Method for preparing phase change material super surface by using ultrafast laser and optical path system

Abstract

The application provides a method for preparing a phase change material super surface by using ultrafast laser and an optical path system, and belongs to the technical field of laser processing. The method comprises the following steps: 1) pretreating a workpiece to be processed; 2) plating a phase change material film on the surface of the workpiece to be processed; 3) forming an ultrafast laser array; and 4) preparing a super surface on the workpiece to be processed which is plated with the phase change material film by using the ultrafast laser array, so as to form a phase change material super surface. The application realizes the processing of the super surface by using the light beam of the ultrafast laser. Compared with the traditional super surface processing process, the whole method is simple in operation, high in processing efficiency, and beneficial to the further popularization and application of the super surface.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser processing, and relates to superfast laser processing technology, in particular to a method for preparing a phase-change material super surface by using superfast laser and an optical path system. BACKGROUND

[0002] A super surface is an artificial structure array formed by a large number of sub-wavelength units arranged periodically or non-periodically on a two-dimensional plane, and can flexibly combine and control the phase, amplitude, frequency and other characteristics of electromagnetic waves, and has wide application prospects in polarization conversion, beam deflection, holographic imaging and the like.

[0003] At present, the preparation process of the super surface includes photoetching, electron beam etching, nanoimprint and femtosecond laser direct writing technologies, wherein the photoetching technology has multiple processing steps and limited material types; the electron beam etching technology has low yield, high processing cost and significant proximity effect; the nanoimprint technology requires expensive template manufacturing and has limited service life, and the pattern transfer process has errors; the femtosecond laser direct writing technology can directly process nanoscale structures and has no limitation on processing materials, but is a single-point processing technology with long production cycle. Due to the complex operation of these technologies, the wide application of the super surface is hindered. SUMMARY

[0004] In view of the problem in the prior art that the operation of the super surface processing technology is complex and hinders the wide application of the super surface, the application provides a method for preparing a phase-change material super surface by using superfast laser and an optical path system.

[0005] The application forms a sub-micron array light beam by shaping the light beam of the superfast laser by using a multi-prism, and prepares a large-area super surface structure by using the sub-micron array light beam, so that the superfast laser is used to process the super surface, and the operation is simple and the processing efficiency is high; and the specific technical scheme is as follows:

[0006] The method for preparing a phase-change material super surface by using superfast laser comprises the following steps:

[0007] 1) Preprocessing a workpiece to be processed;

[0008] 2) Plating a phase-change material film on the surface of the workpiece to be processed;

[0009] 3) Forming a superfast laser array;

[0010] 4) Preparing a super surface on the workpiece to be processed plated with the phase-change material film by using the superfast laser array to form a phase-change material super surface.

[0011] Further limited, the step 3) is specifically as follows:

[0012] 3.1) Generating superfast laser;

[0013] 3.2) regulating the pulse energy of the ultrafast laser;

[0014] 3.3) boosting and reflecting the ultrafast laser;

[0015] 3.4) shaping the ultrafast laser to form an ultrafast laser array.

[0016] Further limited,

[0017] The step 3.1) is specifically: generating an ultrafast laser by using an ultrafast pulse laser;

[0018] The step 3.2) is specifically: adjusting the polarization state of the ultrafast laser by making the ultrafast laser incident on a half-wave plate, and then making the ultrafast laser incident on a polarization beam splitter, and separating the ultrafast laser into a required ultrafast laser and a remaining ultrafast laser by the polarization beam splitter, and rotating the angle of the half-wave plate to regulate the pulse energy of the required ultrafast laser and the pulse energy of the remaining ultrafast laser;

[0019] The step 3.3) is specifically: the required ultrafast laser sequentially passes through a shutter, a second mirror and a third mirror, and the required ultrafast laser is boosted and reflected by the second mirror and the third mirror to be transmitted to a multi-prism mirror;

[0020] The step 3.4) is specifically: shaping the required ultrafast laser by the multi-prism mirror, and the shaped required ultrafast laser sequentially passes through a convex lens and a focusing lens, and the convex lens and the focusing lens adjust the transverse distribution of the required ultrafast laser corresponding to the pulse period to form an ultrafast laser array beam.

[0021] Further limited, the method for preparing a phase change material metasurface by using an ultrafast laser further comprises a step 5) of: on-line observation of the phase change material metasurface by using transmitted light or reflected light.

