| Summary: | 碩士 === 中正理工學院 === 電子工程研究所 === 88 === ABSTRACT
The diffractive optical elements ( DOEs ) based on basic diffraction theorem have the advantages of small size, light weight, fiexibility and ease of duplication. In this thesis, we use Iterative Fourier Transform algorithm( IFT ) to designed a sample element. After that we make use of the Mean Value Compensation algorithm ( MVC ) and dynamic modify technical to redesigned it. We hope the uniformity of output spots intensity can be modified. On the other way, for the purpose of design a DOE for generating variable intensity spots. We use Single Point Modify algorithm ( SPM ) and dynamic weighting functions to design a greyscale DOE.
Besides, we proposed an iterative phase retrieval algorithm based on Discrete Fractional Fourier Transform (DFRT) for designing a binary-phase DOE. We called it: Iterative Discrete Fractional Fourier Transform (IDFRT) method. Using this new approach, we can simplify the design complexity of a Fresnel domain in DOEs, also the on-axis symmetric imaging phenomenon of the DOE designed by the conventional Fourier Transform based algorithm can be avoided.
In this work, efficiency, dynamic range and signal to noise ratio are used as the standard to examine the design performance of DOEs. We also clearly explained in detail the fabrication process and steps to successful make our DOE samples. Latter on, we use different equipments and optical systems to measure the geometry profiles and optical performance of our DOEs.
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