A mirror for linearly amplifying optomechanical driving displacement and a preparation method thereof

Abstract

The present invention relates to a mirror for linearly amplifying the displacement driven by light pressure and a preparation method thereof. The mirror includes a laser irradiation area disposed at the center position of the mirror; a clamping area disposed on the outer ring of the mirror; and a plurality of elastic support arms disposed between the laser irradiation area and the clamping area. The elastic support arms elastically support the laser irradiation area, reducing the stiffness in the direction of the light pressure action and being used for amplifying the displacement driven by light pressure of the laser irradiation area. The arrangement of the plurality of elastic support arms increases the stiffness in the direction of the gravity action, ensuring the linearity of the displacement response of the mirror driven by light pressure and solving the problem of the performance degradation of the mirror in actual use. The mirror of the present invention has the advantages of high conversion efficiency from light energy to mechanical energy, good linearity of displacement response, miniaturization and low cost, and can be widely applied to the field of precision measurement.

Description

Technical Field

[0001] This application relates to the field of precision measurement technology, and particularly relates to a mirror for linearly amplifying the displacement driven by light pressure and a preparation method thereof. Background Art

[0002] When a laser beam irradiates an object, there are various effects that can cause the object to move, including photothermal effect, photoacoustic effect, photoelastic effect, and light pressure effect. Among them, the light pressure effect can precisely generate a tiny force in the piconewton to millinewton range to drive an object, and can push the target object to move without damage, converting light energy into the mechanical energy of the target object. Based on the above energy conversion principle, new optical sensors can be developed. Therefore, the light pressure effect has extremely high application value and potential in precision measurement applications.

[0003] Since the tiny force generated by the light pressure effect cannot overcome the gravity and friction of macroscopic mirrors with centimeter-scale and larger sizes, the displacement amplitude caused by light pressure on ordinary mirrors is only dozens to hundreds of picometers, and the energy conversion efficiency from light energy to mechanical energy is extremely low, making it difficult to be measured by traditional force measuring instruments or displacement sensors. Summary of the Invention

[0004] To solve the above technical problems, this application is proposed. This application provides a mirror for linearly amplifying the displacement driven by light pressure and a preparation method thereof, which solves the problem in the prior art that due to the small displacement response generated by light pressure irradiating on the mirror and the low energy conversion efficiency from light energy to mechanical energy, it is difficult to be measured by traditional force measuring instruments or displacement sensors.

[0005] According to one aspect of this application, a mirror for linearly amplifying the displacement driven by light pressure is provided, including a laser irradiation area disposed at the central position of the mirror; a clamping area disposed on the outer ring of the mirror; and a plurality of elastic support arms disposed between the laser irradiation area and the clamping area. When a laser irradiates the laser irradiation area, the plurality of elastic support arms are used to amplify the displacement driven by the light pressure in the laser irradiation area.

[0006] The clamping area of the mirror can use a multi-point clamping fixture, a single-point bonding fixture, a multi-point bonding fixture, or a magnetic pre-tightening fixture to clamp and fix the mirror. [[ID=I23]]

[0007] In one embodiment, the plurality of elastic support arms and the laser irradiation area and the clamping area are of an integral structure.

[0008] In one embodiment, the plurality of elastic support arms are evenly distributed in a spiral around the center point of the mirror between the laser irradiation area and the clamping area.

[0009] In one embodiment, the radius of the mirror is 10 mm - 20 mm, the radius of the laser irradiation area is 4 mm - 8 mm, and the width of the clamping area is 1 mm - 2 mm.

[0010] In one embodiment, the helix radius of the elastic support arm is 1 mm - 3 mm, the arm width of the elastic support arm is 1 mm - 3 mm, and the thickness of the elastic support arm is 5 μm - 500 μm.

[0011] In one embodiment, the parametric equation C(x, y) of the elastic support arm is

[0012] x = w0 s cos(s), s ∈ [0, 3π / 2]

[0013] y = w0 s sin(s), s ∈ [0, 3π / 2]

[0014] where: w0 is the helix radius of the elastic support arm; s is the independent variable of the parametric equation; ∈ indicates that s takes values in the interval [0, 3π / 2].

[0015] According to another aspect of the present application, a method for preparing a mirror for linearly amplifying the displacement driven by light pressure is provided. (1) Substrate preparation: Select a transparent optical material with a wavelength of 10 nm - 2000 nm and process it to obtain the substrate of the mirror; (2) Coating: Coat the surface of the prepared substrate of the mirror to obtain the mirror.

