Waveguide and higher harmonic generation device

Abstract

The invention provides a waveguide and a higher harmonic generation device. The waveguide and the higher harmonic generation device comprise a waveguide body; the waveguide body is in a cylinder shape, a first through hole is formed in the waveguide body and penetrates through the waveguide body in the length direction of the waveguide body, and a film layer used for reflecting light is arranged on the inner surface of the first through hole. The waveguide is applied to a higher harmonic generation device, the refraction and scattering loss of exciting light can be greatly reduced through the high reflectivity of the film layer to the exciting light, the action area of a laser strong field is effectively concentrated, and the higher harmonic process is limited in the first through hole, so that the generation efficiency of the higher harmonic can be greatly improved, and the generation efficiency of the higher harmonic is improved. And the damage threshold of the hollow waveguide is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical technology, and in particular to a waveguide and a high-order harmonic generating device. Background Art

[0002] With the development of the semiconductor chip industry, lithography light sources, as the core technology of lithography technology, are also developing continuously. From the g-line (436nm) of high-pressure discharge mercury lamps in the ultraviolet band to the i-line (365nm), and then to the excimer lasers KrF (248nm) and ArF (193nm) in the deep ultraviolet band, the most advanced extreme ultraviolet lithography machines currently use 13.5nm (4% bandwidth) extreme ultraviolet light (EUV), and their cost index has risen. However, extreme ultraviolet light is easily absorbed by various materials and even gases, and has the unique characteristic that the refractive index of various materials is close to 1, requiring the use of a large number of multilayer film reflectors with special material surfaces. These expensive light sources and complex reflector systems all require the support of precise 13.5nm light source detection technology. In key areas such as extreme ultraviolet optical performance testing, component surface detection, and photoresist and photodiode verification, miniaturized and economical light sources are urgently needed.

[0003] In recent years, the technology of ultrashort pulse laser excitation of gas medium to generate high-order harmonics has made it possible to cover a wide spectral range from ultraviolet to soft X-rays, especially the realization of the 13.5nm band, which provides an economical and efficient solution for attosecond spectroscopy and ultra-wide spectrum laser light sources. Among these systems, the high-order harmonic source based on hollow waveguide has the advantages of low cost and compact structure, but due to the multiple reflections of light in the hollow waveguide, the light has refraction and scattering losses on the inner wall, resulting in low conversion efficiency. Summary of the invention

[0004] The embodiments of the present application provide a waveguide and a high-order harmonic generating device. By coating the inner surface of a first through hole of the waveguide for transmitting light, the refraction and scattering loss of light is reduced, and the subsequent application in the high-order harmonic generating device can improve the conversion efficiency.

[0005] In a first aspect, an embodiment of the present application provides a waveguide, comprising: a waveguide body; the waveguide body is cylindrical, a first through hole is provided in the waveguide body, the first through hole penetrates the waveguide body along the length direction of the waveguide body, and the inner surface of the first through hole has a film layer for reflecting light.

[0006] In some embodiments, the first through hole is used to fill with gas.

[0007] In some embodiments, a diameter of a circumscribed circle of the shape of the cross section of the first through hole is greater than or equal to 25 μm, and the diameter is less than or equal to 500 μm.

[0008] In some embodiments, the length of the waveguide body is greater than or equal to 5 mm, and the length is less than or equal to 500 mm.

[0009] In some embodiments, at least one second through hole is further provided in the waveguide body, the second through hole penetrates the waveguide body along the length direction of the waveguide body, and the first through hole and the second through hole are separated.

[0010] In some embodiments, the second through hole is used to fill with gas.

[0011] In some embodiments, the first through hole is coaxially arranged with the waveguide body, and a plurality of the second through holes are spaced around the first through hole.

[0012] In a second aspect, an embodiment of the present application further provides a high-order harmonic generating device, which comprises a light source and a waveguide as described in any one of the first aspects; the light source and the waveguide are arranged in sequence along the optical path; the light source is used to provide excitation light, and the waveguide is used to generate high-order harmonics based on the excitation light.

[0013] In some embodiments, the high-order harmonic generating device further includes a focusing device, a filtering device and a spectroscopic device; the light source, the focusing device, the waveguide, the filtering device and the spectroscopic device are sequentially arranged along the optical path.

