High stability white cell

Abstract

The application belongs to the field of gas detection and provides a high-stability White cell, which comprises a main concave mirror with a curvature radius R, a first sub-concave mirror and a second sub-concave mirror with the curvature radius R, which are adjacently arranged along the x-axis direction, the curvature centers of which are located at the midpoints of the adjacent edges and have a relative position difference along the x-axis direction, and a relative position vector d, the modulus of which is greater than 0, the reflection surfaces of the two sub-concave mirrors and the reflection surface of the main concave mirror are oppositely arranged along the z-axis direction and are spaced by R to form a reflection cavity, the x-axis direction is parallel to the focal plane of the main concave mirror, and the z-axis direction is perpendicular to the focal plane of the main concave mirror; an input end arranged on the main concave mirror and used for inputting a light beam; and an output end arranged on the main concave mirror and used for outputting a light beam. The relative angle of the two sub-concave mirrors in the high-stability White cell provided by the application embodiment will not change due to the change of temperature and stress, and the stability is high.

Description

Technical Field

[0001] This application relates to the field of gas detection technology, and in particular to a highly stable White cell. Background Technology

[0002] Gas detection equipment typically requires highly stable gas absorption cells with a high optical path-to-volume ratio, such as Herriot and White cells. White cells, in particular, are suitable for broadband incoherent light sources and are widely used in ultraviolet-diffusion optical spectroscopy (UVDOS) and Fourier transform infrared (FTIR) spectroscopy. These applications often require heating the gas cell to temperatures exceeding 200 degrees Celsius, placing extremely high demands on the temperature and strain stability of the gas cell. Existing White cells use the relative angle of two sub-concave mirrors as the variable for optical path adjustment. After assembly, especially when operating at high temperatures, the relative angle of the two sub-concave mirrors may change due to temperature and stress variations. This can cause the output beam from the gas cell to deviate from the preset position, leading to decreased optical system stability and even gas detection equipment failure. Summary of the Invention

[0003] In view of this, the present application provides a highly stable White cell to solve the problem that existing White cells use the relative angle of two sub-concave mirrors as the variable for optical path adjustment, which easily leads to the beam output from the air cell deviating from the preset position and the optical system stability deteriorating.

[0004] This application provides a highly stable White pool, comprising:

[0005] The principal concave mirror has a radius of curvature R; The first and second sub-concave reflectors have radii of curvature R, are arranged adjacent to each other along the x-axis, have their centers of curvature located at the midpoints of their adjacent sides, and have a relative positional difference along the x-axis. A relative position vector d is generated, the magnitude of which is greater than 0. The reflecting surfaces of the first sub-concave reflector and the second sub-concave reflector are arranged opposite to the reflecting surface of the main concave reflector along the z-axis and spaced apart by R to form a reflecting cavity. The x-axis is parallel to the focal plane of the main concave reflector, and the z-axis is perpendicular to the focal plane of the main concave reflector. The input end is disposed on the main concave reflector and is used to input the light beam; The output end is located on the main concave reflector and is used to output a light beam.

[0006] In one embodiment, the first sub-concave reflector and the second sub-concave reflector are obtained by cutting a concave reflector with a curvature center located at the geometric center and a curvature radius of R along the y-axis and separating it along the x-axis, wherein the y-axis is perpendicular to the x-axis and the z-axis.

[0007] In one embodiment, the high-stability White pool further includes a bottom plate; During the dimming assembly process, the non-reflective surfaces of the first and second sub-concave reflectors are flat against the base plate, and at least one of the first and second sub-concave reflectors is translated along the x-axis to adjust the relative position vector between the curvature centers of the first and second sub-concave reflectors to d. The translation is stopped after the light beam is input through the input end and output through the output end, and the non-reflective surfaces of the first and second sub-concave reflectors are fixed to the base plate.

