Phasing sensing and alignment of telescopes with segmented primary mirrors based on astrophotonics
The sensitivity and resolution of survey observations can be effectively improved by increasing the aperture size of the system,resulting in high-quality deep-field survey data.However,an increase in aperture size not only increases the complexity of the system by introducing new influencing factors,but also alters the mode of operation and the effects of existing components,especially for survey telescopes with segmented primary mirrors.To address this problem,we combine subaperture mirror testing with curvature sensing.This strategy makes it possible to utilize the intensity difference before and after the focal plane.With this strategy,both the alignment tilt and phase differences in the system can be detected,enabling alignment adjustment and maintenance of wavefront stability.In addition,wavefront information across the subapertures was used to maintain continuity,and at the system interface,a fringe pattern was used to align the tilt adjustment direction.Eventually,the correlation coefficient with the original wavefront was>0.8,the decrease in PV value in the segment edge region was>40%,and a co-focus resolution of 2″was achieved,with a co-phasing resolution of 0.08 μm over a 5 μm range.The number of edge interferometric measurement channels(in each block)was reduced from 6 to 2,and the throughput was increased by a factor of 3.To ensure the final fringe resolution of future ultra-large-aperture splicing telescopes,the target size,volume,and weight of the system detector should be effectively reduced.In this regard,the use of astrophotonics devices can effectively increase the integration of the system,reducing the impact of the environment on ground-based systems,and reducing the launch costs and risks of space-based systems.
large telescopeactive opticssingle-shot curvature sensingastrophotonics
NETL
NSTL
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