[0014] In some embodiments, the incident angle of the excitation light when incident on the film layer is greater than 45°.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows: Different from the prior art, the present application provides a waveguide and a high-order harmonic generation device, including a waveguide body; the waveguide body is cylindrical, a first through hole is provided in the waveguide body, the first through hole penetrates the waveguide body along the length direction of the waveguide body, and the inner surface of the first through hole has a film layer for reflecting light. The waveguide is applied to the high-order harmonic generation device, and the high reflectivity of the film layer to the excitation light can greatly reduce the refraction and scattering loss of the excitation light, effectively concentrate the action area of ​​the laser strong field, and confine the high-order harmonic process to the hollow channel (the first through hole), thereby greatly improving the generation efficiency of the high-order harmonics and improving the damage threshold of the hollow waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements / modules and steps with the same reference numerals in the drawings are represented as similar elements / modules and steps. Unless otherwise specified, the figures in the drawings do not constitute proportional limitations.

[0017] Figure 1is a schematic diagram of the structure of a waveguide provided in an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of the structure of another waveguide provided in an embodiment of the present application;

[0019] Figure 3 is a schematic cross-sectional view of a waveguide provided in an embodiment of the present application;

[0020] Figure 4 is a schematic cross-sectional view of another waveguide provided in an embodiment of the present application;

[0021] Figure 5 is a schematic cross-sectional view of another waveguide provided in an embodiment of the present application;

[0022] Figure 6 is a schematic cross-sectional view of another waveguide provided in an embodiment of the present application;

[0023] Figure 7 is a schematic cross-sectional view of a fifth waveguide provided in an embodiment of the present application;

[0024] Figure 8 is a schematic cross-sectional view of a sixth waveguide provided in an embodiment of the present application;

[0025] Fig. 9 It is a structural block diagram of a high-order harmonic generating device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The present application is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0027] For ease of understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those generally understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not used to limit the present application. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0028] It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other, all within the scope of protection of the present application. In addition, although the functional module division is performed in the device schematic, in some cases, the module division can be different from that in the device. In addition, the words "first", "second", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0029] High-order harmonic sources based on hollow waveguides have significant potential advantages such as low cost, simple and compact structure, and small size. However, they have serious reliability problems such as large refraction and scattering losses of the excitation light, easy burning of the inner wall by the excitation light, and low wavelength conversion efficiency, which greatly limit the commercialization of high-order harmonic devices based on hollow waveguides. In addition, the current high-order harmonic devices based on hollow waveguides are difficult to assemble and operate, and have low stability and durability.

[0030] In order to improve the above-mentioned technical problems, the present application provides a waveguide and a high-order harmonic generating device, which reduces the refraction and scattering losses of the excitation light by coating the inner surface of the first through hole, increases the inner wall damage threshold, and thus improves the wavelength conversion efficiency. The overall structure is simple, the installation and adjustment operation is simple, and the cost and volume can be reduced.

[0031] In a first aspect, the present invention provides a waveguide 10, referring to Figure 1 The waveguide 10 comprises: a waveguide body 1. The waveguide body 1 is cylindrical, and a first through hole 2 is provided in the waveguide body 1. The first through hole 2 penetrates the waveguide body 1 along the length direction of the waveguide body 1, and the inner surface of the first through hole 2 has a film layer for reflecting light.

[0032] The waveguide body 1 can be formed of an optical medium, which is a solid optical medium, including dielectric optical media such as glass, sapphire, and diamond, or conductive optical media such as tin-doped indium oxide (ITO) and conductive zinc oxide (AZO). Figure 1 or Figure 2 As shown, the waveguide body 1 may be cylindrical or prism-shaped, that is, the cross-section of the waveguide body 1 may be circular or rectangular.

[0033] like Figures 3 to 7 As shown, the cross-section of the first through hole 2 can be in the shape of a circle, an ellipse, a rectangle, a hexagon, a hexagonal star, etc. Figure 7 When the cross-section of the first through hole 2 is a hexagonal star, each side may be an arc. The cross-section of the first through hole 2 refers to the cross-section of the first through hole 2 on a plane perpendicular to the length direction of the waveguide body 1.

[0034] The inner surface of the first through hole 2 refers to a surface in the first through hole 2 inside the waveguide body 1 that is in direct contact with the inner space of the first through hole 2 , and the inner surface extends from one end of the waveguide body 1 to the other end along the length direction of the waveguide body 1 .