[0008] In one embodiment, the main concave reflector, the first sub-concave reflector, and the second sub-concave reflector are made of glass material through an optical cold working process, and the base plate is made of the same glass material. The side of the first sub-concave reflector and the second sub-concave reflector away from the main concave reflector is fixed to the base plate by an adhesive. Alternatively, the main concave reflector, the first sub-concave reflector, and the second sub-concave reflector are made of metal material through machining processes, and the base plate is made of the same metal material. The side of the first sub-concave reflector and the second sub-concave reflector away from the main concave reflector is fixed to the base plate by threaded fasteners.

[0009] In one embodiment, the reflective surfaces of the main concave mirror, the first sub-concave mirror, and the second sub-concave mirror are coated with a high-reflectivity film, which includes at least one of a high-reflectivity metal film and a multilayer dielectric film.

[0010] In one embodiment, the augmented matrix of the highly stable White pool is expressed as follows: ; ; in, It is the input position vector of the beam. It is the input angle vector of the light beam. It is the output position vector of the beam. It is the output angle vector of the beam. It is the ABCD matrix of a known coaxial optical system. It is the position offset. It is the angular offset.

[0011] In one embodiment, the expression for the matrix T when the light beam enters the reflecting cavity from the input end, completes one cycle of reflection within the reflecting cavity, returns to the reflection point of the principal concave mirror, and is reflected by the reflection point is as follows: ; The light beam enters the reflecting cavity from the input end, and after completing n cyclic reflections within the reflecting cavity, it is output from the output end. The expression for matrix Tn is as follows: ; ; ; ; ; ; ; ; in, It is the optical path matrix of the beam during a single transmission within the reflecting cavity. It is the reflection matrix when the light beam is reflected by any reflection point within the reflecting cavity. yes The inverse matrix, It is the coordinate transformation matrix of the first sub-concave reflector. yes The inverse matrix, It is the position of the optical axis of the first concave mirror. It is the angle of the optical axis of the first concave mirror. It is the coordinate transformation matrix of the second sub-concave mirror. yes The inverse matrix, It is the position of the optical axis of the second sub-concave mirror. It is the angle of the optical axis of the second concave mirror.

[0012] In one embodiment, the matrix T is expressed as follows: ; The expression for the matrix Tn is as follows: .

[0013] In one embodiment, ; ; ; ; in, It refers to the relative position between the optical axes of the first sub-concave mirror and the second sub-concave mirror. It is the relative angle between the optical axes of the first sub-concave reflector and the second sub-concave reflector.

[0014] In one embodiment, the expression for the relative displacement between the output position and the input position of the light beam is as follows: ; The expression for the relative angle between the output angle and the input angle of the beam is as follows: ; The expression for the relative position vector d is as follows: .

[0015] Wherein, d is defined as the vector formed by the line connecting the intersection of the optical axis of the first sub-concave mirror and the optical axis of the second sub-concave mirror with the main concave mirror.

[0016] The high-stability White cell provided in this application embodiment achieves this by setting the radii of curvature of the main concave mirror and the two sub-concave mirrors, as well as the spacing between the main concave mirror and the two sub-concave mirrors, to be the same. The two sub-concave mirrors are arranged adjacent to each other along the x-axis direction parallel to the focal plane of the main concave mirror, with their curvature centers located at the midpoints of their adjacent sides and having a relative positional difference along the x-axis direction. Generate a relative position vector d with a magnitude greater than 0, so that during the dimming assembly process, the relative position difference between the two sub-concave mirrors is used. Instead of using relative angles as variables for optical path adjustment, the relative angle between the two sub-concave mirrors is always 0. When the relative position vector is d, the light beam can enter from the input end of the main concave mirror and exit from the output end of the main concave mirror. After assembly, especially when working in high-temperature environments, the relative angle between the two sub-concave mirrors will not change due to temperature and stress changes, and the relative position change is almost zero, thereby improving the stability of the optical system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the high-stability White pool provided in the embodiments of this application; Figure 2 This is a schematic diagram of the spot position of the high-stability White cell provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the first sub-concave reflector and the second sub-concave reflector provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the concave reflector provided in the embodiment of this application; Figure 5 This is a schematic diagram showing the beam position and parameter annotations in a highly stable White cell provided in this application embodiment. Detailed Implementation

