Light beam reverser

Abstract

The invention provides a light beam reverser which comprises a first cylindrical convex lens, a second cylindrical convex lens, a first reflecting mirror and a second reflecting mirror which are sequentially arranged in the laser transmission direction, and the cylindrical ridge line of the first cylindrical convex lens and the cylindrical ridge line of the second cylindrical convex lens form an included angle of 45 degrees with the polarization direction of an incident light beam. After an incident light beam sequentially passes through the first cylindrical convex lens, the second cylindrical convex lens, the first reflector and the second reflector, the rotation angle of the polarization direction of the incident light beam is 90 degrees, the number of optical elements is small, the optical elements are arranged in a linear or simple right-angle reflection mode, a complex space pyramid lens set does not need to be adjusted, the installation and adjustment difficulty is further reduced, and the installation and adjustment efficiency is improved. The cost is saved, and the usability and reliability of the method are improved to a great extent.

Description

Technical Field

[0001] The invention relates to the field of high-power lasers, belongs to high-precision optical systems, and specifically relates to a beam inverter. Background Art

[0002] Currently, many large-scale laser devices under construction in the world for inertial confinement fusion (ICF) research mostly adopt the "multi-pass amplification" technology route to improve the efficiency of amplifier energy extraction, enhance the compactness of the device, and reduce the scale and cost of the device.

[0003] In the prior art, a pair of cavity mirrors, large-aperture electro-optical switches and polarizers are usually used to complete the four-pass amplification of laser pulses to achieve effective extraction of high-energy pulses, or a large-aperture cavity mirror and an L-turn small-aperture beam reverser (BR) are used to form a multi-pass transmission cavity to achieve four-pass amplification of laser pulses, or three reflectors distributed in an angular cone are used to achieve 90° rotation of the beam. The above beam reverser system is complex, which increases the difficulty of system design and debugging, and the increase in multiple reflections and propagation paths makes the system more susceptible to environmental factors (such as temperature, vibration, etc.), thereby affecting the stability and reliability of the system.

[0004] Therefore, the prior art needs to be further developed. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide a light beam inverter to solve the problems existing in the prior art.

[0006] In order to achieve the above technical objectives, the present invention provides a beam inverter, which includes: a first cylindrical convex lens, a second cylindrical convex lens, a first reflector, and a second reflector arranged in sequence along the laser transmission direction.

[0007] Specifically, the first cylindrical convex lens is identical to the second cylindrical convex lens and has a common focal line.

[0008] Specifically, the cylindrical ridge line of the first cylindrical convex lens is parallel to the cylindrical ridge line of the second cylindrical convex lens and both form an angle θ with the polarization direction of the incident light beam. After the incident light beam passes through the first cylindrical convex lens, the second cylindrical convex lens, the first reflector, and the second reflector in sequence, the polarization direction of the incident light beam rotates by an angle of 2θ.

[0009] Specifically, the cylindrical ridge line of the first cylindrical convex lens and the cylindrical ridge line of the second cylindrical convex lens both form an angle of 45° with the polarization direction of the incident light beam.

[0010] Specifically, the polarization direction of the incident light beam is a vertical polarization direction or a horizontal polarization direction.

[0011] Specifically, the reflection surfaces of the first reflector and the second reflector are both perpendicular to the horizontal plane.

[0012] Specifically, the first reflector forms an angle of 45° with the incident light beam, the incident light beam is incident on the second reflector after being reflected by the first reflector, and the second reflector forms an angle of 45° with the incident light beam after being reflected by the first reflector.

[0013] Specifically, after the incident light beam passes through the first cylindrical convex lens, the second cylindrical convex lens, the first reflector, and the second reflector in sequence, the polarization direction of the incident light beam rotates by an angle of 90°.

[0014] Specifically, the beam inverter further includes a hollow vacuum pipe, which is disposed between the first cylindrical convex lens and the second cylindrical convex lens, and the first cylindrical convex lens and the second cylindrical convex lens are sealed at both ends of the hollow vacuum pipe.