[0022] Further limited, the step 5) is specifically:

[0023] An LED light source or a reflected light source is used to irradiate the phase change material metasurface on the workpiece, a camera collects the corresponding metasurface image of the phase change material metasurface on the workpiece through a focusing lens, and the camera transmits the metasurface image to a display;

[0024] The display receives the metasurface image and displays the metasurface image, realizing on-line observation of the phase change material metasurface.

[0025] Further limited, the step further comprises:

[0026] The step 2) is specifically: depositing a phase change material film on the surface of the workpiece by using a magnetron sputtering technology.

[0027] Further limited, the pretreatment of the workpiece to be processed in step 1) refers to polishing treatment on the surface of the workpiece to be processed.

[0028] The light path system for preparing a phase change material super surface by using an ultrafast laser according to the method described above comprises an ultrafast laser emitting device, a light parameter control unit, a light lifting unit and a light beam shaping unit, the ultrafast laser emitting device is used to generate an ultrafast laser, and the light parameter control unit, the light lifting unit and the light beam shaping unit are sequentially arranged on the outgoing light path of the ultrafast laser from front to back.

[0029] Further limited, the ultrafast laser emitting device is an ultrafast pulse laser, the light parameter control unit comprises a half-wave plate, a polarization beam splitter, a shutter and a laser power meter, the light lifting unit comprises a second mirror and a third mirror, and the light beam shaping unit comprises a multi-prism mirror, a convex lens and a focusing lens, the ultrafast laser generated by the ultrafast pulse laser is incident on the half-wave plate through the first mirror, the polarization beam splitter is arranged at the light exit end of the half-wave plate, the polarization beam splitter divides the ultrafast laser into required ultrafast laser and residual ultrafast laser, the residual ultrafast laser is incident on the laser power meter, and the required ultrafast laser is sequentially incident on the multi-prism mirror through the shutter, the second mirror and the third mirror, and the convex lens and the focusing lens are sequentially arranged on the outgoing light path of the multi-prism mirror from front to back.

[0030] Further limited, the light path system for preparing a phase change material super surface by using an ultrafast laser further comprises an online observation unit, the online observation unit comprises an LED light source, a fifth mirror, a camera, a display, a reflection light source and a flat beam splitter, light generated by the LED light source is reflected on the phase change material super surface of the workpiece to be processed through the fifth mirror, the camera collects the corresponding super surface image of the phase change material super surface of the workpiece to be processed through the flat beam splitter or the focusing lens, and the camera transmits the collected super surface image to the display; the display receives the super surface image and displays the super surface image; light generated by the reflection light source is irradiated on the flat beam splitter, the flat beam splitter is arranged between the focusing lens and the camera, and light generated by the flat beam splitter is irradiated on the focusing lens.

[0031] Compared with the prior art, the beneficial effects of the present application are that:

[0032] 1、The method for preparing a phase change material super surface by using an ultrafast laser, wherein the ultrafast laser refers to the pulse width of the output laser being 10 -15 s to 10 -12Compared with traditional laser processing, the ultrafast laser technology can break through the diffraction limit and realize the processing of nano-scale structure; the application realizes the processing of metasurface by using the beam of ultrafast laser, and the whole method has the advantages of no mask, wide range of applicable materials, single straight writing surface array structure and the like compared with the traditional metasurface processing technology, the operation is simple, the processing efficiency is high, and the application is beneficial to the further popularization and application of metasurface.

[0033] 2、The application forms a submicron array beam (the ultrafast laser array beam is a submicron array beam) by shaping the beam of ultrafast laser through the multi-prism, and prepares a large-area metasurface structure by adjusting the pulse period of the submicron array beam, the application is single processing, and the processing efficiency is extremely high.

[0034] 3、The application also provides the observation unit, the observation unit is used for collecting the metasurface image, and the metasurface image is observed by magnification, so that the prepared metasurface can be observed in real time. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a light path system schematic diagram for preparing the metasurface of phase change material by using the ultrafast laser;

[0036] Figure 2 It is a schematic diagram of the convex array structure prepared by the ultrafast laser;

[0037] Figure 3 It is a schematic diagram of the concave array structure prepared by the ultrafast laser;

[0038] Figure 4 It is a schematic diagram of the position relationship among the prism, the convex lens, the focusing lens and the workpiece;

[0039] Wherein, 1-ultrafast pulse laser, 2-first mirror, 3-half wave plate, 4-polarization beam splitter, 5-shutter, 6-laser power meter, 7-second mirror, 8-third mirror, 9-multi-prism, 10-convex lens, 11-fourth mirror, 12-focusing lens, 13-workpiece, 14-three-dimensional object table, 15-LED light source, 16-fifth mirror, 17-camera, 18-display, 19-reflective light source, 20-flat beam splitter. DETAILED DESCRIPTION

[0040] The technical scheme of the application will be further explained and described below in combination with the drawings and embodiments, but the application is not limited to the following described embodiments.

