Electro-optical scanner based on stoichiometric lithium tantalate crystal

Abstract

The invention discloses a stoichiometric lithium tantalate crystal-based electro-optical scanner, which comprises a laser, a polarizing film, a stoichiometric lithium tantalate crystal, a driving circuit, an optical lens, a filter and a receiver which are sequentially connected from left to right, and is characterized in that a laser beam of the laser is incident from the Y-axis direction of the stoichiometric lithium tantalate crystal; the front face and the back face of the stoichiometric ratio lithium tantalate crystal in the Z-axis direction are provided with periodic triangular ferroelectric domain structures, the stoichiometric ratio lithium tantalate crystal is provided with a top face and a bottom face which are parallel to each other in the X-axis direction, the top face and the bottom face are both plated with metal electrodes, and the driving circuit is connected to the metal electrodes. And an external electric field is applied to the stoichiometric lithium tantalate crystal in the X-axis direction. According to the electro-optical scanner based on the stoichiometric lithium tantalate crystal, on the basis that it is ensured that the electro-optical scanner has a large electro-optical modulation angle, the manufacturing cost and manufacturing difficulty of the electro-optical scanner are effectively reduced, and high practicability is achieved.

Description

Technical Field

[0001] The present application belongs to the field of optical equipment technology, and in particular, relates to an electro-optical scanner based on stoichiometric lithium tantalate crystals. Background Art

[0002] An electro-optical scanner is a device that uses the electro-optic effect of an electro-optical crystal to modulate the direction of a light beam. It changes the propagation direction of light by changing the external electric field of the electro-optical crystal, thereby achieving scanning or modulation of the light beam. Electro-optical scanners have the characteristics of high-speed light beam modulation and low power consumption, and have broad application prospects in optical data storage systems, laser scanning, and optical switches.

[0003] The efficiency of electro-optical scanners is affected by the properties of electro-optical crystals, among which the electro-optic coefficient is a key parameter. Electro-optical crystals with larger electro-optical coefficients can usually provide a larger modulation angle for electro-optical scanners, thereby improving scanning efficiency. At present, the electro-optical crystals commonly used in electro-optical scanners are potassium tantalate niobate crystals or lithium tantalate crystals. Potassium tantalate niobate crystals have a larger electro-optical coefficient, but due to their high price, the production cost of electro-optical scanners is relatively high. Lithium tantalate crystals are low in price but have a smaller electro-optical coefficient, resulting in low scanning efficiency of electro-optical scanners.

[0004] Therefore, reducing the manufacturing cost of the electro-optical scanner while ensuring that the electro-optical scanner has a large electro-optical modulation angle is of great significance to promoting the technological progress of optical equipment. Summary of the invention

[0005] The purpose of the present application is to provide an electro-optical scanner based on a stoichiometric lithium tantalate crystal, which reduces the manufacturing cost of the electro-optical scanner and improves the practicability of the electro-optical scanner while ensuring that the electro-optical scanner has a larger electro-optical modulation angle.

[0006] In order to achieve the above-mentioned technical effect, the present application provides an electro-optical scanner based on a stoichiometric lithium tantalate crystal, comprising: a laser, a polarizer, a stoichiometric lithium tantalate crystal, a drive circuit, an optical lens, a filter and a receiver connected in sequence from left to right, wherein the laser beam of the laser is incident from the Y-axis direction of the stoichiometric lithium tantalate crystal; the front and back sides of the stoichiometric lithium tantalate crystal along the Z-axis direction have a periodic triangular ferroelectric domain structure, the X-axis direction of the stoichiometric lithium tantalate crystal has a top surface and a bottom surface parallel to each other, the top surface and the bottom surface are both plated with metal electrodes, the drive circuit is connected to the metal electrode, and applies an external electric field to the stoichiometric lithium tantalate crystal in the X-axis direction.

[0007] This embodiment uses a stoichiometric lithium tantalate crystal as an electro-optical crystal to make an electro-optical scanner. By designing a periodic triangular ferroelectric domain structure on the Z plane of the stoichiometric lithium tantalate crystal, precise control of the electric field distribution inside the crystal is achieved, thereby achieving modulation of the electro-optical effect. The voltage of the external electric field applied in the X-axis direction is adjusted to adjust the laser deflection angle, thereby achieving electro-optical scanning. The solution of the present application is reasonably designed using the structural characteristics of the stoichiometric lithium tantalate crystal with a small electro-optical coefficient. By designing its domain structure, the electro-optical modulation angle of the electro-optical scanner can be increased, the production cost and difficulty of the electro-optical scanner can be reduced, and the practicality of the electro-optical scanner can be improved.

