CN216670297U - Pyramid wave-front sensor - Google Patents

Abstract

The utility model provides a pyramid wave-front sensor, which comprises a first convergent lens, a field diaphragm, a pyramid prism, a second convergent lens and a detection camera, wherein the first convergent lens, the field diaphragm, the pyramid prism, the second convergent lens and the detection camera are sequentially arranged along the propagation direction of a light beam; and a micro lens array is arranged between the second converging lens and the detection camera and is used for effectively separating the target signal and the sky light background signal on the detection camera. The pyramid wave-front sensor combines the pyramid prism and the micro lens array to realize effective separation of the sky light background signal and the target signal, and is more suitable for detection of weak targets, thereby effectively realizing application of the pyramid wave-front sensor in a daytime natural guide satellite self-adaptive optical system.

Description

Pyramid wavefront sensor

technical field

The utility model relates to the technical field of wavefront sensing, in particular to a pyramid wavefront sensor used in an adaptive optical system for natural guide stars during the day.

Background technique

Adaptive optics is an optical technology that improves the quality of optical imaging by correcting wavefront errors. As an important front-end link in adaptive optics, wavefront sensing technology mainly measures wavefront aberrations caused by atmospheric turbulence and other factors in real time for adaptive optics systems, and provides wavefront signals for wavefront processors. Pyramid wavefront sensor is a new wavefront sensing technology first proposed by astronomer Roberto Ragazzoni in 1996. It mainly realizes wavefront detection in adaptive optics system, and has been applied to many world-class ground-based large apertures. in the adaptive optics system of the astronomical telescope. The optical structure of the pyramid wavefront sensor is shown in Figure 1.

In terms of astronomical detection, pyramid wavefront sensors in adaptive optics systems of ground-based large-aperture telescopes often work at night and use natural guide stars as wavefront reference light sources. In the case of working in the daytime, the optical structure of the pyramid wavefront sensor used in the adaptive optics system of the natural guide star in the daytime is shown in Figure 2, and the obtained mixed signal image of the target and the background is shown in Figure 3, so that the incident signal is only The target signal, the obtained target signal image is shown in Figure 4. According to the comparison between Figure 3 and Figure 4, it can be clearly seen that the relatively weaker target signal in the pupil image is covered by the strong sky light background signal, and the effective information of the target cannot be extracted, resulting in the natural guide star of the pyramid wavefront sensor during the day. Applications in adaptive optics are extremely limited.

Utility model content

The purpose of this utility model is to overcome the defects of the prior art, and propose a pyramid wavefront sensor used in an adaptive optical system for natural guide stars in the daytime, which combines the corner pyramid prism and the microlens array to realize the skylight background signal and the The effective separation of the target signal, and the use of the sky light elimination algorithm to extract the effective target signal, realize the application of the pyramid wavefront sensor in the adaptive optics system of natural guide stars in the daytime.

To achieve the above object, the present utility model adopts the following specific technical solutions:

The pyramid wavefront sensor provided by the utility model comprises a first condensing lens, a field diaphragm, a corner prism, a second condensing lens and a detection camera which are arranged in sequence along the beam propagation direction, and the vertex of the corner prism is located at the first condensing lens At the focal point, the detection plane of the detection camera is conjugated to the plane where the vertex of the corner cube prism is located; a microlens array is arranged between the second condensing lens and the detection camera, and the microlens array is used to compare the target signal on the detection camera with the The skylight background signal is effectively separated.

Preferably, the detection camera forms different sub-pupil images corresponding to each surface of the corner cube, and the number of sub-apertures divided by each sub-pupil image is the same as the number of micro-lenses in the micro-lens array occupied by the sub-apertures.

Preferably, the sky light background signal is presented as a fan-shaped image on each sub-aperture, and the target signal is gathered at the vertex position of the fan-shaped image.

Compared with the prior art, the utility model can achieve the following technical effects:

1. The present utility model combines the corner cube prism and the microlens array to realize the effective separation of the sky light background signal and the target signal. Compared with the use of only the corner cube prism in the natural guide star adaptive optical system during the day, the present utility model is more applicable. It can detect weak targets in the case of low signal-to-noise ratio, and can provide better detection effect under the same signal-to-noise ratio, so as to effectively realize the application of the pyramid wavefront sensor in the adaptive optics system of natural guide stars in daytime.

2. Compared with the Hartmann wavefront sensor used in the natural guide star adaptive optical system during the day, the utility model can provide higher sensitivity.

Description of drawings

FIG. 1 is a schematic diagram of the optical path structure of a traditional pyramid wavefront sensor;

Figure 2 is a schematic diagram of the optical path structure of a traditional pyramid wavefront sensor in an adaptive optics system for natural guide stars during daytime;

Figure 3 is the target and background mixed signal image obtained by the traditional pyramid wavefront sensor under daytime conditions;

Figure 4 is a target signal image obtained by a traditional pyramid wavefront sensor under daytime conditions;

5 is a schematic diagram of an optical path structure of a pyramid wavefront sensor provided according to an embodiment of the present invention;

6 is a target and background mixed signal image obtained by the pyramid wavefront sensor provided according to an embodiment of the present invention under daytime conditions;

FIG. 7 is an image of a target signal obtained by the pyramid wavefront sensor provided according to an embodiment of the present invention under daytime conditions.

