An infrared free electron laser cavity system

Abstract

The application discloses an infrared free electron laser cavity system, which comprises a support mechanism, a vacuum chamber, a vacuum pump, a mirror frame mechanism, a mirror changing mechanism and a fine adjustment mechanism; the vacuum chamber is installed on the support mechanism, the vacuum pump is installed on the vacuum chamber and communicates with the vacuum chamber; the fine adjustment mechanism is installed on the support mechanism, and the mirror changing mechanism is installed on the fine adjustment mechanism; the mirror frame mechanism is installed in the vacuum chamber, and both ends of the mirror frame mechanism are connected with the mirror changing mechanism after extending out of the vacuum chamber. The mirror changing mechanism and the fine adjustment mechanism are arranged outside the vacuum chamber, so that the size of the vacuum chamber is reduced, the structure of the vacuum chamber is simplified, and the overall layout of the oscillator is facilitated. Meanwhile, the fine adjustment mechanism can be separated from the heavy vacuum chamber system, cost is reduced, precision is improved, and higher reliability is obtained.

Description

Technical Field

[0001] This invention relates to the field of free-electron laser cavity technology, specifically to an infrared free-electron laser cavity system. Background Technology

[0002] Free-electron lasers (LEX) are considered the most promising fourth-generation light source after third-generation synchrotron radiation due to their continuous tunability, wide operating wavelength range, good beam quality, high coherence, and high peak power. The LEX cavity, as a key component of the LEX oscillator, is crucial in determining whether infrared laser light can be emitted, its emission efficiency, laser tuning efficiency, and overall laser operating efficiency. Therefore, it requires extremely high precision in its working environment and motion adjustment. To achieve this, in 10... -6 A compact, simple, and reliable free-electron laser optical cavity was designed by precisely adjusting the optical cavity in the ultra-high vacuum space of the pa.

[0003] There are various existing infrared free-electron laser optical cavity systems. For example, patent application CN108418088A discloses an optical resonant cavity for a switchable mirror in a free-electron laser. The vacuum chamber is divided into two parts. The upper cavity is an ultra-high vacuum cavity where the cavity mirror works and is stored; the lower cavity is a low vacuum cavity. A 6-DOF Hexapod for precise adjustment of the cavity mirror is installed in this cavity, separated by a thin film. The upper cavity has two motion controls outside the vacuum: horizontal and vertical. The motion is input into the vacuum chamber through welded bellows. The horizontal motion is used to move the optical mirror to be worked to below the vertical manipulator, and the vertical motion (manipulator) is used to retrieve the optical mirror to be replaced to the storage position and install the optical mirror to be worked onto the optical mirror mount. The Hexapod in the lower cavity is used for fine-tuning the orientation of the working optical mirror. In this design, the driving components need to withstand a large vacuum load during operation and are affected by radiation, which reduces the lifespan of electronic components. Furthermore, the position is maintained by power when using the manipulator to change the mirror. More seriously, the isolation membranes of the upper and lower vacuum chambers restrict the rotational adjustment around the Z-axis. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a simple and reliable free electron laser cavity system that is isolated from the cavity mirror drive and vacuum chamber.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] An infrared free-electron laser cavity system includes a support mechanism, a vacuum chamber, a vacuum pump, a mirror frame mechanism, a mirror changing mechanism, and a fine-tuning mechanism.

[0007] The vacuum chamber is mounted on the support mechanism, and the vacuum pump is mounted on the vacuum chamber and connected to the vacuum chamber.

[0008] The fine adjustment mechanism is installed on the support mechanism, and the mirror changing mechanism is installed on the fine adjustment mechanism.

[0009] The mirror frame mechanism is installed in the vacuum chamber, and two ends of the mirror frame mechanism extend out of the vacuum chamber and are connected with the mirror changing mechanism.

