System for detecting piston error between adjacent spliced mirrors

Abstract

The invention discloses a system for detecting a piston error between adjacent spliced mirrors, and the system comprises: a transmitting unit which is used for providing broadband light; a modulationunit which comprises a spatial light modulator and a scattering medium and is used for dynamically modulating broadband light; a light splitting unit which is used for splitting light and respectivelytransmitting the light to the spectral measurement unit and the reflecting surface of the splicing sub-mirror; a spectral measurement unit which is used for measuring spectral distribution modulatedby the spatial light modulator and the scattering medium; a splicing sub-mirror which is used for reflecting the light beam split by the light splitting unit to the imaging unit; an imaging unit whichis used for collecting diffraction patterns; and a processing unit which is used for controlling the spatial light modulator to adjust the spectral shape and distribution to a specified shape, and isalso used for analyzing and processing the diffraction pattern to obtain a piston error value between two adjacent spliced sub-mirrors. According to the system, the 2pi fuzzy effect is overcome, thedetection range of the piston error of the adjacent splicing mirrors is dynamically adjustable, and a large measurement range and high measurement precision can be realized at the same time.

Description

technical field [0001] The invention relates to the field of detection of spliced ​​mirrors, in particular to a detection system for piston errors between adjacent spliced ​​mirrors. Background technique [0002] The resolution capability of the ground-based telescope imaging system is related to factors such as the telescope's aperture, observation wavelength, and atmospheric seeing. The effect of atmospheric seeing can be well corrected by adaptive optics technology. Under a specific observation wavelength, the ground-based telescope's The resolving power of the imaging system is directly proportional to the effective aperture of the telescope, but with the continuous progress of astronomy, astronomers put forward higher requirements on the aperture of the telescope in order to observe astronomical targets deeper in the universe. However, limited by a series of factors such as mirror blank preparation, optical processing, transportation and adjustment, structural design, a...

AI Technical Summary

Problems solved by technology

However, in the actual application process, the technical measurement results based on monochromatic light sources are modulated by the wavelength of monochromatic light and appear periodic changes, resulting in 2π blurring effect

The 2π fuzzy effect makes the measurement range based on the monochromatic light measurement technology become ±λ due to the influence of the monochromatic light wavelength, thus greatly reducing the application range of the technology

Although the technology based on polychromatic light sources solves the 2π blur effect in monochromatic light source technology to a certain extent, it also introduces a series of other problems. For example, the selection of polychromatic light sources requires accurate calculation of the wavelength of the selected light source, and multiple Chromatic lasers will introduce non-common optical path errors; although it is simple and easy to use filters to filter white light sources, the spectrum obtained by filtering is fixed, and some filters with specific spectral distribution are affected by material properties and it is difficult to select Filters that meet specific needs cause difficulties in engineering applications; that is, in multi-color light source technology, due to the fixed wavelength of the light source used, the measurement range is also fixed, and the measurement range of the piston error between splicing mirrors cannot be dynamically adjusted.

In the process of detecting the piston error between spliced ​​mirrors, a technical solution with high measurement accuracy and a large measurement range is required. However, this is a pair of contradictions. To improve the measurement accuracy, it is necessary to use monochromatic light, and to increase the measurement range, it is necessary to increase Spectral range, can't have both

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