[0016] In one embodiment, the transparent optical material is selected from transparent optical materials in the ultraviolet, visible, and infrared bands, with an optical transmittance greater than 50%. The transparent optical materials include optical glass, optical plastics, and carbon element flakes; the optical glass includes rare earth element optical glass, lead-free optical glass, fluorophosphate optical glass, Asahi Glass, and quartz crystals; the optical plastics include, but are not limited to, polymethyl methacrylate (PMMA), polystyrene (PS), styrene-methyl methacrylate copolymer (NAS), styrene-acrylonitrile copolymer (SAN), polycarbonate (PC), allyl diglycol carbonate (CR-39), 4-methylpentene polymer (TPX), cycloolefin polymer (COP), and cycloolefin copolymer (COC). The carbon element flakes include, but are not limited to, diamond flakes, graphite flakes, and two-dimensional carbon element materials.

[0017] In one embodiment, the substrate of the mirror is prepared by using one of the processing methods such as laser cutting, 3D printing, material self-assembly, etching, and glass molding.

[0018] In one embodiment, the coating includes one of evaporation coating, ion sputtering, physical vapor deposition, chemical vapor deposition, or electroplating.

[0019] In one embodiment, the base surface of the mirror includes the front surface (laser irradiation surface) of the mirror and the back surface of the mirror.

[0020] In one embodiment, the film is one of a dielectric film or a metal film. The metal film is one of a gold film layer, a gold oxide film layer, a silver film layer, a silver oxide film layer, an aluminum film layer, an aluminum oxide film layer, a copper film layer, and a copper oxide film layer. The dielectric film is one of a silicon dioxide film layer, a zirconium oxide film layer, a tantalum oxide film layer, a titanium oxide film layer, a gallium arsenide film layer, and an aluminum gallium arsenide film layer.

[0021] A mirror for linearly amplifying the light-pressure-driven displacement provided by the present application. The mirror includes a laser irradiation area disposed at the central position of the mirror; a clamping area disposed on the outer ring of the mirror; and a plurality of elastic support arms disposed between the laser irradiation area and the clamping area. When laser irradiates the laser irradiation area, the plurality of elastic support arms are used to amplify the light-pressure-driven displacement of the laser irradiation area. By providing a plurality of elastic support arms, the stiffness of the elastic support arms in the gravity direction is increased, and the deformation of the mirror under the action of gravity is reduced. Under the action of a 132 nN light pressure, the mirror can generate a light-pressure-driven displacement of 0.1 nm to 10 μm. The light-pressure-driven displacement of 0.1 nm to 10 μm is a displacement that can be observed by a displacement sensor, which improves the conversion efficiency from light energy to mechanical energy. The mirror of the present application can be widely applied to the field of precision measurement for the precision measurement of light pressure at the macroscopic scale, the on-line measurement of the output power of high-power lasers, or laser processing. Description of the Drawings

[0022] By describing the embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. The drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0023] Figure 1 It is a schematic structural diagram of a mirror for linearly amplifying the light-pressure-driven displacement provided by an exemplary embodiment of the present application;

[0024] Figure 2 It is a front view of a mirror for linearly amplifying the light-pressure-driven displacement provided by an exemplary embodiment of the present application and a schematic diagram of the parametric equation C(x, y) of the spiral curve (in the figure, R represents the radius of the mirror; r represents the radius of the laser irradiation area; L represents the width of the clamping area; h represents the thickness of the laser irradiation area; W represents the arm width of the elastic support arm; w0 represents the radius of the spiral).

[0025] Figure 3 It is a schematic structural diagram of a mirror for linearly amplifying the displacement driven by light pressure in a fixture under the action of light pressure and gravity provided by an exemplary embodiment of the present application;

[0026] Figure 4 It is a schematic diagram of the light pressure load distribution on a mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application ((a) in the figure is the laser power density distribution, and (b) is the light pressure density graduation);

[0027] Figure 5 It is the simulation result of the steady-state displacement field of a mirror for linearly amplifying the displacement driven by light pressure under the action of light pressure provided by an exemplary embodiment of the present application ((a) in the figure is a schematic diagram of the deformation of the mirror, (b) is the result of the light pressure driven displacement field of the mirror, and (c) is the displacement field result of the laser irradiation area);