[0019] In the following description, specific details such as particular device structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known devices, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0020] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0021] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0022] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0023] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0025] like Figure 1 or Figure 2 As shown, this application embodiment provides a high-stability White pool 300, comprising: The concave mirror 101 has a radius of curvature R; The first sub-concave reflector 102 and the second sub-concave reflector 103 have radii of curvature R and are arranged adjacent to each other along the x-axis. The reflecting surface of the first sub-concave reflector 102 has a first curvature center 102a located at the midpoint of the first side, and the reflecting surface of the second sub-concave reflector 103 has a second curvature center 103a located at the midpoint of the second side. The first side and the second side are adjacent to each other, and the relative position difference between the first curvature center 102a and the second curvature center 103a along the x-axis is... A relative position vector d is generated, and the magnitude of d is greater than 0. When the optical axis of the first sub-concave mirror 102 and the optical axis of the second sub-concave mirror 103 are parallel, The reflecting surfaces of the first sub-concave mirror 102 and the second sub-concave mirror 103 are arranged opposite to the reflecting surface of the main concave mirror 101 along the z-axis and spaced apart by R to form a reflecting cavity. The x-axis is parallel to the focal plane of the main concave mirror 101, and the z-axis is perpendicular to the focal plane of the main concave mirror 101. The input terminal 104 is disposed on the main concave reflector 101 and is used to input the light beam; Output end 105 is disposed on the main concave reflector 101 and is used to output beam.

[0026] In the application, the main concave mirror 101, the first sub-concave mirror 102 and the second sub-concave mirror 103 have the same radius of curvature R. The distance between the main concave mirror 101 and the first sub-concave mirror 102 and the second sub-concave mirror 103 is R=2f, where f is the focal length of the main concave mirror 101.

[0027] like Figure 1 , Figure 2 or Figure 3 As shown, the light beam is input into the reflecting cavity from the input end 104. After multiple reflections between the main concave reflector 101, the first sub-concave reflector 102, and the second sub-concave reflector 103, a first row of light spot tracks 106 and a second row of light spot tracks 107 are formed on both sides of the central axis 101a of the reflecting surface of the main concave reflector 101, arranged parallel to each other along the y-direction. The light spots in each row of light spot tracks are approximately uniformly spaced, and the relative position vector between adjacent light spots is 2d. During the dimming assembly process, the relative position difference in the x-direction between the first sub-concave reflector 102 and the second sub-concave reflector 103 can be adjusted. The relative position vector of the first curvature center 102a and the second curvature center 103a along the x-axis is adjusted to d, thereby achieving the purpose of adjusting the relative position vector 2d between adjacent light spots in each row of light spot trajectories, so that there is a light spot located at the output end 105, and the light beam can be output from the output end 105 to outside the reflecting cavity.

[0028] It should be understood that the input terminal 104 and the output terminal 105 can be located at any spot position in the first row of light spot trajectory 106 and the second row of light spot trajectory 107, and the positions of the input terminal 104 and the output terminal 105 can be the same or different. Figure 1 The example shows that the input and output terminals 105 are located at the two ends of the main concave mirror 101 in the x-direction. Figure 3 The example shows that input terminal 104 and output terminal 105 are respectively located at the first and last spot positions of the first row of light spot trajectory 106. In other cases, input terminal 104 and output terminal 105 may also be located at the first and last spot positions of the second row of light spot trajectory 107, or input terminal 104 may be located at the first spot position of the first row of light spot trajectory 106 and output terminal 105 may be located at the last spot position of the second row of light spot trajectory 107.

[0029] like Figure 4As shown, in one embodiment, the first sub-concave reflector 102 and the second sub-concave reflector 103 are obtained by cutting a concave reflector 1023 with a curvature center 1023a located at the geometric center and a curvature radius of R, along a symmetry axis 1023b in the y-axis direction, and separating it in the x-axis direction. The cut first sub-concave reflector 102 and the second sub-concave reflector 103 are as follows: Figure 3 As shown, the y-axis is perpendicular to both the x-axis and z-axis.

