Physical vapor deposition preparation of continuous length metal / dielectric terahertz hollow core waveguide devices

Abstract

The application discloses a kind of physical vapor deposition preparation continuous length metal / medium terahertz hollow core waveguide device, its characteristics are that the device includes: medium pipe rotation unit, winding device and metal evaporation unit, the rotation unit and winding device are respectively arranged in the two sides of evaporation unit;The winding device includes: reel and guide wheel;The evaporation unit is the evaporation cavity with several tungsten boats, and there is metal evaporation material in tungsten boat, and the medium pipe after pretreatment is sent into metal evaporation unit by reel and guide wheel on one side, the uniform metal plating layer is formed on the outer surface of medium pipe by the uniform rotation of medium pipe rotation unit, and the medium pipe after evaporation is wound by the guide wheel and reel on the other side, and the preparation of continuous length metal / medium terahertz hollow core waveguide is completed.The application has the advantages of economic and environmental protection, simple process and the like compared with prior art, and the metal / medium terahertz hollow core waveguide prepared has wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of terahertz hollow waveguide fabrication technology, and in particular to a device for fabricating continuous-length metal / dielectric terahertz hollow waveguides using physical vapor deposition. Background Technology

[0002] Terahertz (THz) waves, with a frequency range of 0.1–10 THz, lie between the microwave and infrared regions of the electromagnetic spectrum. Terahertz technology has been applied in numerous fields, including biomedicine, non-destructive testing, wireless communication, space exploration, and radar imaging, demonstrating significant application value. To achieve low-loss and stable transmission of terahertz waves, various types of terahertz waveguides have been developed, such as metallic tube waveguides, metallic wire waveguides, parallel-plate metallic waveguides, metallic / dielectric hollow-core fibers, and photonic crystal fibers. Metallic / dielectric hollow-core waveguides offer advantages such as low transmission loss, good bending performance, and no end-face loss. However, these waveguides still suffer from limitations such as finite length, complex fabrication processes, and relatively high losses. Developing terahertz waveguides with even lower loss, better bending performance, and unlimited length remains a pressing problem to be solved.

[0003] Traditional methods for fabricating metal / dielectric hollow waveguides involve depositing a metal layer on the outer surface of a dielectric tube using chemical liquid phase deposition (CLP). This process is complex and generates significant amounts of waste liquid, causing environmental pollution. Vapor deposition, on the other hand, is a simpler and more environmentally friendly method that achieves good transmission performance. However, existing vapor deposition equipment has a fixed evaporation direction, allowing metal deposition only on one side of the sample, which cannot guarantee the uniformity of the metal layer. Furthermore, the limited cavity volume restricts the length of the fabricated metal / dielectric hollow waveguides, limiting their widespread application. Currently, no vapor deposition apparatus has been reported for large-scale, continuous fabrication of metal / dielectric hollow waveguides. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a physical vapor deposition (PVD) device for preparing continuous-length metal / dielectric terahertz hollow waveguides. This device employs a mechanism that suspends a dielectric tube within the vapor deposition apparatus and rotates it at a uniform speed. By controlling the vapor deposition time, the required film thickness is adjusted, thus producing continuous-length metal / dielectric terahertz hollow waveguides. The device has a simple structure and effectively solves the problems of traditional vapor deposition devices, which can only deposit metal on one side of the outer surface of a short dielectric tube, and the complex process and environmental pollution caused by liquid phase chemical deposition methods for preparing terahertz waveguides. It also solves the problem that traditional vapor deposition devices cannot mass-produce continuous-length terahertz waveguides. This invention offers advantages such as being economical and environmentally friendly, having a simple process, low waveguide transmission loss, good bending resistance, and stable operation in environments down to -78.5°C. It has significant research and broad application prospects in fields such as communications, biomedicine, basic science, security inspection, and aerospace.