[0015] Beneficial effects: The present invention provides a beam inverter, which includes a first cylindrical convex lens, a second cylindrical convex lens, a first reflector, and a second reflector, which are sequentially arranged along a laser transmission direction. The cylindrical ridge line of the first cylindrical convex lens is parallel to the cylindrical ridge line of the second cylindrical convex lens and both form an angle of 45° with the polarization direction of an incident light beam, so that after the incident light beam passes through the first cylindrical convex lens, the second cylindrical convex lens, the first reflector, and the second reflector in sequence, the polarization direction of the incident light beam rotates by 90°. The number of optical elements is small and they are arranged in a straight line or in a simple right-angle reflection arrangement. There is no need to adjust a complex spatial corner cone group, which further reduces the difficulty of installation and adjustment, saves costs, and greatly improves the availability and reliability of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the optical path of a beam inverter provided in a specific embodiment of the present invention; Figure 2 is a schematic diagram of the confocal line of the first cylindrical convex lens and the second cylindrical convex lens provided in a specific embodiment of the present invention; Figure 3 is a schematic diagram of light beam rotation provided in a specific embodiment of the present invention; Wherein, the reference numerals of the above-mentioned drawings are as follows: 1. First cylindrical convex lens; 2. Second cylindrical convex lens; 3. First reflector; 4. Second reflector; 5. First coordinate system; 6. Second coordinate system; 7. Incident light axis. DETAILED DESCRIPTION In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of this application. In addition, the directional words mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional words used are used to illustrate rather than limit the invention.

[0017] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments.

[0018] See also Figure 1 This embodiment provides a beam inverter, which includes: a first cylindrical convex lens 1, a second cylindrical convex lens 2, a first reflector 3, and a second reflector 4, which are arranged in sequence along the laser transmission direction.

[0019] Specifically, the first cylindrical convex lens 1 and the second cylindrical convex lens 2 are identical and share a common focal line.

[0020] Specifically, the cylindrical ridge line of the first cylindrical convex lens 1 is parallel to the cylindrical ridge line of the second cylindrical convex lens 2 and both form an angle θ with the polarization direction of the incident light beam. After the incident light beam passes through the first cylindrical convex lens 1, the second cylindrical convex lens 2, the first reflector 3, and the second reflector 4 in sequence, the polarization direction of the incident light beam rotates by an angle of 2θ.

[0021] See also Figure 1 , a first cylindrical convex lens 1, a second cylindrical convex lens 2, a first reflector 3, and a second reflector 4 are sequentially placed in the optical path, as shown in FIG. Figure 1 As shown, the first coordinate system 5 has the horizontal direction as the x-axis, the vertical direction as the y-axis, and the direction of the incident light axis 7 as the z-axis. The incident light beam passes through the first cylindrical convex lens 1, the second cylindrical convex lens 2, the first reflector 3, and the second reflector 4 along the incident light axis 7 in sequence.

[0022] See also Figure 2 , the z'-axis of the second coordinate system 6 is coaxial with the z-axis in the first coordinate system 5, the x'-axis and the y'-axis in the second coordinate system 6 form an angle of 45° with the x-axis and the y-axis in the first coordinate system 5 respectively, the first cylindrical convex lens 1 and the second cylindrical convex lens 2 are the same cylindrical convex lenses, have a common focal line F1 / F2, and the cylindrical ridge line of the first cylindrical convex lens 1 and the second cylindrical convex lens 2, that is, the angle between the y' direction and the direction of the incident light axis 7 is θ, then it can be obtained that after the incident light beam passes through the first cylindrical convex lens 1, the second cylindrical convex lens 2, the first reflector 3, and the second reflector 4 in sequence, the angle of rotation of the polarization direction of the incident light beam is 2θ.

[0023] Specifically, the cylindrical ridge line of the first cylindrical convex lens 1 and the cylindrical ridge line of the second cylindrical convex lens 2 both form an angle of 45° with the polarization direction of the incident light beam.

[0024] Specifically, the polarization direction of the incident light beam is a vertical polarization direction or a horizontal polarization direction.

[0025] See also Figure 1 , the polarization direction of the incident light beam is vertical or horizontal, that is, vertical polarization direction or horizontal polarization direction. Since the cylindrical ridges of the first cylindrical convex lens 1 and the second cylindrical convex lens 2 form a certain angle with the polarization direction of the incident light beam, this specific angle relationship is of great significance for realizing the rotation of the polarization direction. The incident light beam in the vertical or horizontal polarization direction will propagate according to their optical properties when passing through the two cylindrical convex lenses. In this case, according to the shape of the cylindrical convex lens and the direction of the incident light axis 7, the incident light beam in the vertical or horizontal polarization direction can accurately interact with the structure of the cylindrical convex lens, thereby laying the foundation for the subsequent polarization direction rotation. In this beam inverter, the vertical or horizontal polarization direction of the incident light beam is directly proportional to the polarization direction of the incident light beam. The incident light beam in the plane polarization direction passes through each component in turn along the incident optical axis 7. Due to the clarity of its polarization direction (vertical or horizontal), the propagation of the light beam in the entire optical path can be precisely controlled. Under the setting of the first coordinate system 5 (the horizontal direction is the x-axis, the vertical direction is the y-axis, and the direction of the incident optical axis 7 is the z-axis) and the second coordinate system 6 (the z' axis is coaxial with the z-axis in the first coordinate system 5, and the x' axis and the y' axis are at an angle of 45° to the x-axis and the y-axis in the first coordinate system 5, respectively), the incident light beam in the vertical or horizontal polarization direction can interact with the first cylindrical convex lens 1, the second cylindrical convex lens 2, the first reflector 3, the second reflector 4 and other components in an expected manner, thereby ensuring the normal operation of the beam inverter.