[0030] like Figure 1 As shown, in one embodiment, the high-stability White pool 100 also includes a base plate 108; During the dimming assembly process, the non-reflective surface (i.e., the opposite surface of the reflective surfaces) of the first sub-concave mirror 102 and the non-reflective surface of the second sub-concave mirror 103 are flatly attached to the base plate 108, so that their optical axes are parallel. ), and translate at least one of the first sub-concave reflector 102 and the second sub-concave reflector 103 along the x-axis direction to adjust the relative position vector between the curvature center 102a of the first sub-concave reflector 102 and the curvature center 103a of the second sub-concave reflector 103 to d (due to The translation stops when the light beam can be input through the input terminal 104 and output through the output terminal 105, and the non-reflective surfaces of the first sub-concave reflector 102 and the second sub-concave reflector 103 are fixed to the base plate 108.

[0031] This application embodiment also provides a method for preparing two sub-concave mirrors (i.e., the first sub-concave mirror 102 and the second sub-concave mirror 103) of a high-stability White pool 100, comprising the following steps: A concave mirror 1023 is fabricated. The concave mirror 1023 has a radius of curvature R, a center of curvature 1023a, and an axis of symmetry 1023b along the y-axis. The center of curvature 1023a is located at the geometric center of the concave mirror 1023. The concave reflector 1023 is cut along the axis of symmetry 1023b to obtain a first sub-concave reflector 102 and a second sub-concave reflector 103. The first sub-concave reflector 102 has a first curvature center 102a, and the second sub-concave reflector 103 has a second curvature center 103a. During the dimming process, the first sub-concave reflector 102 and the second sub-concave reflector 103 are fixed to the dimming device, and the non-reflective surfaces of the two sub-concave reflectors are pressed against but not fixed to the base plate 108. The light beam is input from the input end 104 into the reflection cavity through the light source device. The dimming device is controlled to move the relative position between the first sub-concave reflector 102 and the second sub-concave reflector 103 along the x-direction to adjust the magnitude of the relative position vector of the first curvature center 102a and the second curvature center 103a along the x-axis. The movement of the relative position between the first sub-concave reflector 102 and the second sub-concave reflector 103 is stopped when the light beam is output from the output port 105. At this time, the magnitude of the relative position vector of the first curvature center 102a and the second curvature center 103a along the x-axis is d. During the assembly process after the dimming process is completed, with the magnitude of the relative position vector of the first curvature center 102a and the second curvature center 103a along the x-axis being d, the non-reflective surfaces of the first sub-concave reflector 102 and the second sub-concave reflector 103 are fixed to the base plate 108, thus completing the assembly of the first sub-concave reflector 102 and the second sub-concave reflector 103.

[0032] In application, the dimming device includes at least a displacement platform for moving the first sub-concave reflector 102 and the second sub-concave reflector 103, and a fixing mechanism or clamp for fixing or holding the main concave reflector 101, the first sub-concave reflector 102, the second sub-concave reflector 103 and the base plate 108. The displacement platform can be a two-axis platform that can move along the x-direction and the y-direction, or a three-axis displacement platform that can move along the x-direction, the y-direction and the x-direction.

[0033] In applications, the light source can be any type of laser, such as a tunable laser, specifically a Fabry-Perot laser, a distributed feedback semiconductor laser, a distributed Bragg reflector laser, a vertical-cavity surface-emitting laser, and an external-cavity tunable semiconductor laser; the light source can also be an incoherent light source, such as an ultraviolet or thermal radiation source. The light source can be mounted or integrated into a dimming device.

[0034] In one embodiment, the main concave reflector 101, the first sub-concave reflector 102, and the second sub-concave reflector 103 can be made of glass material through an optical cold working process, and the base plate 108 is made of the same glass material. The side of the first sub-concave reflector 102 and the second sub-concave reflector 103 away from the main concave reflector 101 (i.e., the non-reflective side) can be fixed to the base plate 108 by adhesive. In one embodiment, the main concave reflector 101, the first sub-concave reflector 102, and the second sub-concave reflector 103 can be made of metal material through machining processes, and the base plate 108 is made of the same metal material. The side of the first sub-concave reflector 102 and the second sub-concave reflector 103 away from the main concave reflector 101 (i.e., the non-reflective side) can be fixed to the base plate 108 by threaded fasteners.

