Device for preparing periodically poled crystal by liquid electrode

Abstract

The invention discloses a device for preparing a periodically poled crystal by a liquid electrode, which comprises a base, a fixed vise body, a movable vise body and a connecting device, the movable vise body is connected with the fixed vise body through the connecting device, the fixed vise body and the movable vise body are respectively provided with a baffle plate, a polarization device is arranged in each baffle plate, and a sealing insulating rubber ring is arranged on the outer side of each baffle plate; a pressure sensing device is also arranged between the polarization device of the fixed vise body and the sealing insulating rubber ring; and a crystal sample table is further arranged on the outer side of the baffle plate of the movable vice body, is used for placing a crystal engraved with a periodic electrode, and is positioned on the outer side of the sealing insulating rubber ring. The device is reasonable in structural design and convenient to operate, the operation efficiency can be effectively improved, an electrolyte solution can be uniformly distributed on the surface of a crystal, the electric field distribution on the surface of the crystal is improved, the space electric field on the surface of the crystal is more uniform, the possibility of non-uniform polarization is reduced, and the yield in the production process is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ferroelectric crystal polarization, and in particular relates to a device for preparing periodically polarized crystals using liquid electrodes. Background Art

[0002] Periodic polarization crystal is a nonlinear optical device made of ferroelectric substrate. The nonlinear optical coefficient of ferroelectric is periodically modulated, and the phase mismatch caused by dispersion is compensated by artificially preparing periodic polarization grating structure to achieve efficient nonlinear interaction. It has the advantages of high frequency conversion efficiency, tunability, high damage threshold, etc. The combination of periodic polarization crystal and all-solid-state laser technology can broaden the wavelength range of laser light source and realize laser output of any wavelength within the light transmission range of the matrix crystal.

[0003] With the development of modern quantum technology, periodically polarized crystals can achieve efficient parametric down-conversion (SPDC) through quasi-phase matching technology (QPM: QuasiPhase Matching), which can split a single high-energy photon into two low-energy entangled photons (signal light and idle light). These entangled photons are the basis of technologies such as quantum communication, quantum computing, and quantum key distribution. Periodically polarized crystals play an important role in improving the efficiency of quantum light sources, expanding photon bandwidth, and optimizing frequency conversion processes. In particular, in technologies such as quantum Internet and quantum computing networks, such crystals have become core optical components.

[0004] At present, the main methods for preparing periodically polarized crystals are electric field polarization and direct growth. Among them, electric field polarization is the mainstream method on the market, which is applicable to a variety of materials (such as PPLN, PPKTP). This method is low-cost, simple to operate, and has good repeatability. It can achieve precise control of the inversion domain by designing the electrode structure. Depending on the polarization electrode material used, there are two methods: metal electrode polarization and liquid electrode polarization.

[0005] Metal electrode polarization is to make periodic metal electrodes (such as chromium or aluminum) on ferroelectric crystals. After applying a strong electric field to the crystal, the polarization direction inside the crystal will flip in the area where the electric field direction is opposite to the spontaneous polarization direction. The periodic design of the electrode pattern controls the spatial distribution of polarization flipping, thereby forming a periodic polarization reversal structure inside the crystal. The metal electrode structure is simple and the polarization process cost is low, which is particularly suitable for mass production. However, due to the edge effect of the metal electrode on the surface of the crystal, the high-voltage electric field will be abnormally amplified in the edge area, resulting in uneven local electric field, which will increase the possibility of uneven expansion of the inversion domain, making it more difficult to control the duty cycle of the inversion domain.