[0028] Figure 6 It is a schematic structural diagram of the substrate and the coated mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application ((a) in the figure is the substrate after processing the mirror, and (b) is the structure of the coated mirror);

[0029] Figure 7 It is the experimental result of the light pressure driven displacement measurement of a mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application ((a) in the figure is the comparative example, and (b) is the first embodiment);

[0030] Figure 8 It is a schematic diagram of mirrors with different structural parameters for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application;

[0031] Figure 9 It is a curve of the negative correlation non-linear function relationship between the structural parameters of a mirror for linearly amplifying the displacement driven by light pressure and the light pressure driven displacement and the deformation introduced by gravity;

[0032] Figure 10 It is a comparative curve of the performance improvement after the structure optimization of a mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application.

[0033] 1. Laser irradiation area; 2. Elastic support arm; 3. Clamping area; 4. Fixture. Embodiment

[0034] Next, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited by the exemplary embodiments described herein.

[0035] Application Overview:

[0036] When laser light irradiates an object, there are various effects that can cause the object to move, including photothermal effects, photoacoustic effects, photoelastic effects, and light pressure effects, etc. Among them, the light pressure effect can provide precise micro-forces in the range of pN to mN to drive the object, meeting the movement requirements of small and fragile objects, and technologies such as optical cooling, optical tweezers, and optical manipulation have been developed.

[0037] Optical cooling technology utilizes light pressure to produce a coherent effect between the light field and atoms, redistributing the light field to achieve control of atomic thermal motion. The objects of optical cooling are at the atomic scale of 0.1 nm to 1 nm. Generally, it is considered that when the atomic temperature is as low as 10 -3 K, thermal motion can be overcome, and at this time, stable manipulation of atoms can be achieved. The sizes of the objects moved by optical tweezers and optical manipulation are in the range of 0.1 nm to 100 μm. Optical manipulation technology based on orbital angular momentum and spin angular momentum can achieve absorption and birefringence through the transfer of photon angular momentum, and can move atoms smaller than 0.1 nm, and is applied to frontier fields such as particle orbiting and spin, and orbital / spin coupling. The optical tweezers based on the Talbot effect can also move objects smaller than 0.1 nm at least, and are applied to arrayed optical traps. The scanning laser optical tweezers developed through the time-domain differential principle can move objects up to 100 μm at most. By specially designing the optical fiber to change and modulate the light beam, low-cost deformable optical tweezers, standing-wave optical tweezers, and double-beam optical tweezers can be fabricated, which can move objects up to 100 μm at most and are applied to particle assembly, and efficient microfabrication can be achieved. Holographic optical tweezers and surface plasmon optical tweezers can move objects from 1 nm to 10 nm. These optical cooling, optical tweezers, and optical manipulation technologies are currently widely applied in fields such as quantum mechanics, micro-biology, nano-physics, and chemistry.

[0038] When the size of the irradiated object continues to increase and enters the macroscopic scale, reaching the mm level or even the cm level, the complexity of the problem of moving the object by light pressure begins to increase. Since the light pressure cannot overcome the gravity and friction of macroscopic objects, the way of manipulating the object has changed from optical trapping to light-induced propulsion and light-induced deformation, that is, light pressure-driven motion. Currently, light pressure-driven motion has begun to be applied in precision measurement research fields such as the verification of electromagnetic field force theory, laser parameter measurement, and the traceability of micro-forces. However, due to the extremely small magnitude of light pressure, for example, the displacement amplitude caused by a pulsed laser with a wavelength of 1064 nm and a single-pulse energy of 1 J on a fused silica substrate mirror with a thickness of 5 mm and a diameter of 23.5 mm is only dozens to hundreds of pm, it is very difficult to be measured by traditional force measuring instruments or displacement sensors. Therefore, the key problem in applying light pressure-driven motion is the amplification of light pressure-driven motion.

[0039] Figure 1 It is a schematic diagram of a mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application; Figure 2The front view of a mirror for linearly amplifying the displacement driven by light pressure and the schematic diagram of the parametric equation C(x, y) of the spiral curve provided by an exemplary embodiment of the present application are shown as follows. Figure 1 and Figure 2 As shown, the mirror for linearly amplifying the displacement driven by light pressure includes a laser irradiation area 1 disposed at the center of the mirror; a clamping area 3 disposed on the outer ring of the mirror; and a plurality of elastic support arms 2 disposed between the laser irradiation area 1 and the clamping area 3. When the laser irradiates the laser irradiation area 1, the light pressure will push the laser irradiation area 1 to displace under the elastic support of the plurality of elastic support arms 2.

