Device with three discharge air gaps for generating three-dimensional plasma photonic crystals

Abstract

The present invention provides a device capable of generating three-dimensional plasma photonic crystals with three types of discharge air gaps. The device comprises a vacuum reaction chamber, two water electrodes arranged in the vacuum reaction chamber, and a plasma generating power source electrically connected to the water electrodes; two solid frames that are bonded to each other are arranged between the two water electrodes, and the thickness of the two solid frames is different; a plurality of rectangular through holes are opened on the two solid frames, and the rectangular through holes on the two solid frames are perpendicular to each other, and the rectangular through holes on the two solid frames are crisscrossed to form a mesh through hole structure. The through holes and the positions where the thickness of a single solid frame between adjacent through holes are located together form a discharge air gap. The present invention realizes for the first time the formation of different types of three-dimensional plasma photonic crystals in three staggered discharge air gaps.

Description

Technical Field

[0001] The invention relates to the fields of plasma application and optical technology, in particular to a device with three discharge air gaps capable of generating three-dimensional plasma photonic crystals. Background Art

[0002] Photonic crystals, also known as photonic bandgap materials, are an artificial "crystal" structure formed by arranging two dielectric materials with different dielectric constants in space at a certain period (the size is on the order of the wavelength of light). In recent years, plasma photonic crystals have been widely concerned and studied by scholars at home and abroad as a new type of photonic crystals, and are expected to be applied to many electromagnetic wave control fields such as filters, optical switches, plasma lenses, and plasma stealth. The dielectric constant of a photonic crystal is a periodic function of space, and a plasma photonic crystal is a periodic structure formed by the staggered arrangement of plasma and other dielectric materials. However, it is difficult for conventional plasma photonic crystals to adjust plasma photonic crystals with plasmas of different sizes under the same conditions, and it is also impossible to achieve three-dimensional plasma photonic crystals.

[0003] Dielectric barrier discharge (DBD), also known as silent discharge, is a typical non-equilibrium AC gas discharge. It is usually composed of two parallel electrodes, at least one of which is covered with a dielectric. Dielectric barrier discharge is widely used in many industrial fields such as plasma display, luminescence and ozone synthesis, and is expected to be applied to information processing and local growth of materials. Dielectric barrier discharge is an important method for generating plasma photonic crystals. In previous studies, two flat liquid electrode dielectric barrier discharge devices were used to obtain rich symmetrical plasma photonic crystal structures through nonlinear self-organization of discharge filaments under an AC applied voltage of tens of kHz. However, this type of device can only produce plasma photonic crystals under a single discharge air gap, which can be observed and studied on a two-dimensional plane, and has its own limitations. Summary of the invention

[0004] The purpose of the present invention is to provide a device with three discharge air gaps that can generate three-dimensional plasma photonic crystals, so as to break through the limitation that most existing devices have only one discharge air gap and can only obtain two-dimensional plasma photonic crystals. For the first time, different types of three-dimensional plasma photonic crystals can be formed in three staggered discharge air gaps.

[0005] The present invention is implemented as follows: a device capable of generating three-dimensional plasma photonic crystals comprises a vacuum reaction chamber, two water electrodes arranged in the vacuum reaction chamber and a plasma generating power source electrically connected to the water electrodes; the device is characterized in that two solid frames which are bonded to each other are arranged between the two water electrodes, and the thickness of the two solid frames are different; a plurality of rectangular through holes are opened on the two solid frames, and the rectangular through holes on the two solid frames are perpendicular to each other, and the rectangular through holes on the two solid frames are crisscrossed to form a mesh through hole structure.

[0006] The thickness of the two solid frames is 1-3 mm, and the total thickness of the two solid frames is 3-5 mm. Preferably, the thickness of the two solid frames is 2 mm and 1 mm respectively, and the two solid frames are both square structures with a side length of 100 mm.

[0007] The spacing between adjacent rectangular through holes on the two solid frames is 1-5 mm. Preferably, the size of the rectangular through holes on the two solid frames is 30 mm*2 mm, and the spacing between adjacent rectangular through holes is 2 mm.

[0008] Preferably, the rectangular through holes on the two solid frames are crisscrossed to form 4*4-10*10 square through holes. The size of the square through holes and the spacing between the through holes can be adjusted according to needs and actual conditions.

[0009] Preferably, the rectangular through holes on the two solid frames are crisscrossed to form 8*8 square through holes.

[0010] An air inlet and an air outlet are provided on the wall of the vacuum reaction chamber; the air inlet is connected to a gas premixing chamber, and the gas premixing chamber is connected to a gas ratio regulating device.