The reference numerals include: 1-first converging lens, 2-field diaphragm, 3-corner prism, 4-second converging lens, 5-microlens array, 6-detection camera, 7-sub-pupil Image, 8 ~ sub-aperture.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, its detailed description will not be repeated.

In order to make the purpose, technical solutions and advantages of the present utility model more clearly understood, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

FIG. 5 shows an optical path structure of a pyramid wavefront sensor provided according to an embodiment of the present invention.

As shown in FIG. 5 , the pyramid wavefront sensor provided by the embodiment of the present invention includes a first condensing lens 1 , a field diaphragm 2 , a corner cube prism 3 , a second condensing lens 4 , a microlens The lens array 5 and the detection camera 6, the vertex of the corner cube 3 is located at the focal point of the first condensing lens 1, and the detection plane of the detection camera 6 is conjugated to the plane where the vertex of the cube corner 3 is located, so that the detection plane of the detection camera 6 The 4f optical system is formed with the plane where the apex of the corner cube 3 is located, and the field stop 2 is arranged in front of the apex of the corner cube 3 .

The first condensing lens 1 receives the total incident signal including the target signal and the sky light background signal. After reducing the influence of the sky light background through the field diaphragm 2, it passes through the four faces of the corner cube prism 3 and the second converging lens 4. Refraction Then, through the microlens array 5, the image is finally imaged on the detection camera 6 and presented as four sub-pupil images 7, each sub-pupil image 7 is divided into a plurality of sub-apertures 8, and the sub-apertures divided by each sub-pupil image 7 The number of 8 is the same as the number of microlenses in the microlens array 5 occupied by each sub-beam refracted by the corner cube 3 .

The field diaphragm 2 can limit the field of view of the sky light background and prevent the redundant sky light background from entering the pyramid wavefront sensor. The size of the field diaphragm 2 can be adjusted to ensure that the sky light background signals in each sub-aperture 8 do not overlap.

The microlens array 5 is used to effectively separate the target signal on the detection camera 6 from the sky light background signal. In each sub-aperture 8, the skylight background signal is presented as a fan-shaped image, and the target signal is gathered at the vertex position of the fan-shaped image, so that the target light and skylight background signal are separated on the detection camera 6 through the microlens array 5, and the target light is separated from the sub-pupil. As seen in 7, the target signal is gathered as a dot array image, while the sky light background signal appears as a quarter sector array image.

After passing through the corner cube prism 3, the incident mixed light (that is, the target light and the background light) is divided into four sub-beams, and four sub-pupil images (circles) are formed. The sky light background signal and the target signal are overlapped, and then pass through the microlens. After array 5, the target signal becomes a dot array pattern, and the sky light background signal becomes a fan-shaped array pattern, so as to realize the effective separation of the target signal and the sky light background signal.

Since the target light is a point light source and the sky light background is a surface light source, the target signal is gathered as a point array image, and the sky light background signal is a fan array image.

The mixed signal image of the target and the background obtained by using the pyramid wavefront sensor provided by the embodiment of the present invention is shown in FIG. 6 , and the target signal image obtained is shown in FIG. According to the comparison between FIG. 6 and FIG. 7, it can be seen that through the pyramid wavefront sensor of the embodiment of the present invention, the target signal is gathered into a dot array image, while the sky light background signal is presented as a quarter sector array image, and the target signal can be It is clearly distinguished from the sky light background signal.

The utility model combines the corner cube prism and the microlens array to realize the effective separation of the sky light background signal and the target signal. It can detect weak targets under the condition of signal-to-noise ratio, and can provide better detection effect under the condition of the same signal-to-noise ratio, so as to effectively realize the application of the pyramid wavefront sensor in the adaptive optics system of natural guide stars in daytime.

Compared with the Hartmann wavefront sensor used in the natural guide star adaptive optical system during the day, the utility model can provide higher sensitivity.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations of the present invention, and those of ordinary skill in the art are within the scope of the present invention Variations, modifications, substitutions and variations can be made to the above-described embodiments.

The above specific embodiments of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present utility model shall be included in the protection scope of the claims of the present utility model.

Claims (3)

1. A pyramid wavefront sensor, comprising a first condensing lens, a field diaphragm, a corner prism, a second condensing lens and a detection camera sequentially arranged along the beam propagation direction, and the vertex of the corner prism is located in the first At the focal point of a converging lens, the detection plane of the detection camera is conjugated to the plane where the vertex of the corner cube prism is located; it is characterized in that a microlens is arranged between the second condenser lens and the detection camera The microlens array is used to effectively separate the target signal on the detection camera from the sky light background signal. 2 . The pyramid wavefront sensor according to claim 1 , wherein the detection camera forms different sub-pupil images corresponding to each surface of the corner cube, and the number of sub-apertures divided by each sub-pupil image is 2. 3 . The same number of microlenses in the microlens array occupied by the sub-apertures. 3 . The pyramid wavefront sensor according to claim 2 , wherein the skylight background signal is presented as a fan-shaped image on each sub-aperture, and the target signal is gathered at the vertex position of the fan-shaped image. 4 .

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