[0040] The parametric equation C(x, y) of the elastic support arm is

[0041] x = w0 s cos(s), s ∈ [0, 3π / 2]

[0042] y = w0 s sin(s), s ∈ [0, 3π / 2]

[0043] Where: w0 is the spiral radius of the elastic support arm; s is the independent variable of the parametric equation; ∈ indicates that s takes values in the interval [0, 3π / 2]. The parametric equation C(x, y) describes the shape of the support arm in coordinate form.

[0044] In one embodiment, the plurality of elastic support arms 2 and the laser irradiation area 1 and the clamping area 3 are of an integral structure. This structure has stronger reliability, stability and lifespan than the assembled structure, simplifies the design and manufacturing process of the mirror, and has the advantages of miniaturization and low cost.

[0045] It should be understood that the number of the elastic support arms 2 of the present application can be three. The three elastic support arms 2 form an elastic support structure relative to the mirror for amplifying the elastic displacement response of the mirror.

[0046] In one embodiment, the elastic support arms 2 are distributed in a spiral around the center point of the mirror, that is, the elastic support arms 2 are rotationally symmetrically distributed around the geometric center point of the mirror. This rotational structure of the spiral increases the length of a single elastic support arm 2. When the laser irradiates the mirror, the rotational torques around the x-axis and the y-axis can cancel each other out, reducing the flexural rigidity in the positive z-axis direction (the direction of the light pressure action), ensuring that the laser irradiation area 1 at the center position of the mirror only undergoes a linear displacement in the positive z-axis direction (i.e., the laser irradiation direction) under the action of the light pressure, generating a light pressure-driven displacement, and ensuring the linearity of the light pressure-driven displacement response of the mirror.

[0047] Figure 3It is a schematic structural diagram of a mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application under the action of light pressure and gravity in a fixture, including a laser irradiation area 1, an elastic support arm 2, a clamping area 3, and a fixture 4. The laser irradiation direction (light pressure direction) is as shown by the arrow. The fixture 4 of the mirror can use a multi-point clamping and fixing fixture, a single-point bonding and fixing fixture, a multi-point bonding and fixing fixture, or a magnetic pre-tightening fixture to clamp and fix the mirror. The mirror is vertically installed in the fixture in the xy plane. The positive direction of the z-axis (light pressure acting direction) is perpendicular to the negative direction of the y-axis (gravity acting direction) to prevent the deformation caused by gravitational attraction from offsetting the displacement driven by light pressure. The three support arms form an angle of 120 degrees with each other, and the connecting lines of the three connection points between the support arms and the clamping area form an isosceles triangle, increasing the structural stability of the mirror under the action of gravity.

[0048] Figure 6 It is a schematic structural diagram of the substrate and the coated film of a mirror for linearly amplifying the displacement driven by light pressure provided by an exemplary embodiment of the present application. A preparation method for a mirror for linearly amplifying the displacement driven by light pressure includes (1) substrate preparation, selecting a transparent optical material with a wavelength of 10 nm to 2000 nm, and processing and preparing the substrate of the mirror, as shown in Figure 6 (a); (2) coating, coating the surface of the prepared substrate of the mirror, and the film layer uses a dielectric film with a multi-layer Bragg structure, as shown in Figure 6 (b).

[0049] Specifically, the surface of the substrate of the mirror includes the front surface (laser irradiation surface) and the back surface of the mirror. The transparent optical material is selected from transparent optical materials in the ultraviolet band, visible light band, and infrared band, with an optical transmittance greater than 50%. The transparent optical materials include optical glass, optical plastics, and carbon element thin sheets; the optical glass includes rare earth element optical glass, lead-free optical glass, fluorophosphate optical glass, Asahi Glass, and quartz crystals; the optical plastics include, but are not limited to, polymethyl methacrylate (PMMA), polystyrene (PS), styrene-methyl methacrylate copolymer (NAS), styrene-acrylonitrile copolymer (SAN), polycarbonate (PC), allyl diglycol carbonate (CR-39), 4-methylpentene polymer (TPX), cycloolefin polymer (COP), and cycloolefin copolymer (COC). The carbon element thin sheets include, but are not limited to, diamond thin sheets, graphite thin sheets, and two-dimensional carbon element materials.