[0005] The specific technical solution for realizing the present invention is: a device for preparing continuous-length metal / dielectric terahertz hollow waveguides by physical vapor deposition, characterized in that the device includes: a dielectric tube rotating unit, a winding device, and a metal evaporation unit, wherein the dielectric tube rotating unit and the winding device are respectively disposed on both sides of the metal evaporation unit; the winding device includes: a winding reel and a guide wheel; the metal evaporation unit is a deposition cavity with several tungsten boats, the tungsten boats containing metal deposition material, the pretreated dielectric tube is fed into the metal evaporation unit by the winding reel and guide wheel on one side, and a uniform metal coating is formed on the outer surface of the dielectric tube by the uniform rotation of the dielectric tube rotating unit, and the deposited dielectric tube is wound up by the guide wheel and winding reel on the other side to complete the preparation of continuous-length metal / dielectric terahertz hollow waveguides.

[0006] The medium tube is made of polyethylene, cyclic olefin copolymer, cyclic olefin polymer, polypropylene, polystyrene, polycarbonate, polyimide or polytetrafluoroethylene, and its inner diameter is 1~12 mm and its wall thickness is 50~1500 μm.

[0007] The metal vapor deposition material is silver, copper, gold, nickel, titanium, chromium, or aluminum, and the thickness of the metal coating is 0.1~12 μm.

[0008] This invention involves feeding a pre-treated dielectric tube into a metal evaporation unit via guide wheels. In this unit, a metal layer is formed on the outer surface of the dielectric tube using physical vapor deposition. Simultaneously, the dielectric tube is rotated during evaporation to ensure a more uniform metal layer on its outer surface. The tube is then wound up using guide wheels and a winding reel. A protective layer is subsequently added to the outer surface of the metal / dielectric terahertz hollow waveguide to complete the fabrication of a continuous length of metal / dielectric terahertz hollow waveguide. The metal evaporation unit includes several tungsten boats. Evaporation electrodes heat and evaporate the metal in the tungsten boats to fill the cavity. When the dielectric tube enters the evaporation cavity, a metal layer is deposited on its surface. A dielectric tube rotation unit rotates the dielectric tube during evaporation to ensure a more uniform metal layer. The metal evaporation unit and the dielectric tube rotation unit are separated by an isolation chamber to confine the evaporated metal within the metal evaporation unit and prevent it from depositing on the rotation unit, thus affecting its rotational life. A winding device winds up the prepared metal / dielectric hollow waveguide, with a soft, elastic padding material embedded in the contact area between the product and the evaporation unit. In addition, the inner diameter of the medium tube is 1~12 mm, its thickness is 50~1500 μm, and the thickness of the metal coating is 0.1~12 μm.

[0009] The specific steps for fabricating the continuous-length metal / dielectric terahertz hollow waveguide are as follows: Step 1: Pretreatment of the medium tube Pretreatment of continuous length dielectric tubes includes: cleaning, drying, and plasma treatment; Step 2: Metal plating of the dielectric tube The pretreated dielectric tube is rotated at a constant speed and continuously passed through a metal evaporation unit to deposit a uniform metal layer on the outer surface of the dielectric tube by physical vapor deposition, thus preparing a continuous length metal / dielectric terahertz hollow waveguide. Step 3: Preparation of the protective layer The outer protective layer of the metal / dielectric terahertz hollow waveguide is prepared by coating the outer surface of the metal / dielectric terahertz hollow waveguide with silicone resin or by covering the metal / dielectric terahertz hollow waveguide with heat shrink tubing.

[0010] Compared with existing technologies, this invention has the advantages of uniformly depositing metal layers in all directions of a continuous length dielectric tube, simple and environmentally friendly process, low waveguide transmission loss, good bending resistance, and stable operation in an environment of -78.5°C. It significantly reduces production costs and improves production efficiency, and has important research and broad application prospects in fields such as communications, biomedicine, basic science, security inspection, and aerospace. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a flowchart of the preparation process of the present invention; Figure 3 This is a schematic diagram of a metal / dielectric terahertz hollow waveguide structure. Implementation

[0012] The technical solutions in the embodiments of the present invention will be described in further detail and completely below with reference to the accompanying drawings. The embodiments described herein are used to explain some embodiments of the related invention, not all embodiments. Based on the embodiments in this patent, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0013] See Figure 1 The present invention includes: a dielectric tube rotating unit 1, a winding device 2, and a metal evaporation unit 3. The dielectric tube rotating unit 1 and the winding device 2 are respectively disposed on both sides of the metal evaporation unit 3. The winding device 2 includes: a guide wheel 2-1 and a winding spool 2-2. The metal evaporation unit 3 is a vapor deposition chamber provided with a plurality of tungsten boats 3-1. The tungsten boats 3-1 contain metal vapor deposition material.

