Laser scanning device and laser scanning method based on flexible grating

Abstract

The present invention specifically relates to a laser scanning device and a laser scanning method based on a flexible grating. The laser scanning device comprises an optical fiber laser, an optical fiber amplifier, a spatial light collimator, a flexible grating, a mechanical stretching device, a focusing lens and a receiving device. The laser light beam emitted by the optical fiber laser is power-amplified by the optical fiber amplifier, the spatial light collimator shapes the power-amplified laser light beam into a parallel light beam, the parallel light beam passes through the flexible grating to generate a multi-order diffraction light beam, the mechanical stretching device fixes and stretches the flexible grating to change the position of the diffraction light beam, the diffraction light beam is converged by the focusing lens, and the diffraction light beam is received by the receiving device. The present invention adopts a scanning structure combining a flexible grating and a mechanical stretching device, utilizes the mechanical stretching device to change the period of the flexible grating, and realizes scanning in multiple directions by changing the position of the diffraction light beam, thereby greatly increasing the scanning speed and reducing the scanning cost.

Description

Technical Field

[0001] The invention relates to the technical field of laser scanning, and in particular to a laser scanning device based on a flexible grating. Background Art

[0002] Laser scanning is a key technology used in laser communication, laser radar, laser processing, remote sensing and other fields. Currently, the more mature laser scanning implementation methods include fast-swing mirrors, two-dimensional scanning galvanometers, rotating double optical wedges, servo turntables and microlens arrays. These methods have high scanning costs, complex structures, and can only scan light beams in a single direction, and cannot meet the requirements of scanning multiple laser beams at the same time.

[0003] Patent CN114503007A in the prior art discloses a laser scanning device and a laser scanning system, which realizes laser beam scanning by rotating refractive and reflective optical elements. The scanning device and scanning method are complex, the debugging process is complex, and it is easily affected by stray light. Moreover, the system cannot meet the application requirements of complex scenes such as space laser communication. Patent CN111399124A discloses a laser scanning system, which adopts an all-fiber structure. The device makes the transmitting optical path and the receiving optical path coaxial by using a coaxial connector, which reduces the complexity of the system to a certain extent. However, the position of the light beam must be changed by rotating the entire instrument during operation. Therefore, only laser beam scanning in a single direction can be realized, and simultaneous scanning of multiple beams cannot be realized. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the traditional laser scanning equipment in the prior art, such as complex structure, high cost, complicated operation and low integration, so as to provide a laser scanning equipment based on flexible grating.

[0005] A laser scanning device based on a flexible grating, comprising a fiber laser, a fiber amplifier, a spatial light collimator, a flexible grating, a mechanical stretching device, a focusing lens and a receiving device;

[0006] The laser beam emitted by the fiber laser is power-amplified by the fiber amplifier, the spatial light collimator shapes the power-amplified laser beam into a parallel beam, the parallel beam passes through the flexible grating to generate a multi-order diffraction beam, the mechanical stretching device fixes and stretches the flexible grating to change the position of the diffraction beam, the diffraction beam is converged by the focusing lens, and the diffraction beam is received by the receiving device.

[0007] Furthermore, the focusing lens includes a first focusing lens and a second focusing lens, the receiving device includes a first receiving device and a second receiving device, the diffraction light beam converged by the first focusing lens is received by the first receiving device, and the diffraction light beam converged by the second focusing lens is received by the second receiving device.

[0008] Furthermore, the mechanical stretching device includes a first moving component, a second moving component, a third moving component, a fourth moving component, a fifth moving component, a sixth moving component, a seventh moving component and an eighth moving component, each moving component is respectively connected to a different push rod and placed in a corresponding straight groove, and each moving component is evenly arranged on the flexible grating and is fixedly connected to the flexible grating.

[0009] Furthermore, the first moving assembly, the second moving assembly, the third moving assembly, the fourth moving assembly, the fifth moving assembly, the sixth moving assembly, the seventh moving assembly and the eighth moving assembly have the same specifications.