[0035] In applications, the dimming device can be mounted or integrated into optical cold processing equipment or machining equipment. Optical cold processing equipment may include diamond wire cutting machines, single-sided grinding / polishing machines, CNC optical edge grinding machines, multi-groove ultrasonic cleaning machines, etc. Machining equipment may include multi-axis CNC lathes, horizontal machining centers, fully automatic tapping machines, slow wire cutting machines, CNC cylindrical grinding machines, etc.

[0036] In applications, adhesives may include UV-curable optical adhesives, epoxy optical adhesives, silicone optical adhesives, etc. Threaded fasteners may include countersunk hex socket head cap screws, pan head hex socket set screws, thin flange nuts, countersunk Phillips head screws, etc.

[0037] In one embodiment, the reflecting surfaces of the main concave mirror 101, the first sub-concave mirror 102, and the second sub-concave mirror 103 are respectively coated with high-reflectivity films, which include at least one of high-reflectivity metal films and multilayer dielectric films. By coating the reflecting surfaces of each mirror in the high-stability White cell 100 with high-reflectivity films, the reflectivity of the light beam in the reflecting cavity can be increased, and the transmission loss of the light beam in the reflecting cavity can be reduced, thereby increasing the light intensity of the light beam output from the output end 105. This, in turn, increases the signal strength of the electrical signal converted from the output light beam after being received by the photodetector. When the high-stability White cell is applied to a gas detection device, the accuracy of the gas detection results obtained based on the electrical signal can be improved.

[0038] In one embodiment, a 2×2 ABCD matrix is ​​used for optical analysis of the high-stability White pool 100. Since the optical axes of the first sub-concave mirror 102 and the second sub-concave mirror 103 are not coaxial, a 4×4 augmented matrix is ​​used for optical analysis. The expression for the augmented matrix of the high-stability White pool 100 is as follows: (Expression 1) (Expression 2) in, It is the input position vector of the light beam. It is the input angle vector of the light beam. It is the output position vector of the beam. It is the output angle vector of the light beam. It is the ABCD matrix of a known coaxial optical system. It is the position offset. It is the angular offset.

[0039] In one embodiment, the expression for matrix T when the light beam enters the reflecting cavity from the input end 104, completes one cycle of reflection within the reflecting cavity, returns to the reflection point of the principal concave mirror 101, and is reflected by the reflection point into light beam 109 is as follows: (Expression 3) The light beam enters the reflecting cavity from input terminal 104, completes n cyclic reflections within the reflecting cavity, and is output from output terminal 105. The expression for matrix Tn is as follows: (Expression 4) (Expression 5) (Expression 6) (Expression 7) (Expression 8) (Expression 9) (Expression 10) (Expression 11) in, It is the optical path matrix of a single transmission of a light beam within the reflecting cavity. It is the reflection matrix when the light beam is reflected by any reflection point within the reflecting cavity. yes The inverse matrix, It is the coordinate transformation matrix of the first sub-concave mirror 102. yes The inverse matrix, It is the position of the optical axis of the first concave mirror 102. It is the angle of the optical axis of the first concave mirror 102. It is the coordinate transformation matrix of the second sub-concave mirror 103. yes The inverse matrix, It is the position of the optical axis of the second concave mirror 103. It is the angle of the optical axis of the second concave mirror 103.