[0011] A signal collector is also arranged outside the vacuum reaction chamber. The signal collector comprises a first filter, a second filter, a first photomultiplier tube and a second photomultiplier tube. Both the first photomultiplier tube and the second photomultiplier tube are connected to the oscilloscope.

[0012] The method for producing three-dimensional plasma photonic crystals using the above device comprises the following steps:

[0013] a. setting up a vacuum reaction chamber, installing two water electrodes in the vacuum reaction chamber, and connecting the water electrodes to a plasma generating power source;

[0014] b. Two solid frames are arranged between the two water electrodes, and the thickness of the two solid frames is different; a plurality of rectangular through holes are opened on the two solid frames, and the rectangular through holes on the two solid frames are perpendicular to each other, and the rectangular through holes on the two solid frames are crisscrossed to form a mesh through hole structure; the through holes and the positions of the thickness of the single solid frames between the adjacent through holes jointly form a discharge air gap;

[0015] c. Introducing discharge gas into the vacuum reaction chamber, the discharge gas being air or a mixture of air and argon, adjusting the volume proportion of air in the discharge gas to 60%-100%, and adjusting the gas pressure of the discharge gas in the vacuum reaction chamber to 0.1-0.25atm;

[0016] d. Turn on the switch of the plasma power supply, adjust the voltage of the plasma power supply to 3kV-8kV, and the frequency to 50kHz-55kHz. When the voltage of the plasma power supply reaches the gas breakdown threshold, a three-dimensional plasma photonic crystal can be generated in the discharge air gap between the two water electrodes. The luminous signal of the plasma photonic crystal can be collected by the signal collector outside the vacuum reaction chamber, and the parameters of the plasma photonic crystal can be measured. At the same time, the differences of the plasma photonic crystal can also be observed in the xz and yz directions.

[0017] It should be noted that in the matrix through holes of the square structure, the through holes and pores in the outermost one or two circles are affected by the boundary, so the outermost one or two circles of plasma and the central plasma may not be arranged periodically. The solid frame material is quartz glass.

[0018] The plasma photonic crystal generated by the device of the present invention has three discharge air gaps, so that the parameters of the plasma photonic crystal under different discharge air gaps under the same conditions can be measured simultaneously, and the pattern can be observed in three dimensions. The plasma photonic crystals with more different parameters can also be obtained by changing the size of the through hole and the air gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the device capable of generating three-dimensional plasma photonic crystals in the present invention.

[0020] Figure 2 It is a schematic structural diagram of the middle discharge area of ​​two solid frames bonded together in the present invention.

[0021] Figure 3 are photographs of plasma photonic crystals with three different discharge air gaps obtained in the embodiments of the present invention; wherein (a) is obtained from Figure 1 The right side of the solid frame is taken from (b). Figure 1The left side of the solid frame is taken from (c). Figure 1 The solid frame in the middle is taken from the front, and (d) is taken from Figure 1 Photographed from above the solid frame.

[0022] Figure 4 In (a) and (b) Figure 3 Based on (a) and (b), the corresponding plasma photonic crystal photos are marked with bright and dark spots.

[0023] Figure 5 It was recorded using an oscilloscope Figure 3 (a) and (b) show the discharge conditions of the plasma photonic crystal in one cycle.

[0024] Figure 6 Photomultiplier tubes are used in Figure 1 The left and right ends of the solid frame are measured Figure 3 Schematic diagram of the time and space resolution results of the plasma photonic crystal shown in (a) and (b).

[0025] Figure 7 yes Figure 3 Discharge sequence diagram of the plasma photonic crystal shown in (a) and (b). DETAILED DESCRIPTION

[0026] like Figure 1 As shown, the device of the present invention includes a vacuum reaction chamber 1, a plasma generating power source 5 is provided outside the vacuum reaction chamber 1, two water electrodes 2 connected to the plasma generating power source 5 are provided inside the vacuum reaction chamber 1, and two solid frames 6 bonded together are provided between the two water electrodes 2. A gas ratio adjustment device 9, a gas premixing chamber 10 and a signal collector are also provided outside the vacuum reaction chamber 1. The signal collector includes a first filter 12, a second filter 13, a first photomultiplier tube 14 and a second photomultiplier tube 15, and the first photomultiplier tube 14 and the second photomultiplier tube 15 are both connected to an oscilloscope 11.