[0008] As an improvement to the technical solution of the present application, the polarization directions of the adjacent triangular ferroelectric domain structures in the stoichiometric lithium tantalate crystal are opposite.

[0009] This embodiment makes full use of the characteristics of the stoichiometric lithium tantalate crystal, which has a small polarization reversal voltage and an easily reversible domain structure. By designing a triangular ferroelectric domain structure with periodic reversal of polarization direction in the stoichiometric lithium tantalate crystal, the periodic reversal of the electro-optic coefficient of the stoichiometric lithium tantalate crystal is achieved. When an external electric field is applied to the top and bottom surfaces of the stoichiometric lithium tantalate crystal in the X direction, the deflection angle of the electro-optical scanner can be continuously deflected due to the reversal of the electro-optical coefficient, thereby optimizing the deflection angle of the electro-optical scanner and improving the practicability of the electro-optical scanner.

[0010] As an improvement of the technical solution of the present application, the shape of the triangular ferroelectric domain structure is an isosceles triangle with a base angle of 63.4°.

[0011] This embodiment designs the triangular ferroelectric domain structure to be an isosceles triangle with a base angle of 63.4°, so as to maximize the number of triangular ferroelectric domain structures within a limited stoichiometric ratio of lithium tantalate crystal length and improve the deflection angle of the photoelectric scanner.

[0012] As an improvement of the technical solution of the present application, the period of the triangular ferroelectric domain structure is 0.01-3 mm.

[0013] On the basis of the above improvements, further, the triangular ferroelectric domain structure is obtained by plating metal electrodes on both sides of the stoichiometric lithium tantalate crystal along the Z-axis direction and applying a ferroelectric electric field in the Z direction; the intensity of the ferroelectric electric field is greater than the coercive field strength of the stoichiometric lithium tantalate crystal.

[0014] As an improvement of the technical solution of the present application, the direction and magnitude of the voltage in the external electric field applied in the X-axis direction can be continuously changed.

[0015] Furthermore, the voltage intensity of the external electric field ranges from 50V to 5000V.

[0016] As an improvement of the technical solution of the present application, the Li content of the stoichiometric lithium tantalate crystal is in the range of 49.70%-50% and the coercive field of the stoichiometric lithium tantalate crystal is lower than 100 V / mm.

[0017] As an improvement of the technical solution of the present application, the stoichiometric lithium tantalate crystal has a thickness range of 0.2-10 mm in the X-axis direction and a length range of 1-10 cm in the Y-axis direction.

[0018] As an improvement of the technical solution of the present application, the metal electrode is any one of aluminum, silver and gold electrodes.

[0019] The beneficial effects of this application are:

[0020] 1. The present application uses stoichiometric lithium tantalate crystals as electro-optical crystals to produce an electro-optical scanner. By designing a periodic triangular ferroelectric domain structure on the Z plane of the stoichiometric lithium tantalate crystal, precise control of the electric field distribution inside the crystal is achieved, thereby achieving modulation of the electro-optical effect. The laser deflection angle is adjusted by adjusting the voltage of the external electric field applied in the X-axis direction, thereby achieving electro-optical scanning. The scheme of the present application is reasonably designed using the structural characteristics of the stoichiometric lithium tantalate crystal with a smaller electro-optical coefficient. By designing its domain structure, the electro-optical modulation angle of the electro-optical scanner can be increased, the production cost and difficulty of the electro-optical scanner can be reduced, and the practicality of the electro-optical scanner can be improved.

[0021] 2. The present application makes full use of the characteristics of stoichiometric lithium tantalate crystals, namely, low polarization reversal voltage and easy reversal of domain structure. By designing a triangular ferroelectric domain structure with periodic reversal of polarization direction in the stoichiometric lithium tantalate crystal, the periodic reversal of the electro-optic coefficient of the stoichiometric lithium tantalate crystal is achieved. When an external electric field is applied to the top and bottom surfaces of the stoichiometric lithium tantalate crystal in the X direction, the deflection angle of the electro-optical scanner can be continuously deflected due to the reversal of the electro-optical coefficient, thereby optimizing the deflection angle of the electro-optical scanner and improving the practicability of the electro-optical scanner.