[0010] Advantages: The mirror changing mechanism and the fine adjustment mechanism are arranged outside the vacuum chamber, so that the size of the vacuum chamber is reduced, the structure of the vacuum chamber is simplified, and the overall layout of the oscillator is facilitated. Meanwhile, the fine adjustment mechanism can be separated from the heavy vacuum chamber system, cost is reduced, adjustment is more flexible and convenient, precision is improved, and higher reliability is obtained.

[0011] Preferably, the support mechanism comprises a support bottom plate, four supporting legs and a vacuum chamber support.

[0012] The support bottom plate is installed on the ground, one end of each of the four supporting legs is installed on the support bottom plate, and the other end is connected with the vacuum chamber support through bolts and spherical washers.

[0013] Preferably, the mirror frame mechanism comprises an optical mirror group, an optical mirror support, an optical mirror support connecting rod, a bellows and a mirror frame arm.

[0014] The optical mirror support is connected with the moving end of the bellows, the optical mirror support connecting rod connects the moving end of the bellows with the mirror frame arm, the fixed end of the bellows is fixed on the flange of the vacuum chamber, and the optical mirror group is installed in the middle of the optical mirror support. The bellows is a connecting bridge between the mirror frame system and the vacuum chamber system, which not only ensures the sealing of the vacuum system, but also plays a role in isolating the force and movement of the vacuum chamber system and the mirror frame system and the vacuum.

[0015] Preferably, 8mm target holes are symmetrically arranged on the bottom of each mirror frame arm and the upper side of the atmospheric end of the optical mirror support connecting rod.

[0016] Preferably, the mirror changing mechanism comprises a bottom plate, a mirror changing driving plate, a connecting piece, a precision cross roller guide, a precision screw nut seat, a grating ruler, a grating reading head, a driving mounting seat, a shaft coupling and a stepping reduction motor.

[0017] The bottom plate is installed on the fine adjustment mechanism, the mirror changing driving plate is connected with the bottom plate through the cross roller guide, and the bottom of the connecting piece is installed on the mirror changing driving plate.

[0018] The middle part of the bottom plate and the mirror changing driving plate is provided with a through groove, the precision screw nut seat is installed on the mirror changing driving plate, the grating ruler is fixedly installed on one side of the mirror changing driving plate, and the grating reading head is installed on the same side of the bottom plate.

[0019] One end of the bottom plate is provided with a driving mounting seat; the step deceleration motor is mounted on the driving mounting seat and connected with the precision screw nut seat through a shaft coupling;

[0020] Preferably, the fine adjustment assembly is a six-degree-of-freedom displacement platform, comprising a base and a top plate; the base is mounted on the support mechanism; and the top plate is connected with the mirror changing mechanism.

[0021] Preferably, the base is made of marble to improve the dynamic vibration isolation performance of the precision driving system.

[0022] Preferably, the base and the support bottom plate are connected by screws and nuts as the coarse adjustment of the precision driving system.

[0023] Preferably, the bracket is further provided with a radiation protection plate on one side, the radiation protection plate comprises a wax plate and a lead plate for shielding different kinds of radiation rays; and the wax plate is attached to the lead plate.

[0024] Preferably, the vacuum chamber has a plurality of openings for light in and out, vacuum pumping, detection and as an observation window.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The mirror changing mechanism and the fine adjustment mechanism are arranged outside the vacuum chamber, so that the size of the vacuum chamber is reduced, the structure of the vacuum chamber is simplified, and the overall layout of the oscillator is facilitated. At the same time, the fine adjustment mechanism can be free from the heavy vacuum chamber system, thereby reducing the cost, improving the precision and obtaining higher reliability.

[0027] (2) The present application sets up symmetrical corrugated pipes on both sides, so that the vacuum force is borne by the mirror frame mechanism and balanced left and right. The vacuum force does not act on the mirror changing mechanism and the fine adjustment mechanism. Therefore, the mirror changing mechanism and the fine adjustment mechanism have little load and no deformation caused by external force.