[0006] Liquid electrode polarization is a method of applying a strong electric field on the surface of a ferroelectric crystal through a liquid conductive electrode (such as a salt solution or an ionic liquid) to achieve polarization reversal inside the crystal. Unlike traditional metal electrodes, liquid electrodes can cover the crystal surface more evenly, reduce local electric field distortion, and make the spatial electric field distribution more uniform. However, liquid electrodes require additional packaging or flow channel design to prevent liquid leakage. Common liquid electrode sealing methods include soft film covering sealing, O-ring sealing, dynamic liquid flow channel sealing, etc. When polarizing, it is necessary to select a sealing method based on specific polarization requirements, the characteristics of the periodically polarized crystal, and experimental conditions, which makes the process more complicated and increases the complexity of the operation. It can be learned from the literature that most of the defects of liquid electrodes are caused by defects in the fixture design. For example, bubbles exist between the electrodes, resulting in the electrolyte being unable to fully contact the electrodes; the fixture is not sufficiently sealed, and liquid leaks, resulting in a short circuit; at the same time, the conductivity and uniformity of the liquid electrode will affect the electric field distribution. Once the solution concentration or contact conditions are uneven, it may cause uneven polarization.

[0007] Therefore, although liquid electrode polarization can cover the crystal surface more evenly, reduce local distortion electric field, and obtain a more uniform spatial electric field distribution compared to metal electrode polarization, its larger-scale application is limited due to problems such as defects in the fixture and uniformity of liquid coverage. For this reason, the present invention proposes a device for preparing periodically polarized crystals using liquid electrodes. Summary of the invention

[0008] In order to improve the complex structure of liquid electrode periodic polarization crystals, make the overall operation more convenient, and enable the electrolyte solution to be more evenly distributed on the crystal surface, improve the electric field distribution on the crystal surface, and reduce the possibility of uneven polarization, the present invention provides a device for preparing periodic polarization crystals with liquid electrodes, which improves the complex structure of the liquid electrode, is convenient to operate, and enables the electrolyte solution to be more evenly distributed on the crystal surface, which is beneficial to the preparation of liquid electrode periodic polarization crystals.

[0009] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: A device for preparing periodic polarization crystals with liquid electrodes, comprising a base, a fixed clamp body, a movable clamp body, and a connecting device, wherein the connecting device is installed on the base, the fixed clamp body is arranged at one end thereof, the movable clamp body is arranged at the other end thereof, and the connecting device drives the movable clamp body to reciprocate toward the fixed clamp body; The fixed clamp body and the movable clamp body are both provided with a stop plate, and polarization devices are installed in the stop plates. The two polarization devices are arranged face to face, and a sealing insulating rubber ring is provided on the outer side of the polarization device; A pressure sensing device is also provided between the polarization device of the fixed clamp body and the sealing insulating rubber ring; A crystal sample stage is also arranged outside the baffle plate of the movable clamp body. The crystal sample stage is used to place a crystal engraved with periodic electrodes. The crystal sample stage is located outside the sealing insulating rubber ring.

[0010] Furthermore, the polarization device includes a channel, a liquid tank, and a copper sheet. The liquid tank is cylindrical, one end of which is connected and closed by a copper sheet, and a sealing insulating rubber ring is provided at the other end. There are two channels, one of which is connected to the copper sheet and is used to pass the cable that energizes the copper sheet through it, and the other channel is connected to the liquid tank and communicates with the inner cavity for injecting liquid into the liquid tank.

[0011] Furthermore, the pressure sensing device is a thin film pressure sensor with a pressure value display 7, the thin film end of which is in a circular ring shape, matched with the sealing insulating rubber ring, and the exposed part of the thin film end is coated with sealing insulating silicone.

[0012] Furthermore, the connecting device is a screw drive mechanism.

[0013] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art.

[0014] The present invention arranges a movable clamp body and a fixed clamp body to move and cooperate with each other, clamps the crystal through a sealing insulating rubber ring, and controls the clamping force in combination with pressure data fed back by a pressure sensor to avoid excessive force, etc., thereby improving the complex structure of the liquid electrode, having a reasonable structural design and convenient operation, and can effectively improve the operating efficiency, and can make the electrolyte solution more evenly distributed on the crystal surface, thereby improving the electric field distribution on the crystal surface, making the spatial electric field on the crystal surface more uniform, reducing the possibility of uneven polarization, and thus improving the yield rate in the production process.