[0022] 3. This application designs the triangular ferroelectric domain structure into an isosceles triangle with a base angle of 63.4°, which can maximize the number of triangular ferroelectric domain structures within a limited stoichiometric ratio of lithium tantalate crystal length and improve the deflection angle of the photoelectric scanner.

[0023] The structure of the present application and its other inventive objectives and beneficial effects will be more clearly understood through the description of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 It is a schematic diagram of the structure of an electro-optical scanner based on a stoichiometric lithium tantalate crystal in an embodiment of the present application;

[0026] Figure 2 Schematic diagram of the internal structure of a stoichiometric lithium tantalate crystal in an embodiment of the present application;

[0027] Figure 3 This is a front view of the internal structure of the stoichiometric lithium tantalate crystal in the embodiment of the present application;

[0028] Figure 4 is a top view of the internal structure of a stoichiometric lithium tantalate crystal in an embodiment of the present application;

[0029] Figure 5 This is a schematic diagram of the electric domain arrangement of the stoichiometric lithium tantalate crystal in the embodiment of the present application when the periodic triangular ferroelectric domain structure is not designed;

[0030] Figure 6 It is a schematic diagram of the electric domain arrangement of the triangular ferroelectric domain structure in the stoichiometric lithium tantalate crystal in the embodiment of the present application.

[0031] Description of reference numerals:

[0032] 1. Laser; 2. Polarizer; 3. Stoichiometric lithium tantalate crystal; 4. Driving circuit; 5. Optical lens; 6. Filter; 7. Receiver. DETAILED DESCRIPTION

[0033] The embodiments of the technical solution of the present application will be described in detail below. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Example 1

[0035] Figure 1 is a schematic structural diagram of an electro-optical scanner based on a stoichiometric lithium tantalate crystal in an embodiment of the present application, Figures 2 to 4 It is a schematic diagram of the structure of the stoichiometric lithium tantalate crystal in the embodiment of the present application. Figure 1The electro-optical scanner based on the stoichiometric lithium tantalate crystal shown in the figure includes: a laser 1, a polarizer 2, a stoichiometric lithium tantalate crystal 3, a drive circuit 4, an optical lens 5, a filter 6 and a receiver 7 connected in sequence from left to right, the laser beam of the laser 1 is incident from the Y-axis direction of the stoichiometric lithium tantalate crystal 3; the front and back sides of the stoichiometric lithium tantalate crystal 3 along the Z-axis direction have a periodic triangular ferroelectric domain structure, the X-axis direction of the stoichiometric lithium tantalate crystal 3 has a top surface and a bottom surface parallel to each other, the top surface and the bottom surface are both plated with metal electrodes, the drive circuit 4 is connected to the metal electrode, and applies an external electric field to the stoichiometric lithium tantalate crystal 3 in the X-axis direction.

[0036] Specifically, the laser 1 is used to emit a laser beam, and the polarizer 2 is arranged at the output end of the laser 1 to filter the laser beam emitted by the laser 1 to ensure that only light of a specific polarization direction can pass through. The optical lens 5 is arranged after the stoichiometric lithium tantalate crystal 3 to focus or shape the modulated laser beam. The filter 6 is used to filter out unnecessary wavelengths or stray light to ensure that the receiver 7 only receives the modulated laser beam. The receiver 7 is used to convert the optical signal into an electrical signal for subsequent processing after detecting the modulated laser beam.

[0037] In the electro-optical scanner of the present embodiment, the laser beam emitted by the laser 1 is filtered by the polarizing plate 2 and then vertically incident on the Y-axis direction of the stoichiometric lithium tantalate crystal 3, where it is deflected. The deflection angle of the laser beam is adjusted by precisely controlling the voltage intensity of the external electric field applied to the stoichiometric lithium tantalate crystal 3 by the driving circuit 4.

[0038] In one implementation, the polarization directions of the adjacent triangular ferroelectric domain structures in the stoichiometric lithium tantalate crystal 3 are opposite.

[0039] Specifically, lithium tantalate crystals are ferroelectric crystals. Due to the existence of spontaneous polarization, a domain structure is formed inside the crystal. By controlling the shape and distribution of the domain structure, the electro-optical effect performance of lithium tantalate crystals can be further regulated and optimized. In order to optimize the structure of the electro-optical crystal to increase the electro-optical deflection angle, the inventors of the present application refer to the electro-optical deflector to form a triangular prism-like structure using the domain inversion region and the non-inversion region of the electro-optical crystal, and change the refractive index distribution of the electro-optical crystal by controlling the electric field, thereby achieving the deflection of the light beam. However, due to the limitations of the physical structure or manufacturing process, only part of the area of ​​this triangular prism structure is effectively utilized to achieve the deflection of the light beam, and the electro-optical deflection angle cannot be increased to the ideal deflection angle.