[0041] Embodiment 1

[0042] The embodiment utilizes a method for preparing a phase-change material metasurface by using ultrafast laser, which comprises the following steps:

[0043] 1) Preprocessing the workpiece 13 to be processed; specifically, the preprocessing of the workpiece 13 to be processed refers to polishing the surface of the workpiece 13 to be processed, and the workpiece 13 to be processed in this embodiment is quartz glass, sapphire or silicon wafer, and the surface of the workpiece 13 to be processed is polished to a surface roughness of less than 2 nm, for example, the quartz glass and sapphire are polished to a roughness of 2 nm, and the silicon wafer is polished to a roughness of 0.5 nm.

[0044] 2) Plating a phase-change material film on the surface of the workpiece 13 to be processed;

[0045] 3) Forming an ultrafast laser array;

[0046] 4) Preparing a metasurface on the workpiece 13 to be processed plated with the phase-change material film by using the ultrafast laser array to form a phase-change material metasurface.

[0047] Embodiment 2

[0048] The embodiment utilizes a method for preparing a phase-change material metasurface by using ultrafast laser, which is based on Embodiment 1, and the step 3) is specifically:

[0049] 3.1) Generating an ultrafast laser; further specifically, generating an ultrafast laser by using an ultrafast pulse laser 1;

[0050] 3.2) Adjusting the pulse energy of the ultrafast laser; further specifically, adjusting the polarization state of the ultrafast laser by making the ultrafast laser incident on a half-wave plate 3, then making the ultrafast laser incident on a polarization beam splitter 4, splitting the ultrafast laser into a required ultrafast laser and a residual ultrafast laser by the polarization beam splitter 4, adjusting the angle of the half-wave plate 3, and adjusting the pulse energy of the required ultrafast laser and the pulse energy of the residual ultrafast laser;

[0051] 3.3) Enhancing and reflecting the ultrafast laser; further specifically, the required ultrafast laser sequentially passes through a shutter 5, a second mirror 7 and a third mirror 8, and the required ultrafast laser is enhanced and reflected by the second mirror 7 and the third mirror 8 and transmitted to a multi-prism 9; in this embodiment, the enhancement of the required ultrafast laser refers to increasing the height of the required ultrafast laser;

[0052] 3.4) Shaping the ultrafast laser to form an ultrafast laser array; further specifically, shaping the required ultrafast laser by the multi-prism 9, and the shaped required ultrafast laser sequentially passes through a convex lens 10 and a focusing lens 12, and the convex lens 10 and the focusing lens 12 adjust the transverse distribution of the corresponding pulse period of the required ultrafast laser to form an ultrafast laser array beam.

[0053] The pulse period adjustment process of the ultrafast laser array beam in this embodiment is as follows:

[0054] Referring to Figure 4 , the cone angle of the multi-prism 9 is θ1, the focal length of the convex lens 10 is f1, the focal length of the focusing lens 12 is f2, the distance between the convex lens 10 and the focusing lens 12 is f1+0.5*L0, L0 is the length of the first-order non-diffraction zone, and the value is L0=W0 / tan(arcsin(n*sinθ1)-θ1), wherein n is the refractive index of the multi-prism 9, W0 is the laser radius of the required ultrafast laser, the distance between the convex lens 10 and the focusing lens 12 is equal to the sum of the focal lengths of the two, that is, f1+f2, and the distance between the focusing lens 12 and the workpiece 13 is f2 or so. Since there is a certain deviation between the focal point position of the shaped laser beam after passing through the focusing lens 12 and the focal length of the convex lens 10, the distance between the focusing lens 12 and the workpiece 13 is adjusted to continuously reduce the laser energy until the minimum energy is used to process the microstructure at a certain distance. The distance is the distance f2' between the focusing lens 12 and the workpiece 13;

[0055] The required ultrafast laser passes through the multi-prism 9 with different number of edges, and different ultrafast laser array beams are obtained, for example: the ultrafast laser array beam obtained by the required ultrafast laser passing through a two-prism is a strip structure, the ultrafast laser array beam obtained by the required ultrafast laser passing through a three-prism is a regular hexagonal structure, and the ultrafast laser array beam obtained by the required ultrafast laser passing through a four-prism is a square structure array. If the required ultrafast laser passes through a four-prism, the pulse period T1 of the ultrafast laser array beam finally focused on the workpiece 13 is:

[0056]

[0057] In the formula, λ is the wavelength of the ultrafast laser, the unit is μm; f1 is the focal length of the convex lens 10, the unit is mm; f2 is the focal length of the focusing lens 12, the unit is mm; n is the refractive index of the multi-prism 9; θ1 is the cone angle of the multi-prism 9, the unit is °.