[0015] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are part of this application and are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 It is a schematic structural diagram of an embodiment of the present invention; Figure 2 is a schematic diagram of a connection device according to an embodiment of the present invention; Figure 3 It is a schematic structural diagram of a polarization device according to an embodiment of the present invention; Figure 4is a schematic structural diagram of a pressure sensor device according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the structure of a crystal sample stage according to an embodiment of the present invention.

[0017] In the figure: 1-base; 2-fixed clamp body; 3-movable clamp body; 4-connecting device; 5-first stop plate; 6-first polarization device; 7-display; 8-pressure sensing device; 9-first sealing insulating rubber ring; 10-second stop plate; 11-second polarization device; 12-second sealing insulating rubber ring; 13-crystal sample table; 14-crystal; 15-screw; 16-channel one; 17-channel two; 18-liquid tank; 19-copper sheet one; 20-channel three; 21-channel four; 22-liquid tank; 23-copper sheet two; 24-silica gel.

[0018] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0020] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example

[0022] like Figures 1 to 5As shown, the device for preparing periodic polarization crystals with liquid electrodes described in this embodiment includes a base 1, a fixed clamp body 2, a movable clamp body 3, and a connecting device 4. The fixed clamp body 2 and the movable clamp body 3 are arranged above the base 1. The movable clamp body 3 is connected to the fixed clamp body 2 through the connecting device 4. The connecting device 4 is mainly used to move the movable clamp body 3 so that the movable clamp body 3 and the fixed clamp body 2 are close to clamp the crystal. In this example, the connecting device 4 is a screw drive mechanism, and a screw 15 is arranged. The screw 15 is rotated to drive the movable clamp body 3 to move. It should be noted that the screw drive mechanism is a commonly used mechanical structure in the prior art. Here, only one driving method is given as an example. As for the detailed structure of the screw drive mechanism, it will not be repeated here, and reference is made to the existing literature.

[0023] The outer sides of the fixed clamp body 2 and the movable clamp body 3 are used to fix the first stop plate 5 and the second stop plate 10 respectively. Specifically, the fixed clamp body 2 is fixed with the first stop plate 5, the first stop plate 5 is provided with the first polarization device 6 inside, the outer side is provided with the pressure sensor device 8 with the pressure value display 7 and the first sealing insulating rubber ring 9, as shown in the attached figure, the movable clamp body 3 is fixed with the second stop plate 10, the plate is provided with the second polarization device 11, the plate is provided with the second sealing insulating rubber ring 12 and the crystal sample stage 13, and the crystal 14 engraved with periodic electrodes is placed on the stage. When in use, the screw 15 is rotated to drive the movable clamp body 3 to slide toward the fixed clamp body 2, and the crystal 14 is clamped by the first sealing insulating rubber ring 9 and the second sealing insulating rubber ring 12 fixed on the outer sides of the first stop plate 5 and the second stop plate 10.

[0024] The first sealing insulating rubber ring 9 and the second sealing insulating rubber ring 12 are both smooth, flat and uniform annular silicone rubber rings, which are used to prevent the electrolyte solution from being exposed and causing a short circuit. The two sides of the crystal 14 are divided into +Z and -Z planes. The -Z plane uses a photolithography process to etch periodic electrodes, and the +Z plane does not need photolithography.

[0025] As shown in the accompanying drawings, the first polarization device 6 includes a channel 1 16, a channel 2 17, a liquid tank 1 18 and a copper sheet 1 19, and the wire is connected to the copper sheet 1 19 through the channel 1 16. The second polarization device 11 includes a channel 3 20, a channel 4 21, a liquid tank 2 22 and a copper sheet 2 23, and the wire is connected to the copper sheet 2 23 through the channel 3 20. The external electric field acts on the copper sheet 1 19 and the copper sheet 2 23 through the wire. Both copper sheets are used for uniform conduction. The electrolyte solution is injected into the channel 2 17 and the channel 4 21. The electrolyte solution fills the liquid tank 1 18 and the liquid tank 2 22. Then the electrolyte solution acts on the surface of the crystal 14 to uniformly distribute the electric field on the surface of the crystal 14, thereby reducing the possibility of uneven polarization during the polarization process.