[0040] In order to further solve this problem, the inventor of the present application creatively proposed to utilize the property that the internal domain structure of the stoichiometric lithium tantalate crystal 3 is easy to reverse, and design a periodic triangular ferroelectric domain structure on the front and back sides of the stoichiometric lithium tantalate crystal 3 along the Z-axis direction, and make the polarization directions of the adjacent triangular ferroelectric domain structures in the stoichiometric lithium tantalate crystal 3 opposite, so as to achieve periodic reversal of the electro-optic coefficient of the stoichiometric lithium tantalate crystal 3. When an external electric field is applied to the top and bottom surfaces of the stoichiometric lithium tantalate crystal 3 in the X direction, due to the reversal of the electro-optic coefficient, the deflection angle of the electro-optical scanner can achieve continuous deflection, thereby optimizing the deflection angle of the electro-optical scanner and improving the practicability of the electro-optical scanner.

[0041] In a preferred implementation, the triangular ferroelectric domain structure has an isosceles triangle structure with a base angle of 63.4°.

[0042] Specifically, the triangular ferroelectric domain structure indirectly affects the electro-optical performance of the electro-optical crystal by affecting the number, distribution and orientation of domain walls. The triangular ferroelectric domain structure set in the crystal in the prior art is mainly a right triangle or an equilateral triangle, while the isosceles triangle with a base angle of 63.4° described in the present invention can maximize the number of triangular ferroelectric domain structures within a limited crystal length and improve the deflection angle of the photoelectric scanner.

[0043] It should be understood that an increase in the number of structured domain walls in the triangular ferroelectric domain structure will increase the scattering and loss of the light beam inside the crystal. In a preferred implementation, the triangular ferroelectric domain structure has a structured period of 0.01-3 mm.

[0044] Based on the above embodiments, in one implementation, the triangular ferroelectric domain structure is obtained by plating metal electrodes on both sides of the stoichiometric lithium tantalate crystal 3 along the Z-axis direction and applying a ferroelectric electric field in the Z direction; the intensity of the ferroelectric electric field is greater than the coercive field strength of the stoichiometric lithium tantalate crystal 3.

[0045] Specifically, the triangular ferroelectric domain structure is produced by applying a ferroelectric electric field exceeding its coercive field to change the electric domain inside the material. The detailed production scheme of the triangular ferroelectric domain structure is as follows: first, metal electrodes are plated on the front and back sides (also called "+Z face" and "-Z face") of the stoichiometric lithium tantalate crystal 3 along the Z axis, and the electric domain structure inside the material is arranged regularly by applying a ferroelectric electric field, such as Figure 5 As shown in the figure, the arrows in the figure indicate the direction of the electric domain arrangement in the crystal after the electric field is applied. Then, the metal electrode on the Z surface of the stoichiometric lithium tantalate crystal 3 is removed, a triangular metal electrode is plated, and an electric field opposite to the direction of the ferroelectric electric field is applied to the triangular metal electrode to reverse the ferroelectric domain in the stoichiometric lithium tantalate crystal 3, and a reverse triangular ferroelectric domain structure with a regular arrangement is produced, as shown in FIG. Figure 6 As shown, the blue area in the figure is the metal electrode, and the yellow arrow is the direction of the electric domain arrangement in the crystal. Finally, the metal electrode on the Z surface is removed. The intensity of the ferroelectric electric field is greater than the coercive field intensity of the stoichiometric lithium tantalate crystal 3. This manufacturing method makes the adjacent triangular domain structures present opposite arrangements, which can increase the deflection angle of the photoelectric scanner.

[0046] In one implementation, the direction and magnitude of the voltage in the external electric field applied in the X-axis direction can be continuously changed.

[0047] Specifically, the electro-optical scanner adjusts the laser deflection angle by adjusting the voltage magnitude and direction of the external electric field applied in the X-axis direction, thereby achieving electro-optical scanning. In order to achieve continuous change of the laser deflection angle, the direction and magnitude of the voltage in the external electric field can be continuously changed.

[0048] Preferably, in one implementation, the voltage intensity of the external electric field ranges from 50V to 5000V.