[0010] Furthermore, the fiber laser is a 1550nm tunable laser with a maximum output power of 0.3W.

[0011] Furthermore, the optical fiber amplifier is an erbium-doped optical fiber amplifier.

[0012] Furthermore, the erbium-doped fiber amplifier amplifies the power of the light beam to 5W.

[0013] Furthermore, the flexible grating is made of polydimethylsiloxane, and has a grating period of 2.65 μm and a thickness of 1 mm.

[0014] A laser scanning method based on a laser scanning device based on a flexible grating as described in any of the above items, wherein the laser emitted by the fiber laser is amplified to a specified power by a fiber amplifier and then shaped into parallel light output by a spatial light collimator, and the flexible grating is fixed on a mechanical stretching device, and the light output by the spatial light collimator generates a plurality of diffraction beams with different spatial propagation directions after passing through the flexible grating, wherein the 0th order diffraction beam is always parallel to the direction of the incident light and cannot be scanned, and the stress F applied to the flexible grating in various directions is continuously changed by stretching each moving component in the stretching device, and the ±1st order diffraction beams can form approximately equal scanning areas in the upper and lower areas of the 0th order diffraction beam, respectively, and the scanning angles thereof are +θ and -θ, respectively, and when the receiving end is in the upper area, the parallel light is converged by the first focusing lens and received by the first receiving device; when the receiving end is in the lower area, the parallel light is converged by the second focusing lens and received by the second receiving device.

[0015] The present invention adopts a scanning structure combining a flexible grating and a mechanical stretching device, uses the mechanical stretching device to change the period of the flexible grating, and realizes scanning in multiple directions by changing the position of the diffraction beam, which greatly increases the scanning speed and greatly reduces the scanning cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the structure of the laser scanning based on the flexible grating provided by the present invention;

[0018] Figure 2 A schematic diagram of the structure of the flexible grating provided by the present invention;

[0019] Figure 3 A schematic diagram of the stretching principle of the mechanical stretching device provided by the present invention;

[0020] Figure 4 A schematic diagram of the structure of the flexible grating before and after stretching provided by the present invention;

[0021] Figure 5 This is a schematic diagram of the change of the near-field light spot before and after scanning of the present invention;

[0022] Description of reference numerals:

[0023] 1-Fiber laser; 2-Fiber amplifier; 3-Spatial light collimator;

[0024] 4-flexible grating; 5-mechanical stretching device; 6-first focusing lens;

[0025] 7-first receiving device; 8-second focusing lens; 9-second receiving device; DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] See also Figure 1 , a laser scanning device based on a flexible grating, comprising a fiber laser 1) a fiber amplifier 2, a spatial light collimator 3, a flexible grating 4, a mechanical stretching device 5, a focusing lens and a receiving device;

[0031] Beam generation and amplification part: Fiber laser 1 is the light source of the system, fiber amplifier 2 can amplify the energy of the beam generated by fiber laser 1, and spatial light collimator 3 can collimate the beam for output; fiber laser 1 is connected to fiber amplifier 2, and fiber amplifier 2 is connected to spatial light collimator 3; the laser generated by fiber laser 1 is amplified by fiber amplifier 2 to amplify the beam power, and is collimated for output by spatial light collimator 3;

[0032] Scanning and receiving part: the flexible grating 4 is the scanning structure of the present invention, the mechanical stretching device 5 is a device for fixing and mechanically stretching the flexible grating 4, the focusing lens can converge the diffraction light beam, and finally the receiving device receives the diffraction light beam converged by the focusing lens.

[0033] The focusing lens includes a first focusing lens 6 and a second focusing lens 8 , and the receiving device includes a first receiving device 7 and a second receiving device 9 . The diffraction light beam converged by the first focusing lens 6 is received by the first receiving device 7 , and the diffraction light beam converged by the second focusing lens 8 is received by the second receiving device 9 .

