A dual-wavelength coaxial sighting system capable of automatic collimation

Abstract

The application provides a dual-wavelength coaxial aiming system capable of automatic collimation, which is used for attitude adjustment and target positioning aiming of a picosecond terminal optical path cone target of inertial confinement fusion (ICF). The system comprises automatic collimation optical paths and aiming optical paths of different working wavelengths; the automatic collimation optical paths comprise a light source, a light splitting prism, a secondary mirror, a reflecting mirror and a CCD detector; the aiming optical paths are composed of a primary mirror, a secondary mirror, a lens group, a light splitting prism and a CCD detector group, and each optical element is coaxial; the system multiplexes the secondary mirror, and realizes automatic collimation and positioning aiming through different wavelength transmission and reflection respectively; the system adopts combination of flint and crown glasses to correct chromatic aberration of different wavelengths; the image planes of the dual-wavelength optical paths are located at the same position; and the system adopts a coaxial two-mirror structure, and is compact in structure and small in size.

Description

Technical Field

[0001] The invention belongs to the technical field of optics, and in particular relates to a dual-wavelength coaxial aiming system capable of realizing automatic collimation. Background Art

[0002] Inertial confinement fusion (ICF), a key approach to achieving nuclear fusion, holds significant scientific and practical value for promoting energy innovation, strengthening national defense, and deepening research in physics. ICF uses high-power lasers to uniformly irradiate a target pellet containing thermonuclear material, rapidly compressing the pellet and triggering rapid ignition. Precise target aiming and positioning are crucial in this process, as they directly determine the success rate of the target. Therefore, a cone-bottom aiming scheme is needed that can both adjust the cone's attitude and achieve precise aiming of the target.

[0003] The Chinese patent publication number, CN 101251643B, entitled "Long-focal-length reflective microtelescope with angular resolution," enables automatic collimation and object point imaging. This is achieved primarily by multiplexing primary and secondary mirrors. However, obstructions in the central field of view not only reduce the optical system's light throughput but also reduce the resolution and contrast of the image. This limits the integrity of the field of view and observation accuracy, particularly in precision aiming scenarios requiring high-definition, unobstructed imaging, such as cone-target aiming in ICF experiments. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a dual-wavelength coaxial aiming system that can realize automatic alignment, which is used for attitude adjustment and target positioning and aiming of the inertial confinement fusion (ICF) picosecond terminal optical path to the cone target.

[0005] To achieve the above objectives, this design is implemented through the following technical means:

[0006] A dual-wavelength coaxial aiming system capable of automatic alignment achieves posture adjustment of a cone target and precise aiming of the target point by multiplexing a secondary mirror. The system comprises an automatic alignment optical path and an aiming optical path for different operating wavelengths. The automatic alignment optical path includes a light source, a beam splitter prism, a secondary mirror, a reflector, and a CCD detector. The aiming optical path consists of a primary mirror, a secondary mirror, a lens assembly, a beam splitter prism, and a CCD detector, with all optical components coaxial. The system reuses the secondary mirror to achieve automatic alignment and positioning aiming through transmission and reflection of different wavelengths. A combination of flint and crown glass is used to correct chromatic aberration at different wavelengths. The image planes of the dual-wavelength optical paths are located in the same position. The coaxial dual-mirror structure ensures a compact and small size.

[0007] The primary mirror is used to receive and reflect light emitted from the object surface;

[0008] The secondary mirror has a front and rear surface that is highly transmissive to the working wavelength of the autocollimation system, and a rear surface that is highly reflective to the working wavelength of the aiming optical path system;

[0009] The lens group is used to receive light transmitted or reflected by the secondary mirror;

[0010] The light source is an LED in the visible light band and a main laser in the near infrared band.

[0011] Furthermore, the secondary mirror is an aspherical surface with a conic coefficient.

[0012] Furthermore, the aspheric surface equation satisfies the following equation:

[0013]

[0014] Where z(r, θ) is the sagittal height of the optical surface, r is the radius of the meridian section circle, θ is the direction angle, c is the curvature, and k is the cone coefficient.

[0015] Furthermore, the lens group consists of a doublet lens and a singlet lens, and the doublet lens adopts crown glass and flint glass materials respectively.

[0016] Furthermore, the primary mirror and lens group are both spherical mirrors;

[0017] Furthermore, the beam splitting surface of the beam splitting prism is semi-transparent and semi-reflective for the working wavelength of the autocollimation system and highly transmissive for the working wavelength of the aiming optical path system.