[0058] If the required ultrafast laser passes through a three-prism, the pulse period T2 of the ultrafast laser array beam finally focused on the workpiece 13 is:

[0059]

[0060] In the formula, λ is the wavelength of the ultrafast laser, in units of μm; f1 is the focal length of the convex lens 10, in units of mm; f2 is the focal length of the focusing lens 12, in units of mm; n is the refractive index of the multi-prism mirror 9; and θ1 is the cone angle of the multi-prism mirror 9, in units of °. As can be seen, the wavelength, pulse width, and repetition frequency of the required ultrafast laser collectively affect the pulse period of the ultrafast laser array beam; see Figure 2 Taking the workpiece 13 as a silicon wafer as an example, if the wavelength of the required ultrafast laser is 800 nm, the pulse width is 40 fs, and the pulse energy density corresponding to each sub-beam in the ultrafast laser array beam is 7 mJ / cm 2 , a metasurface with a periodic array of protruding structures can be machined; see Figure 3 Taking the workpiece 13 as a quartz glass as an example, if the wavelength of the required ultrafast laser is 800 nm, the pulse width is 50 fs, and the pulse energy density corresponding to each sub-beam in the ultrafast laser array beam is 50 mJ / cm 2 , a metasurface with a periodic array of recessed structures can be machined.

[0061] The rest are the same as in Example 1.

[0062] Example 3

[0063] This example uses a method for preparing a phase-change material metasurface using an ultrafast laser. Based on Example 2, the steps further include Step 5): on-line observation of the phase-change material metasurface using transmitted light or reflected light.

[0064] Step 5) specifically involves: using the LED light source 15 or the reflected light source 19 to irradiate the phase-change material metasurface on the workpiece 13, and using the camera 17 to collect the corresponding metasurface image of the phase-change material metasurface on the workpiece 13 through the focusing lens 12 or the flat plate spectroscope 20, and using the camera 17 to transmit the metasurface image to the display 18.

[0065] The display 18 receives the metasurface image and displays the metasurface image, thereby achieving on-line observation of the phase-change material metasurface.

[0066] Step 2) specifically involves: using a magnetron sputtering technique to plate a phase-change material film on the surface of the workpiece 13; specifically, using magnetron sputtering to plate a phase-change material film on the metasurface with a periodic array of protruding structures or the metasurface with a periodic array of recessed structures at room temperature, thereby forming a phase-change material metasurface on the workpiece 13.

[0067] Example 4

[0068] The light path system of the superfast laser for preparing the super surface of the phase change material in the embodiment is formed based on the method of the superfast laser for preparing the super surface of the phase change material in the embodiment 3, and comprises a superfast laser emitting device, a light parameter control unit, a light lifting unit and a light beam shaping unit. The superfast laser emitting device is used for generating superfast laser. The light parameter control unit, the light lifting unit and the light beam shaping unit are sequentially arranged on the outgoing light path of the superfast laser from front to back.

[0069] Referring to Figure 1 , the superfast laser emitting device is a superfast pulse laser 1, the light parameter control unit comprises a half-wave plate 3, a polarization beam splitter 4, a shutter 5 and a laser power meter 6, the light lifting unit comprises a second mirror 7 and a third mirror 8, and the light beam shaping unit comprises a multi-prism mirror 9, a convex lens 10 and a focusing lens 12. The superfast laser generated by the superfast pulse laser 1 is incident on the half-wave plate 3 through the first mirror 2. The polarization beam splitter 4 is arranged at the light outgoing end of the half-wave plate 3. The polarization beam splitter 4 divides the superfast laser into required superfast laser and residual superfast laser. The residual superfast laser is incident on the laser power meter 6. The required superfast laser is sequentially incident on the multi-prism mirror 9 through the shutter 5, the second mirror 7 and the third mirror 8. The convex lens 10 and the focusing lens 12 are sequentially arranged on the outgoing light path of the multi-prism mirror 9 from front to back. A workpiece 13 to be processed is placed on a three-dimensional stage 14. The three-dimensional stage 14 is a commonly used stage in optical devices, can move along the X direction, the Y direction and the Z direction, and is a commercially available product. The superfast laser array beam emitted by the focusing lens 12 irradiates the workpiece 13 to be processed, and a super surface is prepared on the workpiece 13 to be processed. The light lifting unit in the embodiment refers to the height of the superfast laser.