[0027] The vacuum reaction chamber 1 is used to generate plasma photonic crystals therein. The vacuum reaction chamber 1 is a horizontal cylindrical structure. Two sealed dielectric containers are symmetrically placed in the vacuum reaction chamber 1. Water is filled in the sealed dielectric containers to form a water electrode 2 with two plates facing each other. In this embodiment, the water electrode 2 is formed by an organic glass tube by setting glass baffles 3 at both ends to block it. The organic glass tube is filled with water. At the same time, a copper ring 4 is set in the organic glass tube. The two copper rings 4 are electrically connected to the positive and negative electrodes of the plasma generating power supply 5 through power lines. The thickness of the glass baffle 3 is between 1.5 mm and 3 mm, which serves as a discharge medium. An air inlet 7 and an air outlet 8 are opened on the wall of the vacuum reaction chamber 1. The air inlet 7 is connected to the gas premixing chamber 10, and the gas premixing chamber 10 is connected to the gas ratio adjustment device 9.

[0028] like Figure 1 As shown, the two solid frames 6 are closely attached to each other, and the plane where the solid frames 6 are located is perpendicular to the axis of the two water electrodes 2, and the two outer side surfaces of the attached solid frames 6 are closely attached to the end surfaces of the two water electrodes 2 ( Figure 1 The solid frame 6 and the water electrode 2 are separated for easy observation. The sizes of the two solid frames 6 are 100mm*100mm*2mm (corresponding to Figure 1 The solid frame 6 that fits together on the right side of the frame) and 100mm*100mm*1mm (corresponding to Figure 1 That is to say, both solid frames are square structures with a side length of 100 mm, but the thicknesses of the two are different. A discharge area is provided in the middle of the two solid frames 6. Figure 2 A schematic diagram of the structure of the discharge area between two solid frames is shown. A number of rectangular through holes are opened on each solid frame, and the rectangular through holes on the two solid frames are perpendicular to each other, so that the two solid frames are attached together, and the rectangular through holes crisscross to form a mesh-like square through hole structure.

[0029] In this embodiment, the length and width of the rectangular through holes on the two solid frames are the same, which are 30 mm and 2 mm respectively. Therefore, the sizes of the rectangular through holes on the two solid frames are 30 mm*2 mm*2 mm and 30 mm*2 mm*1 mm respectively. On each solid frame, the spacing between two adjacent rectangular through holes is 2 mm. Moreover, the long side of the rectangular through hole on one solid frame is parallel to the horizontal plane, and the long side of the rectangular through hole on the other solid frame is perpendicular to the horizontal plane.

[0030] Specifically, in this embodiment, two solid frames are bonded together, and the rectangular through holes are crisscrossed to form 8*8 square through holes with a side length of 2mm and a thickness of 3mm; Figure 2, from the direction of the long side of the rectangular through hole on one solid frame, there are 8*7 (8 rows and 7 columns) 1mm thick discharge air gaps between two adjacent square through holes; from the direction of the long side of the rectangular through hole on the other solid frame, there are 8*7 (8 rows and 7 columns) 2mm thick discharge air gaps between two adjacent square through holes; 3mm thick square through holes are also discharge air gaps, so there are three different discharge air gaps in the discharge area. The discharge area on the solid frame is facing the water electrode 2; the area of ​​the discharge area is smaller than the cross-sectional area of ​​the water electrode 2, and the total area of ​​the solid frame is larger than the cross-sectional area of ​​the water electrode 2.

[0031] The gas ratio regulating device 9 is used to regulate the ratio of the discharge gas filled into the vacuum reaction chamber 1. In this embodiment, argon gas with a volume proportion of 16% and air with a volume proportion of 84% are filled into the vacuum reaction chamber 1 through the gas ratio regulating device 9. After passing through the gas ratio regulating device 9, the argon gas and the air first enter the gas premixing chamber 10, are fully mixed in the gas premixing chamber 10, and then enter the vacuum reaction chamber 1. The gas pressure of the discharge gas in the vacuum reaction chamber 1 is adjusted to 0.15 standard atmospheric pressure. Turn on the switch of the plasma generating power supply 5, adjust its voltage to 5.8kV and the frequency to 52kHz, and different plasma photonic crystals can be generated in the discharge gap between the two water electrodes 2, that is, in the 3mm thick square through hole, 2mm and 1mm thick discharge air gaps, such as Figure 3 and Figure 4 shown. Figure 3 (a) is from Figure 1 The photo of the plasma photonic crystal obtained by taking a photo of the right side of the solid frame 6 bonded together, (b) is from Figure 1 The photo of the plasma photonic crystal obtained by taking a photo of the left side of the solid frame 6 bonded together in the middle, (c) is from Figure 1 The photo of the plasma photonic crystal obtained by taking a photo of the solid frame 6 bonded together in the front, (d) is from Figure 1 The photo of the plasma photonic crystal obtained is taken above the solid frame 6 bonded together. Figure 3 In Figures (a), (b), (c) and (d), the xyz coordinates are established using Figure (a) as a reference. Figure 4 In (a) and (b) Figure 3 Based on (a) and (b), the plasma photonic crystals corresponding to the bright and dark spots are marked. Figure 4 As shown in the figure, the point formed at the 1mm thick discharge gap is called the dark point (S). Figure 1 The relevant parameters are observed and measured on the left side of the solid frame 6; the bow-tie-like shape is formed at the 2mm thick discharge gap, which is called the bow-tie (B). Figure 1Relevant parameters are observed and measured on the right side of the middle solid frame 6; the square through hole is a discharge air gap with a thickness of 3 mm, forming a central bright spot (L) and a four-dot halo (H).