[0035] The film layer can be a dielectric film with high reflectivity for the excitation light, and can include metal film layers such as gold film, silver film, molybdenum film, ruthenium film, etc., or can include interference high-reflectivity films such as zirconium oxide and niobium oxide. The film layer has a reflectivity greater than or equal to 90% and a power greater than or equal to 100W / cm 2 In practical applications, if the thickness of the film layer is greater than 2 μm, it may affect the uniformity of the film layer everywhere, reduce the surface flatness of the film layer, and may enhance the interference of light, making the film layer reflective to light low or even ineffective. In order to reduce the above problems, the thickness of the film layer can be greater than or equal to 5 nm and less than or equal to 2 μm to ensure the uniformity of the film layer and the reflection performance of light. Among them, when using an interference high-reflection film, the thickness of the film layer can be determined based on the half-wave loss design. It can be understood that in order to reduce light loss, the film layer should cover the inner surface of the first through hole in the waveguide 10 where the excitation light is irradiated as much as possible.

[0036] In the waveguide 10, the film layer in the first through hole 2 has a very high reflectivity to light, and the waveguide 10 can be used as a hollow fiber, an anti-resonance fiber, a photonic crystal fiber and other structures. When the waveguide 10 is applied to a high-order harmonic generation device, the film layer in the first through hole 2 has a high reflectivity to the excitation light used to generate high-order harmonics, which can greatly reduce the refraction and scattering losses of the excitation light, effectively concentrate the action area of ​​the laser strong field, and confine the high-order harmonic process to the first through hole, thereby greatly improving the generation efficiency of high-order harmonics and improving the damage threshold of the waveguide 10.

[0037] In order to further reduce the refraction and scattering losses of the excitation light, when the waveguide body 1 is formed by a non-conductive optical medium, the refractive index of the waveguide body 1 to the light can range from 1.5 to 3.0, and the absorption coefficient can range from 0 to 0.2; when the waveguide body 1 is formed by a conductive optical medium, the refractive index of the waveguide body 1 to the light can range from 0 to 1.5, and the absorption coefficient can range from 1.5 to 10.

[0038] In some embodiments, the first through hole 2 is used to fill gas. Specifically, the gas may be nitrogen, helium, neon, argon, krypton, xenon, etc. The gas pressure may be 0-1000 Torr. In this embodiment, by filling the first through hole 2 with a gas medium, when the subsequent ultrafast laser is transmitted in the first through hole 2 as an excitation light, the excitation light may interact with the gas in the first through hole 2 to generate high-order harmonics.

[0039] In some embodiments, when the diameter of the circumscribed circle of the shape of the cross section of the first through hole 2 is less than 25 μm, the waveguide 10 is easily burned by the excitation light, and when the circumscribed circle is greater than 500 μm, the average laser intensity may be too low to effectively excite high-order harmonics. In order to reduce the situation where the waveguide 10 is burned by the excitation light and fails to generate high-order harmonics, in some embodiments, the diameter of the circumscribed circle of the shape of the cross section of the first through hole 2 is greater than or equal to 25 μm, and the diameter of the circumscribed circle of the shape of the cross section of the first through hole 2 is less than or equal to 500 μm. By making the circumscribed circle meet the above-mentioned size range, the situation where the waveguide 10 is burned by the excitation light and fails to generate high-order harmonics can be reduced, thereby improving the reliability of subsequent work. Among them, the circumscribed circle of the shape of the cross section of the first through hole 2 refers to the largest circle that can pass through the cross section of the first through hole 2, such as Figure 7 The largest circle S is shown in .

[0040] In addition, in some embodiments, when the length of the waveguide body 1 is less than 5 mm, the distance for the interaction between the excitation light and the gas in the first through hole is too short, resulting in too low high-order harmonic conversion efficiency; and when the length of the waveguide body 1 is greater than 500 mm, the generated high-order harmonics are absorbed by the excessively long gas path (the distance for the interaction between the excitation light and the gas in the first through hole), and the internal filtering effect causes the efficiency to drop sharply. In order to make the action distance appropriate, in some embodiments, the length of the waveguide body 1 is greater than or equal to 5 mm, and the length of the waveguide body 1 is less than or equal to 500 mm. By making the length of the waveguide body 1 within the above range, the action distance between the excitation light and the gas is appropriate, thereby ensuring the effect of generating high-order harmonics.