[0050] In one embodiment, the substrate preparation is carried out by using one of the processing methods of laser cutting, 3D printing, material self-assembly, etching, and glass molding;

[0051] Specifically, the coating technology is one of evaporation coating, ion sputtering, physical vapor deposition, chemical vapor deposition, or electroplating.

[0052] It should also be understood that the film layer is one of a metal film or a dielectric film. The metal film is one of a gold film layer, a gold oxide film layer, a silver film layer, a silver oxide film layer, an aluminum film layer, an aluminum oxide film layer, a copper film layer, and a copper oxide film layer. The dielectric film is one of a silicon dioxide film layer, a zirconia film layer, a tantalum oxide film layer, a titanium oxide film layer, a gallium arsenide film layer, and an aluminum gallium arsenide film layer.

[0053] Example 1

[0054] Select K9 optical glass, use laser cutting technology, and refer to the parameters of the mirror in Example 1 of Table 1 to cut the quartz glass. Then, coat the surface of the mirror substrate with a dielectric film having a multi-layer Bragg structure. Vertically install the coated mirror in a bolt pre-tightening fixture and perform laser irradiation to calculate the optical pressure and the optical pressure-driven displacement.

[0055] Optical pressure calculation

[0056] Figure 4 is a schematic diagram of the optical pressure load distribution on a mirror for linearly amplifying the optical pressure-driven displacement provided by an exemplary embodiment of the present application ((a) in the figure is the laser power density distribution, and (b) is the optical pressure density distribution); as Figure 4 shown, according to the classical electromagnetic field theory, the relationship between the laser power density distribution and the optical pressure density distribution is deduced. The optical pressure is generated by the linear momentum transfer of the electromagnetic field. The density of the momentum carried by the laser during propagation is the Poynting vector of the electromagnetic field divided by the square of the speed of light in vacuum, as shown in Equation (1).

[0057]

[0058] In Equation (1), is the momentum density, representing the momentum per unit volume; is the Poynting vector, representing the electromagnetic energy flux, and c is the speed of light in vacuum. When the laser interacts with the mirror, due to reflection, the laser momentum changes, which is manifested as a force acting on the mirror, that is, the optical pressure. The optical pressure and the laser momentum change satisfy the momentum theorem, that is, Equation (2).

[0059]

[0060] In Equation 2, F z is the optical pressure, Δt is a sufficiently small time during the laser irradiation of the mirror, R f is the reflectivity, n is the refractive index of the medium, A is the area element, and θ is the incident angle. Here, the description of the optical momentum in the medium adopts the Abraham form. Further simplifying Equation (2) can obtain the relationship between the laser power density distribution P(x, y) and the optical pressure density distribution G z (x, y), as shown in Equation (3).

[0061]

[0062] In this embodiment, the incident laser is a Gaussian beam with a power of 20 W, a spot diameter of 5.5 mm, and an incident angle of 7.5°. It is obliquely irradiated on the laser irradiation area. The laser power density distribution P(x, y) is as shown in Figure 4 (a). The laser power density shows a Gaussian distribution. The maximum value of the power density appears at the center position of the mirror, and the power density gradually decays towards both sides. The average optical pressure F z The formula for calculating the magnitude is as shown in Equation (4)

[0063]

[0064] In Equation (4), P is the average power of the laser, c is the speed of light in vacuum, n is the refractive index of the medium, and the direction of the optical pressure of the incident laser on the mirror is the positive direction of the z-axis. Substituting the parameter values into the above formula, the magnitude of the average optical pressure can be obtained as 132.17 nN.

[0065] (2) Displacement driven by optical pressure

[0066] Figure 5 is the simulation result of the steady-state displacement field of the mirror for linearly amplifying the displacement driven by optical pressure provided by an exemplary embodiment of the present application (in the figure, (a) is a schematic diagram of the deformation of the mirror, with a magnification ratio of 5×10 4 , (b) is the result of the displacement field driven by the optical pressure of the mirror, and (c) is the result of the displacement field of the laser irradiation area). Under the action of the optical pressure, the outermost clamping area of the mirror remains stationary, the laser irradiation area moves linearly along the z-axis, and the three elastic support arms undergo bending deformation. As shown in Figure 5 (b), the displacement u(0, 0) driven by the optical pressure in the laser irradiation area is 25.43 nm. The morphology of the mirror under the action of the optical pressure is as shown in Figure 5 (c). The peak-to-valley (P-V) value of the mirror is less than 0.5 nm, maintaining good flatness. <X

[0067] Figure 7 is the experimental result of the steady-state displacement of the mirror for linearly amplifying the displacement driven by optical pressure provided by an exemplary embodiment of the present application. As shown in Figure 7 (b), for the mirror processed with the parameters in Example 1 of Table 1, under laser irradiation, the displacement driven by the optical pressure generated is 24.90 nm.

