XU Shu yan ZHANG Xu sheng FAN Kuo JU Guo hao,. Suppression of the influence of airflow turbulence on wavefront measurement of large optical system[J]. Editorial Office of Optics and Precision Engineering, 2020,28(1): 80-89
XU Shu yan ZHANG Xu sheng FAN Kuo JU Guo hao,. Suppression of the influence of airflow turbulence on wavefront measurement of large optical system[J]. Editorial Office of Optics and Precision Engineering, 2020,28(1): 80-89DOI:
Suppression of the influence of airflow turbulence on wavefront measurement of large optical system
Airflow disturbance can cause a change in the air refractive index
which will introduce an unknown wavefront measurement error
especially for largeaperture
longfocus optical systems. To suppress this effect
this paper proposes an indoor temperature field control method based on Computational Fluid Dynamics (CFD). First
the cause of the wavefront detection error induced by air disturbance is analyzed
and the feasibility of improving the uniformity of indoor temperature field and restraining the influence of air disturbance using active air supply is expounded based on hydrodynamics theory. Secondly
an indoor temperature field control method using fan array for active air supply is proposed through simulation modeling
which considers the composition of the selfcollimation optical path of an offaxis ThreeMirror Anastigmatic (TMA) telescope (diameter of 500 mm
focal length of 6 000 mm) and the environmental conditions. Finally
the actual optical measurement data before and after temperature field control are compared to verify the effectiveness of the proposed method. The results show that the standard deviation among the seven groups of aberration coefficient measurements (mean values of multiple measurements over a period of time) decreased from 0.034 to 0.005(=632.8 nm). The proposed method can effectively suppress the influence of airflow disturbance
which has certain reference significance for improving the optical detection accuracy of largeaperture longfocus optical systems under nonvacuum conditions.