[0041] In some of the embodiments, at least one second through hole is further provided in the waveguide body 1 , and the second through hole penetrates the waveguide body 1 along the length direction of the waveguide body 1 , and the first through hole 2 and the second through hole are separated.

[0042] The number of the second through holes may be 1 to 18. Figure 8 As shown, the number of second through holes is 6, namely second through holes 31 to second through holes 36, and each second through hole (31, 32, 33, 34, 35, 36) is arranged at intervals from each other. Among them, the inner surface of the second through hole can also be provided with a film layer for reflection, and the film layer can be consistent with the film layer material of the inner surface of the first through hole, which can be arranged according to actual needs and is not limited here.

[0043] In some embodiments, the second through hole is used to fill gas. Specifically, the gas may be nitrogen, helium, neon, argon, krypton, xenon, etc. The heat dissipation capacity of gas is tens to hundreds of times that of solid heat conduction. By filling the second through hole with gas to provide convection heat dissipation, the strong field laser damage threshold of the waveguide is greatly increased.

[0044] In some embodiments, the first through hole 2 is coaxially arranged with the waveguide body 1, and a plurality of second through holes are arranged around the first through hole 2 at intervals. Figure 8 As shown, the central axis of the first through hole 2 coincides with the central axis of the waveguide body 1, and six second through holes (31, 32, 33, 34, 35, 36) are arranged at equal intervals around the first through hole 2. Through the above arrangement, the surrounding hollow confined area can scatter the light field, improve the light field intensity in the central area, reduce the propagation loss, and increase the length of the high-order harmonic action domain.

[0045] In a second aspect, the present application provides a high-order harmonic generating device, referring to Fig. 9 The high-order harmonic generating device 100 includes a light source 20 and a waveguide 10 as in any one of the embodiments of the first aspect. The light source 20 and the waveguide 10 are sequentially arranged along the optical path; the light source 20 is used to provide excitation light, and the waveguide 10 is used to generate high-order harmonics based on the excitation light.

[0046] In this embodiment, the waveguide 10 has the same structure and function as the waveguide described in any one of the embodiments of the first aspect, which will not be described in detail here. The light source 20 can be a variety of types of lasers, such as a femtosecond laser, a nanosecond laser or a continuous wave laser, and the wavelength of the excitation light provided by the light source 20 can be selected according to actual needs. In the high-order harmonic generating device 100, the excitation light provided by the light source 20 interacts with the gas in the first through hole 2 in the waveguide 10 to generate high-order harmonics and emit light of a specific wavelength.

[0047] In some of these embodiments, see Fig. 9 The high-order harmonic generation device 100 further includes a focusing device 30, a filtering device 40 and a light splitting device 50. The light source 20, the focusing device 30, the waveguide 10, the filtering device 40 and the light splitting device 50 are sequentially arranged along the optical path.

[0048] The focusing device 30 may include a focusing lens, such as a convex lens, which can be used to focus the excitation light so that the excitation light is incident on the optical device in the first through hole 2 to ensure the light utilization rate of the excitation light.

[0049] The filter device 40 may include a bandpass filter film or other optical device that can be used to transmit light with a wavelength within a preset range and block the transmission of light with a wavelength not within the preset range, thereby reducing interference from stray light.

[0050] The spectroscopic device 50 refers to an optical device that can be used to make light of different wavelengths propagate in different directions, such as an optical device that can further filter the light emitted by the filtering device 40 to obtain monochromatic light.

[0051] In this embodiment, by setting the above-mentioned devices, the excitation light emitted by the light source 20 can emit light in a specific wavelength range after being incident on the waveguide 10 through the focusing device 30. After these lights pass through the filtering device 40 and the spectroscopic device 50, the desired target monochromatic light, such as the desired extreme ultraviolet light, can be obtained.

[0052] In some embodiments, the incident angle of the excitation light when incident on the film layer is greater than 45°. Through the above arrangement, the excitation light can meet the large-angle reflection condition when reflected on the inner surface of the first through hole 2, so that it is totally reflected on the inner surface, reducing light loss.