[0068] Example 2

[0069] Same as Example 1, the difference is that the parameters of the mirror in Example 2 of Table 1 are referred to.

[0070] Example 3

[0071] Same as Example 1, except that the parameters of the mirror in Example 3 of Table 1 are referred to.

[0072] Example 4

[0073] Same as Example 1, except that the parameters of the mirror in Example 4 of Table 1 are referred to.

[0074] Example 5

[0075] Same as Example 1, except that the parameters of the mirror in Example 5 of Table 1 are referred to.

[0076] Example 6

[0077] Same as Example 1, except that the parameters of the mirror in Example 6 of Table 1 are referred to.

[0078] Example 7

[0079] Same as Example 1, except that the parameters of the mirror in Example 7 of Table 1 are referred to.

[0080] Example 8

[0081] Same as Example 1, except that the parameters of the mirror in Example 8 of Table 1 are referred to.

[0082] Example 9

[0083] Same as Example 1, except that the parameters of the mirror in Example 9 of Table 1 are referred to.

[0084] Example 10

[0085] Same as Example 1, except that the parameters of the mirror in Example 10 of Table 1 are referred to.

[0086] Example 11

[0087] Same as Example 1, except that the parameters of the mirror in Example 11 of Table 1 are referred to.

[0088] Example 12

[0089] Same as Example 1, except that the parameters of the mirror in Example 12 of Table 1 are referred to.

[0090] Comparative example

[0091] The preparation method of the mirror is the same as that of Example 1, except that the elastic arm structure is not processed for the mirror in the comparative example, and the parameters of the mirror in the comparative example of Table 1 are referred to.

[0092] Table 1 Structural parameters and light pressure driven displacement table of different examples and comparative examples

[0093]

[0094]

[0095] (1) Using the finite element method, calculate Examples 2 - 10 in Table 1 to obtain the light pressure driven displacement u and the deformation v introduced by gravity for each group. From the calculation results in Table 1, it can be seen that Example 2 has the best light pressure driven displacement amplification effect. The light pressure driven displacement u at the center position of the mirror is 84.99 nm, but the deformation v introduced by gravity under this set of parameters is 46.37 nm, which is the maximum value among all examples. The relatively large gravity deformation will cause the mirror to rotate around the x-axis in the laser irradiation area under the action of light pressure, resulting in a reduced linear range of displacement response and an increased non-linear error, affecting the effect of linearly amplifying the light pressure driven displacement of the mirror in actual use. The combination with the smallest deformation value introduced by gravity is Example 4, and the deformation v of the mirror along the gravity direction is 0.1 nm, but the light pressure driven displacement u under this parameter combination is also extremely small, being 0.1 nm, and the effect of amplifying the light pressure driven displacement is not achieved.

[0096] (2) It can be analyzed from the results in Table 1 that there is a negative correlation between the helix radius w0, the arm width W, and the thickness h and both the light pressure driven displacement u and the deformation v introduced by gravity. Using the finite element method for parameter scanning analysis, the results are as Figure 9 shown. Figure 9 is the negative correlation non-linear function relationship curve between the structural parameters of the mirror for linearly amplifying the light pressure driven displacement provided by an exemplary embodiment of the present application and the light pressure driven displacement u and the deformation v introduced by gravity; combining the results in Table 1 and Figure 9 it can be seen that adjusting the three geometric shape parameters of the support arm can effectively amplify the light pressure driven displacement response, but at the same time, it will introduce a relatively large gravity deformation along the negative y-axis direction on the mirror, which will affect the geometric shape and rotational symmetry structure of the elastic support arm of the mirror and reduce the linearity of the light pressure driven displacement response of the mirror. Adjusting down the geometric shape of the support arm can increase the stiffness of the support arm in the x and y directions and reduce the deformation of the mirror under the action of gravity, but it will increase the bending stiffness in the z direction and reduce the light pressure driven displacement response.