[0018] Compared with the prior art, the present invention realizes the self-collimation function through the secondary mirror transmission, and the central field of view is unobstructed. The above technical solution conceived by the present invention has achieved the following beneficial effects:

[0019] (1) By multiplexing the secondary mirror with high transmittance and high reflectivity at different working wavelengths, the attitude adjustment of the cone target and the precise aiming of the target can be achieved; at different working wavelengths, the automatic collimation optical path and the aiming optical path can achieve high resolution requirements;

[0020] (2) Taking into account the dual-wavelength band width, the chromatic aberration between different wavelengths is corrected by using a lens combination of flint and crown glass;

[0021] (3) The coaxial two-mirror structure is adopted, which effectively utilizes the system space and shortens the system length, making the entire optical system compact and small in size. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the aiming optical path of a dual-wavelength coaxial aiming system capable of achieving automatic collimation according to the present invention;

[0023] Figure 2This is a principle diagram of an automatic collimation optical path of a dual-wavelength coaxial aiming system capable of realizing automatic collimation according to the present invention;

[0024] Figure 3 Schematic diagram of the modulation transfer function of an embodiment of the present invention with an operating wavelength of 1053 nm ± 5 nm;

[0025] Figure 4 2 is a schematic diagram of the modulation transfer function of an embodiment of the present invention with an operating wavelength of 525 nm ± 5 nm;

[0026] Figure 5 is a spot diagram of an embodiment of the present invention with an operating wavelength of 1053 nm ± 5 nm;

[0027] Figure 6 is a spot diagram of an embodiment of the present invention with an operating wavelength of 525 nm ± 5 nm;

[0028] In the figure: 1. Primary mirror; 2. Secondary mirror; 3. Lens group; 4. Beam splitter prism; 5. Reflector; 6. CCD detector; 7. Light source. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this should not limit the scope of protection of the present invention.

[0030] In inertial confinement fusion (ICF) picosecond terminal systems, cone target posture adjustment and target positioning and aiming are crucial. To achieve this, this embodiment provides a dual-wavelength coaxial aiming system with automatic alignment. This system combines automatic alignment and aiming optical paths at different operating wavelengths to ensure precise adjustment and aiming of the cone target during ICF experiments.

[0031] A dual-wavelength coaxial aiming system capable of realizing automatic collimation comprises an automatic collimation optical path and an aiming optical path with different working wavelengths.

[0032] Automatically collimating the optical path, such as Figure 2 As shown, it includes a light source 7, a beam splitter prism 4, a secondary mirror 2, a reflector 5, and a CCD detector 6. The divergent light beam emitted by the light source 7 is reflected by the beam splitter prism 4, then emitted as parallel light through the lens group 3 and the secondary mirror 2. The parallel light is then reflected by the reflector 5, passes through the secondary mirror 2, the lens group 3, and the beam splitter prism 4 again, and is finally focused on the CCD detector 6, achieving automatic collimation.

[0033] The dual-wavelength coaxial aiming system designed by the present invention for realizing automatic alignment has high imaging resolution under two working wavelengths.

[0034] Aiming light path Figure 1As shown: it includes a primary mirror 1, a secondary mirror 2, a lens group 3, a beam splitter prism 4, and a CCD detector 6. The optical components are coaxial. The light emitted by the object point (such as a specific point on the cone target) is reflected by the primary mirror 1 and the secondary mirror 2 in sequence, and then passes through the lens group 3 and the beam splitter prism 4, and finally forms an image on the CCD detector 6, thereby achieving precise positioning and aiming of the target.

[0035] The primary mirror 1 is concave and adopts a spherical mirror design, which can effectively reduce the manufacturing difficulty and cost. It is used to receive and reflect light emitted by the object surface.

[0036] Secondary mirror 2 uses a conic surface to correct spherical aberration, and its aspheric equation is:

[0037]

[0038] Where z(r, θ) is the sagittal height of the optical surface, r is the radius of the meridian section circle, θ is the direction angle, c is the curvature, and k is the conic coefficient;

[0039] Lens group 3 consists of a doublet and a singlet, made of crown and flint glass materials, respectively. These two materials introduce opposite chromatic aberrations, which can correct the chromatic aberration introduced by dual wavelengths.