[0026] The pressure sensing device 8 is used to detect the pressure during clamping. In this example, it is a thin film pressure sensor with a pressure value display 7. The end of the thin film is in a circular ring shape, which matches the sealing insulating rubber ring. Referring to the attached figure, the size of the pressure sensing device 8 is consistent with the sealing insulating rubber ring and is in the shape of a circular ring. This is to ensure uniform force. During the pressurization process, the magnitude of the artificial force varies. The pressure sensor is used to control the force within a suitable range during the pressurization operation, reduce the difference in experimental variables, and reasonably control the variables. In addition, the exposed part of the pressure sensing device 8 is coated with a sealing insulating silicone 24. This is because the exposed inside of the circular ring of the thin film pressure sensor will come into contact with the electrolyte solution during the polarization process. The silicone is used for sealing and insulation to prevent the electrolyte solution from flowing into the device.

[0027] During operation, a crystal 14 with electrodes engraved thereon is placed on a sample table 13. After the crystal 14 is fixed, the connecting device 4 is rotated to drive the movable clamp body 3 to move, and the crystal 14 is clamped by the first sealing insulating rubber ring 9 and the second sealing insulating rubber ring 12 fixed on the outside of the first stop plate 5 and the second stop plate 10. At the same time, the pressure on the display 7 is observed to control the degree of crystal clamping to avoid crushing the wafer with excessive force. After the crystal is clamped, the electrolyte solution is injected into the channel 2 17 and the channel 4 21 to fill the liquid tank 1 18 and the liquid tank 2 22. Subsequently, an external electric field is applied to the copper sheet 1 19 and the copper sheet 2 23 through a wire. Both copper sheets are used for uniform conduction. After the copper sheets are conductive, the electrolyte liquid is used as a medium for conducting current to apply an electric field to the crystal for polarization. The overall structural design of the present invention is reasonable, easy to operate, and improves the operating efficiency. It can also make the electrolyte solution more evenly distributed on the crystal surface, improve the electric field distribution on the crystal surface, and reduce the possibility of uneven polarization.

[0028] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A device for preparing periodically polarized crystals using liquid electrodes, characterized in that: It comprises a base, a fixed clamp body, a movable clamp body, and a connecting device, wherein the connecting device is installed on the base, the fixed clamp body is arranged at one end thereof, the movable clamp body is arranged at the other end thereof, and the connecting device drives the movable clamp body to reciprocate toward the fixed clamp body; The fixed clamp body and the movable clamp body are both provided with a stop plate, and polarization devices are installed in the stop plates. The two polarization devices are arranged face to face, and a sealing insulating rubber ring is provided on the outer side of the polarization device; A pressure sensing device is also provided between the polarization device of the fixed clamp body and the sealing insulating rubber ring; A crystal sample stage is also arranged outside the baffle plate of the movable clamp body. The crystal sample stage is used to place a crystal engraved with periodic electrodes. The crystal sample stage is located outside the sealing insulating rubber ring.

2. The device for preparing periodically polarized crystals using liquid electrodes according to claim 1, characterized in that: The polarization device includes a channel, a liquid tank, and a copper sheet. The liquid tank is cylindrical, one end of which is connected and closed by a copper sheet, and a sealing insulating rubber ring is provided at the other end. There are two channels, one of which is connected to the copper sheet and is used to pass the cable that energizes the copper sheet through, and the other channel is connected to the liquid tank and communicates with the inner cavity for injecting liquid into the liquid tank.

3. The device for preparing periodically polarized crystals using liquid electrodes according to claim 1, characterized in that: The pressure sensing device is a thin film pressure sensor with a pressure value display 7, the thin film end of which is in a circular ring shape and matches the sealing insulating rubber ring, and the exposed part of the thin film end is coated with sealing insulating silicone.

4. The device for preparing periodically polarized crystals using liquid electrodes according to claim 1, characterized in that: The connecting device is a screw drive mechanism.

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