Research On Tighman Type Near-infrared Dynamic Interferometer And Its Key Technologie

Dynamic interferometry technology has the advantages of non-contact,high precision,and anti-vibration.With the continuous development of near-infrared optics,high-precision dynamic measurement of the optical quality of near-infrared optical systems and internal components has increasingly become the focus of research.To measure the optical quality of a near-infrared optical system with a working wavelength of 1030 nm in a dynamic environment,it is necessary to find a near-infrared dynamic interferometer that adapts to its special wavelength.The operating wavelengths of the existing commercial near-infrared dynamic interferometers abroad are only 1053 nm and 1064 nm.At present,there is no related nearinfrared dynamic interferometer in China.In this thesis,a near-infrared Twyman dynamic interferometer with a working wavelength of 1030 nm is studied,and the high-precision dynamic measurement of the near-infrared optical system and the surface quality and transmitted wavefront of the 1030 nm band of the near-infrared optical system and internal components is realized.First,two near-infrared Twyman dynamic interferometry schemes are designed based on the principle of polarization phase shifting,the optical path reentry scheme and the optical path deflection scheme,and the synchronous phase shifting interference of the two schemes is analyzed by using Jones matrix and Mueller matrix methods.According to the mechanism,the interferometric mathematical models of the two schemes are established.Comparing the advantages and disadvantages of the scheme,the optical path reentrant scheme has a large loss of light energy and the feedback light will interfere with the light source,but the interference cavity does not need a wave plate element to reduce the error source;the optical path deflection scheme has high light energy utilization and the beams are isolated from each other No interference,compact structure,after comprehensive comparison,it is determined as the interferometer scheme.Second,a near-infrared-visible light dual-band interference system is designed.In order to ensure the consistency of the interferometer system under different wavelengths,the achromatic structure design and system film system design of the achromatic interference system including the alignment and imaging mirror groups are studied..Some key technologies in the interferometer setup are solved,including the fringe contrast stabilization technology and the phase shift precision improvement technology.The near-infrared dynamic interferometer product was developed,and the measurement accuracy,repeatability and dynamic measurement capability of the interferometer were examined.The near-infrared optical system was adjusted using an interferometer and its transmitted wavefront was detected online.Third,the error sources of the near-infrared dynamic interferometer are analyzed,including the azimuth angle and phase retardation error of the fast axis of the λ/4 wave plate,the transmission direction angle error of the micro-polarization array,the PBS beam splitting error of the polarization beam splitting prism,and the polarization error in the system.Error introduced by component stress.The Mueller matrix method is used to analyze the influence of various error sources on the measurement results,and the phase calculation error of the fourstep phase-shifting method is analyzed.The stress-induced phase retardation error was measured using the rotating λ/4 wave plate method.Fourth,the wavefront fitting polynomials,including Zernike moment polynomials and Legendre polynomials,are studied when the near-infrared dynamic interferometer measures rectangular components.The orthogonal Zernike moment polynomials in the rectangular domain are obtained by the Gram-Schmidt method,and the influences of the change of the aspect ratio of the rectangle,the angle rotation and the lateral translation on the fitting results are analyzed.Different orders of Legendre polynomials were used to fit the wave surface,and the lowest fitting order was determined.Through simulation,the correspondence between Legendre polynomial and low-order aberrations is studied.The fitting accuracy of the above two polynomials is analyzed and compared,and the applicable range of Zernike moment and Legendre polynomial fitting wavefront is determined.