The iterative angular spectrum (IAS) method has been introduced by Mellin and Nordin for designing finite-aperture diffractive optical elements (FADOEs). We have extended this method to two-dimensional FADOEs and used it to design some optical devices. The first device More
The iterative angular spectrum (IAS) method has been introduced by Mellin and Nordin for designing finite-aperture diffractive optical elements (FADOEs). We have extended this method to two-dimensional FADOEs and used it to design some optical devices. The first device is a 1-to-7 beamsplitter that couples an optical beam to seven single-mode optical fibers with a diffraction efficiency of 84%. The second device is a beam-shaper that converts a Gaussian beam into a nearly flat beam with a diffraction efficiency of 74.8%. The third design is a 1-to-3 asymmetric beamsplitter. The fourth design includes three microlenses with different focal lengths. The desired intensity distribution patterns of all these designs are located at the near field region. We have investigated the sensitivity of the extended method by comparing the results obtained by this method with those obtained by three-dimensional finite difference time domain (3-D FDTD) method using perfect matched layer (PML). Also, a 1-to-5 beamsplitter is fabricated and the experimental results are presented.
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