Design And Development Of A Co-optical Path Type Interferometry System For Complex Surface Elements Based On Optical Fiber Arrays

The optical complex surface element has large surface curvature variation and high degree of surface freedom,which can effectively reduce various aberrations in the optical system.Compared with the spherical optical system,it not only simplifies the system structure,but also improves the performance of the system.It has been greatly favored in the field of optics.With the wide application of optical complex surface elements,how to detect the surface shape of optical complex surface elements with high precision,high efficiency and high versatility has become a key research content in the optical field.At present,Interferometry is one of the most accurate method for measuring the shape of complex optical elements.The CGH method and the tilt wave surface method are mainly used.The CGH method needs to design a compensator for each device under test,so its detection versatility Poor.The traditional tilt wave surface method uses the double-armed interference structure,and its systematic error is difficult to self-eliminate,so its measurement accuracy is affected,and complex error calibration method is needed to calibrate its system error,so the detection efficiency is low,and the traditional The point source generator of the tilt wavefront method uses a pinhole array,and it is not possible to dynamically generate different point source arrays according to different devices to be tested,thus having a certain influence on the detection versatility.In view of the limitations of current detection methods,this paper proposes an optical fiber array type common optical path interferometry method.This measurement method uses a fiber array as a point source generator,which can freely generate a point source array according to the surface shape of the device under test,thereby greatly improving the The versatility of the detection and the use of the optical system of the common optical path effectively reduce the system error,improve the detection accuracy,avoid complicated error calibration,and greatly improve the detection efficiency.Since the fiber array type common optical path interferometry method uses the non-zero interference principle,multiple off-axis interference point sources are used,and the surface shape of the free-form surface is difficult to express with a unified mathematical formula,so it is difficult to use the forward optical design method for the optical path design of a measured piece.In this paper,the "black box" reverse optical path design method is used to carry out mathematical modeling.Through analysis and solution,the optical parameters of the system are obtained,and the optical design technical indexes of the system are proposed.Since the system adopts a common optical path structure and is a non-zero multi-point source interference system,a large field of view standard spherical compensation lens set that satisfies the characteristics of Qiming is required,and currently only a clear lens group of the on-axis point source is required.This paper studies the design method of multi-structure optimization,and through error analysis,it puts forward the accuracy requirements for the installation of the system.Since the system uses a large field of view,the sensitivity of the lens posture is higher than that of the ordinary lens during the loading process.Therefore,this paper studies the method of auxiliary loading and unloading of the center bias meter and installs the experimental system.The spherical surface shape is measured using this system,zygo interferometer and the unerror-calibrated tyman multi-tilt wave surface interferometry system.The PV value of the system is only 0.02 ? away from the zygo interferometer,which proves the detection accuracy of the system,avoids complex error calibration and is highly efficient in detection.By using this system and the zygo interferometer to detect the surface shape of the rotationally symmetric surface element(paraboloid)and the non-rotational symmetric surface element(cylinder surface),testing results of PV value differ with zygo interferometer respectively0.0366 ? and 0.11 ?,It is explained that the system can be used to detect various complex surface elements with high precision,which verifies the universality of the system.