[0097] Table 2 Range analysis table of light pressure driven displacement u

[0098]

[0099] Table 3 Range analysis table of deformation v introduced by gravity

[0100]

[0101] (3) By performing range analysis on the data in Table 1, the influence degrees of the arm width, thickness, and helix radius on the opto-pressure driven displacement and the deformation introduced by gravity can be analyzed. The results of the range analysis are shown in Tables 2 and 3. As can be seen from Table 2, the order of the influence capabilities of the three parameters on the amplification effect of the opto-pressure driven displacement is arm width > thickness > helix radius. The embodiment 2 with the largest opto-pressure driven displacement u has a helix radius of 1 mm, an arm width of 1 mm, and a thickness of 100 μm. As can be seen from Table 3, the order of the influence capabilities of the three parameters on the deformation introduced by gravity is arm width > thickness > helix radius. The one that minimizes the deformation v introduced by gravity is embodiment 3, with a helix radius of 2 mm, an arm width of 3 mm, and a thickness of 300 μm. The influence of the opto-pressure driven displacement and the deformation introduced by gravity can be optimized by adjusting the arm width. In this embodiment, the weight 1 given to embodiment 2 is 90%, and the weight 2 given to embodiment 3 is 10%. Optimization calculations are performed according to weighted summation and rounded up according to the actual processing ability to obtain optimized embodiment 1, where the helix radius of embodiment 1 is 2 mm, the arm width is 1 mm, and the thickness is 100 μm.

[0102] (4) Figure 10 is the performance improvement comparison curve after the optimization of the mirror structure for linearly amplifying the opto-pressure driven displacement provided by an exemplary embodiment of the present application. In Figure 10 , the curve in the figure represents the displacement response curve of the center point of the mirror changing with the magnitude of the opto-pressure under the combined action of the opto-pressure and gravity. In order to compare the change in the linearity of the opto-pressure driven displacement of the mirror before and after the optimization of the structural parameters, the maximum value of the displacement is used to normalize the response curve. In Figure 10 , the gray dashed line is the ideal linear response curve. The smaller the distance between the curve in the figure and the gray dashed line, the better the linearity of the opto-pressure driven displacement response represented by the curve.

[0103] Using the structural parameters of embodiment 2 as the structural parameters before optimization, the response curve is calculated, and the result is as shown by the blue curve in Figure 10 . Under this set of parameters, the value of the opto-pressure driven displacement is the largest, but due to the large deformation introduced by gravity, the linearity of the displacement response decreases, and the maximum non-linear deviation is 23.25% of the maximum value of the opto-pressure driven displacement.

[0104] Using the structural parameters of embodiment 1 as the optimized structural parameters, the response curve is calculated, and the result is as shown in Figure 10As shown by the orange curve in []. After optimization, the linearity of the light pressure-driven displacement curve of the mirror structure is significantly improved. After the light pressure is greater than 80 nN, it coincides with the ideal linear displacement response curve. The maximum non-linear deviation appears at the zero position, and the non-linear deviation is 7.31%. When the light pressure is greater than 15 nN, the non-linear deviation of the displacement response is less than 3.83%. When the light pressure is greater than 50 nN, the non-linear deviation of the displacement response is less than 1.00%. When the light pressure is greater than 50 nN, the optimized mirror structure has good performance in linearly amplifying the light pressure-driven displacement.

[0105] (5) The mirror proposed in the present invention has extremely small deformation in the laser irradiation area under the action of light pressure, and the peak-to-valley value (P-V value) is less than 0.5 nm. The characteristic of small deformation of the mirror is beneficial to the displacement measurement of non-contact optical instruments, and will not introduce geometric errors caused by plane deformation, which is beneficial to improving the stability of the light pressure magnitude and direction during the use of the mirror. If a large deformation occurs in the irradiation area, resulting in a lens effect, it will affect the laser reflection, and then affect the light pressure magnitude and direction, reducing the light pressure-driven displacement amplification effect and linearity.

[0106] (6) Figure 7 is the steady-state displacement experimental result of the mirror for linearly amplifying the light pressure-driven displacement in an exemplary embodiment of the present application under the action of light pressure. As Figure 7 shown, the experimental results show that under the action of the same light pressure, the mirror processed with the structural parameters of Example 1 has a light pressure-driven displacement more than 15 times larger than that of the mirror with an inelastic support arm structure in the comparative example.

