Short-distance high-energy laser spot uniform beam expanding device and method

Abstract

The invention provides a design of a short-distance high-energy laser spot uniform beam expanding device. The method is mainly characterized in that 1064nm small-size light spots output by a laser are subjected to beam expanding treatment by using a combination of a film-coated reflector and a zoom lens, so that centimeter-level light spots are quickly expanded to meter-level light spots within a 10-meter link range, the passive characteristic of the combination of the reflector and the lens is fully utilized, the beam expanding multiplying power of laser is adjusted through a manual adjusting device, and the laser beam expanding efficiency is improved. The meter-scale adjustable light spot size output performance is realized; in addition, the system also has the advantages of high laser transmittance, simple system, good interface universality and the like. The passive lens adjustment-based short-distance high-energy laser spot uniform beam expanding device can be applied to airborne, shipborne and other high-energy laser close-distance large-range application scenes, and can also be applied to other types of indoor or outdoor lasers with similar requirements.

Description

Technical Field

[0001] This invention belongs to the field of laser engineering technology, specifically relating to a short-range high-energy laser beam uniform expansion device. This system utilizes a combination of optical lenses to achieve uniform beam expansion of a 10J-level 1064nm laser beam within a 1-meter to 10-meter link range, thereby achieving high-energy laser radiation over a large area. This system design can be applied to various airborne or shipborne short-range, high-energy, large-spot laser application systems, and has advantages such as being passive, simple, and having an adjustable beam expansion ratio. Background Technology

[0002] With the continuous development of laser technology, there has been a growing demand for high-energy, large-spot-area laser beams at close range. Due to the good focusing properties of lasers, traditional lasers produce narrow beams, typically with a spot diameter on the order of centimeters. For example, patent CN108549157A proposes a high-magnification laser beam expander system, employing a coaxial four-mirror structure combining conical, spherical, and parabolic mirrors to achieve beam expansion. Another patent, CN118091967A, relates to a miniaturized, continuously variable-magnification laser beam expander system. However, both of these patents have limited application scenarios, insufficient beam expansion scale, and cannot achieve meter-level spot sizes.

[0003] In some emerging laser applications, it is necessary to expand the narrow beam of the laser output to the meter level before it is incident on a specific area. Since the output beam of a typical laser is on the centimeter level, expanding this beam to a diameter of about 1 meter within a 10-meter link requires the development of an auxiliary optical system to amplify and guide the beam. This short-range high-energy laser beam uniform expansion system can rapidly expand a small laser beam to a meter-level beam, meeting the needs of large-area laser applications.

[0004] Based on the shortcomings of the existing technology, there is an urgent need to develop a short-distance high-energy laser spot uniform beam expansion device and method. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a device and method for uniform beam expansion of short-distance high-energy laser beams.

[0006] According to the present invention, a short-range high-energy laser spot uniform beam expanding device includes: a reflector 1, a first zoom mirror 2, a second zoom mirror 3, and a rotating wheel 4;

[0007] The incident laser beam is incident on the first zoom lens 2 and the second zoom lens 3 via the reflector 1. The reflector 1 can adjust the angle so that the incident laser passes perpendicularly through the first zoom lens 2 and the second zoom lens 3.

[0008] By rotating the drum 4 to adjust the axial distance between the first zoom lens 2 and the second zoom lens 3, the combined focal length of the beam expander can be changed, thereby adjusting the magnification of the laser beam.

[0009] Preferably, the rotating drum 4 can be rotated manually to adjust the beam expansion ratio within the range of 2m to 10cm beam size;

[0010] At a distance of 10 meters from the laser output device, when the laser reaches a 2m spot size, the distance between the first zoom lens 2 and the second zoom lens 3 should be 19mm; at a distance of 10 meters from the laser output device, when the laser reaches a 10cm spot size, the distance between the first zoom lens 2 and the second zoom lens 3 should be 41mm.

[0011] The focusing stroke is 22mm. In order to improve the adaptability to changes in the state of the incident laser beam, the focusing stroke is appropriately extended by 5mm at both ends, and the overall focusing stroke is 32mm.

[0012] When the size of the light spot needs to be adjusted, manually rotate the rotating drum 4 to move the first zoom lens 2 and the second zoom lens 3 axially to achieve the function.

[0013] Preferably, the laser application band of the device is 1064nm. When the incident laser of 3cm is output to the device with a link length of 10m, the beam is expanded to a diameter of 2m.