[0049] Preferably, in one implementation, the Li content of the stoichiometric lithium tantalate crystal 3 is in the range of 49.70%-50% and the coercive field of the stoichiometric lithium tantalate crystal 3 is lower than 100 V / mm.

[0050] Specifically, the coercive field of the stoichiometric lithium tantalate crystal 3 used in this embodiment is lower than 100 V / mm, so the coercive electric field strength required to reverse the domain structure is low. In addition, it should be noted that the stoichiometric lithium tantalate crystal 3 used in this embodiment has a greater increase in electro-optic coefficient than the lithium tantalate crystal. Under the condition of 633 nm wavelength, the n of the lithium tantalate crystal with the same composition is e 3 r 33 337pm / V, n 0 3 r 13 is 120pm / V. The stoichiometric ratio of lithium tantalate crystal is 3 e 3 r 33 402pm / V, n 0 3 r 13 is 124pm / V. Among them, n e is the extraordinary refractive index, r 33 is the electro-optic coefficient of light polarization and applied electric field along the Z direction, n 0 is the ordinary light refractive index, r 13 is the electro-optic coefficient of the applied electric field along the X direction and the light polarization along the Z direction. It can be seen that the stoichiometric lithium tantalate crystal 3 is highly sensitive to voltage input, has a small polarization reversal voltage, and is easy to reverse the domain structure.

[0051] Preferably, in one implementation, the stoichiometric lithium tantalate crystal 3 has a thickness in the X-axis direction of 0.2-10 mm and a length in the Y-axis direction of 1-10 cm.

[0052] In one implementation, the metal electrode includes any one of an aluminum electrode, a silver electrode or a gold electrode.

[0053] According to the implementation method provided by the present application, some specific experiments were conducted on the present application, that is, lithium tantalate crystals with different stoichiometric ratios were used as the material for making the electro-optical scanner. From these examples, it can be seen that the solution provided by the present application has achieved good results. It should be noted that the following examples are only used to illustrate the present invention in detail and do not limit the protection scope of the invention in any way.

[0054] Example 2

[0055] A stoichiometric lithium tantalate crystal 3 with a lithium content of 49.90% is selected as the electro-optical crystal for making an electro-optical scanner. The stoichiometric lithium tantalate crystal 3 is plated with aluminum electrodes on the top and bottom surfaces along the X direction. The thickness in the X-axis direction is 1 mm, and the length in the Y-axis direction is 6 cm. The internal triangular ferroelectric domain structure has an isosceles triangle with a base angle of 63.4°, and the period of the domain structure is 1 mm.

[0056] Embodiments 3 to 6

[0057] The same electro-optical scanner structure as in Example 2 is used, except that the lithium content of the stoichiometric lithium tantalate crystal 3, the thickness in the X-axis direction, the length in the Y-axis direction, the shape and period of the triangular ferroelectric domain structure are different. The control conditions are detailed in Table 1.

[0058] Comparative Examples 1 to 5

[0059] The same electro-optical scanner structure as in Example 2 is used, except that the lithium content of the stoichiometric lithium tantalate crystal 3, the thickness in the X-axis direction, the length in the Y-axis direction, and the shape and period of the triangular ferroelectric domain structure are different. The control conditions are detailed in Table 1.

[0060] The range of the electro-optical deflection angle was calculated using the following formula 1 for the electro-optical scanners made in Examples 2 to 6 and Comparative Examples 1 to 5, where the laser 1 of the electro-optical scanner was a He-Ne laser.

[0061] Table 2.

[0062]

[0063] Where N is the number of prisms, is the cube of the ordinary light refractive index, r13 is the electro-optic coefficient with applied electric field along the X direction and light polarization along the Z direction, l is the length of the prism unit, h is the height of the prism unit, V is the applied voltage, and d is the thickness in the direction of the applied electric field.

[0064] Table 1 Control conditions of electro-optic crystal in electro-optic scanner

[0065]

[0066]

[0067] Table 2 Electro-optical deflection test results

[0068] Example <![CDATA[n0 3 r13(pm / V)]]> Maximum deflection angle / degree Example 2 131 0.4495 Example 3 130 0.8923 Example 4 135 0.4632 Example 5 130 4.122 Example 6 130 0.3074 Comparative Example 1 109 0.748 Comparative Example 2 102 0.705 Comparative Example 3 130 0.7982 Comparative Example 4 130 0.8402 Comparative Example 5 130 0.8805

[0069] Experimental conclusion:

[0070] Through the experimental data of Examples 2 to 6, it is possible to calculate and analyze the effects of the lithium content, coercive field strength, length of the stoichiometric lithium tantalate crystal, and the shape, bottom angle, and period of the internal triangular ferroelectric domain structure on the maximum deflection angle of the electro-optical scanner, and it is concluded that a stoichiometric lithium tantalate crystal with a triangular ferroelectric domain structure of shorter length and smaller period and a lithium content close to 50% can effectively improve the maximum deflection angle of the electro-optical scanner.