[0028] (3) The coarse adjustment and the fine adjustment of the present application are separated, the length of the adjusting bolt is adjusted to coarsely adjust the displacement in three directions and the rotation around the X and Y directions, and the hexapod six-degree-of-freedom displacement platform is used for fine adjustment, thereby reducing the adjustment pressure of the hexapod six-degree-of-freedom displacement platform and improving the adjustment precision.

[0029] (4) The present application has good repeatability of the direction and position of the light mirror after mirror changing, saves mirror changing time and reduces mirror changing difficulty. Compared with the mechanical hand mirror changing, the positions of the light mirrors in the mirror frame are fixed in the present application. The mirror changing mechanism has long guide rails and high precision, and the crossed roller guide rails can be adjusted in pre-tightening amount at will. The position precision after changing position is monitored by the grating ruler on the mirror changing mechanism, the mirror changing repeatability is good, and the mirror changing and adjusting time is greatly shortened.

[0030] (5) The precise positions of the three mirrors can be reflected on the target outside the vacuum chamber by measuring instruments in advance, and the positions of the mirrors inside the vacuum chamber can be measured at any time without opening the vacuum chamber. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The whole structure schematic diagram of the embodiment of the present application;

[0032] Figure 2 The structure schematic diagram of another perspective of the embodiment of the present application;

[0033] Figure 3 The structure schematic diagram of the support mechanism of the embodiment of the present application;

[0034] Figure 4 The structure schematic diagram of the vacuum chamber of the embodiment of the present application;

[0035] Figure 5 The connection schematic diagram of the mirror frame mechanism and the mirror changing mechanism of the embodiment of the present application;

[0036] Figure 6 The front view of the mirror frame mechanism and the mirror changing mechanism of the embodiment of the present application;

[0037] Figure 7 The structure schematic diagram of the mirror frame mechanism of the embodiment of the present application;

[0038] Figure 8 The partial schematic diagram of the mirror frame mechanism of the embodiment of the present application;

[0039] Figure 9 The partial schematic diagram of another perspective of the mirror frame mechanism of the embodiment of the present application;

[0040] Figure 10 The structure schematic diagram of the fine adjustment mechanism of the embodiment of the present application;

[0041] Figure 11 The front view of the fine adjustment mechanism of the embodiment of the present application;

[0042] In the figure: 1, support mechanism; 11, support bottom plate; 12, support leg; 13, vacuum chamber support; 14, horizontal adjusting bolt; 15, spherical washer; 16, vertical adjusting bolt; 2, vacuum chamber; 21, vacuum chamber flange; 3, vacuum pump; 4, mirror frame mechanism; 41, optical mirror support; 42, optical mirror support connecting rod; 43, mirror frame arm; 44, bellows; 45, target hole; 46, optical mirror group; 5, lens changing mechanism; 51, bottom plate; 52, lens changing drive plate; 53, connecting piece; 54, precision cross roller guide; 55, precision screw nut seat; 56, grating ruler; 57, grating reading head; 58, drive mounting seat; 59, coupling; 510, step-down motor; 6, fine adjustment mechanism; 61, base; 62, top plate; 63, base plate; 7, radiation protection plate; 71, wax plate; 72, lead plate. DETAILED DESCRIPTION

[0043] In order to facilitate those skilled in the art to understand the technical scheme of the present application, the technical scheme of the present application will be further described in conjunction with the drawings of the specification.

[0044] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0045] As shown in Figure 1 , the length and width directions of the support mechanism 1 are respectively taken as the X-axis and the Y-axis, and the height of the support mechanism 1 is taken as the Z-axis to establish a rectangular coordinate system.

[0046] Referring to Figure 1 and Figure 2 , the embodiment discloses an infrared free electron laser cavity system, which comprises a support mechanism 1, a vacuum chamber 2, a vacuum pump 3, a mirror frame mechanism 4, a lens changing mechanism 5 and a fine adjustment mechanism 6.