[0053] The high-order harmonic generating device provided by the present application is described in detail below in conjunction with specific embodiments.

[0054] Embodiment 1: Figure 2 As shown, the waveguide body 1 is made of a sapphire sheet with a length L of 5 cm, a width W of 2 cm, and a thickness H of 5 mm. First, a first through hole 2 is manufactured in the sapphire sheet using a femtosecond laser and chemical etching method. The cross-section of the first through hole 2 is an ellipse, as shown in FIG. Figure 4 As shown, the major axis L1 of the elliptical cross section is 200 μm and the minor axis L2 is 150 μm; then, a zirconium dioxide film layer with a thickness of 9.4 nm is plated on the inner surface of the first through hole 2 using an atomic layer deposition method; then, argon gas is filled into the first through hole 2 and the gas pressure is maintained at about 60 Torr. Next, an 800nm ​​femtosecond laser with a spot diameter of 21mm, a pulse width of 30fs, a pulse energy of 0.3mJ, and a repetition frequency of 10kHz is used as the excitation light, and is focused on the entrance of the first through hole 2 of the sapphire sheet through a convex lens with a focal length of 100mm in a direction parallel to the length of the first through hole 2. However, due to the existence of the focusing cone, the grazing incidence angle of the 800nm ​​excitation light when incident on the film layer on the inner surface of the first through hole 2 is 6°, that is, the incident angle is 84°. Then, through the bandpass filter film and the spectroscopic device 50, the extreme ultraviolet light with a wavelength of 29.6nm in the light emitted by the waveguide 10 can be separated. The photocurrent of the extreme ultraviolet light is subsequently tested by the extreme ultraviolet photodiode to be 33.429nA. When a hollow waveguide without a zirconium dioxide film layer was used to replace the waveguide 10 for the experiment, the photocurrent measured was 1.91779 nA when the other test conditions were the same. It can be seen that the zirconium dioxide film layer can efficiently reflect the excitation light, rarely refract or transmit the excitation light, and reduce the refraction or transmission loss of the excitation light.

[0055] Embodiment 2: Figure 1 and Figure 3As shown, the waveguide body 1 is made of quartz with a length of 5 cm and a cross-sectional diameter D1 of 1500 μm, and the cross-sectional shape of the first through hole 2 is a circle with a diameter D2 of 200 μm; then, a gold film with a thickness of 100 nm is plated on the inner surface of the first through hole 2 using a chemical gold plating method; then, helium is filled into the first through hole 2 and the gas pressure is maintained at about 500 Torr. Next, a 1030 nm femtosecond laser with a spot diameter of 14 mm, a pulse width of 25 fs, a pulse energy of 3 mJ, and a repetition frequency of 1 kHz is used as the excitation light, and is focused at the entrance of the first through hole 2 through a convex lens with a focal length of 500 mm in parallel to the length direction of the first through hole 2. Then, the bandpass filter film and the spectrometer 50 can separate the extreme ultraviolet light with a wavelength of 13.4nm from the light emitted by the waveguide 10. The photocurrent of the extreme ultraviolet light is subsequently tested by an extreme ultraviolet photodiode to be 10.8319nA, and the waveguide 10 can work stably within 10 hours. When the hollow waveguide 10 without the zirconium dioxide film layer is used to replace the above waveguide 10 for the experiment, the photocurrent is measured to be 0.43054nA, and the hollow waveguide 10 burns out after 70 minutes when the other test conditions are the same.

[0056] Embodiment 3: Figure 1 and Figure 7 As shown, the waveguide body 1 is made of quartz with a length of 6 cm and a cross-sectional diameter D1 of 1500 μm, and the diameter D3 of the circumscribed circle of the cross section of the first through hole 2 is 250 μm. A bright silver film with a thickness of 200 nm is plated on the inner surface of the first through hole 2 using a plasma-assisted vacuum silver plating method; then, neon gas is filled into the first through hole 2, and the gas pressure is maintained at about 200 Torr. Next, a 515nm femtosecond laser with a spot diameter of 10 mm, a pulse width of 35 fs, a pulse energy of 1.5 mJ, and a repetition frequency of 10 kHz is used as the excitation light, and is focused at the entrance of the first through hole 2 through a convex lens with a focal length of 200 mm in parallel to the length direction of the first through hole 2. Then, the extreme ultraviolet light with a wavelength of 20.6 nm in the light emitted by the waveguide 10 is separated through a bandpass filter film and a spectroscopic device 50, and its photocurrent is tested by an extreme ultraviolet photodiode to be 45.027 nA, and it can work stably within 8 hours. When the uncoated hollow waveguide 10 was used to replace the waveguide 10 for the experiment, the photocurrent was measured to be 12.2317 nA under the same other test conditions, and the hollow waveguide 10 was burned out after 40 minutes.