[0032] use Figure 1 The signal collector measures the discharge sequence of the points (i.e., discharge wires) in the above-mentioned discharge area, and observes the corresponding waveform on the oscilloscope 11, such as Figure 5 As shown in the figure, it can be seen that in each half of the external voltage cycle, these current pulses are roughly divided into three pulses, corresponding to Δt 1 , Δt 2 , Δt 3 Three time periods. Starting from the voltage zero point, the first pulse and the second pulse (two current envelopes) are at the rising edge of the absolute value of the voltage, and the third pulse is at the falling edge of the absolute value of the voltage. Figure 6 As shown, Figure 6 (a) and (b) are for Figure 4 The discharge sequence of some of the points marked in (a) and (b) is introduced. Point S discharges twice, once at the first pulse on the rising edge, and once at the third pulse on the falling edge. Point L only discharges at the third pulse on the falling edge. Point B also discharges at the first pulse on the rising edge, but point S discharges before point B; H discharges at the second pulse on the rising edge (a series of current envelopes); point L also discharges at the current pulse on the falling edge, but point S discharges before point L. Therefore, the discharge sequence of different substructures of the three-dimensional plasma photonic crystal on the xy plane (starting from the voltage zero point) is: SBHSL, such as Figure 7 As shown, Figure 7 (a)-(e) correspond to the discharge of SBHSL. The different air gaps lead to certain differences in the formed plasma photonic crystals. In addition, plasma can also be observed in the xz and yz directions, such as Figure 3 As shown in (c) and (d).

Claims

1. A device having three discharge air gaps capable of generating three-dimensional plasma photonic crystals, characterized in that: The invention comprises a vacuum reaction chamber, two water electrodes arranged in the vacuum reaction chamber and a plasma generating power supply electrically connected to the water electrodes; the invention is characterized in that two solid frames which are bonded to each other are arranged between the two water electrodes, and the thickness of the two solid frames are different; a plurality of rectangular through holes are opened on the two solid frames, and the rectangular through holes on the two solid frames are perpendicular to each other, and the rectangular through holes on the two solid frames are crisscrossed to form a mesh through hole structure; the plasma generating power supply acts on the two water electrodes, so as to generate a three-dimensional plasma photonic crystal between the two water electrodes.

2. The device for generating three-dimensional plasma photonic crystals with three discharge air gaps according to claim 1, characterized in that: The thickness of the two solid borders is 1-3mm.

3. The device for generating three-dimensional plasma photonic crystals with three discharge air gaps according to claim 2, characterized in that: The thicknesses of the two solid frames are 2 mm and 1 mm respectively, and both solid frames are square structures with a side length of 100 mm.

4. The device for generating three-dimensional plasma photonic crystals with three discharge air gaps according to claim 1, characterized in that: The spacing between adjacent rectangular through holes on the two solid frames is 1-5 mm.

5. The device for generating three-dimensional plasma photonic crystals with three discharge air gaps according to claim 4, characterized in that: The sizes of the rectangular through holes on the two solid frames are both 30 mm*2 mm, and the spacing between adjacent rectangular through holes is 2 mm.

6. The device for generating three-dimensional plasma photonic crystals with three discharge air gaps according to claim 1, characterized in that: The rectangular through holes on the two solid frames are crisscrossed to form 4*4-10*10 square through holes.

7. The device for generating three-dimensional plasma photonic crystals with three discharge air gaps according to claim 6, characterized in that: The rectangular through holes on the two solid frames are crisscrossed to form 8*8 square through holes.

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