A Piston Error Detection System Between Adjacent Splicing Mirrors

Abstract

The present application discloses a piston error detection system between adjacent splicing mirrors, including: a transmitting unit for providing broadband light; a modulation unit including a spatial light modulator and a scattering medium for dynamically modulating broadband light; a light splitting unit , used to split the light and transmit it to the reflective surface of the spectral measurement unit and the spliced ​​sub-mirror respectively; the spectral measurement unit is used to measure the spectral distribution modulated by the spatial light modulator and the scattering medium; the spliced ​​sub-mirror is used to split the light of the spectroscopic unit The final light beam is reflected to the imaging unit; the imaging unit is used to collect the diffraction pattern; the processing unit is used to control the spatial light modulator to adjust the spectral shape and distribution to a specified shape, and is also used to analyze and process the diffraction pattern to obtain adjacent Piston error value between two spliced ​​sub-mirrors. The system overcomes the 2π ambiguity effect, makes the detection range of the adjacent splicing mirror piston error dynamically adjustable, and can realize large measurement range and high measurement accuracy 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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