Study On The Multilayer Diffracitive Element With Wide Field Of View And Wavwband

In recent years, the development of the diffractive optical elements caused the great concern of the national scientists for its unique properties, such as the high diffraction efficiency, the unique characteristics of the dispersion, freedom of design, wide material optional and the excellent function of light wave transformation. These properties promoted the optical system to achieve integration, miniaturization and array and opened a new field of optics. It has a very important practical significance and broad application prospects.This article summarized the shortcomings of the single-layer diffractive element and the double-layer diffractive element and proposed a three-layer diffractive optical element, which can be applied to the wide spectral and large field angle imaging optical system. The main tasks are as follows:Firstly, this article summarized the background and research status of the binary optical elements and the multilayer diffractive optical element and analyzed the diffraction efficiency characteristics of the single-layer diffractive element and the double-layer diffractive element. It can be found that the diffraction efficiency decrease rapidly while the field of view increase of the double-layer optical element. This discovery proved that the application of the double-layer optical element in the optical system may affect the imaging quality.Secondly, the structure of the three-layer diffractive optical element was given base on the diffraction efficiency theory of the double-layer diffractive element. The three-layer DOE replace the air (between the two microstructures of double-layer DOE) with the material which has different dispersions and refraction efficiency, so that the more parameters can be got to control the diffraction efficiency. The design theory and the formulas of the diffraction efficiency when the light normal incidence and oblique incidence.Secondly, the structure of the three-layer diffractive optical element was given base on the diffraction efficiency theory of the double-layer diffractive element. The three-layer DOE replace the air (between the two microstructures of double-layer DOE) with the material which has different dispersions and refraction efficiency, so that the more parameters can be got to control the diffraction efficiency. The design theory and the formulas of the diffraction efficiency were given when the light normal incidence and oblique incidence. It can be found the three-layer diffractive optical element can be applied to a wide spectral and large field angle imaging optical system through the comparison with the double-layer diffractive optical element. Furthermore, the material selection of the three-layer diffractive optical element had been studied. The material selection rules was given in this article.Finally, the three-layer diffractive optical element was applied in the60°field of view eyepiece system for helmet display and40°field of view objective system for night vision. The higher image quality and the light-small have been obtained.