[0107] (8) Figure 8 is a schematic diagram of mirrors with different structural parameters for linearly amplifying the light pressure-driven displacement provided by an exemplary embodiment of the present application. In the figure, (a) is Example 2, (b) is Example 6, and (c) is Example 12. Figure 8 (a) In Example 2, it has a relatively longer support arm length compared to other embodiments, and other parameters are the same as those in Example 1. Example 2 has the smallest stiffness in the light pressure direction, so the light pressure-driven displacement is the largest, but the deformation introduced by gravity is also the largest. The longer support arm leads to a decrease in structural stability. Example 2 is suitable for applications with higher requirements for the amplitude of the light pressure-driven displacement and applications in a microgravity environment. Figure 8 (b) In Example 6, it has a relatively wider arm width compared to other embodiments, and other parameters are the same as those in Example 1. Increasing the arm width can increase the structural stability and reduce the deformation introduced by gravity, but it will also reduce the light pressure-driven displacement. Figure 8In (b), Example 12 has a greater thickness compared to other examples. The other parameters are the same as those of Example 1. From the result comparison in Table 1, it can be seen that increasing the thickness will improve the structural stability but significantly reduce the light-pressure-driven displacement. Example 6 and Example 12 are applicable to applications with high requirements for the stability of light-pressure-driven displacement and applications with relatively high laser power.

[0108] (9) The mirror proposed by the present invention for linearly amplifying the light-pressure-driven displacement is a new concept mirror. By fabricating an elastic structure on the macroscopic mirror to provide elastic support for the area irradiated by the laser, the mirror can move a longer stroke under the action of the same magnitude of light pressure, effectively amplifying the light-pressure-driven motion of the mirror. It has the advantages of large displacement response, good linearity, high light energy to mechanical energy conversion efficiency, miniaturization, and low cost, and can be widely applied in the field of precision measurement, such as: precision measurement of light pressure at the macroscopic scale, on-line measurement of the output power of high-power lasers, and applications such as laser processing.

[0109] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A mirror for linearly amplifying the displacement driven by light pressure, characterized in that: including a laser irradiation area, which is arranged at the central position of the mirror; a clamping area, which is arranged on the outer ring of the mirror; a plurality of elastic support arms, which are arranged between the laser irradiation area and the clamping area. When the laser irradiates the laser irradiation area, the plurality of elastic support arms are used to amplify the light pressure driving displacement of the laser irradiation area; the plurality of elastic support arms and the laser irradiation area and the clamping area are of an integral structure; the plurality of elastic support arms are evenly distributed between the laser irradiation area and the clamping area in a spiral around the center point of the mirror.

2. The mirror for linearly amplifying light pressure-driven displacement according to claim 1, wherein: the radius of the mirror is 10 mm - 20 mm, the radius of the laser irradiation area is 4 mm - 8 mm, and the width of the clamping area is 1 mm - 2 mm.

3. The mirror for linearly amplifying optomechanical displacement according to claim 2, wherein: the spiral radius of the elastic support arm is 1 mm - 3 mm, the arm width of the elastic support arm is 1 mm - 3 mm, and the thickness of the elastic support arm is 5 μm - 500 μm.

4. A mirror for linearly amplifying light-pressure-driven displacement according to claim 3, wherein: the parametric equation C(x, y) of the elastic support arm is x = w0 s cos(s), s ∈ [0, 3π / 2] y = w0 s sin(s), s ∈ [0, 3π / 2] where: w0 is the spiral radius of the elastic support arm, and s is the independent variable of the parametric equation.

5. A method for preparing a mirror for linearly amplifying the light pressure driving displacement according to any one of claims 1 - 4, characterized in that: (1) Substrate preparation, selecting a transparent optical material with a wavelength of 10 nm - 2000 nm, and processing and preparing the substrate of the mirror; (2) Coating, coating the surface of the prepared substrate of the mirror to obtain the mirror.

6. The preparation method of a mirror for linearly amplifying the displacement driven by optical pressure according to claim 5, characterized in that, In the step (1), the substrate of the mirror is processed and prepared by using one of laser cutting, 3D printing, material self-assembly, etching or glass molding.

7. The preparation method of a mirror for linearly amplifying optomechanical displacement according to claim 5, characterized in that, The coating in the step (2) includes one of evaporation coating, ion sputtering, physical vapor deposition, chemical vapor deposition and electroplating.

8. The preparation method of a mirror for linearly amplifying the displacement driven by light pressure according to claim 5, characterized in that, The film in the step (2) is one of a dielectric film or a metal film.

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