[0014] The invention works as follows: The pre-treated dielectric tube 4 is fed into the metal evaporation unit 3 by a guide wheel 2-1 and a winding reel 2-2 on one side. Through the uniform rotation of the dielectric tube rotation unit 1, the metal in the dielectric tube 4 evaporates within the tungsten boat 3-1, depositing a metal layer on its surface, thus forming a uniform metal coating on the outer surface of the dielectric tube 4. The deposited dielectric tube 4 is then wound up by the guide wheel 2-1 and the winding reel 2-2 on the other side, completing the fabrication of a continuous-length metal / dielectric terahertz hollow waveguide.

[0015] See Figure 2 The specific steps for fabricating the continuous-length metal / dielectric terahertz hollow waveguide are as follows: S1: Pretreatment of the surface of the medium tube The inner diameter of the selected medium tube is 1~12 mm, and the thickness of the medium layer is 50~1500 μm. The medium tube is cleaned with detergent, ethanol and deionized water for 3 min each. After drying, it is treated with plasma including but not limited to nitrogen, hydrogen, oxygen or argon for 1~10 minutes.

[0016] S2: Deposit a metal layer on the outer surface of the media tube using physical vapor deposition. First, the evaporation power supply is turned on, maintaining the metal evaporation rate at 1–4 Å / s. Second, the dielectric tube 4 rotates at a constant speed of 1–10 r / min, driven by the dielectric tube rotation unit 1. Finally, a metal layer of 0.1–12 μm thickness is deposited on the outer surface of the dielectric tube within the evaporation chamber.

[0017] S3: Wind up the metal / dielectric terahertz hollow waveguide at point 2-2 on the winding reel. S4: Prepare a protective layer on the outer surface of the metal / dielectric terahertz hollow waveguide. The protective layer includes, but is not limited to, silicone resin or heat shrink tubing, to complete the setting of the outer protective layer of the metal / dielectric terahertz hollow waveguide of continuous length.

[0018] The following example, using the fabrication of a terahertz hollow waveguide suitable for 300 GHz, will provide a clearer and more complete description of the present invention: Example

[0019] See Figure 3 A metallic silver reflective layer 4-1 was deposited on the outer surface of the dielectric tube 4 using physical vapor deposition. Subsequently, a silicone resin protective layer 4-2 was coated on the outer surface of the metallic silver reflective layer 4-1 to complete the fabrication of the metal / dielectric terahertz hollow waveguide. The specific fabrication process is as follows: (1) A PP plastic tube with a wall thickness of 350 μm and an inner diameter of 5 mm was selected as the medium tube 4. The medium tube was ultrasonically cleaned with detergent, ethanol and deionized water in sequence. The cleaning time was 3 min for each time, and then it was dried. (2) The outer surface of the dielectric tube 4 is subjected to plasma gas treatment for 5 min, and the gas is oxygen. (3) Place the pretreated medium tube 4 into the evaporation chamber of the vapor deposition instrument and perform vacuum treatment on the chamber to reduce the vacuum degree to 3.7×10. -3 Pa; (4) Adjust the rotation speed of the medium tube rotating unit 1 so that the medium tube 4 rotates at a constant speed of 2 r / min under the rotation of the medium tube rotating unit 1. (5) Turn on the evaporation power supply and adjust the voltage to keep the evaporation rate of metallic silver at 1.9~2.1 Å / s; (6) When the deposition thickness of the metallic silver reflective layer 4-1 reaches 3μm, the metal / dielectric terahertz hollow waveguide is wound up at the winding disk 2-2; (7) Coat the outer surface of the metal / dielectric tube with a silicone resin protective layer 4-2 to complete the fabrication of the metal / dielectric terahertz hollow waveguide.