[0070] Preferably, the light beam shaping unit in the embodiment further comprises a fourth mirror 11. The fourth mirror 11 is arranged between the convex lens 10 and the focusing lens 12. Specifically, the convex lens 10, the fourth mirror 11 and the focusing lens 12 are sequentially arranged on the outgoing light path of the multi-prism mirror 9 from front to back.

[0071] The light path system of the phase change material super surface prepared by the ultrafast laser in the embodiment further comprises an online observation unit, the online observation unit comprises an LED light source 15, a fifth mirror 16, a camera 17, a display 18, a reflecting light source 19 and a flat plate spectroscope 20, the light generated by the LED light source 15 is reflected by the fifth mirror 16 and then irradiates on the phase change material super surface of the workpiece 13 to be processed, the camera 17 collects the corresponding super surface image of the phase change material super surface of the workpiece 13 to be processed through the flat plate spectroscope 20 or the focusing lens 12 and transmits the collected super surface image to the display 18; the display 18 receives the super surface image and displays the super surface image; the reflecting light source 19 generates light which irradiates on the flat plate spectroscope 20, and the flat plate spectroscope 20 is arranged between the focusing lens 12 and the camera 17. In use, the LED light source 15 is turned on, the light generated by the LED light source 15 is reflected by the fifth mirror 16 and then irradiates on the phase change material super surface of the workpiece 13 to be processed, and the camera 17 collects the corresponding super surface image of the phase change material super surface of the workpiece 13 to be processed through the focusing lens 12 and transmits the collected super surface image to the display 18. Alternatively, the reflecting light source 19 is turned on, the light generated by the reflecting light source 19 irradiates on the flat plate spectroscope 20, the light generated by the flat plate spectroscope 20 irradiates on the focusing lens 12, the phase change material super surface of the workpiece 13 to be processed is imaged through the focusing lens 12, and the camera 17 collects the corresponding super surface image of the phase change material super surface of the workpiece 13 to be processed through the flat plate spectroscope 20 and transmits the collected super surface image to the display 18. The reflecting light source 19 in the embodiment is also a light source generated by an LED.

Claims

1. A method for preparing phase change material metasurfaces using ultrafast lasers, characterized in that, Includes the following steps: 1) Pre-process the workpiece to be processed (13); 2) Deposit a phase change material film on the surface of the workpiece (13); 3) Forming an ultrafast laser array; 3.1) Generating ultrafast lasers; 3.2) Modulating the pulse energy of ultrafast lasers; Step 3.2) specifically involves: incident an ultrafast laser onto a half-wave plate (3), adjusting the polarization state of the ultrafast laser, then incident the ultrafast laser onto a polarizing beam splitter (4), and using the polarizing beam splitter (4) to split the ultrafast laser into the desired ultrafast laser and the remaining ultrafast laser, rotating the angle of the half-wave plate (3) to regulate the pulse energy of the desired ultrafast laser and the pulse energy of the remaining ultrafast laser; 3.3) The ultrafast laser is boosted and reflected; Step 3.3) specifically involves the following steps: the required ultrafast laser passes through the shutter (5), the second mirror (7), and the third mirror (8) in sequence. The required ultrafast laser is then lifted and reflected by the second mirror (7) and the third mirror (8) and transmitted to the multi-faceted mirror (9). 3.4) The ultrafast laser is shaped to form an ultrafast laser array; Step 3.4) specifically involves: shaping the required ultrafast laser using a multi-faceted mirror (9), and then passing the shaped ultrafast laser through a convex lens (10) and a focusing lens (12) in sequence. The lateral distribution of the pulse period corresponding to the required ultrafast laser is adjusted by the convex lens (10) and the focusing lens (12) to form an ultrafast laser array beam. 4) A metasurface is prepared on the workpiece (13) coated with a phase change material film using an ultrafast laser array to form a phase change material metasurface; By adjusting the distance between the focusing lens (12) and the workpiece (13), the applied laser energy is continuously reduced until the microstructure is processed only at this distance using the minimum energy. This distance is the distance f2' between the focusing lens (12) and the workpiece (13). The length of the first-order non-diffraction zone formed between the polygonal mirror (9), the convex lens (10), the focusing lens (12), and the workpiece (13) is: L0=W0 / tan(arcsin(n*sinθ1)-θ1) In the formula, L0 is the length of the first-order diffraction-free region; W0 is the laser radius of the required ultrafast laser; n is the refractive index of the polygonal mirror 9; θ1 is the cone angle of the polygonal mirror (9); The distance between the convex lens (10) and the focusing lens (12) is f1+0.5*L0.