[0026] Specifically, the reflection surfaces of the first reflector 3 and the second reflector 4 are both perpendicular to the horizontal plane.

[0027] Specifically, the first reflector 3 forms an angle of 45° with the incident light beam. The incident light beam is incident on the second reflector 4 after being reflected by the first reflector 3 . The second reflector 4 forms an angle of 45° with the incident light beam after being reflected by the first reflector 3 .

[0028] It can be understood that since the first reflector 3 makes an angle of 45° with the incident light beam and its reflecting surface is perpendicular to the horizontal plane, when the incident light beam in the vertical or horizontal polarization direction reaches the first reflector 3, according to the law of reflection, the light beam will be reflected in a specific direction. The 45° angle setting ensures that the light beam can be accurately reflected in a predetermined direction and propagate toward the second reflector 4. The second reflector 4 makes an angle of 45° with the incident light beam after reflection by the first reflector 3 and its reflecting surface is perpendicular to the horizontal plane. When the light beam after reflection by the first reflector 3 reaches the second reflector 4, the 45° angle causes the light beam to be reflected again in the expected direction. This precise angle setting ensures that the light beam can be accurately reversed or reach the propagation direction required for the subsequent optical path after two reflections.

[0029] Specifically, after the incident light beam passes through the first cylindrical convex lens 1, the second cylindrical convex lens 2, the first reflector 3, and the second reflector 4 in sequence, the polarization direction of the incident light beam rotates by 90°.

[0030] For further explanation, see Figure 3 , assuming that the angle between the y' axis and the y axis (vertical axis) is θ, taking the incident light with the polarization direction in the vertical direction as an example, the incident light is decomposed into two vector components along the x' axis and the y' axis, wherein the component parallel to the x' axis remains unchanged in size and flipped 180° in direction after passing through the first cylindrical convex lens 1 and the second cylindrical convex lens 2; the component parallel to the y' axis remains unchanged in size and direction after passing through the first cylindrical convex lens 1 and the second cylindrical convex lens 2, the two components after passing through the first cylindrical convex lens 1 and the second cylindrical convex lens 2 are synthesized, the angle between the polarization direction of the synthesized light beam and the polarization direction of the incident light is 2θ (the synthesized light beam and the incident light beam are symmetric about the y' axis), the polarization direction of the synthesized light beam is horizontally flipped 180° again after being reflected by the first reflector 3 and the second reflector 4, the final polarization direction of the outgoing light is rotated by an angle of 2θ compared with the polarization direction of the incident light, when θ=45°, the polarization direction of the outgoing light is rotated by 90° compared with the polarization direction of the incident light.

[0031] See also Figure 3, if the cylindrical ridge line of the first cylindrical convex lens 1 and the cylindrical ridge line of the second cylindrical convex lens 2 are both at an angle of 45° with the polarization direction of the incident light beam, assuming that the plane of the incident light beam is abcd (clockwise direction), the first cylindrical convex lens 1 and the second cylindrical convex lens 2 change the electric field vector distribution of the light beam through their special shapes and specific angle relationship with the polarization direction of the light beam, thereby affecting the polarization direction. The plane of the light beam after the incident light beam passes through the first cylindrical convex lens 1 and the second cylindrical convex lens 2 is cbad, and the first reflector 3 and the second reflector 4 are reflected by The electromagnetic field boundary conditions during the reflection process are used to further change the polarization state of the light beam. The beam plane of the incident light beam incident on the first reflector 3 is cbad, and the beam plane of the incident light beam incident on the second reflector 4 after reflection by the first reflector 3 is bcda. Finally, the beam plane of the outgoing light beam after passing through the second reflector 4 is bcda, that is, under the synergistic effect of the above-mentioned components, the incident light beam passes through the first cylindrical convex lens 1, the second cylindrical convex lens 2, the first reflector 3, and the second reflector 4 in sequence, and its polarization direction is finally rotated by 90°.