[0040] The beam splitting surface of the beam splitting prism 4 is semi-reflective and semi-transparent for the working wavelength of the automatic collimation optical path, and highly transmissive for the working wavelength of the aiming optical path, so as to ensure the correct separation and transmission of the two different working wavelengths.

[0041] The specific indicators are shown in Table 1.

[0042] Table 1

[0043]

[0044] The surface parameters of each component are shown in Table 2.

[0045] Table 2

[0046]

[0047]

[0048] The imaging performance analysis of the dual-wavelength coaxial aiming system designed above is carried out, mainly including the modulation transfer function and spot diagram of the aiming optical path and the automatic collimation optical path. Figure 3 、 Figure 4 、 Figure 5 and Figure 6 shown.

[0049] Imaging performance of the aiming optical path: The operating wavelength is 1053nm±5nm, the modulation transfer function curves of each field of view are close to the diffraction limit, the MTF at the cutoff frequency of 90lp / mm is greater than 0.2, the object space resolution can reach 11.11μm, and the point diagrams of each field of view are within the Airy disk. The imaging quality is close to the diffraction limit, and the system has excellent focusing performance.

[0050] Collimated optical path imaging performance: When operating in the visible light band of 590nm±5nm, the modulation transfer function curve is close to the diffraction limit, the RMS radius is smaller than the Airy disk radius, and the angular resolution is approximately 6", which means that the system can accurately resolve tiny angular changes.

[0051] In summary, the dual-wavelength coaxial aiming system with automatic alignment, designed in this embodiment, achieves high resolution at both the automatic alignment and aiming optical paths at operating wavelengths of 525nm±5nm and 1053nm±5nm, demonstrating excellent imaging performance. The aiming optical path offers high-precision imaging capabilities and near-diffraction-limited imaging quality, making it suitable for high-precision aiming tasks in ICF experiments. The automatic alignment optical path, on the other hand, offers excellent angular resolution, making it suitable for optical measurement and calibration tasks.

Claims

1. A dual-wavelength coaxial aiming system capable of automatic alignment, used for cone target attitude adjustment and target positioning and aiming in an inertial confinement fusion picosecond terminal system, characterized in that: It includes automatic collimation optical path and aiming optical path with different working wavelengths; among them, The automatic collimation optical path includes a reflector, a secondary mirror, a lens group, a beam splitter, a CCD detector, and a light source; the divergent light beam from the light source is reflected by the beam splitter, then passes through the lens group and the secondary mirror to form parallel light, which is then reflected by the reflector and sequentially passes through the secondary mirror, the lens group, and the beam splitter to be focused on the CCD detector; The aiming optical path includes a primary mirror, a secondary mirror, a lens group, a beam splitter prism, and a CCD detector placed on the same optical axis. Light emitted from the object point is reflected by the primary mirror and the secondary mirror in sequence, and then passes through the lens group and the beam splitter prism to form an image on the CCD detector. The secondary mirror has high transmittance for the working wavelength of the automatic collimation optical path and high reflection for the working wavelength of the aiming optical path; the lens group is used to receive the light transmitted or reflected by the secondary mirror and correct the chromatic aberration caused by different wavelengths; the splitting surface of the spectroscopic prism is semi-reflective and semi-transparent for the working wavelength of the automatic collimation optical path, and has high transmittance for the working wavelength of the aiming optical path.

2. The dual-wavelength coaxial aiming system capable of achieving automatic alignment according to claim 1, characterized in that: The primary mirror is a concave spherical mirror, which is used to receive and reflect light emitted from the object surface.

3. The dual-wavelength coaxial aiming system capable of achieving automatic alignment according to claim 1, characterized in that: The secondary mirror is an aspheric lens with a conic coefficient, and its aspheric equation is: Where z(r, θ) is the sagittal height of the optical surface, r is the radius of the meridian section circle, θ is the direction angle, c is the curvature, and k is the cone coefficient.

4. The dual-wavelength coaxial aiming system capable of achieving automatic alignment according to claim 1, characterized in that: The lens group consists of a doublet lens and a singlet lens. The doublet lens adopts crown glass and flint glass materials respectively to correct chromatic aberration introduced by dual wavelengths.

5. The dual-wavelength coaxial aiming system capable of achieving automatic alignment according to claim 1, characterized in that: The light source is an LED in the visible light band and a main laser in the near infrared band.

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