[0014] The first zoom lens 2 is a concave lens with a focal length of -60m; the second zoom lens 3 is a convex lens with a focal length of -150mm; choosing a negative focal length lens can avoid laser focusing in the optical path.

[0015] Preferably, the coating of mirror 1 is a 1064nm band reflective film;

[0016] At the operating wavelength of 1064nm, the reflectivity is >95%; for the spectral components outside the operating wavelength range, the coating design allows transmission with a transmittance >98%; the single-pulse damage threshold of the coating to 1064nm laser is not less than 10J.

[0017] Preferably, the rotary cylinder 4 is sealed, so that its interior is not affected by dust, thus ensuring the working effect of the optical components.

[0018] Preferably, the reflector 1 is positioned above the rotating drum 4, and the rotating drum 4 is equipped with a first zoom lens 2 and a second zoom lens 3.

[0019] Preferably, it also includes a fixed bracket 5, which separates the reflector 1 and the rotating cylinder 4. When the spot size and divergence angle of the incident laser change, the distance between the reflector 1 and the rotating cylinder 4 can be calculated and adjusted according to the actual optical path to ensure the laser output of the effective aperture.

[0020] Preferably, the first zoom lens 2 and the second zoom lens 3 are coaxially arranged on the rotating cylinder 4, and their normals coincide with their optical center points.

[0021] Preferably, the light rays emitted from the reflector 1 are parallel to the normals of the first zoom lens 2 and the second zoom lens 3, and the center of the light rays emitted from the reflector 1 overlaps with the optical center points of the first zoom lens 2 and the second zoom lens 3.

[0022] A method for uniform beam expansion of a short-range high-energy laser spot according to the present invention includes the following steps:

[0023] Step 1: All devices are installed on the fixed bracket 5. When the external laser reaches the system through the reflector 1, the orientation and pitch angle of the reflector 1 are adjusted to ensure that the external laser reaches the first zoom lens 2 vertically.

[0024] Step 2: After the external laser passes through the first zoom lens 2, it then passes through the second zoom lens 3 and is output to the outside of the system to achieve beam expansion;

[0025] Step 3: When the beam magnification needs to be adjusted, rotate the rotating drum 4 to change the distance between the first zoom lens 2 and the second zoom lens 3, thereby changing the overall size of the beam and completing the beam magnification adjustment.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This system has the advantages of being passive, having high laser transmittance, being simple, having good interface versatility, and having adjustable beam expansion ratio. It is an effective means to solve the problem of short-distance high-energy laser beam expansion.

[0028] 2. This invention utilizes a combination of coated reflectors and zoom lenses to expand the 1064nm small-sized light spot output by the laser, enabling the centimeter-sized light spot to be rapidly expanded to the meter-sized range within a 10-meter link, thus fully utilizing the passive characteristics of the reflector and lens combination to achieve laser beam expansion.

[0029] 3. This invention achieves adjustable spot size output performance on the meter scale by setting a manual adjustment device to adjust the beam expansion ratio of the laser; in addition, by setting two zoom lenses coaxially inside the rotating cylinder and setting the two main parts of the reflector and rotating cylinder on the fixed bracket, not only can the laser beam expansion be better realized, but the internal optical path and beam expansion effect can be kept unchanged when the application platform or the fixed bracket is operated as a whole, so that the beam expansion device can be used in a mobile manner.

[0030] 4. This invention has a wide range of applications. It can be used in high-energy laser short-range, large-scale applications such as airborne and shipborne applications, as well as other types of indoor or outdoor laser applications with similar requirements.

[0031] 5. This invention breaks through the conventional design of fixed magnification and fixed position of traditional desktop laser beam expander systems, overcomes the shortcomings of small beam expansion magnification over short distances, and can expand centimeter-level laser beams to meter-level beams over short distances. Moreover, the beam expansion magnification is tunable within a certain range, which has significant advantages and improvements in terms of flexibility and ease of operation for desktop beam expander systems.

[0032] 6. In the application scenarios of this invention, the laser energy reaches the Joule level. The sealed design of the device avoids the risk of laser leakage in the desktop optical path, ensures the overall sealed and controllable optical path, and improves the safety of use. Attached Figure Description

[0033] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0035] The diagram shows:

[0036] Detailed Implementation

[0037] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0038] This invention addresses the issue of uniform beam expansion technology for short-range high-energy laser spots, proposing a device and method for achieving uniform beam expansion of short-range high-energy laser spots. Here, short-range high-energy laser refers to pulsed lasers achieving quantities in the 10J range within a 1-meter to 10-meter link.