[0047] Referring to Figure 3The support mechanism 1 comprises a support base plate 11, support legs 12 and a vacuum chamber support 13. The support base plate 11 can be installed on the ground. One end of the four support legs 12 is installed on the support base plate 11, and the other end is connected with the vacuum chamber support 13 through eight horizontal adjusting bolts 14 and eight vertical adjusting bolts 16 to complete the six-dimensional adjustment of the position of the vacuum chamber 2. Specifically, the eight horizontal adjusting bolts 14 are used for the translational movement of the vacuum chamber support 13 along the X and Y directions, and the rotational adjustment and locking around the Z axis. The other eight vertical adjusting bolts 16 are used for the translational movement of the vacuum chamber support 13 along the Z direction, and the rotational adjustment and locking around the X and Y axes. The head of each bolt is a hemispherical head rotatable mechanism, or a ball-type gasket 15 is used at the root to facilitate the surface fitting in the case of processing, installation error and non-perpendicularity of the bolt, so as to maintain the stability of the support of the vacuum chamber 2.

[0048] The vacuum chamber 2 is fixedly installed on the vacuum chamber support 13, and the vacuum pump 3 is installed at the upper end of the vacuum chamber 2 and communicates with the vacuum chamber 2. Specifically, referring to Figure 4 The vacuum chamber 2 has a cylindrical structure and has nine openings. One opening at the upper end is used for communication with the vacuum pump 3, and two openings at the left and right are fixed through the vacuum chamber flanges 21. The middle opening of the three openings at the front end provides a channel for light beam transmission, and the left and right two openings are observation windows, which facilitate the observation of the approximate position of the mirror by the human eye. The three openings at the rear end are respectively a light beam outlet, a vacuum measurement opening and a rough pumping opening. The vacuum chamber 2 realizes ultrahigh vacuum through the vacuum pump 3, and provides an ultrahigh vacuum environment of 2x10 -6 Pa for the light mirror.

[0049] Referring to Figures 5 to 9 The mirror frame mechanism 4 comprises a light mirror support 41, a light mirror support connecting rod 42, a mirror frame arm 43, a bellows 44 and a light mirror group 46. Two light mirror support connecting rods 42 are respectively connected with the dynamic end of the bellows 44. The fixed end flanges of the two bellows 44 are fixed on the vacuum chamber flanges 21 at the two ends of the vacuum chamber 2, and the dynamic end of the two bellows 44 is symmetrically fixed on the two ends of the light mirror support 41. The light mirror group 46 is installed in the middle part of the light mirror support 41. Specifically, the light mirror group 46 has three light mirrors, and the middle part of the light mirror support 41 is located in the vacuum chamber 2 and is provided with three installation grooves corresponding to the three light mirrors. In this embodiment, the bellows 44 is sleeved on the light mirror support connecting rod 42. The bellows 44 is used to seal the vacuum chamber 2 and does not transmit the movement of the light mirror support to the vacuum chamber.

[0050] It should be noted that three light mirrors are designed in the embodiment of the present application, and in fact, the number of light mirrors can be 2 to 5.

[0051] In this embodiment, the installation accuracy of the vacuum chamber 2 is much lower than that of the mirror frame mechanism 4, and does not need to be adjusted online. The design will realize the movement separation of the vacuum chamber 2 and the mirror frame mechanism 4 through the soft connection of the bellows 44. When any vibration or accidental impact occurs on the vacuum chamber 2, it will not affect the precise optical mirror system. At the same time, the precise adjustment of the optical mirror system does not have to be carried with the heavy vacuum chamber system.

[0052] By setting the symmetrical bellows 44, the vacuum force is borne by the mirror frame located in the vacuum chamber 2, and is balanced left and right. The vacuum force does not act on the mirror changing mechanism 5 and the fine adjustment mechanism 6, so that the mirror changing mechanism 5 and the fine adjustment mechanism 6 have almost no load and no deformation caused by external force.