[0034] The fiber laser 1 is a 1550nm tunable laser with a maximum output power of 0.3W.

[0035] The optical fiber amplifier 2 is an erbium-doped optical fiber amplifier.

[0036] The erbium-doped fiber amplifier amplifies the power of the light beam to 5W.

[0037] Figure 2 This is a schematic diagram of the structure of a flexible grating. The material used for the flexible grating is an elastic polymer material. The flexible grating is made by laser direct writing. Its grating period is in the micron order and the grating thickness is in the sub-millimeter order.

[0038] Figure 3 The figure is a stretching principle diagram of a mechanical stretching device, wherein the mechanical stretching device 5 comprises a first moving component 5-1, a second moving component 5-2, a third moving component 5-3, a fourth moving component 5-4, a fifth moving component 5-5, a sixth moving component 5-6, a seventh moving component 5-7 and an eighth moving component 5-8, each moving component is respectively connected to a different push rod and is placed in a corresponding straight groove, each moving component clamps a corner of the flexible grating, moves in the corresponding straight groove, and performs a divergent stretching action, when the push rod moves, the eight moving components also move accordingly, at this time the flexible grating is subjected to equal pulling force F in eight directions, the components are limited by push rods in the horizontal and vertical directions to maintain synchronization, ensuring that the eight clamping points are always on the square contour, the push rods in the horizontal and vertical directions can be pushed by rotating the screw, and each moving component is controlled to expand outward, thereby achieving uniform stretching of the clamped flexible grating.

[0039] The first moving assembly 5-1, the second moving assembly 5-2, the third moving assembly 5-3, the fourth moving assembly 5-4, the fifth moving assembly 5-5, the sixth moving assembly 5-6, the seventh moving assembly 5-7 and the eighth moving assembly 5-8 have the same specifications.

[0040] Figure 4 The figure is a schematic diagram of the structure of the flexible grating 4 before and after stretching. The flexible grating 4 is made of polydimethylsiloxane, has a grating period of 2.65μm and a thickness of 1mm. When the flexible grating 4 is subjected to equal tensile forces in 8 directions at the same time, the flexible grating is stretched uniformly in equal proportion while maintaining its initial shape, and its grating period is increased proportionally accordingly. It can be seen from the diffraction law that when the grating period of the flexible grating increases, the diffraction angle of the ±1st order diffraction light beam decreases, and vice versa, the diffraction angle increases, thereby achieving the purpose of spatial scanning.

[0041] Figure 5 Schematic diagram of the change of near-field spot before and after scanning. After the flexible grating 4 is stretched, the distance between the ±1st order diffraction beam and the 0th order diffraction beam is reduced from 14mm to 8mm, corresponding to a spatial scanning angle of 6°

[0042] The present invention also includes a laser scanning method based on a flexible grating-based laser scanning device as described in any of the above items, wherein the laser emitted by the fiber laser 1 is amplified to a specified power by a fiber amplifier 2, and then shaped into parallel light output by a spatial light collimator 3, and the flexible grating 4 is fixed on a mechanical stretching device 5, and the light output by the spatial light collimator 3 generates a plurality of diffraction beams with different spatial propagation directions after passing through the flexible grating 4, wherein the 0th order diffraction beam is always parallel to the direction of the incident light and cannot be scanned, and the stress F in each direction applied to the flexible grating 4 is continuously changed by stretching each moving component in the stretching device 5, and the ±1st order diffraction beams can form approximately equal scanning areas in the upper and lower regions of the 0th order diffraction beam, respectively, and the scanning angles thereof are +θ and -θ, respectively. When the receiving end is in the upper region, the parallel light is converged by the first focusing lens 6 and received by the first receiving device 7; when the receiving end is in the lower region, the parallel light is converged by the second focusing lens 8 and received by the second receiving device 9.