[0039] like Figure 1 As shown, the short-range high-energy laser beam uniform expansion device includes: a reflector 1, a first zoom lens 2, a second zoom lens 3, and a rotating drum 4. The coating of the reflector 1 has high reflectivity for 1064nm wavelength lasers, and the coatings of the first zoom lens 2 and the second zoom lens 3 have high transmittance for 1064nm wavelength lasers. The incident laser beam is incident on the first zoom lens 2 and the second zoom lens 3 via the reflector 1. The reflector 1 can be adjusted to make the incident laser pass perpendicularly through the first zoom lens 2 and the second zoom lens 3. The axial distance between the first zoom lens 2 and the second zoom lens 3 is adjusted by rotating the drum 4 to change the combined focal length of the beam expansion device, thereby realizing the adjustment of the laser beam spot magnification. All devices are fixed on the fixed bracket 5, which facilitates system integration and optical path fixing and adjustment.

[0040] The first zoom lens 2 and the second zoom lens 3 are coaxially mounted on the rotating cylinder 4, with their normals coinciding with their optical centers, and the distance between them is adjustable from 19mm to 41mm. The light rays emitted from the reflector 1 are parallel to the normals of the first zoom lens 2 and the second zoom lens 3, and the center of the light rays emitted from the reflector 1 overlaps with the optical centers of the first zoom lens 2 and the second zoom lens 3. When the application platform or fixed bracket 5 is operated as a whole, the internal optical path and beam-expanding effect remain unchanged, enabling the beam expander to be used while the entire device is movable.

[0041] This invention utilizes the above-mentioned system components to develop a system and device capable of uniformly expanding a high-energy laser beam over short distances. This system employs a combination of a reflector and a zoom lens to uniformly expand the spot size of a 1064nm laser beam from the centimeter level to the meter level. The system offers advantages such as being passive, having high laser transmittance, being simple, having good interface versatility, and adjustable beam expansion ratio. It is an effective means to solve the difficulties of short-distance high-energy laser beam expansion.

[0042] The system works as follows:

[0043] Step 1: All devices are installed on the fixed bracket 5. When the external laser reaches the system through the reflector 1, the orientation and pitch angle of the reflector 1 are adjusted to ensure that the external laser reaches the first zoom lens 2 vertically.

[0044] Step 2: After the external laser passes through the first zoom lens 2, it then passes through the second zoom lens 3 and is output to the outside of the system to achieve beam expansion;

[0045] Step 3: When the beam magnification needs to be adjusted, rotate the rotating drum 4 to change the distance between the first zoom lens 2 and the second zoom lens 3, thereby changing the overall size of the beam and completing the beam magnification adjustment.

[0046] The laser application band of this device is 1064nm. In order to expand the beam of a 3cm incident laser to a diameter of 2m when the output link length is 10m after the device, the first zoom lens 2 is selected as a concave lens with a focal length of -60m; the second zoom lens 3 is selected as a convex lens with a focal length of -150mm. Selecting a negative focal length lens can avoid laser focusing in the optical path.

[0047] By fully utilizing the manually rotatable structure of the rotating drum 4, the beam expansion ratio can be adjusted from a large spot size of 2m to a small spot size of 10cm. At 10 meters from the laser output device, when the laser reaches a 2m spot size, the distance between the first zoom lens 2 and the second zoom lens 3 should be 19mm; at 10 meters from the laser output device, when the laser reaches a 10cm spot size, the distance between the first zoom lens 2 and the second zoom lens 3 should be 41mm, with a focusing stroke of 22mm. To improve adaptability to changes in the incident laser beam state, the focusing stroke is appropriately extended by 5mm at both ends, resulting in an overall focusing stroke of 32mm. When the spot size needs adjustment, the rotating drum 4 is manually rotated to move the first zoom lens 2 and the second zoom lens 3 axially, thus achieving the function.

[0048] To ensure that the laser incident on the device can vertically illuminate the first zoom lens 2 and the second zoom lens 3, the reflector bracket is designed to have two-dimensional manual adjustment capability in pitch and azimuth, ensuring that the emitted light spot has a certain directional capability.

[0049] To avoid the incidence of ineffective spectra, the coating of the reflector 1 uses a 1064nm band reflective film, while other bands are transmissive. The reflectivity of 1064nm is >95%, and the transmittance of other bands is >98%. The coating is required to withstand a maximum 1064nm laser energy of not less than 10J.

[0050] The optical components in the optical path are all reflection and transmission components. While the light spot expands or shrinks, the wavefront energy distribution of the incident laser does not change, ensuring that the light field energy distribution characteristics of the outgoing light spot are consistent with those of the incident light spot.