[0053] In this embodiment, 8mm target holes 45 are symmetrically opened on the bottom of the two mirror frame arms 43 and the upper side of the atmospheric end of the optical mirror support connecting rod 42 to place the targets. The joint arm is used to calibrate the relative position relationship of the three optical mirrors in the vacuum chamber 2 and the four targets on the mirror frame arm 43. The laser tracker is used to install the optical mirror to the correct position through the four targets. When the optical mirror group 46 is displaced, the displacement amount of the optical mirror can be observed on the software matched with the laser tracker, which is very beneficial to the debugging of the laser and the position checking of the optical mirror in the working process.

[0054] The mirror changing mechanism 5 includes a bottom plate 51, a mirror changing drive plate 52, a connecting piece 53, a precise cross roller guide rail 54, a precise screw nut seat 55, an optical grating ruler 56, an optical grating reading head 57, a drive mounting seat 58, a shaft coupling 59 and a step reduction motor 510.

[0055] The bottom plate 51 is installed on the fine adjustment mechanism 6; the mirror changing drive plate 52 is connected with the bottom plate 51 through the cross roller guide rail 54. The bottom of the connecting piece 53 is installed on the mirror changing drive plate 52, and the mirror changing arm 43 is installed on both ends of the connecting piece 53. The top of the mirror changing arm 43 is connected with the atmospheric end of the mirror frame connecting piece 42. The middle part of the bottom plate 51 and the mirror changing drive plate 52 has a through slot penetrating up and down, and the precise screw nut seat 55 is installed on the mirror changing drive plate 52. The optical grating ruler 56 is fixedly installed on one side of the mirror changing drive plate 52, and the optical grating ruler 56 reading head is installed on the same side of the bottom plate 51; one end of the bottom plate 51 is provided with the drive mounting seat 58. The step reduction motor 510 is installed on the drive mounting seat 58, and the step reduction motor 510 is connected with the precise screw nut seat 55 through the shaft coupling 59. The precise cross roller guide rail 54 is installed between the mirror changing drive plate 52 and the bottom plate 51.

[0056] The lens changing driving plate 52 is rigidly connected with the lens holder mechanism 4; the step deceleration motor 510 drives the precise screw nut seat 55 and the lens changing driving plate 52 thereon to move along the length direction of the precise cross roller guide rail 54 through the shaft coupling 59, and then drives the lens holder mechanism 4 and the optical lens thereon to move through the target positioning optical lens coordinate, so as to achieve the purpose of precise lens changing. On the other hand, the screw nut seat is fixed on the lens changing driving plate 52, and the grating ruler 56 is also fixedly installed on the side surface of the lens changing driving plate 52. When the lens changing driving plate 52 moves, the corresponding displacement occurs between the grating ruler 56 and the grating reading head 57, and the reading on the grating ruler 56 is the displacement of the precise screw nut seat 55 and the optical lens thereon. Therefore, the optical lens displacement reading is obtained by reading the reading on the grating ruler 56.

[0057] Referring to Figure 10 and Figure 11 , the fine adjustment assembly is a Hexapod six-degree-of-freedom displacement platform. The Hexapod is a commercial product, which includes a base 61 and a top plate 62. A base plate 63 is installed on the base 61, and the lens changing mechanism 5 is installed on the top plate 62. The top plate 62 is driven by software to realize adjustment of six degrees of freedom, and three rotation centers can be set at any position in the software as needed.

[0058] Specifically, the base 61 and the support bottom plate 11 are respectively provided with a plurality of bolts and nuts in the X and Y directions, and the position of the base 61 in the horizontal plane is adjusted by adjusting the screwing degree of the bolts and nuts.

[0059] In some embodiments, the base 61 is made of marble. Marble has high stability, high strength, high hardness, can maintain high precision under high load, is magnetically resistant, and can improve the anti-vibration performance of the system.