[0043] During use, the present invention only needs to adjust the mechanical stretching device and control the period of the flexible grating, that is, control the position of the diffraction beam, to achieve multi-directional laser beam scanning. The scanning method has a simple and compact structure, simple operation, fast scanning speed and good stability.

[0044] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A laser scanning device based on a flexible grating, characterized in that: It comprises a fiber laser (1), a fiber amplifier (2), a spatial light collimator (3), a flexible grating (4), a mechanical stretching device (5), a focusing lens and a receiving device; The laser beam emitted by the fiber laser (1) is power-amplified by the fiber amplifier (2), the spatial light collimator (3) shapes the power-amplified laser beam into a parallel beam, the parallel beam passes through the flexible grating (4) to generate a multi-order diffraction beam, the mechanical stretching device (5) fixes and stretches the flexible grating (4) to change the position of the diffraction beam, the diffraction beam is converged by the focusing lens, and the diffraction beam is received by the receiving device.

2. The laser scanning device according to claim 1, characterized in that: The focusing lens comprises a first focusing lens (6) and a second focusing lens (8); the receiving device comprises a first receiving device (7) and a second receiving device (9); the diffraction light beam converged by the first focusing lens (6) is received by the first receiving device (7); and the diffraction light beam converged by the second focusing lens (8) is received by the second receiving device (9).

3. The laser scanning device according to claim 1, characterized in that: The mechanical stretching device (5) comprises a first moving assembly (5-1), a second moving assembly (5-2), a third moving assembly (5-3), a fourth moving assembly (5-4), a fifth moving assembly (5-5), a sixth moving assembly (5-6), a seventh moving assembly (5-7) and an eighth moving assembly (5-8), each moving assembly being connected to a different push rod and placed in a corresponding straight groove, each moving assembly being evenly arranged on the flexible grating (4) and fixedly connected to the flexible grating (4).

4. The laser scanning device according to claim 3, characterized in that: The first moving assembly (5-1), the second moving assembly (5-2), the third moving assembly (5-3), the fourth moving assembly (5-4), the fifth moving assembly (5-5), the sixth moving assembly (5-6), the seventh moving assembly (5-7) and the eighth moving assembly (5-8) have the same specifications.

5. The laser scanning device according to claim 1, characterized in that: The optical fiber laser (1) is a 1550nm tunable laser with a maximum output power of 0.3W.

6. The laser scanning device according to claim 1, characterized in that: The optical fiber amplifier (2) is an erbium-doped optical fiber amplifier.

7. The laser scanning device according to claim 6, characterized in that: The erbium-doped fiber amplifier amplifies the power of the light beam to 5W.

8. The laser scanning device according to claim 1, characterized in that: The flexible grating (4) is made of polydimethylsiloxane, has a grating period of 2.65 μm and a thickness of 1 mm.

9. A laser scanning method based on the laser scanning device based on a flexible grating according to any one of claims 1 to 8, characterized in that: The laser light emitted by the fiber laser (1) is amplified to a specified power by the fiber amplifier (2) and then shaped into parallel light output by the spatial light collimator (3). The flexible grating (4) is fixed on the mechanical stretching device (5). The light output by the spatial light collimator (3) generates a plurality of diffraction light beams with different spatial propagation directions after passing through the flexible grating (4). The 0th order diffraction light beam is always parallel to the direction of the incident light and cannot be scanned. By stretching each movable component in the stretching device (5), the stress F applied to the flexible grating (4) in each direction is continuously changed. The ±1st order diffraction light beams can be respectively placed in two areas above and below the 0th order diffraction light beam to form approximately equal scanning areas, and the scanning angles thereof are +θ and -θ respectively. When the receiving end is in the upper area, the parallel light is converged by the first focusing lens (6) and received by the first receiving device (7); when the receiving end is in the lower area, the parallel light is converged by the second focusing lens (8) and received by the second receiving device (9).

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