Photonics

Photonics

Aspherical surface in Lumerical FDTD

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    • Yuan0710
      Subscriber

      Dear all,

      Recently, I want to create an aspherical lens in Lumerical, and the formula follows extended asphere

      https://neurophysics.ucsd.edu/Manuals/Zemax/ZemaxManual.pdf (page 298)

      However, the schematic of the surface is quite different from the Zemax.

      I also used python to check the surface, and here is my code:

      C2=-579.0611352914399
      c2=-7.810334943869855E+003
      
      z2=1/C2*r**2/(1+np.sqrt(1-(1+c2)*1/C2**2*r**2))
         -6.754857777025000E-001*(r/cab)**4
         -1.806357591187000E-001*(r/cab)**6
         +1.771543787203000E-001*(r/cab)**8
         -2.757627677274*(r/cab)**10
         +4.527528774838001*(r/cab)**12
         -2.658990544222000*(r/cab)**14
         -9.080232875091999E-1*(r/cab)**16
      
      
      plt.plot(r,z2)
      plt.xlabel("radius")
      plt.show()
      

      The correct aspherical surface should be :

    • Greg Baethge
      Ansys Employee

      Thanks for posting on the forum. Could you check the x span and y span defined in the "Geometry" tab? They should be large enough to cover the full width of the lens. I ran a quick test, it seemed to work:

      I only copied and pasted the custom term from your post.

    • Yuan0710
      Subscriber

      This is my current geometry setting but the schematic is wrong.

      However, it is strange about the results of the aspherical surface.
      Recently, I successfully used "import surface" to establish my aspherical lens, though.

      Sincerely
    • Greg Baethge
      Ansys Employee

      I have to admit I've never really used this surface object. I'm more familiar with the surface import, that would have been an alternative I would have suggested.
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