Research On Performance Evaluation Method Of Key Optical Components Of Integral Field Unit

With the development of astronomical observation technology,astronomical spectral analysis technology has been called an important means of modern astrophysical observation,through the sampling of the light emitted by the star,we can get rich spectral information from the analysis of the spectrometer.This process is completed by the integral field unit(IFU).IFU can obtain the three-dimensional spectral information of the target by single exposure at the same time.It has many advantages,such as large field of view,high spatial resolution,high transmission efficiency,small volume and so on.Based on the core of FASOT-IFU,this thesis introduces the key optical elements of FASOT-IFU,including microlens,microplate and Vgroove.The main function of the microplate is to fix the fiber array,and the main function of the microlens is to couple the light into the fiber,so the alignment of the two directly determines the transmission efficiency of the IFU,the main function of the V-groove is to fix the fiber at the emitting end of the IFU,so as to prevent the spectral aliasing of the emitting spot of the adjacent fiber.The accuracy of these three optical elements will directly affect the optical transmission efficiency of FASOT-IFU,so it is necessary to detect the accuracy.Based on the project of "research and development of FASOT-IFU system equipment",this paper designs and builds a set of high-precision optical element detection system based on machine vision,focusing on the construction of detection system and element measurement error,analyzing the measurement methods and results of each key optical element in detail,and analyzing the impact of element accuracy on the performance of IFU.The main detection methods of microplate and microlens are Blob analysis and Canny operator based subpixel edge extraction,in the case of effective hardware equipment,optimize the accuracy of detection system from the algorithm,transform traditional pixel level contour extraction into sub-pixel edge extraction with higher accuracy,the high precision grating scale made by CIOMP is used to calibrate the micro field of vision and improve the measurement accuracy of the detection system as a whole.The total error of machine vision detection system is analyzed from three aspects: camera imaging error,lens magnification error and system focusing error.The measurement error of the system is ±3?m when using low magnification lens and ±2?m when using high magnification lens.In order to ensure the arrangement accuracy of the FASOT-IFU fiber array,the three-dimensional alignment of the hole-array and the standard array on the microporous plate is carried out,and the distribution accuracy of the microporous plate array is analyzed from the macroscopic and microscopic aspects.The main method of V-groove detection is Hough line extraction.According to the linear equation of Vgroove edge,the arrangement accuracy of optical fiber fixed on V-groove is simulated and calculated.Aiming at the alignment of microlens and microplate,a set of alignment system is designed and built in this paper.The front optical path of the alignment system is high uniform parallel light,this system is equipped with three micro imaging systems to observe the alignment of microlens and microplate,Finally,the alignment of microlens and microplate can be judged by detecting the uniformity of the light spot.In order to improve the performance of IFU as a whole,the alignment error can be minimized from three aspects: axial mismatch,lateral mismatch and angular mismatch.