[0051] To ensure a clean working environment for the first zoom lens 2 and the second zoom lens 3, the rotating cylinder 4 is sealed, preventing dust from affecting its interior and ensuring the working performance of the optical components.

[0052] To improve the scalability of the system, a fixed bracket 5 is used to separate the reflector 1 and the rotating cylinder 4. When the spot size and divergence angle of the incident laser change, the distance between the reflector 1 and the rotating cylinder 4 can be calculated and adjusted according to the actual optical path to ensure the laser output of the effective aperture.

[0053] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0054] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A short-range high-energy laser spot uniform beam expander, characterized in that, include: A reflecting mirror (1), a first zoom lens (2), a second zoom lens (3), and a rotating wheel (4); The incident laser beam is incident on the first zoom lens (2) and the second zoom lens (3) via the reflector (1). The reflector (1) can adjust the angle so that the incident laser beam passes perpendicularly through the first zoom lens (2) and the second zoom lens (3). By rotating the wheel cylinder (4) to adjust the axial distance between the first zoom lens (2) and the second zoom lens (3), the combined focal length of the beam expander can be changed, thereby realizing the adjustment of the spot magnification of the laser beam.

2. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The rotating drum (4) can be rotated manually to adjust the beam expansion ratio within the range of 2m spot size to 10cm spot size. When the laser output device is 10 meters away, and the laser spot reaches a 2m spot size, the distance between the first zoom lens (2) and the second zoom lens (3) should be 19mm; when the laser output device is 10 meters away, and the laser spot reaches a 10cm spot size, the distance between the first zoom lens (2) and the second zoom lens (3) should be 41mm. The focusing stroke is 22mm. In order to improve the adaptability to changes in the state of the incident laser beam, the focusing stroke is appropriately extended by 5mm at both ends, and the overall focusing stroke is 32mm. When the size of the light spot needs to be adjusted, manually rotate the rotating drum (4) to move the first zoom lens (2) and the second zoom lens (3) axially to achieve the function.

3. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The laser application band of this device is 1064nm. When the incident laser is 3cm long and the output link length is 10m, the beam is expanded to a diameter of 2m. The first zoom lens (2) is a concave lens with a focal length of -60m; the second zoom lens (3) is a convex lens with a focal length of -150mm; choosing a negative focal length lens can avoid laser focusing in the optical path.

4. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The coating of the reflector (1) is a 1064nm band reflective film; At the operating wavelength of 1064nm, the reflectivity is >95%; for the spectral components outside the operating wavelength range, the coating design allows transmission with a transmittance >98%; the single-pulse damage threshold of the coating to 1064nm laser is not less than 10J.

5. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The rotating wheel (4) is sealed, so its interior is not affected by dust, thus ensuring the working effect of the optical components.

6. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The reflector (1) is positioned above the rotating cylinder (4), and the rotating cylinder (4) is equipped with a first zoom lens (2) and a second zoom lens (3).

7. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, It also includes a fixed bracket (5) to separate the reflector (1) and the rotating wheel (4). When the spot size and divergence angle of the incident laser change, the distance between the reflector (1) and the rotating wheel (4) can be calculated and adjusted according to the actual optical path to ensure the laser output of the effective aperture.

8. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The first zoom lens (2) and the second zoom lens (3) are coaxially mounted on the rotating cylinder (4), and their normals coincide with their optical center points.

9. The short-distance high-energy laser spot uniform beam expander according to claim 1, characterized in that, The light rays emitted from the reflector (1) are parallel to the normals of the first zoom lens (2) and the second zoom lens (3), and the center of the light rays emitted from the reflector (1) overlaps with the optical center points of the first zoom lens (2) and the second zoom lens (3).

10. A method for beam expansion using the short-distance high-energy laser spot uniform beam expander according to any one of claims 1 to 9, characterized in that, Includes the following steps: Step 1: All devices are installed on the fixed bracket (5). When the external laser reaches the system through the reflector (1), adjust the orientation and pitch angle of the reflector (1) to ensure that the external laser reaches the first zoom lens (2) vertically. Step 2: After the external laser passes through the first zoom lens (2), it passes through the second zoom lens (3) and is output to the outside of the system to achieve beam expansion; Step 3: When the beam magnification needs to be adjusted, rotate the rotating drum (4) to change the distance between the first zoom lens (2) and the second zoom lens (3), thereby changing the overall size of the beam and completing the beam magnification adjustment.

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