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            round pillars
    polarization insenstive ![]()
      rectangular pillars
  for circular polarization ![]()
          cross-type pillar
x-arm length TM polarization y-arm length TE polarization ![]()
    transmission and phase
    vs pillar radius     calculated using RCWA     Pillars from 0-to-2pi phase     are selected and saved in     a meta-atom library     to use as building blocks     for metasurface layout ![]()
  englarged GDS mask showing
  meta-atoms placed at positions   in metasurface to minimize   target wavefront error ![]()
    rectangular and cross-shape
    meta-atoms placed at each     position on the surface     according to the phase with     the lowest target wavefront     error ![]()
GDS mask showing metasurface
layout with weighted optimization to split TE and TM polarization
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Metalens and Grating Simulation and Design
Features of PlanOpSim MetaCell     Gratings: 1D, 2D, blazed, slanted, subwavelength, high NA,         volume holographic     Metasurface pillars     Full wave Maxwell solver     Rigorous Coupled Wave Analysis (RCWA) Features of PlanOpSim MetaCell + MetaComponent     Metalenses: polarization sensitive and insensitive     Flat diffractive lenses     Beam shapers, beam splitters, diffusers, CGHs     Metagratings     Forward design - three ways:         Input phase as an analytical expression, such as a lens formula         Input Zemax wavefront surface response (binary2 surface)         Use Python to create customized wavefront     Inverse design: Input target pattern     Interative Fourier Transform Algorithm (IFTA) used for inverse design         to create alternative metalens     Parameter sweep to evaluate IFTA designs against merit functions         and minimize target pattern error     Export GDSII fabrication files Types of User Licenses PlanOpSim software is available for online operation or with a dongle for     local operation. User licenses can either be permanent or annually renewable     subscriptions. Subscription user licenses can reduce initial cost, offer more thorough     software evaluations or provide practical solutions for short-term     projects. Subscription user licenses can be converted to permanent licenses Zemax interface Importing Zemax files into PlanOpSim for metalens and grating     applications extends Zemax ray tracing to physical structure designs.     A full wave Maxwell solver and RCWA analysis are used to create     individual metacells and to build libraries of meta-atoms for     metasurface design. Exporting metalens and grating designs to Zemax makes it easy to include     PlanOpSim's physical optics results in familiar optical system layouts in     Zemax. Forward design - three ways An analytical expression, such as a lens formula, can be used to input the     ideal design. Zemax can be imported as a wavefront surface response (binary2 surface). A customized input wavefront can be described in a Python script Inverse design - and IFTA For inverse design a target pattern is imported, such as a JSON     image file. Iterative Fourier Transform Algorithm (IFTA) is used to create a     metasurface phase design. IFTA starts by creating a random     phase distribution in the near field, based on an input     far field amplitude.     The projected pattern is evaluated against the target, and each     iteration improves the phase design until a desired pattern     is developed.     It takes PlanOpSim just seconds to develop, evaluate and improve     many metasurface phase designs. Then, optimization by a parameter sweep shows the best choice based on     design criteria. Parameter sweep The Parameter Sweep in PlanOpSim is used to optimize designs for     best performance and fabrication     Minimum and maximum ranges for each parameter can be specified,     as well as the number of steps to vary in each range.     Parameters can be varied linearly or randomly. The Parameter Sweep also makes it easy to see how performance     changes when varying such parameters as wavelength     and angle of incidence. Results, including spot size, spot location and wavefront can be shown     quickly, and they can be changed using a separate slider bar     for each variable. PlanOpSim MetaCell - RCWA The MetaCell program is for defining layers of structures for gratings,     coatings and metasurfaces.     For gratings and coatings these structures can be individual layers     each having its own material and thickness.     For metasurfaces these structures can be individual pillars.     Each pillar can have its own material, dimensions and shape.     PlanOpSim includes round, rectangular and cross-shapes. The MetaCell program includes a full wave Maxwell solver and     Rigorous Coupled Wave Analysis (RCWA) for simulating the phase     and transmission of gratings, coatings and pillars. To design metasurfaces, pillars having high transmission over 0-to-2pi     phase, are selected to create pillar groups called meta-atoms.     These pillar groups are also called nanoscale building blocks.     Each meta-atom (pillar group) is stored in a library, along with other     meta-atoms.     A meta-atom can include pillars of different shapes.     Meta-atoms in the library are used by the PlanOpSim Meta Component     program to construct metasurface layouts, as described in the next     section. PlanOpSim MetaComponent The MetaComponent program is for creating and optimizing metasurface     structures and exporting GDSII fabrication files. The MetaComponent program uses meta-atoms from the MetaCell library     to design a metasurface. The metasurface is constructed of spatially     varying meta-atoms. PlanOpSim places a meta-atom at each location     on the surface determined by a weighted least square error optimization     compared to the phase and amplitude given by the target. The finished metasurface design is used to export a GDSII fabrication file.     On the left is one example of a GDSII metasurface consisting of     round pillars and another with a combination of rectangular and     cross-shape pillars.     Click on each image to enlarge it.
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