[0060] In this embodiment, there are two kinds of coarse adjustment. One is the adjustment of the position of the vacuum chamber, which is completed by adjusting the horizontal adjustment bolts 14 and the vertical adjustment bolts 16 to adjust the six degrees of freedom of the vacuum chamber. The other is the adjustment of the base 61 of the Hexapod, which is completed by adjusting the bolts and nuts around the support bottom plate 11 to adjust the displacement and rotation of the base 61 in the horizontal plane. The coarse adjustment of the marble in the height direction is completed by the anchor bolts on the support bottom plate 11.

[0061] In this embodiment, the coarse adjustment and the fine adjustment are separated. The coarse adjustment is as described in the above section, and the fine adjustment is completed by the hexapod six-degree-of-freedom displacement platform, which reduces the adjustment pressure of the hexapod control platform and improves the adjustment accuracy.

[0062] In some embodiments, the bracket is further provided with a radiation protection plate 7, which includes a wax plate 71 and a lead plate 72. The two materials are used to shield different radiation. The wax plate 71 is attached to the lead plate 72. The radiation protection plate 7 is perpendicular to the radiation surface of the light beam line and is used for radiation protection of the hexapod six-degree-of-freedom displacement platform.

[0063] The embodiment can realize real-time online mirror replacement. Since the radius of the spherical oscillating mirror and the diameter of the central hole of the laser output are related to the wavelength of the laser, in order to obtain a wide range of laser wavelength output, 3-5 oscillating mirrors with different radii are usually stored in one optical cavity. The oscillating mirror can be replaced in real time during the operation of the free electron laser according to the wavelength requirement;

[0064] The embodiment can realize precise fine adjustment of the oscillating mirror. Whether the infrared laser can emit light and the output power after emission are closely related to the position and direction between the upstream and downstream mirrors. The adjustment step of the mirror center in the Y and Z directions should be in the order of microns, and the adjustment accuracy should be ±50 microns; the adjustment step of the mirror center in the X axis (laser direction) should be in the order of sub-microns, and the adjustment accuracy should be 1 micron. The angle adjustment step of the pitch and roll angles of the upstream and downstream mirrors should be 5 micro-radians (μrad), and the angle accuracy should be ±50 μrad.

[0065] In the specific working process of the embodiment, the joint arm is used to calibrate the three mirrors in the vacuum chamber 2 and the plurality of target holes 45 on the mirror frame arm 43 and the mirror support connecting piece, to determine the positional relationship between the mirrors and the target holes 45. The laser tracker is used to complete the installation of the mirror group, and then when the mirror replacement driving plate 52 is driven to move by the step deceleration motor 510, the replacement of the three mirror working positions is completed. The grating ruler 56 and the grating reading head 57 are used to read, and at the same time, the displacement of the mirror can be observed on the software matched with the laser tracker.

[0066] The whole system of the embodiment is small in size and simple, so the economy and operation reliability are greatly improved. At the same time, the smaller size is more conducive to the layout of the oscillator system. For example, generally, the upstream optical cavity does not set the mirror replacement mechanism 5 due to space reasons, but only sets the mirror precise adjustment mechanism. The optical cavity of the design can be installed with the mirror replacement mechanism 5. In this way, the paired use of the upstream and downstream mirrors is more conducive to the debugging and light emission efficiency of the laser.

[0067] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0068] The above-described embodiments only represent the implementation of the application, the protection scope of the application is not limited to the above-described embodiments, and for those skilled in the art, several modifications and improvements can be made without departing from the concept of the application, and these all belong to the protection scope of the application.

