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    • #65776
      Vinamra Chaturvedi

      For a real world experiment, involving laser annealing of a Vanadium thin film, I wish to monitor the laser beam intensity on the VO2 surface, as it appears just at the onset of this phase change.Assuming this involves an appearance of a thin film of oxide ( ie, different from a very very thin native oxide).
      This being the case VO2 transition to V2O5 is fairly rapid ( very small temperature change window) in the laser annealing experiment.
      I wish to use FDTD based module as a predictive tool, to stop the laser, just before this other phase appears.
      Can I monitor the field intensity and power in my model, right on the surface of Vanadium ( more precisely the mix of V(a metal) & VO2 (metaloxide:a dielectric)? Is it safe to assume that in this model the Input source is a laser source ( as in the real experiment? What changes should I apply to the Input Source in this model other than the exciting wavelength changes,for it to “best-fit” my experiment.
      I have made changes to

    • #66112
      Scott Newman


      From this and your other post it appears there is some confusion in regards to material management in OptiFDTD. First let me clarify the difference between Materials and Profiles, which you are using interchangeably and it is not true.

      1. Material – This is what generates (calculates) your refractive index. You can choose between dielectric, dispersive, and nonlinear. It would appear you are attempting to use Lorentz-Drude materials. However, it would also appear you are trying to use materials from an older product as the material definitions in the library should look like VO2_Metallic_LD_250nm-800nm and VO2_Metallic_LD_800nm-1500nm. These indicate that they are Lorentz-Drude fits as well as the wavelength range over which they are fitted. I would recommend in your case to do your own fit which can be done from the Lorentz-Drude form using the “Fit Curve…” utility for each of your materials.
      2. Profiels – These provide the cross sectional information to a waveguide. In 2D it is just assigned a material while in 3D you must setup the layers which are then assigned materials.

      Note that in the example you are citing the waveguide Linear1 is assigned to the profile Channel_Au which has a layer that is assigned the Gold material, Linear2 is assigned to the Channel_SiO2 profile which has a layer that is assigned SiO2. You would either need to replace the material assignments in those profiles or you would setup your own profiles and assign them to the appropriate waveguide.

      Also note to model a real world laser you will be using a Gaussian source and you need to be aware of location of the focus point as our Gaussian source sets the beam waist along the input plane.


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