[0071] Through the experimental data of Example 3 and Comparative Examples 1-2, the influence of the type of electro-optical crystal on the maximum deflection angle of the electro-optical scanner can be calculated and analyzed, and the conclusion is drawn: compared with lithium tantalate crystals and lithium niobate crystals with the same composition, the stoichiometric lithium tantalate crystals with an inverted triangular ferroelectric domain structure have a better improvement effect on the maximum deflection angle of the electro-optical scanner.

[0072] Through the experimental data of Example 3 and Comparative Examples 3 to 5, it is possible to calculate and analyze the influence of the shape of the triangular ferroelectric domain structure inside the stoichiometric lithium tantalate crystal on the maximum deflection angle of the electro-optical scanner, and conclude that an isosceles triangle with a base angle of 63.4° can maximize the number of triangular ferroelectric domain structures within the limited length of the stoichiometric lithium tantalate crystal, and has a better effect on improving the maximum deflection angle of the photoelectric scanner.

[0073] It can be seen from the above embodiments, comparative examples and experimental conclusions that the electro-optical scanner based on the stoichiometric lithium tantalate crystal provided by the present application can effectively reduce the manufacturing cost of the electro-optical scanner while ensuring that the electro-optical scanner has a large electro-optical modulation angle, and has strong practicality. It can be further seen that the beneficial effects of the present application are significant.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electro-optical scanner based on a stoichiometric lithium tantalate crystal, characterized in that: include: A laser (1), a polarizing plate (2), a stoichiometric lithium tantalate crystal (3), a driving circuit (4), an optical lens (5), a filter (6) and a receiver (7) are connected in sequence from left to right. The laser beam of the laser (1) is incident from the Y-axis direction of the stoichiometric lithium tantalate crystal (3). The front and back sides of the stoichiometric lithium tantalate crystal (3) along the Z-axis direction have a periodic triangular ferroelectric domain structure. The stoichiometric lithium tantalate crystal (3) has a top surface and a bottom surface parallel to each other in the X-axis direction. The top surface and the bottom surface are both plated with metal electrodes. The driving circuit (4) is connected to the metal electrode and applies an external electric field to the stoichiometric lithium tantalate crystal (3) in the X-axis direction.

2. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to claim 1, characterized in that: The polarization directions of the adjacent triangular ferroelectric domain structures in the stoichiometric lithium tantalate crystal (3) are opposite.

3. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to claim 1, characterized in that: The shape of the triangular ferroelectric domain structure is an isosceles triangle with a base angle of 63.4°.

4. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to claim 1, characterized in that: The period of the triangular ferroelectric domain structure is 0.01-3 mm.

5. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to any one of claims 1 to 3, characterized in that: The triangular ferroelectric domain structure is produced by plating metal electrodes on both sides of the stoichiometric lithium tantalate crystal (3) along the Z-axis direction and applying a ferroelectric electric field in the Z direction; the intensity of the ferroelectric electric field is greater than the coercive field intensity of the stoichiometric lithium tantalate crystal (3).

6. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to claim 1, characterized in that: The direction and magnitude of the voltage in the external electric field applied in the X-axis direction can be continuously changed.

7. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to claim 6, characterized in that: The voltage intensity of the external electric field ranges from 50V to 5000V.

8. The electro-optical scanner based on stoichiometric lithium tantalate crystal as claimed in claim 1, characterized in that: The Li content of the stoichiometric lithium tantalate crystal (3) ranges from 49.70% to 50% and the coercive field strength of the stoichiometric lithium tantalate crystal (3) is lower than 100 V / mm.

9. The electro-optical scanner based on stoichiometric lithium tantalate crystal as claimed in claim 1, characterized in that: The stoichiometric lithium tantalate crystal (3) has a thickness in the X-axis direction of 0.2-10 mm and a length in the Y-axis direction of 1-10 cm.

10. The electro-optical scanner based on stoichiometric lithium tantalate crystal according to claim 1, characterized in that: The metal electrode includes any one of an aluminum electrode, a silver electrode or a gold electrode.

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