[0040] In one embodiment, substituting expressions 5-11 into expression 1 yields the following expression for matrix T: (Expression 12) It can be proven that the expression for matrix Tn is as follows: (Expression 13) In one embodiment, combining expressions 1 and 13, the output position vector of the light beam when it enters the reflecting cavity from the input end 104, completes n cyclic reflections within the reflecting cavity, and exits from the output end 105 is obtained. and the output angle vector of the beam The expression is as follows: (Expression 14) (Expression 15) From expressions 14 and 15, we can conclude that... Assuming it is constant, when the light beam enters the reflecting cavity from the input end 104 and completes n cycles of reflection within the reflecting cavity before exiting from the output end 105, the output position and output angle of the light beam are only related to the relative position and relative angle between the first sub-concave reflector 102 and the second sub-concave reflector 103, as detailed below: (Expression 16) (Expression 17) in, It refers to the relative position between the optical axis of the first sub-concave mirror 102 and the optical axis of the second sub-concave mirror 103. It is the relative angle between the optical axis of the first sub-concave mirror 102 and the optical axis of the second sub-concave mirror 103.

[0041] From expressions 14 and 15, we can also derive the following expression for the relative displacement between the output position and the input position of the light beam when it enters the reflecting cavity from the input end 104, completes n cycles of reflection within the reflecting cavity, and is output from the output end 105: (Expression 18) The expression for the relative angle between the output angle and the input angle of the beam is as follows: (Expression 19) The expression for the relative position vector is as follows: (Expression 20) Wherein, d is defined as the vector formed by the line connecting the intersection of the optical axis of the first sub-concave mirror and the optical axis of the second sub-concave mirror with the main concave mirror.

[0042] In expression 20, the first term The second term is determined by the translation distance of the first sub-concave reflector 102 and the second sub-concave reflector 103. The tilt angle of the first sub-concave mirror 102 and the second sub-concave mirror 103 is determined by the tilt angle of the first sub-concave mirror 102 and the second sub-concave mirror 103. Since the first sub-concave mirror 102 and the second sub-concave mirror 103 are cut from a single concave mirror 1023, this results in... Very small, no need to tilt the first sub-concave mirror 102 and the second sub-concave mirror 103 pair Compensation is performed so that, since there is no need to tilt the first sub-concave reflector 102 and the second sub-concave reflector 103, they can be flatly fixed to the base plate 108. After fixing, there is no redundant space that would cause the first sub-concave reflector 102 and the second sub-concave reflector 103 to tilt, thereby reducing the relative angle between the optical axis of the first sub-concave reflector 102 and the optical axis of the second sub-concave reflector 103. It is 0, and its change is 0. Also equal to 0, the relative position between the optical axis of the first sub-concave mirror 102 and the optical axis of the second sub-concave mirror 103. Change It is also 0. Because the relative position, rather than the relative angle, between the first sub-concave mirror 102 and the second sub-concave mirror 103 is used as the variable for optical path adjustment during the dimming assembly process, the flat contact relationship between the first and second sub-concave mirrors 102 and 103 and the base plate 108 remains unchanged. This maintains the stability of the relative position and relative angle between the first and second sub-concave mirrors 102 and 103. After assembly, especially when working in high-temperature environments, the relative angle between the first and second sub-concave mirrors 102 and 103 will not change due to temperature and stress variations, and the relative position change is almost zero, thereby improving the stability of the optical system. The relative displacement between the output and input positions of the beam. Change The value is also 0. Similarly, we can obtain the relative angle between the output angle and the input angle of the beam. Change The input and output positions of the optical system are also stable and unchanged, as the input and output positions are also 0.

[0043] In the embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of the apparatus is only a logical functional division, and in actual implementation, there may be other division methods, such as multiple apparatuses being combined or integrated.

[0044] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A highly stable White cell, characterized in that, include: The principal concave mirror has a radius of curvature R; The first and second sub-concave reflectors have radii of curvature R, are arranged adjacent to each other along the x-axis, have their centers of curvature located at the midpoints of their adjacent sides, and have a relative positional difference along the x-axis. A relative position vector d is generated, the magnitude of which is greater than 0. The reflecting surfaces of the first sub-concave reflector and the second sub-concave reflector are arranged opposite to the reflecting surface of the main concave reflector along the z-axis and spaced apart by R to form a reflecting cavity. The x-axis is parallel to the focal plane of the main concave reflector, and the z-axis is perpendicular to the focal plane of the main concave reflector. The input end is disposed on the main concave reflector and is used to input the light beam; The output end is located on the main concave reflector and is used to output a light beam.