2. The method for preparing phase change material metasurfaces using ultrafast lasers as described in claim 1, characterized in that, Step 3.1) specifically involves generating an ultrafast laser using an ultrafast pulsed laser (1).

3. The method for preparing phase change material metasurfaces using ultrafast lasers as described in claim 1 or 2, characterized in that, The method for preparing phase change material metasurfaces using ultrafast lasers also includes step 5): online observation of the phase change material metasurface using transmitted or reflected light.

4. The method for preparing phase change material metasurfaces using ultrafast lasers as described in claim 3, characterized in that, Step 5) specifically involves: The phase change material metasurface on the workpiece (13) is illuminated by an LED light source (15) or a reflected light source (19). The camera (17) acquires the metasurface image corresponding to the phase change material metasurface on the workpiece (13) through a focusing lens (12). The camera (17) transmits the metasurface image to the display (18). The display (18) receives and displays metasurface images, enabling online observation of the metasurface of the phase change material.

5. The method for preparing phase change material metasurfaces using ultrafast lasers as described in claim 1, characterized in that, Step 2) specifically involves depositing a phase change material film on the surface of the workpiece (13) using magnetron sputtering technology.

6. The method for preparing phase change material metasurfaces using ultrafast lasers as described in claim 1, characterized in that, The pretreatment of the workpiece (13) in step 1) refers to polishing the surface of the workpiece (13).

7. The optical path system for preparing phase change material metasurfaces using ultrafast lasers according to claim 4, characterized in that, It includes an ultrafast laser emitting device, an optical parameter control unit, an optical enhancement unit, and a beam shaping unit. The ultrafast laser emitting device is used to generate ultrafast lasers, and the optical parameter control unit, optical enhancement unit, and beam shaping unit are arranged sequentially from front to back in the output optical path of the ultrafast laser.

8. The optical path system for preparing phase change material metasurfaces using ultrafast lasers as described in claim 7, characterized in that, The ultrafast laser emitting device is an ultrafast pulsed laser (1). The optical parameter control unit includes a half-wave plate (3), a polarizing beam splitter (4), a shutter (5), and a laser power meter (6). The optical enhancement unit includes a second mirror (7) and a third mirror (8). The beam shaping unit includes a multi-faceted mirror (9), a convex lens (10), and a focusing lens (12). The ultrafast laser generated by the ultrafast pulsed laser (1) is incident on the half-wave plate (3) through the first mirror (2). The polarizing beam splitter (4) is set at the light output end of the half-wave plate (3). The polarizing beam splitter (4) splits the ultrafast laser into the required ultrafast laser and the remaining ultrafast laser. The remaining ultrafast laser is incident on the laser power meter (6). The required ultrafast laser passes through the shutter (5), the second mirror (7) and the third mirror (8) in sequence and is incident on the polygonal mirror (9). The convex lens (10) and the focusing lens (12) are arranged in the output light path of the polygonal mirror (9) from front to back.

9. The optical path system for preparing phase change material metasurfaces using ultrafast lasers as described in claim 7, characterized in that, The optical path system for preparing phase change material metasurfaces using ultrafast lasers also includes an online observation unit. The online observation unit includes an LED light source (15), a fifth reflecting mirror (16), a camera (17), a display (18), a reflective light source (19), and a flat beam splitter (20). The light generated by the LED light source (15) is reflected by the fifth reflecting mirror (16) and then irradiates the phase change material metasurface of the workpiece (13). The camera (17) acquires the metasurface image corresponding to the phase change material metasurface of the workpiece (13) through the flat beam splitter (20) or the focusing lens (12). The camera (17) transmits the acquired metasurface image to the display (18). The display (18) receives the metasurface image and displays the metasurface image. The light generated by the reflective light source (19) irradiates the flat beam splitter (20). The flat beam splitter (20) is positioned between the focusing lens (12) and the camera (17). The light generated by the flat beam splitter (20) irradiates the focusing lens (12).

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