The Design Fabrication And Testing Of Diffractive Element In The Infrared Optical Lens

With unique temperature characteristics and dispersion characteristics, combined with traditional refractive element or reflective element, the diffractive optical element may well eliminate system thermal aberration and chromatic aberration in the system, with its more design variables, simple system structure, light weight, better image quality of the optical system, and lower production costs[1-4], which has been widely used in optical communications, optical computing, optical sensing, entertainment consumption, biomedical and military fields. In recent years, with the technology developing and progressing, it has already been available to etch high precision micro structure on the surface of a variety of optical materials, which was made into refractive-diffractive or reflective-diffractive hybrid diffractive optical elements, with good imaging results in the system.The research background and significances is introduced in this paper and significance of the subject. The historical development and production process at home and abroad of diffractive optical elements is discussed. The imaging theory of diffractive elements is expounded, including scalar diffraction theory and vector diffraction theory. Its phase characteristics, diffraction efficiency, The chromatic and thermal properties is studied and applied to the subject to derive the imaging characteristics in the reflective-diffractive hybrid system. A new hybrid optical system on the basis of the old one was designed by introducing the diffractive surface. The imaging quality was evaluated from many aspects such spot diagram, energy concentration, optical modulation transfer function. According to the processing assembly and calibration the tolerance of the system was calculated, temperature characteristics of the system was analysed, the results showed that the image quality significantly improved and the new system was not sensitive to heat. Different production methods are summarized and their characteristics are compared. The main process to the reflective-diffractive hybrid mirror in the aluminum surface is described in detail by using single-point diamond turning technology and the processing results are given. The surface detection methods are outlined, White-light interferometer are used for detection. The impact of sources of error are analysed contacting the processing. Finally, The work of the text is summarized and prospects are made.