2. The high-stability White cell as described in claim 1, characterized in that, The first sub-concave reflector and the second sub-concave reflector are obtained by cutting a concave reflector with a curvature center located at the geometric center and a curvature radius of R along the y-axis and separating it along the x-axis, wherein the y-axis is perpendicular to the x-axis and the z-axis.

3. The high-stability White cell as described in claim 1 or 2, characterized in that, It also includes the base plate; During the dimming assembly process, the non-reflective surfaces of the first and second sub-concave reflectors are flat against the base plate, and at least one of the first and second sub-concave reflectors is translated along the x-axis to adjust the relative position vector between the curvature centers of the first and second sub-concave reflectors to d. The translation is stopped after the light beam is input through the input end and output through the output end, and the non-reflective surfaces of the first and second sub-concave reflectors are fixed to the base plate.

4. The high-stability White pool as described in claim 3, characterized in that, The main concave reflector, the first sub-concave reflector, and the second sub-concave reflector are made of glass material through an optical cold working process. The base plate is made of the same glass material. The side of the first sub-concave reflector and the second sub-concave reflector away from the main concave reflector is fixed to the base plate with adhesive. Alternatively, the main concave reflector, the first sub-concave reflector, and the second sub-concave reflector are made of metal material through machining processes, and the base plate is made of the same metal material. The side of the first sub-concave reflector and the second sub-concave reflector away from the main concave reflector is fixed to the base plate by threaded fasteners.

5. The high-stability White cell as described in claim 1 or 2, characterized in that, The reflective surfaces of the main concave mirror, the first sub-concave mirror, and the second sub-concave mirror are coated with a high-reflectivity film, which includes at least one of a high-reflectivity metal film and a multilayer dielectric film.

6. The high-stability White cell as described in claim 1 or 2, characterized in that, The expression for the augmented matrix of the highly stable White pool is as follows: ； ； in, It is the input position vector of the beam. It is the input angle vector of the light beam. It is the output position vector of the beam. It is the output angle vector of the beam. It is the ABCD matrix of a known coaxial optical system. It is the position offset. It is the angular offset.

7. The high-stability White pool as described in claim 6, characterized in that, The expression for the matrix T when the light beam enters the reflecting cavity from the input end, completes one cycle of reflection within the reflecting cavity, returns to the reflection point of the principal concave mirror, and is reflected by the reflection point is as follows: ； The light beam enters the reflecting cavity from the input end, and after completing n cyclic reflections within the reflecting cavity, it is output from the output end. The expression for matrix Tn is as follows: ； ； ； ； ； ； ； ； in, It is the optical path matrix of the beam during a single transmission within the reflecting cavity. It is the reflection matrix when the light beam is reflected by any reflection point within the reflecting cavity. yes The inverse matrix, It is the coordinate transformation matrix of the first sub-concave reflector. yes The inverse matrix, It is the position of the optical axis of the first concave mirror. It is the angle of the optical axis of the first concave mirror. It is the coordinate transformation matrix of the second sub-concave mirror. yes The inverse matrix, It is the position of the optical axis of the second sub-concave mirror. It is the angle of the optical axis of the second concave mirror.

8. The high-stability White pool as described in claim 7, characterized in that, The expression for matrix T is as follows: ； The expression for the matrix Tn is as follows: 。 9. The high-stability White cell as described in claim 8, characterized in that: ； ； ； ； in, It refers to the relative position between the optical axes of the first sub-concave mirror and the second sub-concave mirror. It is the relative angle between the optical axes of the first sub-concave reflector and the second sub-concave reflector.

10. The high-stability White cell as described in claim 9, characterized in that, The expression for the relative displacement between the output position and the input position of the beam is as follows: ； The expression for the relative angle between the output angle and the input angle of the beam is as follows: ； The expression for the relative position vector d is as follows: ； Wherein, d is defined as the vector formed by the line connecting the intersection of the optical axis of the first sub-concave mirror and the optical axis of the second sub-concave mirror with the main concave mirror.

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