the metal wire. Assuming the metal wire is tilted downwards, when the wire is long, the laser spot position is marked as a. Then, by adjusting the forward and backward translation dimension (Y-axis) of the high-precision five-dimensional adjustment frame, the wire length is shortened. At this point, the laser spot is located at position b. The change in horizontal position of the focused spot from position a to position b is denoted as... The change in position in the vertical direction is denoted as Therefore, the offset from position a to position b is: (1) Knowing the height offset of the metal wire, the height of the metal wire can be leveled by adjusting the height and pitch (pitch angle (θ)) of the high-precision five-dimensional adjustment frame. The second step is to adjust the left and right position offset of the metal wire. Since the telescope imaging real-time monitoring system uses the shadow imaging method, it is not possible to directly observe the degree of left and right offset of the metal wire. At this time, it is necessary to use the change in the shape and position of the focused spot of the laser on the surface of the metal wire to judge the degree of left and right offset of the metal wire.

[0026] Figure 3 (b) is a schematic diagram for adjusting the left and right spatial position of the metal wire. When the laser irradiates the surface of the metal wire, we first consider a fixed position when the metal wire is relatively long. By adjusting the left and right translation dimension (X-axis) of the high-precision five-dimensional adjustment frame, we observe the changes in the shape and position of the focused spot on the surface of the metal wire. We find the position where the focused spot is the smallest, roundest, and brightest. This position indicates that it is the focal point of the laser irradiating the surface of the metal wire. This position is marked on the computer screen. ; Then, by adjusting the forward and backward translation dimension (Y-axis) of the high-precision five-dimensional adjustment frame, the metal wire is shortened, and the length change is... Recorded as Assume the shape of the light spot has changed and the spot position is no longer at the marked location. At this point, shift to the right, and record the position of the light spot on the computer screen at this moment. The distance of the light spot position offset is This indicates that the metal wire is currently positioned slightly to the left of the diagram, within the right triangle. In the given information, the off-axis angle of the off-axis parabolic mirror is... and the distance of the light spot position offset The hypotenuse can be obtained using trigonometric functions. for ; In triangle In the given information, based on the Law of Cosines and the properties of trigonometric functions, given both sides... and length change and the included angle on both sides , can be obtained Corresponding edges The length is Then, using the cosine theorem formula, the left and right position offsets can be calculated. The angle is: (2) Knowing the left and right offset, the left and right offset of the metal wire can be leveled by adjusting the left and right and rotation (yaw angle (φ)) of the high-precision five-dimensional adjustment frame.

[0027] Figure 4 The image shows the metal wire observed under the real-time monitoring system of the telescope imaging system during the experiment. The white circle indicates the position where the laser irradiates a longer section of the metal wire. By adjusting the high-precision five-position adjustment frame left and right (X-axis), the position where the focused spot is the smallest, brightest, and most rounded is found, i.e., the focal point. The alignment of the metal wire can be determined by observing the changes in the shape and position of the focused spot when the wire length is changed. This experimental method can quickly and efficiently adjust the alignment of the metal wire. It only requires pre-installing multiple metal wires of different diameters or lengths on an L-shaped multi-wire clamping structure to achieve rapid switching of the metal wires. It has the advantages of simple operation, high precision, and quick and easy operation, overcoming the shortcomings of poor adjustment precision and cumbersome operation procedures in traditional methods.

[0028] This invention uses an L-shaped multi-wire clamping structure to fix the metal wire, combined with a high-precision five-dimensional adjustment frame and a telescope imaging real-time monitoring system. It uses the properties of trigonometric functions and the law of cosines to calculate the offset of the metal wire, realizing accurate alignment of the metal wire and rapid wire replacement under vacuum conditions. It avoids the trouble of opening the cover and evacuating the vacuum multiple times, and has the advantages of simple operation, high precision, and fast and efficient operation.

[0029] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention. Where there is no conflict, the above embodiments and features described therein can be combined with each other.

Claims

1. A device for adjusting strong terahertz radiation generated by laser irradiation of a micrometer-scale metal wire, characterized in that, include: The vacuum cavity (4) has a laser incident window, an observation window and a terahertz emission window on its wall surface; The target assembly is located inside the vacuum cavity (4) and includes a multi-wire clamping structure (6) for simultaneously fixing multiple metal wires (5) and a high-precision five-dimensional adjustment frame (7) for driving the multi-wire clamping structure (6) to move. An optical focusing assembly is disposed inside the vacuum cavity (4). The femtosecond laser beam is focused by the laser incident window and then points to the target assembly. It is used to focus the femtosecond laser pulse onto the surface of the metal wire (5) to form a laser focus. The telescope imaging real-time monitoring system is set opposite to the observation window and is used to perform two-dimensional shadow imaging of the metal wire (5) and the laser focus to provide collimation status feedback in real time. The high-precision five-dimensional adjustment frame (7) is configured to receive feedback signals from the telescope imaging real-time monitoring system and drive the multi-wire clamping structure (6) to perform three-dimensional linear displacement and at least two-dimensional angular deflection based on the feedback signals, thereby realizing the collimation adjustment of the metal wire (5).

2. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 1, characterized in that, The high-precision five-dimensional adjustment frame (7) achieves angle deflection in at least two dimensions: pitch angle and yaw angle.

3. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 1, characterized in that, The telescope imaging real-time monitoring system includes a commercial telescope (8) and a scientific-grade CCD camera (9). The signal output terminal of the scientific-grade CCD camera (9) is connected to a computer (11). The telescope imaging real-time monitoring system is configured to quantitatively calculate the offset of the metal wire by analyzing the position and shape changes of the laser spot on the computer screen when the laser is focused on the surface of the metal wire and moves.

4. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 3, characterized in that, The quantitative calculation of the wire offset includes: Based on the horizontal variation of the light spot l 1 and vertical change l 2. According to the formula Calculate the elevation offset angle; Based on the spot position offset distance l 3. Change in wire length l 4. The off-axis angle α of the optical focusing component is determined using a geometric model and the law of cosines, according to the formula... Calculate the left and right offset angles.

5. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 1, characterized in that, The multi-wire clamping structure (6) is an L-shaped structure. Its upright section has multiple micro-holes for inserting and clamping metal wires (5), and its horizontal section is fixedly connected to the driving end of the five-dimensional adjustment frame (7).

6. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 1 or 5, characterized in that, The high-precision five-dimensional adjustment frame (7) is sealed to the wall of the vacuum chamber (4) through a vacuum flange. Its drive end, which extends into the vacuum chamber, is fixed to the L-shaped multi-wire clamping structure (6), which can realize linear displacement in the X, Y, and Z axis directions, as well as pitch angle and yaw angle adjustment around the Y axis.

7. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 1, characterized in that, The optical focusing assembly includes, in sequence along the optical path, a femtosecond laser (1), a laser energy attenuator (2), and an off-axis parabolic mirror (3).

8. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 7, characterized in that, The laser energy attenuator (2) is a set of detachable attenuation plates with adjustable attenuation factor, used to attenuate the focused intensity of the laser to prevent the metal wire (5) from being ablated by the focused laser during the collimation process, which would cause damage to the target material.

9. The adjustment device for generating strong terahertz radiation by laser irradiation of a micrometer-scale metal wire according to claim 7, characterized in that, The off-axis angle of the off-axis parabolic reflector (3) is... focal length is mm, which can focus the incident laser onto the surface of the metal wire (5).

10. A method for adjusting the generation of strong terahertz radiation from a micrometer-scale metal wire by laser irradiation, characterized in that: Step S1: Initial focus marking: Turn on the femtosecond laser (1), and the laser pulse passes through the laser energy attenuator (2) and the off-axis parabolic mirror (3) in sequence to form a filamentary white light focus in the air; observe and mark the position of the white light focus as point P on the computer screen through the telescope imaging real-time monitoring system; Step S2: Target introduction and pre-alignment: The L-shaped multi-wire clamping structure (6) is driven by the high-precision five-dimensional adjustment frame (7) to move the target wire in the pre-installed multi-metal wire (5) so that its image coincides with point P on the computer display screen (11); Step S3: Precise collimation based on imaging feedback: Keep the laser energy attenuator (2) in working state, and observe the shape and position of the laser spot on the surface of the metal wire (5) in real time through the telescope imaging real-time monitoring system; adjust the high and low offset and left and right offset sequentially through the high-precision five-dimensional adjustment frame (7) until the laser spot remains the smallest, roundest and stable at different length positions of the metal wire (5), thus completing the collimation; Step S4: Terahertz radiation generation: Remove or adjust the laser energy attenuator (2) to allow the femtosecond laser to irradiate the collimated metal wire (5) with the energy required for the experiment, thereby generating terahertz radiation; Step S5: The terahertz radiation generated by the terahertz radiation detection is emitted through the terahertz emission window and collected and its energy measured by the terahertz radiation collection and detection system.

11. The method for adjusting strong terahertz radiation generated by laser irradiation of a micrometer-scale metal wire according to claim 10, characterized in that: The adjustment of the high and low offset in step S3 is specifically as follows: Adjust the Y-axis dimension of the high-precision five-dimensional adjustment frame (7) to change the irradiation point of the laser on the metal wire (5), and record the change in the horizontal direction l1 and the change in the vertical direction l2 when the light spot moves from point a to point b on the computer screen (11); According to the formula The offset in the vertical direction is calculated. ; Based on the offset in the vertical direction The Z-axis dimension and pitch angle of the high-precision five-dimensional adjustment frame (7) are adjusted synchronously to eliminate the offset in the high and low directions.

12. The method for adjusting strong terahertz radiation generated by laser irradiation of a micrometer-scale metal wire according to claim 10, characterized in that: The adjustment of the left and right offset in step S3 is specifically as follows: Adjust the X-axis dimension of the high-precision five-dimensional adjustment frame (7) to find and mark the position O where the laser forms the roundest and brightest spot on the surface of the metal wire (5); Adjust the Y-axis dimension of the high-precision five-dimensional adjustment frame (7), change the length l4 of the metal wire (5), and observe the distance l3 from point O to point O' of the light spot position; Combined with the off-axis angle of the off-axis parabolic mirror (3) By constructing a geometric model and applying the law of cosines, according to the formula The offset angles in the left and right directions are calculated. ; Based on the offset angle in the left and right directions The X-axis dimension and yaw angle of the high-precision five-dimensional adjustment frame (7) are adjusted synchronously to eliminate the offset in the left and right directions.

13. The method for adjusting strong terahertz radiation generated by laser irradiation of a micrometer-scale metal wire according to claims 10-12, characterized in that, When it is necessary to replace the metal wire (5) target material, the other pre-installed metal wire (5) on the L-shaped multi-wire clamping structure (6) is moved to the P position by operating the high-precision five-dimensional adjustment frame (7). The entire process is maintained at a vacuum degree of 10 in the vacuum chamber (4). -5 Completed under the condition of Pa.

Images