[0020] The metal / dielectric terahertz hollow waveguide fabricated above exhibits a linear transmission loss of 1.36 dB / m at a frequency of 300 GHz. Furthermore, this waveguide can achieve stable terahertz wave transmission in an environment of -78.5°C.

[0021] This invention addresses the problem that traditional chemical liquid phase deposition (CLP) methods for fabricating metal / dielectric terahertz hollow waveguides generate large amounts of waste liquid and consume significant raw materials, making them uneconomical and environmentally unfriendly. It proposes a physical vapor deposition (PVD) apparatus to address this issue. Furthermore, traditional PVD methods for fabricating metal / dielectric terahertz hollow waveguides cannot produce continuous lengths of these waveguides. This invention improves upon traditional apparatus, enabling the mass production of continuous length metal / dielectric terahertz hollow waveguides.

[0022] The above description uses specific examples to illustrate the implementation methods and results of the present invention, but it should not be construed as a limitation on the invention patent. Furthermore, for those skilled in the art, any modifications made without departing from the core concept of the present invention fall within the protection scope of the present invention. Therefore, all creations utilizing the concept of the present invention are included within the scope of the claims of this patent.

Claims

1. An application of a physical vapor deposition apparatus in the fabrication of continuous-length metal / dielectric terahertz hollow waveguides, characterized in that, The device includes a dielectric tube rotating unit, a winding device, and a metal evaporation unit. The dielectric tube rotating unit and the winding device are respectively located on both sides of the metal evaporation unit. The winding device includes a guide wheel and a winding spool. The metal evaporation unit is a deposition chamber with several tungsten boats containing metal deposition material. The pre-treated dielectric tube is fed into the metal evaporation unit by the winding spool and guide wheel on one side. Through the uniform rotation of the dielectric tube rotating unit, a uniform metal coating is formed on the outer surface of the dielectric tube. The deposited dielectric tube is then wound up by the guide wheel and winding spool on the other side to complete the fabrication of a continuous length of metal / dielectric terahertz hollow waveguide.

2. The application of the physical vapor deposition apparatus according to claim 1 in the fabrication of continuous-length metal / dielectric terahertz hollow waveguides, characterized in that, The medium tube is made of polyethylene, cyclic olefin copolymer, cyclic olefin polymer, polypropylene, polystyrene, polycarbonate, polyimide or polytetrafluoroethylene, with an inner diameter of 1~12mm and a wall thickness of 50~1500μm.

3. The application of the physical vapor deposition apparatus according to claim 1 in the fabrication of continuous-length metal / dielectric terahertz hollow waveguides, characterized in that, The metal vapor deposition material is silver, copper, gold, nickel, titanium, chromium, or aluminum, and the thickness of the metal coating is 0.1~12μm.

4. The application of the physical vapor deposition apparatus according to claim 1 in the fabrication of continuous-length metal / dielectric terahertz hollow waveguides, characterized in that, The specific steps for fabricating the continuous-length metal / dielectric terahertz hollow waveguide are as follows: Step 1: Pretreatment of the medium tube Pretreatment of continuous length dielectric tubes includes: cleaning, drying, and plasma treatment; Step 2: Metal plating of the dielectric tube The pretreated dielectric tube is rotated at a constant speed and continuously passed through a metal evaporation unit to deposit a uniform metal layer on the outer surface of the dielectric tube by physical vapor deposition, thus preparing a continuous length metal / dielectric terahertz hollow waveguide. Step 3: Preparation of the protective layer The outer protective layer of the metal / dielectric terahertz hollow waveguide is prepared by coating the outer surface of the metal / dielectric terahertz hollow waveguide with silicone resin or by covering the metal / dielectric terahertz hollow waveguide with heat shrink tubing.

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