[0057] Embodiment 4: Figure 1 and Figure 8As shown, the waveguide body 1 is made of quartz with a length of 5.5 cm and a cross-sectional diameter of 1200 μm. The cross-sectional diameters of the first through hole 2 and the second through holes (31, 32, 33, 34, 35, 36) are both 200 μm. A bright molybdenum film with a thickness of 400 nm is plated on the inner surface of the first through hole 2 and the second through hole (31, 32, 33, 34, 35, 36) by chemical vapor deposition of reduced MoC l5; then, krypton gas is filled into the first through hole 2, and the gas pressure is maintained at about 100 Torr. Next, a 400nm femtosecond laser with a spot diameter of 12 mm, a pulse width of 22 fs, a pulse energy of 0.4 mJ, and a repetition frequency of 10 kHz is used as the excitation light, and is focused on the entrance of the first through hole 2 through a convex lens with a focal length of 400 mm in parallel to the length direction of the first through hole 2, wherein the excitation light mainly interacts with the gas filled in the first through hole 2. Next, the bandpass filter and the spectrometer 50 are used to separate the extreme ultraviolet light with a wavelength of 57.1 nm from the light emitted by the waveguide 10, and the photocurrent is tested by an extreme ultraviolet photodiode to be 160.039 nA, and it can work stably within 4 hours. When the uncoated hollow waveguide 10 is used to replace the above waveguide 10 for the experiment, the photocurrent is measured to be 20.2065 nA, and the hollow waveguide 10 burns out after 10 minutes when the other test conditions are the same.

[0058] The larger the photocurrent, the higher the EUV power and the higher the high-order harmonic conversion efficiency. In summary, the waveguide provided by the present application can not only reduce the leakage of excitation light, but also significantly improve the conversion efficiency, which can be achieved by adding only one coating process without increasing any installation difficulty, and retaining the advantages of the hollow waveguide, such as low cost, small size, and simple and compact structure.

[0059] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A waveguide, characterized in that: include: Waveguide body; The waveguide body is in a columnar shape, and a first through hole is arranged in the waveguide body. The first through hole penetrates the waveguide body along the length direction of the waveguide body, and an inner surface of the first through hole has a film layer for reflecting light.

2. The waveguide according to claim 1, characterized in that The first through hole is used for filling gas.

3. The waveguide according to claim 1, characterized in that A diameter of a circumscribed circle of a cross-sectional shape of the first through hole is greater than or equal to 25 μm, and the diameter is less than or equal to 500 μm.

4. The waveguide according to claim 1, characterized in that The length of the waveguide body is greater than or equal to 5 mm, and the length is less than or equal to 500 mm.

5. The waveguide according to claim 1, characterized in that At least one second through hole is also provided in the waveguide body. The second through hole penetrates the waveguide body along the length direction of the waveguide body, and the first through hole and the second through hole are spaced apart.

6. The waveguide according to claim 5, characterized in that The second through hole is used for filling gas.

7. The waveguide according to claim 6, characterized in that The first through hole is coaxially arranged with the waveguide body, and a plurality of the second through holes are spaced around the first through hole.

8. A high-order harmonic generating device, characterized in that: comprising a light source and a waveguide as claimed in any one of claims 1 to 7; The light source and the waveguide are sequentially arranged along the light path; The light source is used to provide excitation light, and the waveguide is used to generate high-order harmonics based on the excitation light.

9. The high-order harmonic generating device according to claim 8, characterized in that: The high-order harmonic generating device also includes a focusing device, a filtering device and a light splitting device; The light source, the focusing device, the waveguide, the filtering device and the light splitting device are arranged in sequence along the light path.

10. The high-order harmonic generating device according to claim 8 or 9, characterized in that: The incident angle of the excitation light when incident on the film layer is greater than 45°.

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