[0032] Specifically, the beam inverter further includes a hollow vacuum pipe, which is disposed between the first cylindrical convex lens 1 and the second cylindrical convex lens 2, and the first cylindrical convex lens 1 and the second cylindrical convex lens 2 are sealed at both ends of the hollow vacuum pipe.

[0033] It should be further explained that a hollow vacuum pipe is added between the first cylindrical convex lens 1 and the second cylindrical convex lens 2, and the first cylindrical convex lens 1 and the second cylindrical convex lens 2 are sealed at both ends of the hollow vacuum pipe to prevent the light beam from penetrating the air at its focal line after being converged by the first cylindrical convex lens 1, thereby affecting the transmission quality of the light beam. The existence of the hollow vacuum pipe provides a stable optical environment for the transmission of the light beam between the first cylindrical convex lens 1 and the second cylindrical convex lens 2. Compared with the air environment, the refractive index of the light beam in the vacuum environment is basically constant and there is no refractive index fluctuation caused by factors such as air flow and temperature changes. This stable optical environment helps the light beam to propagate according to the expected optical laws, so that the characteristics of the light beam such as the polarization state and propagation direction after passing through the first cylindrical convex lens 1 can be more accurately received and processed by the second cylindrical convex lens 2, thereby improving the working stability and accuracy of the entire beam inverter.

[0034] It should be noted here that the present invention provides a beam inverter, which includes a first cylindrical convex lens, a second cylindrical convex lens, a first reflector, and a second reflector, which are arranged in sequence along the laser transmission direction. The cylindrical ridge line of the first cylindrical convex lens and the cylindrical ridge line of the second cylindrical convex lens both form an angle of 45° with the polarization direction of the incident light beam, so that after the incident light beam passes through the first cylindrical convex lens, the second cylindrical convex lens, the first reflector, and the second reflector in sequence, the polarization direction of the incident light beam rotates by 90°. The number of optical elements is small and they are arranged in a straight line or in a simple right-angle reflection arrangement. There is no need to adjust a complex spatial corner cone group, which further reduces the difficulty of installation and adjustment, saves costs, and greatly improves the usability and reliability of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] The various technical features described above can be combined arbitrarily. Although all possible combinations of these technical features are not described, any combination of these technical features should be considered to be covered by this specification as long as there is no contradiction in such combination.

[0037] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A beam inverter, characterized in that: The light beam inverter comprises: a first cylindrical convex lens (1), a second cylindrical convex lens (2), a first reflecting mirror (3), and a second reflecting mirror (4) which are arranged in sequence along the laser transmission direction.

2. The beam inverter according to claim 1, characterized in that: The first cylindrical convex lens (1) is identical to the second cylindrical convex lens (2) and has a common focal line.

3. The beam inverter according to claim 1, characterized in that: The cylindrical ridge line of the first cylindrical convex lens (1) is parallel to the cylindrical ridge line of the second cylindrical convex lens (2), and both have an angle θ with the polarization direction of the incident light beam. After the incident light beam passes through the first cylindrical convex lens (1), the second cylindrical convex lens (2), the first reflector (3), and the second reflector (4) in sequence, the polarization direction of the incident light beam rotates by an angle of 2θ.

4. The beam inverter according to claim 3, characterized in that: The cylindrical ridge line of the first cylindrical convex lens (1) and the cylindrical ridge line of the second cylindrical convex lens (2) both form an angle of 45° with the polarization direction of the incident light beam.

5. The beam inverter according to claim 3, characterized in that: The polarization direction of the incident light beam is a vertical polarization direction or a horizontal polarization direction.

6. The beam inverter according to claim 5, characterized in that: The reflection surfaces of the first reflector (3) and the second reflector (4) are both perpendicular to the horizontal plane.

7. The beam inverter according to claim 6, characterized in that: The first reflector (3) forms an angle of 45° with the incident light beam, the incident light beam is incident on the second reflector (4) after being reflected by the first reflector (3), and the second reflector (4) forms an angle of 45° with the incident light beam after being reflected by the first reflector (3).

8. The beam inverter according to claim 7, characterized in that: After the incident light beam passes through the first cylindrical convex lens (1), the second cylindrical convex lens (2), the first reflector (3), and the second reflector (4) in sequence, the polarization direction of the incident light beam rotates by 90 degrees.

9. The beam inverter according to claim 1, characterized in that: The light beam inverter further comprises a hollow vacuum pipe, wherein the hollow vacuum pipe is arranged between the first cylindrical convex lens (1) and the second cylindrical convex lens (2), and the first cylindrical convex lens (1) and the second cylindrical convex lens (2) are sealed at both ends of the hollow vacuum pipe.

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