Claims

1. An infrared free-electron laser optical cavity system, characterized in that: It includes a support mechanism (1), a vacuum chamber (2), a vacuum pump (3), a lens frame mechanism (4), a lens changing mechanism (5), and a fine-tuning mechanism (6); The vacuum chamber (2) is mounted on the support mechanism (1), and the vacuum pump (3) is mounted on the vacuum chamber (2) and communicates with the vacuum chamber (2); The fine-tuning mechanism (6) is mounted on the support mechanism (1), and the lens changing mechanism (5) is mounted on the fine-tuning structure; The lens frame mechanism (4) is installed inside the vacuum chamber (2). Both ends of the lens frame mechanism (4) extend out of the vacuum chamber (2) and are connected to the lens changing mechanism (5). The lens changing mechanism (5) includes a base plate (51), a lens changing drive plate (52), a connector (53), a precision cross roller guide (54), a precision lead screw nut seat (55), a grating ruler (56), a grating reading head (57), a drive mounting base (58), a coupling (59), and a stepper motor (510). The base plate (51) is installed on the fine adjustment mechanism (6). The lens changing drive plate (52) is installed on the base plate (51). The bottom of the connector (53) is installed on the lens changing drive plate (52), and the two sides of the top are respectively connected to the flange connector (53). The atmospheric end is connected; the middle of the base plate (51) and the mirror changing drive plate (52) has a through groove that runs through the top and bottom, and the precision lead screw nut seat (55) is installed on the mirror changing drive plate (52); the grating ruler (56) is fixedly installed on one side of the mirror changing drive plate (52), and the reading head of the grating ruler (56) is installed on the same side of the base plate (51); a drive mounting seat (58) is installed at one end of the base plate (51); the stepper motor (510) is installed on the drive mounting seat (58), and the stepper motor (510) is connected to the precision lead screw nut seat (55) through a coupling (59); the precision cross roller guide (54) is installed at both ends between the mirror changing drive plate (52) and the base plate (51).

2. The infrared free-electron laser optical cavity system according to claim 1, characterized in that: The support mechanism (1) includes a support base plate (11), a support leg (12), and a vacuum chamber support (13); The base plate (11) of the support is installed on the ground. One end of the four legs (12) is installed on the base plate (11), and the other end is connected to the vacuum chamber support (13) by the horizontal adjusting bolt (14) and the vertical adjusting bolt (16).

3. The infrared free-electron laser optical cavity system according to claim 1, characterized in that: The frame mechanism (4) includes a lens support (41), a lens support connecting rod (42), a frame arm (43), a bellows (44), and a lens assembly (46). The optical mirror support (41) is connected to the moving end of the bellows (44); the optical mirror support connecting rod (42) connects the moving end of the bellows (44) to the mirror frame arm (43); the fixed end of the bellows (44) is fixed on the vacuum chamber flange (21); the optical mirror assembly (46) is installed in the middle of the optical mirror support (41).

4. The infrared free-electron laser optical cavity system according to claim 3, characterized in that: Target holes (45) are symmetrically opened at the bottom of the two mirror arms (43) and on the upper side of the atmospheric end of the optical mirror support connecting rod (42).

5. The infrared free-electron laser optical cavity system according to claim 1, characterized in that: The fine-tuning mechanism (6) is a six-degree-of-freedom displacement platform, including a base (61), a base plate (63), and a top plate (62). The base (61) is mounted on the support mechanism (1); the top plate (62) is connected to the lens changing mechanism (5).

6. The infrared free-electron laser optical cavity system according to claim 5, characterized in that: The base (61) is made of marble.

7. The infrared free-electron laser optical cavity system according to claim 5, characterized in that: The position of the base (61) and the support plate (11) is adjusted using screws and nuts.

8. The infrared free-electron laser optical cavity system according to claim 3, characterized in that: A radiation protection plate (7) is also provided on one side of the optical mirror support (41). The radiation protection plate (7) includes a wax plate (71) and a lead plate (72). The wax plate (71) and the lead plate (72) are attached to each other.

9. The infrared free-electron laser optical cavity system according to claim 2, characterized in that: The vacuum chamber (2) has multiple openings.

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